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  • 1.
    Adamopoulos, Othon
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Papadopoulos, Triantafillos
    Nanostructured bioceramics for maxillofacial applications2007In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 18, no 8, p. 1587-1597Article in journal (Refereed)
    Abstract [en]

    Biomaterials science and technology have been expanding tremendously the recent years. The results of this evolution are obvious in maxillofacial applications especially with the contemporary development of Nanotechnology. Among biomaterials, bioceramics possess a specific field due to various interactions with the biological tissues. The combination of bioceramics and nanotechnology has resulted in enhanced skeletal interactions in maxillofacial applications. Nanotechnology secures better mechanical properties and more effective biological interactions with jaws. The main production methods for the synthesis of nanostructured materials include plasma arcing. chemical vapour deposition, sol-gel and precipitation. The bioceramics in Dentistry comprise inert, bioactive, resorbable and composite systems. The purpose of the present article is to describe the available nanotechnology methods and how these could be addressed to synthesise maxillofacial bioceramics with advanced properties for better biological applications. Additionally, it describes specific clinical applications in maxillofacial surgery of these biomaterials-either by themselves or in combination with others-that can be promising candidates for bone tissue engineering. Such applications include replacement of lost teeth, filling of jaws defects or reconstruction of mandible and temporomandibular joint.

  • 2.
    Agholme, Fredrik
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics and Sports Medicine. Linköping University, Faculty of Health Sciences.
    Andersson, Therese
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Tengvall, P
    University of Gothenburg.
    Aspenberg, Per
    Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics and Sports Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Orthopaedics in Linköping.
    Local bisphosphonate release versus hydroxyapatite coating for stainless steel screw fixation in rat tibiae2012In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 23, no 3, p. 743-752Article in journal (Refereed)
    Abstract [en]

    Implant fixation in bone can be improved by a coating that delivers bisphosphonates locally, or by a hydroxyapatite (HA) coating. In this study, we compared these different types of coatings. For mechanical testing, 30 rats were assigned into three groups, and similar screws were implanted bilaterally in the proximal tibiae. The rats received screws that were either uncoated, coated with nano-crystalline hydroxyapatite or coated with a bisphosphonate releasing protein matrix. After 4 weeks, one screw was subjected to pull-out testing, and the contra-lateral one to torsion testing. For morphology, 30 rats were assigned to similar treatment groups, but received only one screw each. Bisphosphonates enhanced the pull-out force by 41% (P = 0.02) compared to controls, HA increased the pull-out force although not significantly. Conversely, HA increased the maximal torque by 64% (P = 0.02). Morphometry showed higher bone volume around bisphosphonate screws in comparison to HA-coated screws (P andlt; 0.001) and controls (P andlt; 0.001). The results suggest that bisphosphonates improve fixation by increasing the amount of surrounding bone, whereas HA mainly improves bone to implant attachment.

  • 3.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Öhman Mägi, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Compressive fatigue properties of an acidic calcium phosphate cement—effect of phase composition2017In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 28, no 3, article id 41Article in journal (Refereed)
    Abstract [en]

    Calcium phosphate cements (CPCs) are synthetic bone grafting materials that can be used in fracture stabilization and to fill bone voids after, e.g., bone tumour excision. Currently there are several calcium phosphate-based formulations available, but their use is partly limited by a lack of knowledge of their mechanical properties, in particular their resistance to mechanical loading over longer periods of time. Furthermore, depending on, e.g., setting conditions, the end product of acidic CPCs may be mainly brushite or monetite, which have been found to behave differently under quasi-static loading. The objectives of this study were to evaluate the compressive fatigue properties of acidic CPCs, as well as the effect of phase composition on these properties. Hence, brushite cements stored for different lengths of time and with different amounts of monetite were investigated under quasi-static and dynamic compression. Both storage and brushite-to-monetite phase transformation was found to have a pronounced effect both on quasi-static compressive strength and fatigue performance of the cements, whereby a substantial phase transformation gave rise to a lower mechanical resistance. The brushite cements investigated in this study had the potential to survive 5 million cycles at a maximum compressive stress of 13 MPa. Given the limited amount of published data on fatigue properties of CPCs, this study provides an important insight into the compressive fatigue behaviour of such materials. 

  • 4. Ballerini, Lucia
    et al.
    Franke-Stenport, Victoria
    Borgefors, Gunilla
    Johansson, Carina B.
    Örebro University, Department of Clinical Medicine.
    Comparison of histomorphometrical data obtained with two different image analysis methods2007In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 18, no 8, p. 1471-1479Article in journal (Refereed)
    Abstract [en]

    A common way to determine tissue acceptance of biomaterials is to perform histomorphometrical analysis on histologically stained sections from retrieved samples with surrounding tissue, using various methods. The “time and money consuming” methods and techniques used are often “in house standards”. We address light microscopic investigations of bone tissue reactions on un-decalcified cut and ground sections of threaded implants. In order to screen sections and generate results faster, the aim of this pilot project was to compare results generated with the in-house standard visual image analysis tool (i.e., quantifications and judgements done by the naked eye) with a custom made automatic image analysis program. The histomorphometrical bone area measurements revealed no significant differences between the methods but the results of the bony contacts varied significantly. The raw results were in relative agreement, i.e., the values from the two methods were proportional to each other: low bony contact values in the visual method corresponded to low values with the automatic method. With similar resolution images and further improvements of the automatic method this difference should become insignificant. A great advantage using the new automatic image analysis method is that it is time saving—analysis time can be significantly reduced.

  • 5. Ballerini, Lucia
    et al.
    Franke-Stenport, Victoria
    Borgefors, Gunilla
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Johansson, Carina B.
    Comparison of histomorphometrical data obtained with two different image analysis methods2007In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 18, no 8, p. 1471-1479Article in journal (Refereed)
    Abstract [en]

    A common way to determine tissue acceptance of biomaterials is to perform histomorphometrical analysis on histologically stained sections from retrieved samples with surrounding tissue, using various methods. The "time and money consuming" methods and techniques used are often "in house standards". We address light microscopic investigations of bone tissue reactions on un-decalcified cut and ground sections of threaded implants. In order to screen sections and generate results faster, the aim of this pilot project was to compare results generated with the in-house standard visual image analysis tool (i.e., quantifications and judgements done by the naked eye) with a custom made automatic image analysis program. The histomorphometrical bone area measurements revealed no significant differences between the methods but the results of the bony contacts varied significantly. The raw results were in relative agreement, i.e., the values from the two methods were proportional to each other: low bony contact values in the visual method corresponded to low values with the automatic method. With similar resolution images and further improvements of the automatic method this difference should become insignificant. A great advantage using the new automatic image analysis method is that it is time saving-analysis time can be significantly reduced.

  • 6. Borzacchiello, A
    et al.
    Mayol, L
    Gärskog, O
    Umeå University, Faculty of Medicine, Clinical Sciences, Otorhinolaryngology.
    Dahlqvist, A
    Umeå University, Faculty of Medicine, Clinical Sciences, Otorhinolaryngology.
    Ambrosio, L
    Evaluation of injection augmentation treatment of hyaluronic acid based materials on rabbit vocal folds viscoelasticity.2005In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 16, no 6, p. 553-557Article in journal (Refereed)
    Abstract [en]

    For patients with type 1 Gaucher disease, challenges to patient care posed by clinical heterogeneity, variable progression rates, and potential permanent disability that can result from untreated or suboptimally treated hematologic, skeletal, and visceral organ involvement dictate a need for comprehensive, serial monitoring. An updated consensus on minimum recommendations for effective monitoring of all adult patients with type 1 Gaucher disease has been developed by the International Collaborative Gaucher Group (ICGG) Registry coordinators. These recommendations provide a schedule for comprehensive and reproducible evaluation and monitoring of all clinically relevant aspects of this disease. The initial assessment should include confirmation of deficiency of beta-glucocerebrosidase, genotyping, and a complete family medical history. Other assessments to be performed initially and at regular intervals include a complete physical examination, patient-reported quality of life using the SF-36 survey, and assessment of hematologic (hemoglobin and platelet count), visceral, and skeletal involvement, and biomarkers. Specific radiologic imaging techniques are recommended for evaluating visceral and skeletal pathology. All patients should undergo comprehensive regular assessment, the frequency of which depends on treatment status and whether therapeutic goals have been achieved. Additionally, reassessment should be performed whenever enzyme therapy dose is altered, or in case of significant clinical complication.

  • 7. Briggs, Ewan P
    et al.
    Walpole, Andrew R
    Wilshaw, Peter R
    Karlsson, Marjam
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Surface Biotechnology.
    Pålsgård, Eva
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Surface Biotechnology.
    Formation of highly adherent nano-porous alumina on Ti-based substrates: a novel bone implant coating2004In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 15, no 9, p. 1021-1029Article in journal (Refereed)
    Abstract [en]

    Thin, nano-porous, highly adherent layers of anodised aluminium formed on the surface of titanium alloys are being developed as coatings for metallic surgical implants. The layers are formed by anodisation of a 1–5 m thick layer of aluminium which has been deposited on substrate material by electron beam evaporation. The surface ceramic layer so produced is alumina with 6–8 wt % phosphate ions and contains 5×108 cm–2 pores with a 160 nm average diameter, running perpendicular to the surface. Mechanical testing showed the coatings'' shear and tensile strength to be at least 20 and 10 MPa, respectively. Initial cell/material studies show promising cellular response to the nano-porous alumina. A normal osteoblastic growth pattern with cell number increasing from day 1 to 21 was shown, with slightly higher proliferative activity on the nano-porous alumina compared to the Thermanox control. Scanning electron microscopy (SEM) examination of the cells on the porous alumina membrane showed normal osteoblast morphology. Flattened cells with filopodia attaching to the pores and good coverage were also observed. In addition, the pore structure produced in these ceramic coatings is expected to be suitable for loading with bioactive material to enhance further their biological properties.

  • 8.
    Brohede, Ulrika
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Forsgren, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Roos, Stefan
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Multifunctional implant coatings providing possibilities for fast antibiotics loading with subsequent slow release2009In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 20, no 9, p. 1859-1867Article in journal (Refereed)
    Abstract [en]

    The possibility to fast-load biomimetic hydroxyapatite coatings on surgical implant with the antibiotics Amoxicillin, Gentamicin sulfate, Tobramycin and Cephalothin has been investigated in order to develop a multifunctional implant device offering sustained local anti-bacterial treatment and giving the surgeon the possibility to choose which antibiotics to incorporate in the implant at the site of surgery. Physical vapor deposition was used to coat titanium surfaces with an adhesion enhancing gradient layer of titanium oxide having an amorphous oxygen poor composition at the interface and a crystalline bioactive anatase TiO2 composition at the surface. Hydroxyapatite (HA) was biomimetically grown on the bioactive TiO2 to serve as a combined bone in-growth promoter and drug delivery vehicle. The coating was characterized using scanning and transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The antibiotics were loaded into the HA coatings via soaking and the subsequent release and antibacterial effect were analyzed using UV spectroscopy and examination of inhibition zones in a Staphylococcus aureus containing agar. It was found that a short drug loading time of 15 min ensured antibacterial effects after 24 h for all antibiotics under study. It was further found that the release processes of Cephalothin and Amoxicillin consisted of an initial rapid drug release that varied unpredictably in amount followed by a reproducible and sustained release process with a release rate independent of the drug loading times under study. Thus, implants that have been fast-loaded with drugs could be stored for ~10 min in a simulated body fluid after loading to ensure reproducibility in the subsequent release process. Calculated release rates and measurements of drug amounts remaining in the samples after 22 h of release indicated that a therapeutically relevant dose could be achieved close to the implant surface for about 2 days. Concluding, the present study provides an outline for the development of a fast-loading slow-release surgical implant kit where the implant and the drug are separated when delivered to the surgeon, thus constituting a flexible solution for the surgeon by offering the choice of quick addition of antibiotics to the implant coating based on the patient need.

  • 9.
    Carlson, Johan
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Nilsson, M
    Biomaterials Lab, Department of Orthopaedics, Biomedical Centre, Lund.
    Fernández, E
    Research Centre in Biomedical Engineering, Polytechnical University of Catalonia, Barcelona.
    Planell, J. A.
    Research Centre in Biomedical Engineering, Polytechnical University of Catalonia, Barcelona.
    Monitoring the setting of calcium-based bone cements using pulse-echo ultrasound2002In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 13, no 12, p. 1135-1141Article in journal (Refereed)
    Abstract [en]

    We present a new technique, based on pulse-echo ultrasound, for monitoring the entire setting process of injectable bone cement. This research has been motivated by the lack of satisfying standards. The main problem with existing standards is the subjectivity, which leads to poor reproducibility. Because of this the results are not comparable between different research groups. A strong advantage with the proposed technique is that if low-intensity ultrasound is used, it provides a non-destructive analysis method. Once the cement paste has been applied to the measurement cell, no manipulation is needed throughout the entire setting process. The problem of the ultrasound affecting the setting of certain cement materials has been investigated, and solutions are discussed. The propagation of ultrasound is temperature-dependent, and therefore a technique for automatic compensation for temperature variations is discussed briefly. The testing was performed on -calcium sulfate hemihydrate (CSH) and mixtures of CSH and -tricalcium phosphate (-TCP). The results show that the acoustic properties of the cement are strongly correlated with the setting time, the density, and the adiabatic bulk modulus. The measured initial and final setting times agree well with the Gillmore needles standard. An important difference compared to the standards, is that the technique presented here allows the user to follow the entire setting process on-line.

  • 10.
    Chen, Song
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Gururaj, Satwik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Xia, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Synthesis of Ag doped calcium phosphate particles and their antibacterial effect as additives in dental glass ionomer cements2016In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 27, no 11, article id 172Article in journal (Refereed)
    Abstract [en]

    Developing dental restorations with enhanced antibacterial properties has been a constant quest for materials scientists. The aim of this study was to synthesize silver doped calcium phosphate particles and use them to improve antibacterial properties of conventional glass ionomer cement. The Ag doped monetite (Ag-DCPA) and hydroxyapatite (Ag-HA) were synthesized by precipitation method and characterized using X-ray diffraction, scanning electron microscope and X-ray fluorescence spectroscopy. The antibacterial properties of the cements aged for 1 day and 7 days were evaluated by direct contact measurement using staphylococcus epidermis Xen 43. Ion concentrations (F- and Ag+) and pH were measured to correlate to the results of the antibacterial study. The compressive strength of the cements was evaluated with a crosshead speed of 1 mm/min. The glass ionomer cements containing silver doped hydroxyapatite or monetite showed improved antibacterial properties. Addition of silver doped hydroxyapatite or monetite did not change the pH and ion release of F-. Concentration of Ag+ was under the detection limit (0.001 mg/L) for all samples. Silver doped hydroxyapatite or monetite had no effect on the compressive strength of glass ionomer cement.

  • 11.
    Chen, Song
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Mestres, Gemma
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Lan, Weihua
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Xia, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Cytotoxicity of modified glass ionomer cement on odontoblast cells2016In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 27, no 7, article id 116Article in journal (Refereed)
    Abstract [en]

    Recently a modified glass ionomer cement (GIC) with enhanced bioactivity due to the incorporation of wollastonite or mineral trioxide aggregate (MTA) has been reported. The aim of this study was to evaluate the cytotoxic effect of the modified GIC on odontoblast-like cells. The cytotoxicity of a conventional GIC, wollastonite modified GIC (W-mGIC), MTA modified GIC (M-mGIC) and MTA cement has been evaluated using cement extracts, a culture media modified by the cement. Ion concentration and pH of each material in the culture media were measured and correlated to the results of the cytotoxicity study. Among the four groups, conventional GIC showed the most cytotoxicity effect, followed by W-mGIC and M-mGIC. MTA showed the least toxic effect. GIC showed the lowest pH (6.36) while MTA showed the highest (8.62). In terms of ion concentration, MTA showed the largest Ca2+ concentration (467.3 mg/L) while GIC showed the highest concentration of Si4+ (19.9 mg/L), Al3+ (7.2 mg/L) and Sr2+ (100.3 mg/L). Concentration of F- was under the detection limit (0.02 mg/L) for all samples. However the concentrations of these ions are considered too low to be toxic. Our study showed that the cytotoxicity of conventional GIC can be moderated by incorporating calcium silicate based ceramics. The modified GIC might be promising as novel dental restorative cements.

  • 12. Damadzadeh, B.
    et al.
    Jabari, H.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Airola, K.
    Moritz, N.
    Vallittu, P.
    Effect of ceramic filler content on the mechanical and thermal behaviour of poly-L-lactic acid and poly-L-lactic-co-glycolic acid composites for medical applications2010In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 21, no 9, p. 2523-2531Article in journal (Refereed)
    Abstract [en]

    One main application of resorbable poly-Llactic acid (PLLA) and poly-L-lactic-co-glycolic acid (PLGA) based materials is in medical implants. In this study composites were made from PLLA and PLGA with hydroxyapatite (HAp) respective b-tricalcium phosphate (b-TCP) fillers. The filler content and particle size were varied, and the thermal properties as well as the mechanical strength of the composites were investigated. The composites were made by an extrusion compounding process giving 2–2.5 mm diameter sized profiles. The results verified that the thermal stability of the composites was reasonable during the optimized compounding conditions. Scanning electron microscopy revealed that the fillers were well dispersed in the polymer matrices. The mechanical properties were improved by the addition of the fillers. The optimum mechanical properties for the extruded profiles were obtained with the HAp fillers. The E-modulus was increased from 3.3 to 4.6 GPa by addition of filler particles (30 wt%) whereas the flexural strength was reduced from 133 to 106 MPa.

  • 13.
    De Pieri, Andrea
    et al.
    Natl Univ Galway Ireland NUI Galway, Regenerat Modular & Dev Engn Lab REMODEL, Galway, Ireland;Natl Univ Galway Ireland NUI Galway, Ctr Res Med Devices CURAM, SFI, Galway, Ireland;Proxy Biomed Ltd, Galway, Ireland.
    Ribeiro, Sofia
    Natl Univ Galway Ireland NUI Galway, Regenerat Modular & Dev Engn Lab REMODEL, Galway, Ireland;Natl Univ Galway Ireland NUI Galway, Ctr Res Med Devices CURAM, SFI, Galway, Ireland;Medtron Sofradim Prod, Trevoux, France.
    Tsiapalis, Dimitrios
    Natl Univ Galway Ireland NUI Galway, Regenerat Modular & Dev Engn Lab REMODEL, Galway, Ireland;Natl Univ Galway Ireland NUI Galway, Ctr Res Med Devices CURAM, SFI, Galway, Ireland.
    Eglin, David
    AO Res Inst Davos, Clavadelerstr 8, CH-7270 Davos, Switzerland.
    Bohner, Marc
    RMS Fdn, POB 203,Bischmattstr 12, CH-2544 Bettlach, Switzerland.
    Dubruel, Peter
    Univ Ghent, Polymer Chem & Biomat Res Grp, Krijgslaan 281 S4 Bis, B-9000 Ghent, Belgium.
    Procter, Philip
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. CPP SARL Divonne Les Bains, F-01220 Divonne Les Bains, France.
    Zeugolis, Dimitrios I.
    Natl Univ Galway Ireland NUI Galway, Regenerat Modular & Dev Engn Lab REMODEL, Galway, Ireland;Natl Univ Galway Ireland NUI Galway, Ctr Res Med Devices CURAM, SFI, Galway, Ireland.
    Bayon, Yves
    Medtron Sofradim Prod, Trevoux, France.
    Joint academic and industrial efforts towards innovative and efficient solutions for clinical needs2018In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 29, no 8, article id 129Article, review/survey (Refereed)
    Abstract [en]

    The 4(th) Translational Research Symposium (TRS) was organised at the annual meeting of the European Society for Biomaterials (ESB) 2017, Athens, Greece, with a focus on 'Academia-Industry Clusters of Research for Innovation Catalysis'. Collaborations between research institutes and industry can be sustained in several ways such as: European Union (EU) funded consortiums; syndicates of academic institutes, clinicians and industries; funding from national governments; and private collaborations between universities and companies. Invited speakers from industry and research institutions presented examples of these collaborations in the translation of research ideas or concepts into marketable products. The aim of the present article is to summarize the key messages conveyed during these lectures. In particular, emphasis is put on the challenges to appropriately identify and select unmet clinical needs and their translation by ultimately implementing innovative and efficient solutions achieved through joint academic and industrial efforts.

  • 14.
    Emami, Nazanin
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Söderholm, Karl-Johan M.
    Department of Dental Biomaterials, University of Florida.
    Influence of light-curing procedures and photo-initiator/co-initiator composition on the degree of conversion of light-curing resins2005In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 16, no 1, p. 47-52Article in journal (Refereed)
    Abstract [en]

    Objective: The hypothesis that the degree and rate of conversion can be modified favourably by using different light-curing procedures and different photo initiator/co-initiator combinations was tested.Method: A photo-initiator (0.02 mM/g resin); either camphorquinone (CQ) or 1-phenyl-1,2-propanedione (PPD), was mixed with bisGMA:TEGDMA (50:50 by weight). In addition, a co-initiator (0.04 mM/g resin); either N,N-dimethyl-p-aminobenzoic acid ethylester (DABE), N,N-cyanoethylmethylaniline (CEMA), or 2-dimethylaminoethyl methacrylate (DMAEMA), was added. These six combinations were subjected to three curing conditions (standard curing, soft-start curing or LED curing). The conversion levels (DC) were determined with differential scanning calorimetry (DSC). The DSC results were analysed using a general linear model (GLM) and Duncans multiple range test and regular t-test.Results: The fastest conversion initially was obtained by standard curing, followed by LED curing and soft-start curing. After 40 s of curing, conventional curing and soft-start curing produced a higher DC than LED curing. However, strong interactions occurred between the different variables (curing method, initiator and co-initiator). Initially, CQ was more efficient than PPD, but after 40 s, this difference was insignificant.Conclusion: By using soft-start curing and an appropriate photo initiator/co-initiator combination it is possible to achieve slow curing and a high DC at within a curing time of 40 s.

  • 15. Esposito, M
    et al.
    Hirsch, Jan M
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Oral and Maxillofacial Surgery.
    Lekholm, U
    Thomsen, P
    Failure patterns of four osseointegrated oral implant systems1997In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 8, no 12, p. 843-847Article in journal (Refereed)
    Abstract [en]

    The aim of this metanalysis was to investigate possible differences in failure patterns among four different osseointegrated oral implant systems. Only systems with a supposed scientific validation, based on long-term follow-up studies, were selected for this analysis, i.e. the Brånemark system, the Calcitek Integral system, the Interpore IMZ system and the Straumann ITI system. While several prospective reports could be found on the Brånemark system, only a few retrospective investigations concerning the ITI and the IMZ systems were available. No data on the Integral system could be employed. Despite these limitations, a substantial difference in failure patterns among various implant systems was observed. The Brånemark implants showed a higher incidence of early failures, though sharply decreasing over time. On the contrary, IMZ implant characterized by rougher surfaces displayed a lower incidence of early failures, but showed constant or increased failure rates over time. For the ITI implants, for example, a higher prevalence of late failures, attributable to chronic bacterial infection (peri-implantitis), was observed when compared to the Brånemark system. With the exception of the latter implant system, prospective long-term follow-up studies, using similar and well-defined success criteria, are needed for the others to confirm the current preliminary findings.

  • 16.
    Ferraz, Natalia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    Carlsson, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    Hong, Jaan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Ott, Marjam Karlsson
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    Influence of nanoporesize on platelet adhesion and activation2008In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 19, no 9, p. 3115-21Article in journal (Refereed)
    Abstract [en]

    In this study we have evaluated the influence of biomaterial nano-topography on platelet adhesion and activation. Nano-porous alumina membranes with pore diameters of 20 and 200 nm were incubated with whole blood and platelet rich plasma. Platelet number, adhesion and activation were determined by using a coulter hematology analyzer, scanning electron microscopy, immunocytochemical staining in combination with light microscopy and by enzyme immunoassay. Special attention was paid to cell morphology, microparticle generation, P-selectin expression and beta-TG production. Very few platelets were found on the 200 nm alumina as compared to the 20 nm membrane. The platelets found on the 20 nm membrane showed signs of activation such as spread morphology and protruding filipodia as well as P-selectin expression. However no microparticles were detected on this surface. Despite the fact that very few platelets were found on the 200 nm alumina in contrast to the 20 nm membrane many microparticles were detected on this surface. Interestingly, all microparticles were found inside circular shaped areas of approximately 3 mum in diameter. Since this is the approximate size of a platelet we speculate that this is evidence of transient, non-adherent platelet contact with the surface, which has triggered platelet microparticle generation. To the authors knowledge, this is the first study that demonstrates how nanotexture can influence platelet microparticle generation. The study highlights the importance of understanding molecular and cellular events on nano-level when designing new biomaterials.

  • 17.
    Forsgren, Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    A novel method for local administration of strontium from implant surfaces2010In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 21, no 5, p. 1605-1609Article in journal (Refereed)
    Abstract [en]

    This study proves that a film of Strontianite (SrCO(3)) successfully can be formed on a bioactive surface of sodium titanate when exposed to a strontium acetate solution. This Strontianite film is believed to enable local release of strontium ions from implant surfaces and thus stimulate bone formation in vivo. Depending on the method, different types of films were achieved with different release rates of strontium ions, and the results points at the possibility to tailor the rate and amount of strontium that is to be released from the surface. Strontium has earlier been shown to be highly involved in the formation of new bone as it stimulates the replication of osteoblasts and decreases the activity of osteoclasts. The benefit of strontium has for example been proved in studies where the number of vertebral compression fractures in osteoporotic persons was drastically reduced in patients receiving therapeutical doses of strontium. Therefore, it is here suggested that the bone healing process around an implant may be improved if strontium is administered locally at the site of the implant. The films described in this paper were produced by a simple immersion process where alkali treated titanium was exposed to an aqueous solution containing strontium acetate. By heating the samples at different times during the process, different release rates of strontium ions were achieved when the samples were exposed to simulated body fluid. The strontium containing films also promoted precipitation of bone like apatite when exposed to a simulated body fluid.

  • 18.
    Forsgren, Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Paz, María Dolores
    León, Betty
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Laser induced surface structuring and ion conversion in the surface oxide of titanium: possible implications for the wetability of laser treated implants.2013In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 24, no 1, p. 11-15Article in journal (Refereed)
    Abstract [en]

    In the present study, commercially pure titanium was irradiated with UV-light with varying wavelengths using a Q-switched Nd:YAG-laser. This was performed in order to investigate if a laser treatment can be employed to rapidly introduce hydrophilic properties to titanium surfaces, which is believed to facilitate protein adsorption and cell attachment. It was demonstrated that irradiation with 355 nm light (10 Hz, 90 mJ/shot) for 1 min or more caused an ion conversion of Ti(4+) to Ti(3+) sites in the surface oxide which lead to an increase in hydrophilicity of the surface. Furthermore, shorter irradiation times at 355 nm caused a surface structuring that gave rise to an unexpected and unstable hydrophobic state at the surface. Irradiation with 266 nm light (10 Hz, 40 mJ/shot) did not introduce any ion conversion in the surface oxide, nor did it give rise to any hydrophobicity of the surface.

  • 19. Franke Stenport, V
    et al.
    Johansson, C
    Joo Heo, S
    Aspenberg, Per
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Orthopaedics and Sports Medicine. Östergötlands Läns Landsting, Orthopaedic Centre, Department of Orthopaedics Linköping.
    Albrektsson, T
    Titanium implants and BMP-7 in bone: An experimental model in the rabbit2003In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 14, no 3, p. 247-254Article in journal (Refereed)
    Abstract [en]

    This study evaluates the effect of rhBMP-7/OP-1 on the osseointegration of commercially pure titanium implants in an experimental implant model in rabbits. Threaded titanium implants with two transverse parallel canals were inserted in the femur and tibia of rabbits. The canals were filled with, 10 ╡g of BMP-7/collagen carrier, pure collagen carrier or were left empty as a control. The stiffness of the implant fixation was evaluated by Resonance Frequency Analysis (RFA) at baseline and four weeks postoperativly. Percentage of bone ingrowth in the canals was measured on microradiographs. Histomorphometry along the threaded part of the implants was performed on 15 ╡m thin sections. The results from the RFA demonstrated a higher mean value for the BMP-7 treated implants in the tibia than the carrier treated implants but not compared to the control implants. The control implants in the tibia demonstrated more bone ingrowth in the upper canal than to the carrier or the BMP-7 treated implants. Apart from these differences there were no significant effects of BMP. In this study BMP-7 did not contribute to any substantially improved bone anchorage of titanium implants.

  • 20. Franke-Stenport, Victoria
    et al.
    Johansson, Carina B.
    Örebro University, Department of Health Sciences. Örebro University, Department of Clinical Medicine.
    Joo Heo, S.
    Aspenberg, P.
    Albrektsson, T.
    Titanium implants and BMP-7 in bone: an experimental model in the rabbit2003In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 14, no 3, p. 247-254Article in journal (Refereed)
    Abstract [en]

    This study evaluates the effect of rhBMP-7/OP-1 on the osseointegration of commercially pure titanium implants in an experimental implant model in rabbits. Threaded titanium implants with two transverse parallel canals were inserted in the femur and tibia of rabbits. The canals were filled with, 10 microg of BMP-7/collagen carrier, pure collagen carrier or were left empty as a control. The stiffness of the implant fixation was evaluated by Resonance Frequency Analysis (RFA) at baseline and four weeks postoperatively. Percentage of bone ingrowth in the canals was measured on microradiographs. Histomorphometry along the threaded part of the implants was performed on 15 microm thin sections. The results from the RFA demonstrated a higher mean value for the BMP-7 treated implants in the tibia than the carrier treated implants but not compared to the control implants. The control implants in the tibia demonstrated more bone ingrowth in the upper canal than to the carrier or the BMP-7 treated implants. Apart from these differences there were no significant effects of BMP. In this study BMP-7 did not contribute to any substantially improved bone anchorage of titanium implants.

  • 21.
    Grandfield, Kathryn
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Palmquist, Anders
    Dept of Biomaterials, Sahlgrenska Academy, University of Gothenburg, Göteborg.
    Goncalves, Stephane
    Teknimed S.A., Vic en Bigorre, Frankrike.
    Taylor, Andy
    Finsbury Development Ltd, Leatherhead, UK.
    Taylor, Mark
    Pera, Melton Mowbray, UK.
    Emanuelsson, Lena
    Dept of Biomaterials, Sahlgrenska Academy, University of Gothenburg, Göteborg.
    Thomsen, Peter
    Dept of Biomaterials, Sahlgrenska Academy, University of Gothenburg, and, Institute for Biomaterials and cell Therapy (IBCT), Göteborg.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Free form fabricated features on CoCr implants with and without hydroxyapatite coating in vivo: a comparative study of bone contact and bone growth induction2011In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 22, no 4, p. 899-906Article in journal (Refereed)
    Abstract [en]

    The current study evaluates the in vivo response to free form fabricated cobalt chromium (CoCr) implants with and without hydroxyapatite (HA) plasma sprayed coatings. The free form fabrication method allowed for integration of complicated pyramidal surface structures on the cylindrical implant. Implants were press fit into the tibial metaphysis of nine New Zealand white rabbits. Animals were sacrificed and implants were removed and embedded. Histological analysis, histomorphometry and electron microscopy studies were performed. Focused ion beam was used to prepare thin sections for high-resolution transmission electron microscopy examination. The fabricated features allowed for effective bone in-growth and firm fixation after 6 weeks. Transmission electron microscopy investigations revealed intimate bone-implant integration at the nanometre scale for the HA coated samples. In addition, histomorphometry revealed a significantly higher bone contact on HA coated implants compared to native CoCr implants. It is concluded that free form fabrication in combination with HA coating improves the early fixation in bone under experimental conditions.

  • 22. Grant, S. C.
    et al.
    Celper, S.
    Gauffin-Holmberg, Isabel
    KTH.
    Simpson, N. E.
    Blackband, S. J.
    Constantinidis, I.
    Alginate assessment by NMR microscopy2005In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 16, no 6, p. 511-514Article in journal (Refereed)
    Abstract [en]

    Alginate hydrogels have long been used to encapsulate cells for the purpose of cell transplantation. However, they also have been criticized because they fail to consistently maintain their integrity for extended periods of time. Two issues of critical importance that have yet to be thoroughly addressed concerning the long-term integrity of alginate/poly-L-lysine/alginate microcapsules are: (i) are there temporal changes in the alginate/poly-L-lysine interaction and (ii) are there temporal changes in the alginate gel structure. NMR microscopy is a non-invasive analytical technique that can address these issues. in this report, we present data to demonstrate the utility of H-1 NMR microscopy to (i) visualize the poly-L-lysine layer in an effort to address the first question, and (ii) to observe temporal changes in the alginate matrix that may represent changes in the gel structure.

  • 23.
    Hedberg, Yolanda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Wang, Xin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Hedberg, Jonas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Lundin, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Blomberg, Eva
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Surface-protein interactions on different stainless steel grades: effects of protein adsorption, surface changes and metal release2013In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 24, no 4, p. 1015-1033Article in journal (Refereed)
    Abstract [en]

    Implantation using stainless steels (SS) is an example where an understanding of protein-induced metal release from SS is important when assessing potential toxicological risks. Here, the protein-induced metal release was investigated for austenitic (AISI 304, 310, and 316L), ferritic (AISI 430), and duplex (AISI 2205) grades in a phosphate buffered saline (PBS, pH 7.4) solution containing either bovine serum albumin (BSA) or lysozyme (LSZ). The results show that both BSA and LSZ induce a significant enrichment of chromium in the surface oxide of all stainless steel grades. Both proteins induced an enhanced extent of released iron, chromium, nickel and manganese, very significant in the case of BSA (up to 40-fold increase), whereas both proteins reduced the corrosion resistance of SS, with the reverse situation for iron metal (reduced corrosion rates and reduced metal release in the presence of proteins). A full monolayer coverage is necessary to induce the effects observed.

  • 24.
    Hulsart Billström, Gry
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Orthopaedics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Janson, Oscar
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Welch, Ken
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Hong, Jaan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Clinical Immunology.
    Thromboinflammation as bioactivity assessment of H2O2-alkali modified titanium surfaces2019In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 30, no 6, article id 66Article in journal (Refereed)
    Abstract [en]

    The release of growth factors from platelets, mediated by the coagulation and the complement system, plays an important role in the bone formation around implants. This study aimed at exploring the thromboinflammatory response of H2O2-alkali soaked commercially pure titanium grade 2 discs exposed to whole human blood, as a way to assess the bioactivity of the discs. Commercially pure titanium grade 2 discs were modified by soaking in H2O2, NaOH and Ca(OH)2. The platelet aggregation, coagulation activation and complement activation was assessed by exposing the discs to fresh whole blood from human donors. The platelet aggregation was examined by a cell counter and the coagulation and complement activation were assessed by ELISA-measurements of the concentration of thrombin-antithrombin complex, C3a and terminal complement complex. The modified surface showed a statistically significant increased platelet aggregation, coagulation activation and complement activation compared to unexposed blood. The surface also showed a statistically significant increase of coagulation activation compared to PVC. The results of this study showed that the H2O2-alkali soaked surfaces induced a thromboinflammatory response that indicates that the surfaces are bioactive.

  • 25.
    Hulsart-Billström, Gry
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Orthopaedics.
    Piskounova, Sonya
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.
    Gedda, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Biomedical Radiation Sciences.
    Andersson, Britt-Marie
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Orthopaedics.
    Bergman, Kristoffer
    Hilborn, Jöns
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.
    Larsson, Sune
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Orthopaedics.
    Bowden, Tim
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.
    Morphological differences in BMP-2-induced ectopic bone between solid and crushed hyaluronan hydrogel templates2013In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 24, no 5, p. 1201-1209Article in journal (Refereed)
    Abstract [en]

    The possibility to affect bone formation by using crushed versus solid hydrogels as carriers for bone morphogenetic protein 2 (BMP-2) was studied. Hydrogels, based on chemical crosslinking between hyaluronic acid and poly(vinyl alcohol) derivatives, were loaded with BMP-2 and hydroxyapatite. Crushed and solid forms of the gels were analyzed both in vitro via a release study using I-125 radioactive labeling of BMP-2, and in vivo in a subcutaneous ectopic bone model in rats. Dramatically different morphologies were observed for the ectopic bone formed in vivo in the two types of gels, even though virtually identical release profiles were observed in vitro. Solid hydrogels induced formation of a dense bone shell around non-degraded hydrogel, while crushed hydrogels demonstrated a uniform bone formation throughout the entire sample. These results suggest that by crushing the hydrogel, the construct's three-dimensional network becomes disrupted. This could expose unreacted functional groups, making the fragment's surfaces reactive and enable limited chemical fusion between the crushed hydrogel fragments, leading to similar in vitro release profiles. However, in vivo these interactions could be broken by enzymatic activity, creating a macroporous structure that allows easier cell infiltration, thus, facilitating bone formation.

  • 26.
    Hulterström, Anna Karin
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Dental Technology/Dental Materials Science.
    Berglund, Anders
    Umeå University, Faculty of Medicine, Department of Odontology, Dental Technology/Dental Materials Science.
    Ruyter, Ivar Eystein
    Wettability, water sorption and water solubility of seven silicone elastomers used for maxillofacial prostheses2008In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 19, no 1, p. 225-231Article in journal (Refereed)
    Abstract [en]

    The wettability, water sorption and solubility of silicone elastomers used for maxillofacial prostheses were studied. The hypothesis was, that a material that has absorbed water would show an increase in the wettability and thus also the surface free energy of the material.

    Seven silicone elastomers, both addition- and condensation type polymers, were included. Five specimens of each material were subjected to treatment according to ISO standards 1567:1999 and 10477: 2004 for water sorption and solubility. The volumes of the specimens were measured according to Archimedes principle. The contact angle was measured with a contact angle goniometer at various stages of the sorption/solubility test.

    Wettability changed over the test period, but not according to theory. The addition type silicones showed little or no sorption and solubility, but two of the condensation type polymers tested had a significant sorption and solubility. This study showed that condensation type polymers may show too large volumetric changes when exposed to fluids, and therefore should no longer be used in prosthetic devices. The results of this study also suggests that it might be of interest to test sorption and solubility of materials that are to be implanted, since most of the materials had some solubility.

  • 27.
    Ingrassia, Deanna
    et al.
    New York Stem Cell Fdn, Res Inst, 619 West 54th St,3rd Floor, New York, NY 10019 USA..
    Sladkova, Martina
    New York Stem Cell Fdn, Res Inst, 619 West 54th St,3rd Floor, New York, NY 10019 USA..
    Pujari-Palmer, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Xia, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    de Peppo, Giuseppe Maria
    New York Stem Cell Fdn, Res Inst, 619 West 54th St,3rd Floor, New York, NY 10019 USA..
    Stem cell-mediated functionalization of titanium implants2017In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 28, no 9, article id 133Article in journal (Refereed)
    Abstract [en]

    Prosthetic implants are used daily to treat edentulous people and to restore mobility in patients affected by skeletal defects. Titanium (Ti) is the material of choice in prosthetics, because it can form a stable bond with the surrounding bone following implantation-a process known as osseointegration. Yet, full integration of prosthetic implants takes time, and fails in clinical situations characterized by limited bone quantity and/or compromised regenerative capacity, and in at-risk patients. Intense research efforts are thus made to develop new implants that are cost-effective, safe, and suited to every patient in each clinical situation. In this study, we tested the possibility to functionalize Ti implants using stem cells. Human induced pluripotent stem cell-derived mesenchymal progenitor (iPSC-MP) cells were cultured on Ti model disks for 2 weeks in osteogenic conditions. Samples were then treated using four different decellularization methods to wash off the cells and expose the matrix. The functionalized disks were finally sterilized and seeded with fresh human iPSC-MP cells to study the effect of stem cell-mediated surface functionalization on cell behavior. The results show that different decellularization methods produce diverse surface modifications, and that these modifications promote proliferation of human iPSC-MP cells, affect the expression of genes involved in development and differentiation, and stimulate the release of alkaline phosphatase. Cell-mediated functionalization represents an attractive strategy to modify the surface of prosthetic implants with cues of biological relevance, and opens unprecedented possibilities for development of new devices with enhanced therapeutic potential.

  • 28. Jansson, E
    et al.
    Kalltorp, M
    Linkoping Univ, Dept Phys & Measurement Technol, Appl Phys Lab, SE-58183 Linkoping, Sweden Univ Gothenburg, Inst Anat & Cell Biol, SE-40530 Gothenburg, Sweden.
    Johansson, A
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Thomsen, P
    Linkoping Univ, Dept Phys & Measurement Technol, Appl Phys Lab, SE-58183 Linkoping, Sweden Univ Gothenburg, Inst Anat & Cell Biol, SE-40530 Gothenburg, Sweden.
    On the formation of fibrous capsule and fluid space around machined and porous blood plasma clot coated titanium2001In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 12, no 10-12, p. 1019-1024Article in journal (Refereed)
    Abstract [en]

    Machined and machined submicron porous titanium, with and without a thin blood plasma coating (100 nm), were implanted for 7 or 28 days in subcutaneous pockets on the back of the rat. After explantation the specimens were analyzed by light microscopy with respect to thickness of the fibrous capsule, the fluid space width between implants and fibrous capsule, and formation of blood vessels. The results at 7 days indicate a thinnest fluid space for the plasma clot coated porous titanium surface, and the spaces vanished at the light microscopic level after 28 days outside all the analyzed surfaces. The thickness of the fibrous capsule increased outside the different surfaces at 7-28 days, and in this respect no significant differences were observed between the different surfaces at any time. Analysis of neovascularization showed that the number of vessels and proportion of vessels in the fibrous capsule increased with time at all surfaces, except machined Ti where the number instead decreased from 7 to 28 days. The average distance between the blood vessels and the fluid space increased with time for all types of surfaces. The results in the present study indicate that the healing process around titanium can be modulated by porosity and thin pre-prepared plasma coatings. (C) Kluwer Academic Publishers.

  • 29. Jo, Y. S.
    et al.
    Kim, D. K.
    Muhammed, Mamoun
    KTH, Superseded Departments, Materials Science and Engineering.
    Synchronous delivery systems composed of Au nanoparticles and stimuli-sensitive diblock terpolymer2004In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 15, no 12, p. 1291-1295Article in journal (Refereed)
    Abstract [en]

    A method to construct synchronous delivery systems via direct self-assembly of Au nanoparticles on the poly[(N-isopropylacrylamide-r-acrylamide)-b-L-lactic acid] (PNAL) nanospheres has been presented in this paper. To achieve amphiphilic diblock terpolymer, hydrophobic poly (L-lactic acid) (PLLA) block was added to poly(N-isopropylacrylamide-r-ac rylamide) (PNA) block via Michel-type addition reaction. Lower critical solubility temperature (LCST) was modulated at 35.6 degreesC which is close to the body temperature, but higher than poly(N-isopropylacrylamide) (PNIPAAm) homopolymer by controlling the ratio between isopropylacrylamide (IPAAm) monomers and acrylamide (AAm) monomers. Using this amphiphilic diblock terpolymer, PNAL nanospheres were fabricated by emulsion/evaporation technique followed by direct self-assembly of Au nanoparticles on the PNAL nanospheres due to the high affinity of amino groups donated from PNA block. The 'core' site of Au@)PNAL nanospheres can load various lyphophilic drugs. Moreover, Au nanoparticles in the 'shell' domain of PNAL nanospheres give optimal environment to conjugate various biomolecules. Therefore, it is expected that Au@PNAL hybrid nanospheres can be utilized in synchronous delivery of both biomolecules in the 'shell' domain and various therapeutic drugs in the 'core' domain.

  • 30. Kalltorp, M
    et al.
    Carlen, A
    Thomsen, P
    Olsson, J
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Analysis of rat plasma proteins desorbed from gold and methyl- and hydroxyl-terminated alkane thiols on gold surfaces2000In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 11, no 3, p. 191-199Article in journal (Refereed)
    Abstract [en]

    It is believed that adsorbed blood or plasma components, such as water, peptides, carbohydrates and proteins, determine key events in the concomitant inflammatory tissue response close to implants. The aim of the present study was to develop a procedure for the collection and analysis of minor amounts of proteins bound to solid metal implant surfaces. The combination of a sodium dodecyl sulfate washing method coupled with a polyacylamide gel electrophoretic protein separation technique (SDS-PAGE), Western blot and image analysis enabled the desorption, identification and semiquantification of specific proteins. The analyzed proteins were albumin, immunoglobulin G, fibrinogen and fibronectin. Concentration procedures of proteins were not required with this method despite the small area of the test surfaces. The plasma proteins were adsorbed to pure gold and hydroxylated and methylated gold surfaces, which elicit different tissue responses in vivo and plasma protein adsorption patterns in vitro. The image analysis revealed that the pure gold surfaces adsorbed the largest amount of total and specific proteins. This is in accordance with previous ellipsometry/antibody experiments in vitro. Further, the principles described for the protein analysis can be applied on implant surfaces ex vivo. (C) 2000 Kluwer Academic Publishers.

  • 31. Lewitus, Dan Y.
    et al.
    Rios, Fabian
    Rojas, Ramiro
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. New Jersey Center for Biomaterials, Rutgers, The State University of New Jersey, United States .
    Kohn, Joachim
    Molecular design and evaluation of biodegradable polymers using a statistical approach2013In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 24, no 11, p. 2529-2535Article in journal (Refereed)
    Abstract [en]

    The challenging paradigm of bioresorbable polymers, whether in drug delivery or tissue engineering, states that a fine-tuning of the interplay between polymer properties (e.g., thermal, degradation), and the degree of cell/tissue replacement and remodeling is required. In this paper we describe how changes in the molecular architecture of a series of terpolymers allow for the design of polymers with varying glass transition temperatures and degradation rates. The effect of each component in the terpolymers is quantified via design of experiment (DoE) analysis. A linear relationship between terpolymer components and resulting T-g (ranging from 34 to 86 A degrees C) was demonstrated. These findings were further supported with mass-per-flexible-bond analysis. The effect of terpolymer composition on the in vitro degradation of these polymers revealed molecular weight loss ranging from 20 to 60 % within the first 24 h. DoE modeling further illustrated the linear (but reciprocal) relationship between structure elements and degradation for these polymers. Thus, we describe a simple technique to provide insight into the structure property relationship of degradable polymers, specifically applied using a new family of tyrosine-derived polycarbonates, allowing for optimal design of materials for specific applications.

  • 32.
    Lilja, Mirjam
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Genvad, Axel
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Åstrand, Maria
    Sandvik Tooling Sverige AB, Stockholm.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Influence of microstructure and chemical composition of sputter deposited TiO2 thin films on in vitro bioactivity2011In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 22, no 12, p. 2727-2734Article in journal (Refereed)
    Abstract [en]

    Functionalisation of biomedical implants viasurface modifications for tailored tissue response is agrowing field of research. Crystalline TiO2 has been provento be a bone bioactive, non-resorbable material. In contactwith body fluids a hydroxyapaptite (HA) layer forms on itssurface facilitating the bone contact. Thus, the path ofimproving biomedical implants via deposition of crystallineTiO2 on the surface is interesting to follow. In thisstudy we have evaluated the influence of microstructureand chemical composition of sputter deposited titaniumoxide thin films on the in vitro bioactivity. We find thatboth substrate bias, topography and the flow ratio of thegases used during sputtering affect the HA layer formed onthe films after immersion in simulated body fluid at 37C.A random distribution of anatase and rutile crystals, formedat negative substrate bias and low Ar to O2 gas flow ratios,are shown to favor the growth of flat HA crystal structureswhereas higher flow ratios and positive substrate biasinduced growth of more spherical HA structures. Thesefindings should provide valuable information when optimizingthe bioactivity of titanium oxide coatings as well asfor tailoring process parameters for sputtered-based productionof bioactive titanium oxide implant surfaces.

  • 33.
    Lilja, Mirjam
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Sörensen, Jan Henrik
    Christian-Albrechts Universitet Kiel.
    Brohede, Ulrika
    Sandvik Coromant.
    Åstrand, Maria
    Sandvik Coromant.
    Procter, Philip
    Arnoldi, Jörg
    Steckel, Hartwig
    Christian-Albrechts Universitet Kiel.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Drug loading and release of Tobramycin from Hydroxyapatite coated fixation pins2013In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 24, no 9, p. 2265-2274Article in journal (Refereed)
    Abstract [en]

    This paper evaluates the loading and release properties of Tobramycin incorporated by adsorptive loading from a solution into plasma sprayed and biomimetically coated Hydroxyapatite (HA) fixation pins. The aim of this study is to contribute towards designing a functional implant surface offering local release of the antibiotic agent to prevent post-surgical infections. Cathodic arc deposition is used to coat stainless steel fixation pins with a bioactive, anatase phase dominated, TiO2 coating onto which a HA layer is grown biomimetically. The loading and release properties are evaluated by studying the subsequent release of Tobramycin using high performance liquid chromatography and correlated to the differences in HA coating microstructure and the physical conditions under loading. The results from these studies show that a dual loading strategy consisting of a solution temperature of 90 °C and a pressure of 6 bar during a loading time of 5 min release a sufficient amount of Tobramycin to guarantee the inhibition of Staphylococcus aureus up to 2 days for plasma sprayed HA coatings and for 8 days for biomimetic coatings. The present study emphasizes the advantages of the nanoporous structure of biomimetically deposited HA over the more dense structure of plasma sprayed HA coatings in terms of antibiotic incorporation and subsequent sustained release and provides a valuable outline for the design of implant surfaces aiming for a fast-loading and controlled, local drug administration.

  • 34. Liljensten, E
    et al.
    Larsson, C
    Thomsen, P
    Blomkvist, G
    Hirsch, Jan M
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Oral and Maxillofacial Surgery.
    Wedenberg, C
    Studies of the healing of bone grafts, and the incorporation of titanium implants in grafted bone: an experimental animal model1998In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 9, no 9, p. 535-541Article in journal (Refereed)
    Abstract [en]

    An insufficient quality and amount of bone often necessitate the clinical use of implants together with bone transplants. The present study describes an experimental animal model for the study of implants in bone grafts. Circular defects were made bilaterally in the tibia of 36 rabbits. The defects received either autologous cortical bone (control), demineralized bone matrix (DBM), plasma-augmented DBM or were left empty (without bone graft). In all defects a titanium implant was centrally placed and anchored in the opposite cortex. Evaluation with light microscopic morphometry showed that the insertion of a threaded titanium implant centrally in a cortical defect was followed by a spontaneous healing of the defect after 6 mon. After 6 wk, all implants in cortical grafts were well integrated with a significantly higher bone-to-implant contact than in the DBM and plasma-augmented groups. After 6 mon, all experimental groups had a mean bone area within the threads ranging between 69% and 80% and a mean bone-to-implant contact between 31% and 42%. The results from the present study indicate that the model allows comparative studies on the early formation, resorption and remodelling of bone around implants after modification of implant, graft and host properties.

  • 35.
    Lindahl, Carl
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Borchardt, Per
    Department of Chemistry and Materials Technology, SP Technical Research Institute of Sweden.
    Lausmaa, Jukka
    Department of Chemistry and Materials Technology, SP Technical Research Institute of Sweden.
    Xia, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Studies of early growth mechanisms of hydroxyapatite on single crystalline rutile: a model system for bioactive surfaces2010In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 21, no 10, p. 2743-2749Article in journal (Refereed)
    Abstract [en]

    Previous studies have shown that crystalline titanium oxide is in vitro bioactive and that there are differences in the HA formation mechanism depending on the crystalline direction of the titanium oxide surface. In the present study, the early adsorption of calcium and phosphate ions on three different surface directions of the single-crystal rutile TiO2 substrate has been investigated. A crucial step in the nucleation of HA is believed to be the adsorption of Ca2+ and PO4 3− from phosphate buffer solutions. The (001), (100) and (110) single crystalline rutile surfaces were soaked in phosphate buffer saline solution for 10 min, 1 h and 24 h at 37°C. The surfaces were then analyzed using time-of-flight secondary ion mass spectrometry (TOF-SIMS) and X-ray photoelectron spectroscopy (XPS). The results show that the adsorption of Ca2+ and PO4 3− is faster on the (001) and (100) surfaces than on the (110) surface. This study also shows that TOF-SIMS can be used as a tool to better understand the adsorption of calcium and phosphate ions and the growth mechanism of HA. This knowledge could be used to tailor new bioactive surfaces for better biological reaction.

  • 36.
    Lindgren, M
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Åstrand, M
    Wiklund, Urban
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Investigation of boundary conditions for biomimetic HA deposition on titanium oxide surfaces2009In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 20, no 7, p. 1401-1408Article in journal (Refereed)
    Abstract [en]

    To improve the clinical outcome of metal implants, i.e. earlier loading and reduction of the incidence of revision surgery, better bone bonding ability is wanted. One method to achieve this is to change the surface chemistry to give a surface that facilitates bone bonding in vivo, i.e. a bioactive surface. Crystalline titanium oxide has recently been proven to be bioactive in vitro and is an interesting option to the more common hydroxylapatite (HA) coatings on implants. A materials possible in vitro bioactivity is tested through soaking in simulated body fluid and studies of possible HA formation on the surface. For bioactive materials, the formed HA layer can also be used as a coating. The aim of the current paper is to investigate some boundary conditions for HA formation on crystalline titanium oxide surfaces regarding influence from coating thickness, soaking time and soaking temperature. The influence from soaking time and temperature on the HA growth were investigated on oxidised Ti samples, (24 h at 800°C) resulting in a rutile surface structure. The oxidised samples were tested at three temperatures (4, 37 and 65°C) and four times (1 h, 1 day, 1 week and 4 weeks). The influence from titanium coating thickness on the HA growth was investigated via depositing thin films of crystalline titanium dioxide on Ti plates using a reactive magnetron sputtering process. Four different PVD runs with coating thicknesses between 19 and 74 nm were tested. The soaking temperature had an effect on the HA formation and growth on both rutile surfaces and native oxide on Ti substrates. Higher temperatures lead to easier formation of HA. It was even possible, at 65°C, to grow HA on native titanium oxide from soaking in PBS. The coating quality was better for HA formed at 65°C compared to 37°C. All PVD-coatings showed HA growth after 1 week in PBS at 37°C, thus even very thin coatings of crystalline titanium oxide coatings are bioactive.

  • 37.
    Liu, Wenguang
    et al.
    Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada.
    Griffith, May
    Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada.
    Li, Fengfu
    University of Ottawa Eye Institute and Ottawa Health Research Institute, Ottawa, ON, Canada.
    Alginate microsphere-collagen composite hydrogel for ocular drug delivery and implantation2008In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 19, no 11, p. 3365-3371Article in journal (Refereed)
    Abstract [en]

    A composite collagen hydrogel containing protein encapsulated alginate microspheres was developed for ocular applications. Bovine serum albumin (BSA) served as a drug model. The composite hydrogel retained optical clarity and mechanical robustness of control hydrogels without microspheres. A sustained release of BSA was achieved during an 11-day period in neutral phosphate buffer. The composite hydrogel supported human corneal epithelial cell growth and had adequate mechanical strength and excellent optical clarity for possible use as therapeutic lens for drug delivery and/or use as corneal substitute for transplantation into patients who have corneal diseases.

  • 38.
    López, Alejandro
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Unosson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Direct and interactive effects of three variables on properties of PMMA bone cement for vertebral body augmentation2011In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 22, no 6, p. 1599-1606Article in journal (Refereed)
    Abstract [en]

    PMMA bone cements are widely used for vertebral body augmentation procedures vertebroplasty and balloon kyphoplasty. Although there are studies in the literature on the direct effects of relevant variables on the properties of these cements, there are none on the interactive effects. In the present work, such a study was performed on both types of effects, with the variables being the concentration of initiator (benzoyl peroxide), the concentration of crosslinker (ethylene glycol dimethacrylate), and the liquid-to-powder ratio used in preparing the cement; and the properties being the compressive strength, the compressive modulus, the doughing time, the setting time, and the maximum polymerization temperature. Two additional properties obtained from the viscosity-versustime curves, namely the time at the onset of curing, and the critical curing rate were also studied. Significant interactive effects between the amount of crosslinker and the amount of radical initiator were found to affect the doughing time and the critical curing rate. These effects were explained in terms of the reaction kinetics. It was concluded that interactive effects may exist and should be taken into account when designing bone cement formulations.

  • 39.
    Montazerolghaem, Maryam
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Jacobson Rasmusson, Annica
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical pharmacogenomics and osteoporosis.
    Melhus, Håkan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical pharmacogenomics and osteoporosis.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Karlsson Ott, Marjam
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Simvastatin-doped pre-mixed calcium phosphate cement inhibits osteoclast differentiation and resorption2016In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 27, no 5, article id 83Article in journal (Refereed)
    Abstract [en]

    Simvastatin, a cholesterol lowering drug, has been shown to have positive effects on fracture healing and bone regeneration based on its dual effect; bone anabolic and anti-resorptive. In this study the focus has been on the anti-resorptive effect of the drug and its impact on the degradation of acidic calcium phosphate cement. The drug was added to the pre-mixed acidic cement in three different doses (0.1, 0.25 and 0.5 mg/g cement) and the release was measured. Furthermore the effect of the loaded cements on osteoclast differentiation and resorption was evaluated by TRAP activity, number of multinucleated cells, gene expression and calcium ion concentration in vitro using murine bone marrow macrophages. The simvastatin did not affect the cell proliferation while it clearly inhibited osteoclastic differentiation at all three doses as shown by TRAP staining, TRAP activity and gene expression. Consistent with these results, simvastatin also impaired resorption of cements by osteoclasts as indicated by reduced calcium ion concentrations. In conclusion, our findings suggest that simvastatin-doped pre-mixed acidic calcium phosphate cement inhibits the osteoclastic mediated resorption of the cement thus slowing down the degradation rate. In addition with simvastatin's bone anabolic effect it makes the cement-drug combination a promising bone graft material, especially useful for sites with compromised bone formation.

  • 40.
    Montazerolghaem, Maryam
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Ning, Yi
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Karlsson Ott, Marjam
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Mestres, Gemma
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Simvastatin and zinc synergistically enhance osteoblasts activityand decrease the acute response of inflammatory cells2016In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 27, no 2, article id 23Article in journal (Refereed)
    Abstract [en]

    Several ceramic biomaterials have been suggested as promising alternatives to autologous bone to replace or restore bone after trauma or disease. The osteoinductive potential of most scaffolds is often rather low by themselves and for this reason growth factors or drugs have been supplemented to these synthetic materials. Although some growth factors show good osteoinductive potential their drawback is their high cost and potential severe side effects. In this work the combination of the well-known drug simvastatin (SVA) and the inorganic element Zinc (Zn) is suggested as a potential additive to bone grafts in order to increase their bone regeneration/ formation. MC3T3-E1 cells were cultured with Zn (10 and 25 mu M) and SVA (0.25 and 0.4 mu M) for 10 days to evaluate proliferation and differentiation, and for 22 days to evaluate secretion of calcium deposits. The combination of Zn (10 mu M) and SVA (0.25 mu M) significantly enhanced cell differentiation and mineralization in a synergetic manner. In addition, the release of reactive oxygen species (ROS) from primary human monocytes in contact with the same concentrations of Zn and SVA was evaluated by chemiluminescence. The combination of the additives decreased the release of ROS, although Zn and SVA separately caused opposite effects. This work shows that a new combination of additives can be used to increase the osteoinductive capacity of porous bioceramics.

  • 41.
    Murase, Kohei
    et al.
    BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Sweden.
    Stenlund, Patrik
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials. BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Sweden ; University of Gothenburg, Sweden.
    Thomsen, Peter
    BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Sweden.
    Lausmaa, Jukka
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials. BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Sweden.
    Palmquist, Anders
    BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Sweden ; University of Gothenburg, Sweden.
    Three-dimensional modeling of removal torque and fracture progression around implants.2018In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 29, no 7, article id 104Article in journal (Refereed)
    Abstract [en]

    In the present study, a model for simulations of removal torque experiments was developed using finite element method. The interfacial retention and fracturing of the surrounding material caused by the surface features during torque was analyzed. It was hypothesized that the progression of removal torque and the phases identified in the torque response plot represents sequential fractures at the interface. The 3-dimensional finite element model fairly accurately predicts the torque required to break the fixation of acid-etched implants, and also provides insight to how sequential fractures progress downwards along the implant side.

  • 42.
    Myllymaa, Katja
    et al.
    Microsensor Laboratory, School of Engineering and Technology, Savonia University of Applied Sciences, Kuopio, Finland; Department of Physics, University of Kuopio, Kuopio, Finland.
    Myllymaa, Sami
    Department of Physics, University of Kuopio, Kuopio, Finland.
    Korhonen, Hannu
    Department of Physics, University of Kuopio, Kuopio, Finland.
    Lammi, Mikko
    Departmentof Applied Biotechnology, University of Kuopio, Kuopio; Biocenter Kuopio, University of Kuopio, Kuopio, Finland.
    Saarenpää, Hanna
    Department of Chemistry, University of Joensuu, Joensuu, Finland.
    Suvanto, Mika
    Department of Chemistry, University of Joensuu, Joensuu, Finland.
    Pakkanen, Tapani
    Department of Chemistry, University of Joensuu, Joensuu, Finland.
    Tiitu, Virpi
    Department of Biomedicine, Anatomy, University of Kuopio, Kuopio, Finland.
    Lappalainen, Reijo
    Department of Physics, University of Kuopio, Kuopio, Finland.
    Improved adherence and spreading of Saos-2 cells on polypropylene surfaces achieved by surface texturing and carbon nitride coating.2009In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 20, no 11, p. 2337-2347, article id 19507005Article in journal (Refereed)
    Abstract [en]

    The adhesion and contact guidance of human primary osteogenic sarcoma cells (Saos-2) were characterized on smooth, microstructured (MST) and micro- and nano-structured (MNST) polypropylene (PP) and on the same samples with a silicon-doped carbon nitride (C(3)N(4)-Si) coating. Injection molding was used to pattern the PP surfaces and the coating was obtained by using ultra-short pulsed laser deposition (USPLD). Surfaces were characterized using atomic force microscopy and surface energy components were calculated according to the Owens-Wendt model. The results showed C(3)N(4)-Si coated surfaces to be significantly more hydrophilic than uncoated ones. In addition, there were 86% more cells in the smooth C(3)N(4)-Si coated PP compared to smooth uncoated PP and 551%/476% more cells with MST/MNST C(3)N(4)-Si coated PP than could be obtained with MST/MNST uncoated PP. Thus the adhesion, spreading and contact guidance of osteoblast-like cells was effectively improved by combining surface texturing and deposition of osteocompatible C(3)N(4)-Si coating.

  • 43.
    Olofsson, Johanna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Pettersson, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Teuscher, Nico
    Fraunhofer, Institute for Mechanics of Material.
    Heilmann, Andreas
    Fraunhofer, Institute for Mechanics of Material.
    Larsson, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Grandfield, Kathryn
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Jacobson, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Fabrication and evaluation of SixNy coatings for total joint replacements2012In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 23, no 8, p. 1879-1889Article in journal (Refereed)
    Abstract [en]

    Wear particles from the bearing surfaces of joint implants are one of the main limiting factors for total implant longevity. Si3N4 is a potential wear resistant alternative for total joint replacements. In this study, SixNy-coatings were deposited on cobalt chromium-discs and Si-wafers by a physical vapour deposition process. The tribological properties, as well as surface appearance, chemical composition, phase composition, structure and hardness of these coatings were analysed. The coatings were found to be amorphous or nanocrystalline, with a hardness and coefficient of friction against Si3N4 similar to that found for bulk Si3N4. The low wear rate of the coatings indicates that they have a potential as bearing surfaces of joint replacements. The adhesion to the substrates remains to be improved.

  • 44.
    Persson, Cecilia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Berg, Svante
    Stockholm Spine Center.
    Strategies towards injectable, load-bearing materials for the intervertebral disc: a review and outlook2013In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 24, no 1, p. 1-10Article, review/survey (Refereed)
    Abstract [en]

    Currently available treatments for the degenerated intervertebral disc present disadvantages, such as surgical invasiveness and inadequate load distribution results. Load-bearing, injectable materials may be interesting for future therapies, but have not been studied in depth.

    In this study, the existing literature was screened for studies on injectable materials for the intervertebral disc and a rationale for load-bearing, injectable materials was formulated. Requirements for such a material were discussed, partly based on the experience of materials used for similar applications.

    Important properties were discussed and found to include biocompatibility, bioactivity, porosity, handling, injectability, working time, setting time, radiopacity, containment and mechanical properties, where several of these properties are linked to one another.

    In conclusion, there is a need for consensus on the properties of new materials developed for use in minimally invasive procedures in the spine. A substantial amount of attention may need to be given to non-toxic setting reactions.

  • 45.
    Qin, Tao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Han, Yuanyuan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Zhang, Peng
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Wani, Ishtiaq Hassan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Nikolajeff, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Leifer, Klaus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Uppsala Univ, Dept Engn Sci, Div Appl Mat Sci, Angstromlab, Lagerhyddsvagen 1, S-75237 Uppsala, Sweden..
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Template-free synthesis of phosphate-based spheres via modified supersaturated phosphate buffer solutions2017In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 28, no 7, article id 99Article in journal (Refereed)
    Abstract [en]

    Modified supersaturated phosphate buffer solutions were used to synthesize phosphate-based spheres, including calcium phosphate (CaP), strontium phosphate (SrP) and barium phosphate (BaP). A series of ions concentrations in the modified phosphate buffer solutions were investigated in order to study their effects in precipitates morphologies. During synthesis, it was found that magnesium was the key factor in sphere formation. The morphologies of calcium phosphate, strontium phosphate and barium phosphate precipitates varied as the concentration of magnesium ions varied. When sufficient magnesium was provided, the precipitates appeared spherical, and the diameter was in range of 0.5-2 mu m. The morphologies, compositions and structure of spheres were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and N-2 adsorption analysis. Moreover, the application of magnesium substituted calcium phosphate spheres in dentin tubules occlusion was investigated.

  • 46. Ramires, P. A.
    et al.
    Wennerberg, Ann
    Johansson, Carina B.
    Örebro University, Department of Health Sciences. Örebro University, Department of Clinical Medicine.
    Cosentino, F.
    Tundo, S.
    Milella, E.
    Biological behavior of sol-gel coated dental implants2003In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 14, no 6, p. 539-545Article in journal (Refereed)
    Abstract [en]

    The biocompatibility of dental implants coated with titania/hydroxyapatite (HA) and titania/bioactive glass (BG) composites obtained via sol-gel process was investigated using an in vitro and in vivo model. A device for the in vitro testing of screw-shaped dental implants was developed, in order to well compare the two experimental models studying the behavior of human MG63 osteoblast-like cells seeded onto a particular geometry. The expression of some biochemical parameters of osteoblastic phenotype (alkaline phosphatase specific activity, collagen and osteocalcin production) and some indications on cells morphology obtained by scanning electron microscopy were evaluated. The in vitro and in vivo models were compared after implants insertion in rabbit tibia and femur. The removal torque and histomorphometric parameters (percentage of bone in contact with implant surface and the amount of bone inside the threaded area) were examined. A good agreement was found between the in vitro and in vivo models. These experiments showed better performances of HA and BG sol-gel coated dental implants with respect to uncoated titanium; in particular, it was found that in vitro the HA coating stimulates osteoblastic cells in producing higher level of ALP and collagen, whereas in vivo this surface modification resulted in a higher removal torque and a larger bone-implant contact area. This behavior could be ascribed to the morphology and the chemical composition of the implants with rough and bioactive surfaces.

  • 47.
    Sandberg, Tomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Surface Biotechnology.
    Carlsson, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Surface Biotechnology.
    Karlsson Ott, Marjam
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Surface Biotechnology.
    Interactions between human neutrophils and mucin-coated surfaces2009In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 20, no 2, p. 621-631Article in journal (Refereed)
    Abstract [en]

    Recently, we showed microscopically that bovine (BSM), porcine (PGM) and human (MG1) mucin coatings could suppress the adhesion of neutrophils to a polyethylene terephthalate-based model biomaterial (Thermanox). Here, using the release of reactive oxygen species (ROS) as a marker of material-induced neutrophil activation, the strong surface-passivating effects of these mucin coatings were corroborated. Under optimal adsorption conditions, all mucin species performed equally well, thus indicating a high degree of functional homology between the mucins. Cell adhesion and morphology correlated well with the release of ROS. Quartz crystal microbalance (QCM-D) analysis linked low neutrophil activation to efficient mucin surface-shielding. Interestingly, the shielding power appeared equal for thick expanded and thin compact mucin coatings. Combined mucin-serum coatings were found to be highly surface-passivating. Particularly, since our data suggested partly synergistic mucin-serum action, we highlight the possibility that pre-adsorbed mucins could provide favorable support for adsorbing host components.

  • 48.
    Sandin, Karin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Inorganic Chemistry.
    Kloo, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Inorganic Chemistry.
    Nevsten, Pernilla
    Wallenberg, Reine L.
    Olsson, Lars-Fride
    Formation of carbonated apatite particles from a supersaturated inorganic blood serum model2009In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 20, no 8, p. 1677-1687Article in journal (Refereed)
    Abstract [en]

    Pathological calcification is common among for instance dialysis patients, and this causes an increase in mortality risk. An elevated serum phosphate concentration among those patients strongly correlates to this increase. In this work investigations of the conditions, composition, crystallinity and morphology of in vitro calcification are performed and related to results from in vivo studies. The study was performed under conditions mimicking physiological ones, i.e. a pH around 7.40, a temperature of 37A degrees C, an ionic strength of 150 mM and ion concentrations close to those in human serum including the effects of elevated phosphate concentrations. The course of precipitation involves an initial precipitate that subsequently re-dissolves to give another precipitate, in accordance with the well-known Ostwald ripening theory. The final bulk precipitate consists of a macroscopically amorphous carbonated apatite. The amorphous apatite is formed from assemblies of spherical particles in the mu m range, in turn composed of nano-crystalline needles of about 10 x 100 nm. Even the initially formed precipitate, as well as a small amount of precipitate that occurs on the liquid surface, consist of a carbonated calcium phosphate. The in vitro observed carbonated apatite bears strong resemblance to in vivo cardiovascular calcification known from literature.

  • 49.
    Shah, Furqan A.
    et al.
    University of Gothenburg, Sweden; BIOMATCELL VINN Excellence Centre of Biomaterials and Cell Therapy, Sweden.
    Stenlund, Patrik
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Medicinteknik. University of Gothenburg, Sweden; BIOMATCELL VINN Excellence Centre of Biomaterials and Cell Therapy, Sweden.
    Martinelli, Anna
    Chalmers University of Technology, Sweden.
    Thomsen, Peter
    University of Gothenburg, Sweden; BIOMATCELL VINN Excellence Centre of Biomaterials and Cell Therapy, Sweden.
    Palmquist, Anders
    University of Gothenburg, Sweden; BIOMATCELL VINN Excellence Centre of Biomaterials and Cell Therapy, Sweden.
    Direct communication between osteocytes and acid-etched titanium implants with a sub-micron topography2016In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 27, no 11, article id 167Article in journal (Refereed)
    Abstract [en]

    The osteocyte network, through the numerous dendritic processes of osteocytes, is responsible for sensing mechanical loading and orchestrates adaptive bone remodelling by communicating with both the osteoclasts and the osteoblasts. The osteocyte network in the vicinity of implant surfaces provides insight into the bone healing process around metallic implants. Here, we investigate whether osteocytes are able to make an intimate contact with topologically modified, but micrometre smooth (Sa < 0.5 µm) implant surfaces, and if sub-micron topography alters the composition of the interfacial tissue. Screw shaped, commercially pure (cp-Ti) titanium implants with (i) machined (Sa = ~0.2 µm), and (ii) two-step acid-etched (HF/HNO3 and H2SO4/HCl; Sa = ~0.5 µm) surfaces were inserted in Sprague Dawley rat tibia and followed for 28 days. Both surfaces showed similar bone area, while the bone-implant contact was 73 % higher for the acid-etched surface. By resin cast etching, osteocytes were observed to maintain a direct intimate contact with the acid-etched surface. Although well mineralised, the interfacial tissue showed lower Ca/P and apatite-to-collagen ratios at the acid-etched surface, while mineral crystallinity and the carbonate-to-phosphate ratios were comparable for both implant surfaces. The interfacial tissue composition may therefore vary with changes in implant surface topography, independently of the amount of bone formed. Implant surfaces that influence bone to have higher amounts of organic matrix without affecting the crystallinity or the carbonate content of the mineral phase presumably result in a more resilient interfacial tissue, better able to resist crack development during functional loading than densely mineralised bone.

  • 50.
    Stenfelt, Sonya
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Polymer Chemistry.
    Hulsart-Billström, Gry
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Orthopaedics.
    Gedda, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science.
    Bergman, Kristoffer
    Larsson, Sune
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Orthopaedics.
    Hilborn, Jöns
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Polymer Chemistry.
    Bowden, Tim
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Polymer Chemistry.
    Pre-incubation of chemically crosslinked hyaluronan-based hydrogels, loaded with BMP-2 and hydroxyapatite, and its effect on ectopic bone formation2014In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 25, no 4, p. 1013-1023Article in journal (Refereed)
    Abstract [en]

    The effects of pre-incubation of hyaluronan hydrogels, for different lengths of time after the initiation of chemical crosslinking and prior to injection, were explored both by investigating the in vitro BMP-2 release kinetics from the hydrogel and by studying the ectopic bone formation in rats. From the curing profile, obtained from rheological analysis, appropriate pre-incubation times (1 min, 5 h and 3 days) were selected, to prepare slightly, moderately and fully cured hydrogels. Comparable release profiles were observed for all three test groups in vitro. Furthermore, radiography, pQCT and histology of the explanted grafts showed cancellous bone formation in all groups after 5 weeks in vivo. However, longer pre-incubation times gave rise to an increase in bone volume, but a decrease in bone density. Moreover, the 5 h and the 3 days grafts appeared to be more ordered and resistant to deformation from the surrounding tissue than the 1 min grafts. The observed variations in mechanical and biological properties could potentially be used to adapt the treatment for a specific indication.

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