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  • 1. Ajalloueian, Fatemeh
    et al.
    Zeiai, Said
    Rojas, Ramiro
    Department of Chemistry, Division of Polymer Chemistry, Uppsala University, Sweden.
    Fossum, Magdalena
    Hilborn, Jöns
    One-Stage Tissue Engineering of Bladder Wall Patches for an Easy-To-Use Approach at the Surgical Table2013In: Tissue Engineering. Part C, Methods, ISSN 1937-3384, Vol. 19, no 9, 688-696 p.Article in journal (Refereed)
    Abstract [en]

    We present a method for producing a cell-scaffold hybrid construct at the bedside. The construct is composed of plastic-compressed collagen together with a poly(e-caprolactone) (PCL)-knitted mesh that yields an integrated, natural-synthetic scaffold. This construct was evaluated by seeding of minced bladder mucosa, followed by proliferation in vitro. High mechanical strength in combination with a biological environment suitable for tissue growth was achieved through the creation of a hybrid construct that showed an increased tensile strength (17.9 +/- 2.6 MPa) when compared to plastic-compressed collagen (0.6 +/- 0.12 MPa). Intimate contact between the collagen and the PCL fabric was required to ensure integrity without delamination of the construct. This contact was achieved by surface alkaline hydrolysis of the PCL, followed by adsorption of poly(vinyl) alcohol. The improvement in hydrophilicity of the PCL-knitted mesh was confirmed through water contact angle measurements, and penetration of the collagen into the mesh was evaluated by scanning electron microscopy (SEM). Particles of minced bladder mucosa tissue were seeded onto this scaffold, and the proliferation was followed for 6 weeks in vitro. Results obtained from phase contrast microscopy, SEM, and histological staining indicated that cells migrated from the minced tissue particles and reorganized on the scaffold. Cells were viable and proliferative, with morphological features characteristic of urothelial cells. Proliferation reached the point at which a multilayer with a resemblance to stratified urothelium was achieved. This successful method could potentially be used for in vivo applications in reconstructive urology as an engineered autologous tissue transplant without the requirement for in vitro culture before transplantation.

  • 2.
    Ajaxon, Ingrid
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Can Bone Void Fillers Carry Load?: Behaviour of Calcium Phosphate Cements Under Different Loading Scenarios2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Calcium phosphate cements (CPCs) are used as bone void fillers and as complements to hardware in fracture fixation. The aim of this thesis was to investigate the possibilities and limitations of the CPCs’ mechanical properties, and find out if these ceramic bone cements can carry application-specific loads, alone or as part of a construct. Recently developed experimental brushite and apatite cements were found to have a significantly higher strength in compression, tension and flexion compared to the commercially available CPCs chronOS™ Inject and Norian® SRS®. By using a high-resolution measurement technique the elastic moduli of the CPCs were determined and found to be at least twice as high compared to earlier measurements, and closer to cortical bone than trabecular bone. Using the same method, Poisson's ratio for pure CPCs was determined for the first time. A non-destructive porosity measurement method for wet brushite cements was developed, and subsequently used to study the porosity increase during in vitro degradation. The compressive strength of the experimental brushite cement was still higher than that of trabecular bone after 25 weeks of degradation, showing that the cement can carry high loads over a time span sufficiently long for a fracture to heal. This thesis also presents the first ever fatigue results for acidic CPCs, and confirms the importance of testing the materials under cyclic loading as the cements may fail at stress levels much lower than the material’s quasi-static compressive strength. A decrease in fatigue life was found for brushite cements containing higher amounts of monetite. Increasing porosity and testing in a physiological buffer solution (PBS), rather than air, also decreased the fatigue life. However, the experimental brushite cement had a high probability of surviving loads found in the spine when tested in PBS, which has previously never been accomplished for acidic CPCs. In conclusion, available brushite cements may be able to carry the load alone in scenarios where the cortical shell is intact, the loading is mainly compressive, and the expected maximum stress is below 10 MPa. Under such circumstances this CPC may be the preferred choice over less biocompatible and non-degradable materials.

  • 3.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Acciaioli, Alice
    Istituto Ortopedico Rizzoli, Laboratorio di Tecnologia Medica.
    Lionello, Giacomo
    Istituto Ortopedico Rizzoli, Laboratorio di Tecnologia Medica.
    Ginebra, Maria-Pau
    Biomaterials, Biomechanics and Tissue Engineering Group, Dept. of Materials Science and Metallurgy, Technical University of Catalonia (UPC).
    Öhman, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Baleani, Massimilliano
    Istituto Ortopedico Rizzoli, Laboratorio di Tecnologia Medica.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Elastic properties and strain-to-crack-initation of calcium phosphate bone cements: revelations of a high-resolution measurement technique2017In: Journal of The Mechanical Behavior of Biomedical Materials, ISSN 1751-6161, E-ISSN 1878-0180, Vol. 74, 428-437 p.Article in journal (Refereed)
    Abstract [en]

    Calcium phosphate cements (CPCs) should ideally have mechanical properties similar to those of the bone tissue the material is used to replace or repair. Usually, the compressive strength of the CPCs is reported and, more rarely, the elastic modulus. Conversely, scarce or no data are available on Poisson's ratio and strain-to-crack-initiation. This is unfortunate, as data on the elastic response is key to, e.g., numerical model accuracy. In this study, the compressive behaviour of brushite, monetite and apatite cements was fully characterised. Measurement of the surface strains was done using a digital image correlation (DIC) technique, and compared to results obtained with the commonly used built-in displacement measurement of the materials testers. The collected data showed that the use of fixed compression platens, as opposed to spherically seated ones, may in some cases underestimate the compressive strength by up to 40%. Also, the built-in measurements may underestimate the elastic modulus by up to 62% as compared to DIC measurements. Using DIC, the brushite cement was found to be much stiffer (24.3 ± 2.3 GPa) than the apatite (13.5 ± 1.6 GPa) and monetite (7.1 ± 1.0 GPa) cements, and elastic moduli were inversely related to the porosity of the materials. Poisson's ratio was determined to be 0.26 ± 0.02 for brushite, 0.21 ± 0.02 for apatite and 0.20 ± 0.03 for monetite. All investigated CPCs showed low strain-to-crack-initiation (0.17–0.19%). In summary, the elastic modulus of CPCs is substantially higher than previously reported and it is concluded that an accurate procedure is a prerequisite in order to properly compare the mechanical properties of different CPC formulations. It is recommended to use spherically seated platens and measuring the strain at a relevant resolution and on the specimen surface.

  • 4.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Acciaioli, Alice
    Lionello, Giacomo
    Ginebra, Maria-Pau
    Öhman, 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.
    Baleani, Massimiliano
    Compressive strength increase of calcium phosphate bone cements is accompanied by a stiffness increase2016Conference paper (Other academic)
  • 5.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Holmberg, Anders
    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.
    The influence of porosity on the fatigue properties of brushite cement2016In: Biomaterials for tissue engineering models, 2016Conference paper (Other academic)
  • 6.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Holmberg, Anders
    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 a high-strength, degradable calcium phosphate bone cement – influence of porosity and environmentManuscript (preprint) (Other academic)
  • 7.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Maazouz, Yassine
    Biomaterials, Biomechanics and Tissue Engineering Group, Dept. of Materials Science and Metallurgy, Technical University of Catalonia .
    Ginebra, Maria-Pau
    Biomaterials, Biomechanics and Tissue Engineering Group, Dept. of Materials Science and Metallurgy, Technical University of Catalonia .
    Öhman, 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.
    A non-drying porosity evaluation method for calcium phosphate cements2014In: 26th Symposium and Annual Meeting of the International Society for Ceramics in Medicine, 2014, 68-68 p.Conference paper (Refereed)
  • 8.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Maazouz, Yassine
    Ginebra, Maria-Pau
    Öhman, 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.
    Evaluation of a porosity measurement method for wet calcium phosphate cements2015In: Journal of biomaterials applications, ISSN 0885-3282, E-ISSN 1530-8022, Vol. 30, no 5, 526-536 p.Article in journal (Refereed)
    Abstract [en]

    The porosity of a calcium phosphate cement is a key parameter as it affects several important properties of the cement. However, a successful, non-destructive porosity measurement method that does not include drying has not yet been reported for calcium phosphate cements. The aim of this study was to evaluate isopropanol solvent exchange as such a method. Two different types of calcium phosphate cements were used, one basic (hydroxyapatite) and one acidic (brushite). The cements were allowed to set in an aqueous environment and then immersed in isopropanol and stored under three different conditions: at room temperature, at room temperature under vacuum (300 mbar) or at 37􏰀C. The specimen mass was monitored regularly. Solvent exchange took much longer time to reach steady state in hydroxyapatite cements compared to brushite cements, 350 and 18 h, respectively. Furthermore, the immersion affected the quasi-static compressive strength of the hydroxyapatite cements. However, the strength and phase composition of the brushite cements were not affected by isopropanol immersion, suggesting that isopropanol solvent exchange can be used for brushite calcium phosphate cements. The main advantages with this method are that it is non-destructive, fast, easy and the porosity can be evaluated while the cements remain wet, allowing for further analysis on the same specimen. 

  • 9.
    Ajaxon, Ingrid
    et al.
    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.
    Mechanical Properties of Brushite Calcium Phosphate Cements2017In: The World Scientific Encyclopedia of Nanomedicine and Bioengineering II: Bioimplants, Regenerative Medicine, and Nano-Cancer Diagnosis and Phototherapy: Volume 3: Design of Bioactive Materials for Bone Repair and Regeneration / [ed] Shi, D., Singapore: World Scientific Pte Ltd. , 2017Chapter in book (Refereed)
  • 10.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Öhman, 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 Acidic Calcium Phosphate Cement2014In: Proceedings of 7th World Congress of Biomechanics, 2014Conference paper (Refereed)
  • 11.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Öhman, 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.
    Long-term in vitro degradation of a high-strength brushite cement in water, PBS, and serum solution2015In: BioMed Research International, ISSN 2314-6133, E-ISSN 2314-6141, 575079Article in journal (Refereed)
    Abstract [en]

    Bone loss and fractures may call for the use of bone substituting materials, such as calcium phosphate cements (CPCs). CPCs can be degradable, and, to determine their limitations in terms of applications, their mechanical as well as chemical properties need to be evaluated over longer periods of time, under physiological conditions. However, there is lack of data on how the in vitro degradation affects high-strength brushite CPCs over longer periods of time, that is, longer than it takes for a bone fracture to heal. This study aimed at evaluating the long-term in vitro degradation properties of a high-strength brushite CPC in three different solutions: water, phosphate buffered saline, and a serum solution. Microcomputed tomography was used to evaluate the degradation nondestructively, complemented with gravimetric analysis. The compressive strength, chemical composition, and microstructure were also evaluated. Major changes from 10 weeks onwards were seen, in terms of formation of a porous outer layer of octacalcium phosphate on the specimens with a concomitant change in phase composition, increased porosity, decrease in object volume, and mechanical properties. This study illustrates the importance of long-term evaluation of similar cement compositions to be able to predict the material’s physical changes over a relevant time frame. 

  • 12.
    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, 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. 

  • 13.
    Alanko, Rosanna
    et al.
    Jönköping University, School of Health and Welfare, HHJ. Prosthetics and Orthotics.
    Oskarsson, Tina
    Jönköping University, School of Health and Welfare, HHJ. Prosthetics and Orthotics.
    Kommunikation mellan patient och ortopedingenjör: En kvalitativ studie2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    En studie har genomförts med syftet att undersöka diabetespatienters tolkning av informationen som ges av deras respektive ortopedingenjör under ett patientmöte samt undersöka vad ortopedingenjören anser sig ha förmedlat för information till patienten under patientmötet. Metoden i studien är kvalitativ där intervjuer med semistrukturerade öppna frågor har använts. I studien ingick två ortopedingenjörer samt två diabetespatienter. Efter avslutade intervjuer har materialet från intervjuerna analyserats och bildat kategorier. Dessa kategorier har sedan använts för att finna skillnader samt likheter mellan ortopedingenjörens och patientens tolkningar. Patientmötens har spelats in för att få möjligheten att se vart missförstånd uppstått. Genomgående i resultatet var att ortopedingenjören anser sig ha förmedlat mer information än vad patienten beskriver under intervjuerna. Några missförstånd upptäcktes men kommunikationen mellan parterna var god.  

  • 14.
    Altmann, Brigitte
    et al.
    University of Freiburg .
    Karygianni, Lamprini
    University of Freiburg .
    Al-Ahmad, Ali
    University of Freiburg .
    Butz, Frank
    University of Freiburg .
    Bächle, Maria
    University of Freiburg .
    Adolfsson, Erik
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    Fürderer, Tobias
    Courtois, Nicolas
    Palmero, Paola
    Politecnico di Torino.
    Follo, Marie
    University of Freiburg .
    Chevalier, Jérôme
    Université de Lyon.
    Steinberg, Thorsten
    University of Freiburg .
    Kohal, Ralf Joachim
    University of Freiburg .
    Assessment of Novel Long-Lasting Ceria-Stabilized Zirconia-Based Ceramics with Different Surface Topographies as Implant Materials2017In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028Article in journal (Refereed)
    Abstract [en]

    The development of long-lasting zirconia-based ceramics for implants, which are not prone to hydrothermal aging, is not satisfactorily solved. Therefore, this study is conceived as an overall evaluation screening of novel ceria-stabilized zirconia-alumina-aluminate composite ceramics (ZA8Sr8-Ce11) with different surface topographies for use in clinical applications. Ceria-stabilized zirconia is chosen as the matrix for the composite material, due to its lower susceptibility to aging than yttria-stabilized zirconia (3Y-TZP). This assessment is carried out on three preclinical investigation levels, indicating an overall biocompatibility of ceria-stabilized zirconia-based ceramics, both in vitro and in vivo. Long-term attachment and mineralized extracellular matrix (ECM) deposition of primary osteoblasts are the most distinct on porous ZA8Sr8-Ce11p surfaces, while ECM attachment on 3Y-TZP and ZA8Sr8-Ce11 with compact surface texture is poor. In this regard, the animal study confirms the porous ZA8Sr8-Ce11p to be the most favorable material, showing the highest bone-to-implant contact values and implant stability post implantation in comparison with control groups. Moreover, the microbiological evaluation reveals no favoritism of biofilm formation on the porous ZA8Sr8-Ce11p when compared to a smooth control surface. Hence, together with the in vitro in vivo assessment analogy, the promising clinical potential of this novel ZA8Sr8-Ce11 as an implant material is demonstrated. 

  • 15. Augustine, Robin
    Arrowroot (Maranta arundinacea) is an edible starch, commercially available as powder, prepared from the roots of the plant family Marantaceae. Arrowroot is well known for its medicinal effects and use as chief ingredient in infant cookies. Arrowroot in film form is prepared and its microwave absorption characteristics, permittivity, loss factor, conductivity, skin depth, and heating coefficient are analyzed. The results are quite promising and can be concluded that arrowroot in film form is a potential candidate for several applications in medical field, when compared with well studied chitosan film2009In: Microwave and Optical Technology Letters, Vol. 51, no 5Article in journal (Refereed)
    Abstract [en]

    Arrowroot (Maranta arundinacea) is an edible starch, commercially available as powder, prepared from the roots of the plant family Marantaceae. Arrowroot is well known for its medicinal effects and use as chief ingredient in infant cookies. Arrowroot in film form is prepared and its microwave absorption characteristics, permittivity, loss factor, conductivity, skin depth, and heating coefficient are analyzed. The results are quite promising and can be concluded that arrowroot in film form is a potential candidate for several applications in medical field, when compared with well studied chitosan film

  • 16. Augustine, Robin
    Biocompatibility study of beta tricalcium phosphate bioceramics and chitosan biopolymer and their use as phantoms for medical imaging applications2009In: Microwave and Optical Technology Letters, Vol. 51, no 12Article in journal (Refereed)
    Abstract [en]

    Beta tricalcium phosphate (b-TCP) bioceramics and chitosan biopolymers are used as biomedical implants because of their better biocompatibility and good bioresorption characteristics. As they are biomaterials, they have good interactions with microwave frequencies. b-TCP and chitosan powder, films, pellets, and gel are prepared and studied at the S-band microwave frequencies. Dielectric parameters such as dielectric constant, dielectric loss, conductivity, and S-parameters are evaluated. Dielectric parameters of different forms of b-TCP and chitosan show resemblance with that of human tissues. Hence, these materials can also be considered as potential phantoms for specific absorption rate measurements as well as in microwave imaging applications. V

  • 17. Augustine, Robin
    Biocompatibility study of hydroxyapatite-chitosan composite for medical applications at microwave frequencies2008In: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 50, no 11, 2931-2934 p.Article in journal (Refereed)
    Abstract [en]

    Hydroxyapatite (HAp, Ca10(PO4)6(OH)2) bioceramic and chitosan (poly [(β-1-4) d-glucosamine]) biopolymer show good biocompatibility in vivo. They have biological origin and show excellent interactions with microwave. Microwave study of HAp made using different drying techniques and their composites with chitosan in the ISM band is presented. Pastes are made using HAp and chitosan with different ratios of mixing. The dielectric properties of this composites match with that of human fat, collagen tissues. Some of the compositions exhibit dielectric property close to that of natural bone. This makes them more biocompatible and better substitutes for natural bone. Thus composite bioceramics can be considered as phantom model constituents for imaging purposes.

  • 18.
    Berglund, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Branting-Ekenbäck, C
    Ohlson, M
    En översikt över chairside CAD/CAM-system i Sverige. Garanteras patientsäkerheten genom CE-märkningen av utrustning och material?2013Report (Other academic)
    Abstract [sv]

    Inom odontologin har Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) blivit allt vanligare, främst på tandtekniska laboratorier, men tekniken blir också vanligare på tandläkarklinikerna, s.k. chairside CAD/CAM. Chairside CAD/CAM innebär att tandläkaren efter preparationen av en tand framställer tandersättningen i tre steg. I första steget används en intraoral scanner istället för den traditionella avtryckstagningen (Mörmann et al., 2002; Beuer et al., 2008; Hehn, 2001). Man kan även scanna modeller och avtryck, vilket kan vara bra om patienten har svårt att gapa eller har hög salivproduktion, då scannrarna är känsliga för fuktiga miljöer (Kachalia et al., 2010). Det digitala avtrycket överförs till datorn, där uppgifterna bearbetas och en modell av tänderna skapas i 3D. I det andra steget designar tandläkaren tandersättningen på 3D-modellen. Här bestämmer tandläkaren kusphöjd, kontakter approximalt, utsträckning mot preparationsgränsen och utseende på tandersättningen. I det tredje steget fräses tandersättningen fram ur ett keramblock i en fräsmaskin. Ofta målas kronan här för att karaktärisera den och ge den ett mer tandlikt utseende innan den bränns i ugn. Med större möjligheter att själv kunna sköta hela processen fram till färdig tandkonstruktion måste tandläkaren fundera över hur kvaliteten och säkerheten hos de färdiga produkterna kan säkerställas. Färdiga tandtekniska arbeten räknas som specialanpassade medicintekniska produkter och ska inte CE-märkas men de material som ingår i arbetet är oftast CE-märkta. Lag (1993:584) om medicintekniska produkter och Läkemedelsverkets föreskrifter (LVFS 2003:11) om medicintekniska produkter innehåller krav på att medicintekniska produkter som släpps ut på marknaden ska vara lämpliga och säkra för sina användningsområden genom att krav ställs som ska leda till att allvarliga avvikelser, olyckor och tillbud på grund av produkterna så långt som möjligt ska kunna undvikas. Avvikelser inkluderar här både funktionsfel och misstänkta biverkningar. Innan ett tandtekniskt laboratorium får börja leverera tandtekniska arbeten till tandläkare måste ett antal krav vara uppfyllda för att bl.a. säkerställa säkerheten hos dessa produkter för patienterna. Laboratoriet ska vara registrerat hos Läkemedelsverket och vid registreringen måste man intyga att man har en tillverkningsverksamhet som uppfyller de krav för specialanpassade medicintekniska produkter som ställs i LVFS 2003:11. Medicintekniska produkter ska konstrueras och tillverkas på ett sådant sätt att de inte äventyrar patienternas kliniska tillstånd eller säkerhet, användarnas eller i förekommande fall andra personers hälsa och säkerhet, när de används under avsedda förhållanden och för sitt avsedda ändamål. Riskerna med att använda produkterna ska vara acceptabla med tanke på fördelarna för patienten och förenliga med en hög hälso-och säkerhetsnivå. Detta innefattar omfattande krav både på produkt och tillverkningsprocess. Det finns en del oklarheter rörande hur det regelverk som styr framställningen av tandtekniska arbeten tillämpas för arbeten tillverkade med chairside CAD/CAM.

  • 19.
    Bäckman, Sandra
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Biomechanics and Biomedicine.
    Produktutvecklingsprojekt: En applikation till användandet av oxygenbehandling i hemmet.2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    According to statistics, in 2010 there were 26 individuals seen by a group of 100,000 who were depending in home oxygen therapy (HOT). Oxygen treatment adds a certain amount of Oxygen to the patient because the ability to breathe correctly and sufficiently is negatively affected.

    The dominant disease that leads to HOT is COPD, chronic obstructive pulmonary disease. As the name suggests, it is a chronic disease which gives inflammatory changes to the lung bronchioles. These changes affect the breathing surface which results in that the individuals’ respiratory capacity becomes reduced.

    The project used methods from dynamic product development with the user in focus. This to obtain a functional prototype that could be used by the target group and to fulfill the purpose, goals and requirements set for the project's results. An important component of the project therefore was to work with the collection of data. For this, various methods were used to obtain information from users as well as prescribers of HOT. All of the methods used have been tested earlier and proven reliable. This project collected information from interviews, observations, matrix arrays, risk analysis and usability testing in patients with HOT.

    The prototype developed in the project resulted in that the target group could perform live test without any risks during testing. The results showed that the aim and objective for the project were fulfilled, expressed in that patients would be able to move the oxygen tube used in HOT.

    It was further concluded that the results fulfilled the patients' desire and opportunity to move the Oxygen tube in their home and at the same time answered the questions that the project was to answer. There were no existing solutions to the problem which is included in the project, but it was possible to develop a first prototype that met the purpose and object of the project.

  • 20.
    Cai, Bing
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Geopolymer-based drug formulations for oral delivery of opioids2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Opioid therapy for chronic pain generally use controlled release formulations to deliver analgesic drugs around-the-clock. Controlled release dosage forms can enlarge the therapeutic effect by controlling the rate and site of release. However, with high drug content, opioid formulations are easily targeted for non-medical use. With the increasing concern of opioid abuse, tamper-resistance becomes an important attribute for opioid controlled-release dosage forms. Geopolymers have been studied as drug carrier for opioids to improve the tamper-resistance but there are still some issues, such as curing condition and fast drug release in acid, have not been studied in detail yet. This thesis focuses on the optimization and evaluation of the geopolymer-based formulation on its controlled-release and tamper-resistance properties with the aim of achieving optimal therapeutic outcomes and reducing abuse potential.

    In this work, we showed some further improvement and evaluations on geopolymer-based drug formulations. The mechanical strength and porosity of geopolymers could be influenced by the curing conditions: high humidity for at least 48 hours could improve its mechanical strength, but elevated temperature only accelerated the geopolymerization but promoted water evaporation, leading to shrinkage and crack formation. Incorporating pH-sensitive organic polymers could improve the acid resistance of geopolymer formulation and thus reduce the risk of dose dumping. Comparing to a commercial opioid tablet, the geopolymer matrix have higher mechanical strength and could offer better resistance against physical manipulation and extraction under heating. The results provided solid experimental support on the potential for geopolymer as matrix for oral opioid delivery systems.

  • 21.
    Cai, Bing
    et al.
    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.
    Bredenberg, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Evaluation of the resistance of a geopolymer-based drug delivery system to tampering2014In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 465, no 1-2, 169-174 p.Article in journal (Refereed)
    Abstract [en]

    Tamper-resistance is an important property of controlled-release formulations of opioid drugs. Tamper-resistant formulations aim to increase the degree of effort required to override the controlled release of the drug molecules from extended-release formulations for the purpose of non-medical use. In this study, the resistance of a geopolymer-based formulation to tampering was evaluated by comparing it with a commercial controlled-release tablet using several methods commonly used by drug abusers. Because of its high compressive strength and resistance to heat, much more effort and time was required to extract the drug from the geopolymer-based formulation. Moreover, in the drug-release test, the geopolymer-based formulation maintained its controlled-release characteristics after milling, while the drug was released immediately from the milled commercial tablets, potentially resulting in dose dumping. Although the tampering methods used in this study does not cover all methods that abuser could access, the results obtained by the described methods showed that the geopolymer matrix increased the degree of effort required to override the controlled release of the drug, suggesting that the formulation has improved resistance to some common drug-abuse tampering methods. The geopolymer matrix has the potential to make the opioid product less accessible and attractive to non-medical users.

  • 22.
    Cai, Bing
    et al.
    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.
    Bredenberg, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Mellgren, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    The effect of curing conditions on compression strength and porosity of metakaolin-based geopolymers2013In: Developments in Strategic Materials and Computational Design IV, John Wiley & Sons, 2013Conference paper (Refereed)
    Abstract [en]

    Geopolymers have been suggested to use as construction, waste treatment and fire proof materials and even drug delivery material due to its excellent mechanical strength, chemical stability and flame resistance. The aim of this study was to investigate the influence of temperature, time and humidity during curing on mechanical strength and porosity of geopolymers.

    The geopolymer precursor paste was obtained by mixing metakaolin, waterglass and de-ionized water. The paste was molded into cylindrical rubber moulds (6  12 mm) and cured under different conditions: i.e. temperatures (ambient temperature, 37°C and 90°C), humidity and time (24, 48 and 96 hours). The compressive strength was determined using a universal testing machine. Helium pycnometer was used to measure the porosity. Via x-ray diffraction the phase composition of the cured samples was determined.

    Elongated curing slightly decreased the total porosity of the tested geopolymers. Higher curing temperature increased the compressive strength after 24 hour but did not affect strength for longer curing times. In general, the samples cured in moisture had higher mechanical strength than those cured in air. But low compression strength of samples cured under high temperature and long time showed that some water content in geopolymer was essential to retaining its microstructure.

  • 23.
    Cai, Bing
    et al.
    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.
    Bredenberg, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Li, Hao
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Otolaryngology and Head and Neck Surgery.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Bioceramic microneedles with flexible and self-swelling substrate2015In: European journal of pharmaceutics and biopharmaceutics, ISSN 0939-6411, E-ISSN 1873-3441, Vol. 94, 404-410 p.Article in journal (Refereed)
    Abstract [en]

    To reduce the effort required to penetrate the skin and optimize drug release profiles, bioceramic microneedle arrays with higher-aspect-ratio needles and a flexible and self-swelling substrate have been developed. Swelling of the substrate can assist in separating it from the needles and leave them in the skin as a drug depot. The preparation procedures for this bioceramic microneedle are described in the paper. Clonidine hydrochloride, the model drug, was released in a controlled manner by the microneedle device in vitro. Results showed that the microneedle array with a flexible and self-swelling substrate released the drug content faster than the array with a rigid substrate. Disintegration of the needle material and diffusion of the drug molecules are believed as the main control mechanisms of the drug release from these microneedle arrays. Ex vivo skin penetration showed that they can effectively penetrate the stratum corneum without an extra device. This work represents a progression in the improvement of bioceramic microneedles for transdermal drug delivery.

  • 24.
    Cai, Yanling
    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.
    Strømme, Maria
    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.
    Biofilm elimination and detachment using photocatalytic TiO2 surfaces2011In: Conference, 2011Conference paper (Refereed)
  • 25.
    Cai, Yanling
    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.
    Strømme, Maria
    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.
    Biofilm susceptibility to photocatalytic dental mateirals2011In: Conference, 2011Conference paper (Refereed)
  • 26.
    Cai, Yixiao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Edin, Fredrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Otolaryngology and Head and Neck Surgery.
    Jin, Zhe
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Physiology.
    Alexsson, Andrei
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Rheumatology.
    Gudjonsson, Olafur
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Liu, Wei
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Otolaryngology and Head and Neck Surgery.
    Rask-Andersen, Helge
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Otolaryngology and Head and Neck Surgery.
    Karlsson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Li, Hao
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Otolaryngology and Head and Neck Surgery.
    Strategy towards independent electrical stimulation from cochlear implants: Guided auditory neuron growth on topographically modified nanocrystalline diamond2016In: Acta Biomaterialia, ISSN 1742-7061, E-ISSN 1878-7568, Vol. 31, 211-220 p.Article in journal (Refereed)
    Abstract [en]

    Cochlear implants (CI) have been used for several decades to treat patients with profound hearing loss. Nevertheless, results vary between individuals, and fine hearing is generally poor due to the lack of discrete neural stimulation from the individual receptor hair cells. A major problem is the deliverance of independent stimulation signals to individual auditory neurons. Fine hearing requires significantly more stimulation contacts with intimate neuron/electrode interphases from ordered axonal re-growth, something current CI technology cannot provide.

    Here, we demonstrate the potential application of micro-textured nanocrystalline diamond (NCD) surfaces on CI electrode arrays. Such textured NCD surfaces consist of micrometer-sized nail-head-shaped pillars (size 5 5 lm2) made with sequences of micro/nano-fabrication processes, including sputtering, photolithography and plasma etching.

    The results show that human and murine inner-ear ganglion neurites and, potentially, neural progenitor cells can attach to patterned NCD surfaces without an extracellular matrix coating. Microscopic methods revealed adhesion and neural growth, specifically along the nail-head-shaped NCD pillars in an ordered manner, rather than in non-textured areas. This pattern was established when the inter-NCD pillar distance varied between 4 and 9 lm.

    The findings demonstrate that regenerating auditory neurons show a strong affinity to the NCD pillars, and the technique could be used for neural guidance and the creation of new neural networks. Together with the NCD’s unique anti-bacterial and electrical properties, patterned NCD surfaces could provide designed neural/electrode interfaces to create independent electrical stimulation signals in CI electrode arrays for the neural population.

  • 27. Capece, Sabrina
    et al.
    Chiessi, Ester
    Cavalli, Roberta
    Giustetto, Pierangela
    Grishenkov, Dmitry
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Paradossi, Gaio
    A general strategy for obtaining biodegradable polymer shelled microbubbles as theranostic devices2013In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 49, no 51, 5763-5765 p.Article in journal (Refereed)
    Abstract [en]

    Fabrication of multifunctional ultrasound contrast agents (UCAs) has been recently addressed by several research groups. A versatile strategy for the synthesis of UCA precursors in the form of biodegradable vesicles with a biocompatible crosslinked polymer shell is described. Upon ultrasound irradiation, acoustic droplet vaporization transforms such particles into microbubbles behaving as UCAs. This proof of concept entails the features of a potential theranostic microdevice.

  • 28. Capese, Sabrina
    et al.
    Chiessi, E.
    Cavalli, R.
    Giustetto, P.
    Grishenkov, Dmitry
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Paradossi, Gaio
    Diapartimento di Chimica, Università di Roma Tor Vergata.
    A general strategy for the obtainment of biodegradable polymer shelled microbubbles as theranostic device2013Conference paper (Refereed)
    Abstract [en]

    Introduction

    Fabrication of multifunctional ultrasound contrast agents (UCAs) has been addressed by many research groups.1,2 Recently a poly(vinyl alcohol) shelled microbubble 3 has shown a remarkable chemical and physical stability and versatility for the surface functionalization, leading to a platform for multimodality imaging (ultrasounds, magnetic resonance, single photon emission computer tomography) and targeting inflammation and tumours4. In this contribution we present a new strategy for the synthesis of UCAs precursors in the form of vesicles with a biodegradable crosslinked polymer shell.

    Methods

    Deposition of methacryloyl-derivative of hydrophilic and biodegradable polymers as dextran (DexMA50) or hyaluronic acid (HAMA30) on a lipid vesicle with a liquid perfluoropentane core, 5,6 followed by a photopolymerization of the methacrylate moiety allows the obtainment of polymer shelled vesicles.

    Results

    Lipid shelled vesicles with a perfluorocarbon (PFC) core (Figure 1a) undergo an acoustic droplet vaporization (ADV),7 upon ultrasounds (US) irradiation, transforming such particles into ultrasound effective microbubbles (Fig 1b). The process is reversible as the US are switched off (Fig 1c). In the “microbubble” state, i.e. during US irradiation, the system is echogenic at low mechanical index, allowing their use as UCAs. In this contribution we show that additional functions can be implemented into the microbubbles. For example, we demonstrated the possibility to obtain shells with a thermoreversible behaviour.

    Conclusions

    This new class of polymer shelled vesicles/microbubbles entails features desired in a potential theranostic microdevice.

  • 29.
    Cardemil, Carina
    et al.
    Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden, Department of Oral and Maxillofacial Surgery, Örebro University Hospital, Örebro, Sweden, BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Gothenburg, Sweden .
    Elgali, Ibrahim
    Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden, BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Gothenburg, Sweden.
    Xia, Wei
    Applied Materials Science, Department of Engineering Sciences, Uppsala University, Uppsala, Sweden, BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Gothenburg, Sweden.
    Emanuelsson, Lena
    Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden, BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Gothenburg, Sweden.
    Norlindh, Birgitta
    Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden, BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Gothenburg, Sweden.
    Omar, Omar
    Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden, BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Gothenburg, Sweden.
    Thomsen, Peter
    Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden, BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Gothenburg, Sweden .
    Strontium-doped calcium phosphate and hydroxyapatite granules promote different inflammatory and bone remodelling responses in normal and ovariectomised rats2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 12, e84932Article in journal (Refereed)
    Abstract [en]

    The healing of bone defects may be hindered by systemic conditions such as osteoporosis. Calcium phosphates, with or without ion substitutions, may provide advantages for bone augmentation. However, the mechanism of bone formation with these materials is unclear. The aim of this study was to evaluate the healing process in bone defects implanted with hydroxyapatite (HA) or strontium-doped calcium phosphate (SCP) granules, in non-ovariectomised (non-OVX) and ovariectomised (OVX) rats. After 0 (baseline), six and 28d, bone samples were harvested for gene expression analysis, histology and histomorphometry. Tumour necrosis factor-α (TNF-α), at six days, was higher in the HA, in non-OVX and OVX, whereas interleukin-6 (IL-6), at six and 28d, was higher in SCP, but only in non-OVX. Both materials produced a similar expression of the receptor activator of nuclear factor kappa-B ligand (RANKL). Higher expression of osteoclastic markers, calcitonin receptor (CR) and cathepsin K (CatK), were detected in the HA group, irrespective of non-OVX or OVX. The overall bone formation was comparable between HA and SCP, but with topological differences. The bone area was higher in the defect centre of the HA group, mainly in the OVX, and in the defect periphery of the SCP group, in both non-OVX and OVX. It is concluded that HA and SCP granules result in comparable bone formation in trabecular bone defects. As judged by gene expression and histological analyses, the two materials induced different inflammatory and bone remodelling responses. The modulatory effects are associated with differences in the spatial distribution of the newly formed bone.

  • 30.
    Carlsson, Elin
    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.
    Mestres, Gemma
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Treerattrakoon, Kiatnida
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Orthopaedics.
    Lopez, Alejandro
    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.
    Larsson, Sune
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Orthopaedics.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    In vitro and in vivo response to low-modulus PMMA-based bone cement2015In: BioMed Research International, ISSN 2314-6133, E-ISSN 2314-6141, 594284Article in journal (Refereed)
    Abstract [en]

    The high stiffness of acrylic bone cements has been hypothesized to contribute to the increased number of fractures encountered after vertebroplasty, which has led to the development of low-modulus cements. However, there is no data available on the in vivo biocompatibility of any low-modulus cement. In this study, the in vitro cytotoxicity and in vivo biocompatibility of two types of low-modulus acrylic cements, one modified with castor oil and one with linoleic acid, were evaluated using human osteoblast-like cells and a rodent model, respectively. While the in vitro cytotoxicity appeared somewhat affected by the castor oil and linoleic acid additions, no difference could be found in the in vivo response to these cements in comparison to the base, commercially available cement, in terms of histology and flow cytometry analysis of the presence of immune cells. Furthermore, the in vivo radiopacity of the cements appeared unaltered. While these results are promising, the mechanical behavior of these cements in vivo remains to be investigated.

  • 31.
    Carlström, Mikael
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    Wargsjö, Hampus
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    Printing Prosthetics: Designing an additive manufactured arm for developing countries2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The traditional prosthetic arms that are being fitted in developing countries are facing major issues in suppling patients with proper assistive aids. Not only is the process time consuming with every single unit having to be customized for the user but some parts can’t be locally produced which drives up price even further. The objective of this master thesis was to develop a prosthetic arm for developing countries with the help of additive manufacturing (3D printing) for the client 3D Life Prints which are based in Nairobi, Kenya. A prosthesis is used to aid an amputee in daily living activities. With additive manufacturing the intention is that a local manufacturing process could be developed and improved which would reduce the time of fitting and distributing a prosthesis. The initial prosthesis, that was the origin of the design, was a below elbow prosthetic arm that was being developed by the client. The prosthesis was fabricated with the additive manufacturing process fused deposition modelling (FDM) which has the advantage of providing the cheapest printers. To summarize the aim of the project the research questions that was established was as followed

    1. How are conventional prosthetic arms generally being manufactured, distributed and used compared to additive manufactured prostheses in Nairobi, Kenya? 

    2. Who is the primary user of prosthetic arms in developing countries, what problems are they facing with current solutions and what factors are considered as the most important? And why?

    3. How should additive manufactured prostheses be designed for optimal usage in developing countries?

    In addition to answer the research questions the aim was that the development of the system would lead to enhanced functionality for the user and to facilitate manufacturing for the organization.

    To get a general overview of additive manufacturing prostheses the fields theories that was studied included context of developing countries, user centred design (since the aim was to approve on a product which needed to suit a specific user), upper limb prostheses and additive manufacturing. As a result, from different stages of the design process a final design was reached called the “3D Life Arm”.  The final system was comprised of four main components, the Harness system, the Insert, the Cover and the Socket. These components used additive manufacturing in both rigid material (Harness parts, Socket and Insert) and flexible material (the Cover). Locally available components were used for parts not feasible to additive manufacture e.g. fishing wire and screws. The two factors that were concluded to be the most important for the user were the aesthetic appeal and cost. With social stigmas playing a major part according to users and experts in Nairobi, the prosthesis needs to resemble the missing limb as much as possible. It was concluded that cost was the major factor when designing prostheses for developing countries since user just wasn’t able to afford the prostheses that was being manufactured in Nairobi. In the end a cost and time analysis was conducted to verify what price the complete system would need to be manufactured. With three printers all parts could be printed for the price of 282 SEK and would take approximately 15 hours and 15 minutes to print which is considerably lower than that of the functional prosthesis being distributed in Nairobi. Further evaluations need to be done to establish that the prosthesis will manage the strains and stresses of daily living activities of the user and a complete fitting strategy needs to be evaluated further. It’s the authors belief however, that with the help of fully educated prosthetist there is a future for additive manufacturing of upper limb amputees. 

  • 32.
    Chen, Song
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Yu, Shun
    Engqvist, Håkan
    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.
    Synthesis and characterization of monetite with thin nacreous structure2016Conference paper (Refereed)
  • 33.
    Chen, Song
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Öhman, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Jefferies, Steven R.
    Gray, Holly
    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.
    Quasi-static compressive strength and compressive fatigue limit of dental cements2016Conference paper (Refereed)
  • 34.
    Chudinova, Ekaterina
    et al.
    Tomsk Polytechnic University, Tomsk, Russia.
    Surmeneva, Maria
    Tomsk Polytechnic University, Tomsk, Russia.
    Koptyug, Andrey
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Skoglund, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Sharanova, A
    Tomsk Polytechnic University, Tomsk, Russia.
    Loza, K
    University of Duisburg-Essen, Germany.
    Epple, M
    University of Duisburg-Essen, Germany.
    Surmenev, Roman
    Tomsk Polytechnic University, Tomsk, Russia.
    Hydroxyapatite coating and silver nanoparticles assemblies on additively manufactured Ti6Al4V scaffolds2015Conference paper (Other academic)
  • 35. Clemente, Francesco
    et al.
    D'Alonzo, Marco
    Controzzi, Marco
    Edin, Benoni B.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology.
    Cipriani, Christian
    Non-Invasive, Temporally Discrete Feedback of Object Contact and Release Improves Grasp Control of Closed-Loop Myoelectric Transradial Prostheses2016In: IEEE transactions on neural systems and rehabilitation engineering, ISSN 1534-4320, E-ISSN 1558-0210, Vol. 24, no 12, 1314-1322 p.Article in journal (Refereed)
    Abstract [en]

    Human grasping and manipulation control critically depends on tactile feedback. Without this feedback, the ability for fine control of a prosthesis is limited in upper limb amputees. Although various approaches have been investigated in the past, at present there is no commercially available device able to restore tactile feedback in upper limb amputees. Based on the Discrete Event-driven Sensory feedback Control (DESC) policy we present a device able to deliver short-lasting vibrotactile feedback to transradial amputees using commercially available myoelectric hands. The device (DESC-glove) comprises sensorized thimbles to be placed on the prosthesis digits, a battery-powered electronic board, and vibrating units embedded in an arm-cuff being transiently activated when the prosthesis makes and breaks contact with objects. The consequences of using the DESC-glove were evaluated in a longitudinal study. Five transradial amputees were equipped with the device for onemonth at home. Through a simple test proposed here for the first time-the virtual eggs test-we demonstrate the effectiveness of the device for prosthetic control in daily life conditions. In the future the device could be easily exploited as an add-on to complement myoelectric prostheses or even embedded in prosthetic sockets to enhance their control by upper limb amputees.

  • 36.
    Cronskär, Marie
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Production of Customized Hip Stem Prostheses: a Comparison Between Machining and Additive Manufacturing2013In: Rapid prototyping journal, ISSN 1355-2546, E-ISSN 1758-7670, Vol. 19, no 5, 365-372 p.Article in journal (Refereed)
    Abstract [en]

    Purpose - The purpose of this paper is to study the use of the additive manufacturing (AM) method, electron beam melting (EBM), for manufacturing of customized hip stems. The aim is to investigate EBM's feasibility and commercial potential in comparison with conventional machining, and to map out advantages and drawbacks of using EBM in this application. One part of the study concerns the influence on the fatigue properties of the material, when using the raw surface directly from the EBM machine, in parts of the implant.Design/methodology/approach - The research is based on a case study of manufacturing a batch of seven individually adapted hip stems. The stems were manufactured both with conventional machining and with EBM technology and the methods were compared according to the costs of materials, time for file preparation and manufacturing. In order to enhance bone ingrowths in the medial part of the stem, the raw surface from EBM manufacturing is used in that area and initial fatigue studies were performed, to get indications on how this surface influences the fatigue properties.Findings - The cost reduction due to using EBM in this study was 35 per cent. Fatigue tests comparing milled test bars with raw surfaced bars indicate a reduction of the fatigue limit by using the coarse surface.Originality/value - The paper presents a detailed comparison of EBM and conventional machining, not seen in earlier research. The fatigue tests of raw EBM-surfaces are interesting since the raw surface has shown to enhance bone ingrowths and therefore is suitable to use in some medical applications.

  • 37. Dal Maso, Fabien
    et al.
    Raison, Maxime
    Lundberg, Arne
    Arndt, Anton
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Begon, Mickaël
    Coupling between 3D displacements and rotations at the glenohumeral joint during dynamic tasks in healthy participants.2014In: Clinical Biomechanics, ISSN 0268-0033, E-ISSN 1879-1271, Vol. 29, no 9, 1048-1055 p.Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Glenohumeral displacements assessment would help to design shoulder prostheses with physiological arthrokinematics and to establish more biofidelic musculoskeletal models. Though displacements were documented during static tasks, there is little information on their 3D coupling with glenohumeral angle during dynamic tasks. Our objective was to characterize the 3D glenohumeral displacement-rotation couplings during dynamic arm elevations and rotations.

    METHODS: Glenohumeral displacements were measured from trajectories of reflective markers fitted on intracortical pins inserted into the scapula and humerus. Bone geometry was recorded using CT-scan. Only four participants were recruited to the experiment due to its invasiveness. Participants performed dynamic arm abduction, flexion and axial rotations. Linear regressions were performed between glenohumeral displacements and rotations. The pin of the scapula of one participant moved, his data were removed from analysis, and results are based on three participants.

    FINDINGS: The measurement error of glenohumeral kinematics was less than 0.15mm and 0.2°. Maximum glenohumeral displacements were measured along the longitudinal direction and reached up to +12.4mm for one participant. Significant couplings were reported especially between longitudinal displacement and rotation in abduction (adjusted R(2) up to 0.94).

    INTERPRETATION: The proposed method provides the potential to investigate glenohumeral kinematics during all kinds of movements. A linear increase of upward displacement during dynamic arm elevation was measured, which contrasts with results based on a series of static poses. The systematic investigation of glenohumeral displacements under dynamic condition may help to provide relevant recommendation for the design of shoulder prosthetic components and musculoskeletal models.

  • 38.
    Dehestani, Mahdi
    et al.
    Purdue University.
    Zemlyanov, Dmitry Yu
    Purdue University.
    Adolfsson, Erik
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    Stanciu, Lia A.
    Purdue University.
    Improving bioactivity of inert bioceramics by a novel Mg-incorporated solution treatment2017In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 425, 564-575 p.Article in journal (Refereed)
    Abstract [en]

    Zirconia/alumina ceramics possess outstanding mechanical properties for dental and orthopedic applications, but due to their poor surface bioactivities they exhibit a weak bone-bonding ability. This work proposes an effective 30-min solution treatment which could successfully induce formation of bone-like apatite on the surface of 3Y-TZP and a ternary composite composed of yttria-stabilized zirconia, ceria-stabilized zirconia, and alumina (35 vol% 3Y-TZP + 35 vol% 12Ce-TZP + 30 vol% Al2O3) after 3 weeks immersion in simulated body fluid (SBF). XRD was used for phase identification in the ceramic materials. The influence of solution treatment on the surface chemistry and its role on apatite formation were investigated via SEM, EDS and XPS. In vitro apatite-forming ability for the solution-treated and untreated samples of the composite and individual substrates of 3Y-TZP, 12Ce-TZP, and Al2O3 was evaluated by immersion in SBF. Apatite crystals were formed only on 3Y-TZP and composite substrates, implying that it is mainly the 3Y-TZP constituent that contributes to the bioactivity of the composite. Further, it was found from the XPS analysis that the zirconia material with higher phase stability (12Ce-TZP) produced less Zr–OH functional groups on its surface after solution treatment which accounts for its weaker bioactivity compared to 3Y-TZP. 

  • 39.
    Dranvik, Madeleine
    et al.
    Jönköping University, School of Health and Welfare, HHJ. Prosthetics and Orthotics.
    Nyholm, Hanna
    Jönköping University, School of Health and Welfare, HHJ. Prosthetics and Orthotics.
    Jämförelse av två ankelortosers inversionsrestriktion före och efter fysisk aktivitet2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 40.
    Ek, Rebecca
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Hong, Jaan
    Uppsala University, Immunology, Genetics and Pathology.
    Dejanovic, Slavko
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Blood coagulation on electron beam melted implant surfaces, implications for bone growth2011In: Proccedings of EBS 2011, Dublin, 2011Conference paper (Other academic)
    Abstract [en]

    INTRODUCTION

    Implants for arthroplasty, plates and screws for orthopedics, maxillofacial and dentistry are more frequently being customised. Ti and CoCr alloys are common materials for bone implants. Surface roughness, porosity and choice of material may have an impact on the bone ingrowth. EBM (Electron Beam Melting) is a 3D-printing technique melting metallic powder layer by layer according to the corresponding CAD (Computer Aided Design) model of implants1.With EBM technology customised implants can be manufactured with a lower cost compared to conventional technologies2. Implants for bone replacement made from CT images with EBM technology will fit accurate and lead to simpler and better planed surgeries also3. The EBM technique, as such, is always resulting with rough surface on the implants (typically 20-45µm). That roughness can be controlled, in some extent, by changing the process parameters. Some authors claim that roughened surfaces are promoting bone ingrowth4.

    This work was aiming on the question: are EBM made surfaces good for bone ingrowth and is it possible to change the bone ingrowth by varying the machine settings? In order to answer this question a number of coin like specimens of CoCr were manufactured with the different surface roughness. The blood chamber model has shown how the first steps of bone healing were proceeding on specimen surfaces, indicating how the coagulation and complement systems can behave in vivo5.

     

    EXPERIMENTAL METHODS

    The manufacture of the test specimens was carried out with Arcam A2 EBM® equipment.  Process parameters were changed in the software EBM controle6 and three groups of eight specimens with different parameter setting were made. The specimens were then tested with whole blood from two individuals in a modified version of the blood chamber model named above7. Surface roughness was characterised with a stylus profiler Dektak® 6M.

     

    RESULTS AND DISCUSSION

    Table 1 percents Ra (average roughness) and plt (platelets) activated for each group.

     

                                             Table 1

    group         Ra mean      std                    plt mean   std

    1              35.0µm        3.24µm           92.9%       5.25%

    2              28.5µm        2.14µm           85.3%       7.61%

    3              28.2µm        1.75µm           84.4%       10.3%

     

    The results indicate that rougher surfaces are more thrombogenic which could imply that they are more suitable for bone ingrowth then smooth surfaces. Increase of total surface area (due to larger roughness) might be a reason for the improved trombogenic response.

     

     

    Figure 1 shows how many platelets were stuck on the specimen surfaces. Horizontal lines represent mean values and standard deviation.

     

    CONCLUSION

    The surface properties of EBM produced implants are affected by the made parameters. The results in Figure 1 corresponds well with previous results that rougher surfaces promotes bone ingrowth4. The increased thrombogenicity and platelet binding with rougher surfaces indicates that EBM made surfaces can affect the final bone response and will possibly suit as implant material.

     

    REFERENCES

    1. Raennar, L.E., et al., Efficientcooling with tool inserts manufactured by electronbeam melting. Rapid Prototyping Journal. 13:128-35, 2007

    2. Cronskaer, M. Applications of Electron Beam Melting to Titanium Hip Stem Implants

    3. Mazzoli, A., et al., Direct fabrication through electron beam melting technology of custom cranial implants designed in a PHANToM-based haptic environment. Materials and Design. 30:318-3192, 2009

    4. Frosch, K.H., et al., Metallic Biomaterials in Skeletal Rapair. Eur J Trauma. 32:149-59, 2006

    5. Thor A., et al.. The role of whole blood in thrombin generation in contact with various titanium surfaces. Biomaterials. 28:966-97, 2007

    6. Arcam AB (www.arcam.com)

    7. Hong, J., et al., A new in vitro model to study interaction between whole blood and biomaterials. Studies of platelet and coagulation activation acid the effect of aspirin. Biomaterials. 20:603-611, 1999

  • 41.
    Engstrand Unosson, Johanna
    et al.
    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.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    An evaluation of methods to determine the porosity of calcium phosphate cements2015In: Journal of Biomedical Materials Research. Part B - Applied biomaterials, ISSN 1552-4973, E-ISSN 1552-4981, Vol. 103, no 1, 62-71 p.Article in journal (Refereed)
    Abstract [en]

    The porosity of a material can be determined using a diversity of methods; however, the results from these methods have so far not been compared and analyzed for calcium phosphate cements (CPCs). The aim of this study was to compare a fast and easy method for porosity measurements with some commonly used porosity methods for CPCs. The investigated method is based on the assumption that when a wet cement sample is dried, the volume of the evaporated water is equal to the volume of pores within the cement. Moreover, different methods of drying the cements were evaluated for acidic CPCs. The results showed that drying at room temperature (22°C ±1°C) is preferable, since a phase transformation was observed at higher temperatures. The results also showed that drying for 24 hours in vacuum was sufficient to achieve water free cements. The porosity measured was found to vary between the porosity methods evaluated herein, and to get a complete picture of a cement’s porosity more than one method is recommended. Water evaporation, is, however, a fast and easy method to estimate the porosity of CPCs and could simplify porosity measurements in the future.

  • 42.
    Eriksson, Siw
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Sandsjö, Leif
    University of Borås, Faculty of Caring Science, Work Life and Social Welfare. MedTech West.
    Three-dimensional Fabrics as Medical Textiles2015In: Advances in 3D Textiles: A volume in Woodhead Publishing Series in Textiles / [ed] X. Chen, Woodhead Publishing Limited, 2015, 305-340 p.Chapter in book (Other academic)
    Abstract [en]

    The number of 3D textile applications in medicine is rapidly increasing as new technology and procedures are introduced in health care.  A first estimate of current medical applications of both general and 3D textiles is presented based on the medical devices classification system established by the US Food and Drug Administration. The textile specifics for these applications are covered from a textile technique perspective where the different 3D weaving as well as knitting, braiding and non-woven techniques are described and how their properties they can contribute in medical applications. In addition, emerging opportunities based on smart textiles as part of textile systems are described on a general level. The strong application areas of 3D medical textiles, i.e. wound management, vascular grafting and scaffolding for tissue engineering are covered in detail both from the medical and textiles perspective. Finally, some future lines of development are suggested and a short discussion on how new 3D textiles applications can be developed in close cooperation between the textile industry and the health care sector is presented.

  • 43.
    Errando-Herranz, Carlos
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Vastesson, Alexander
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Zelenina, Marina
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics.
    Pardon, Gaspard
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Bergström, Gunnar
    Wijngaart, Wouter van der
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Haraldsson, Tommy
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Brismar, Hjalmar
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics.
    Gylfason, Kristinn B.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Biocompatibility of OSTE polymers studied by cell growth experiments2013In: Proceedings of the 17th Int. Conf. on Miniaturized Systems for Chemistry  and Life Sciences (microTAS), Freiburg, Germany, 2013Conference paper (Refereed)
    Abstract [en]

    The recently introduced OSTE polymer technology has shown very useful features for microfluidics for lab-on-a-chip applications. However, no data has yet been published on cell viability on OSTE. In this work, we study the biocompatibility of three OSTE formulations by cell growth experiments. Moreover, we investigate the effect of varying thiol excess on cell viability on OSTE surfaces. The results show poor cell viability on one OSTE formulation, and viability comparable with polystyrene on a second formulation with thiol excess below 60%. In the third formulation, we observe cell proliferation. These results are promising for cell-based assays in OSTE microfluidic devices.

  • 44.
    Ferraz, Natalia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Hoess, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Thormann, Annika
    Heilmann, Andreas
    Shen, Jinhui
    Tang, Liping
    Karlsson Ott, Marjam
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Role of Alumina Nanoporosity in Acute Cell Response2011In: Journal of Nanoscience and Nanotechnology, ISSN 1533-4880, Vol. 11, no 8, 6698-6704 p.Article in journal (Refereed)
    Abstract [en]

    This work studied the effect of nanoporous alumina in acute cellular response in an in vivo model. Nanoporous alumina membranes, with pore size diameters of 20 and 200 nm, were fabricated by anodic oxidation of aluminium. The membranes were thereafter characterized in terms of pore size distribution and chemical composition. To evaluate acute inflammatory response, the membranes were implanted in the peritoneal cavity of mice. Cell recruitment to the implant site was determined by fluorescence activated cell sorting (FACS) analysis. Cell adhesion to material surfaces was studied in terms of cell number, type, and morphology using scanning electron microscopy (SEM) and immunocytochemical staining followed by fluorescence microscopy. The fabricated nanoporous alumina membranes were found to have narrow pore size distribution. The in vivo study showed that 200 nm alumina membranes induced stronger inflammatory response than 20 nm membranes. This was reflected by the number of implant-associated phagocytes and the number of cells recruited to the implantation site. Since both pore-size membranes possess similar chemical composition, we believe that the observed difference in cell recruitment and adhesion is an effect of the material nanotopography. Our results suggest that nanotopography can be used to subtly control the recruitment and adherence of phagocytic cells during the acute inflammatory response to alumina membranes.

  • 45.
    Ferraz, Natalia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Fellström, Bengt
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences.
    Pradhan, Sulena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    In vitro and in vivo toxicity of rinsed and aged nanocellulose-polypyrrole composites2012In: Journal of Biomedical Materials Research. Part A, ISSN 1549-3296, Vol. 100A, no 8, 2128-2138 p.Article in journal (Refereed)
    Abstract [en]

    Novel composites of nanocellulose and the conducting polymer polypyrrole (PPy) are herein suggested as potential candidates for active ion-extraction membranes in electrochemically controlled hemodialysis. This work has defined processing parameters to obtain a biocompatible nanocellulose-PPy composite and for the first time, the effect of the composite ageing on cell viability has been studied.

    The influence of rinsing and extraction process steps, as well as ageing under different conditions (i.e. in air, at –20 ˚C and in argon), on the electroactivity and cytotoxicity of a PPy-nanocellulose composite has been investigated. The biocompatibility evaluation was based on indirect toxicity assays with fibroblasts and monocyte cell lines and an acute toxicity test in mice, while the electroactivity was evaluated by cyclic voltammetry experiments.

    The as-prepared composite did not induce any cytotoxic response in vitro or in vivo. Extensive rinsing and 48 hour incubation in biological buffer previous to the preparation of the culture medium extracts were, however, necessary to obtain a non-cytotoxic composite. The as-prepared composite was also found to exhibit acceptable electrochemical performance, which was retained upon 4 weeks storage in argon atmosphere.  It was shown that ageing of the composite had a negative effect on biocompatibility, regardless of the storage condition. Thus, to allow for long time storage of electroactive nanocellulose-PPy hemodialysis membranes, the degradation of PPy upon storage must be controlled. The present results show that the biocompatibility of PPy composites depends on the rinsing and pre-treatment of the composite material as well as the aging of the material.

  • 46.
    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, 11-15 p.Article 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.

  • 47.
    Fredriksson, Ingemar
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Larsson, Marcus
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Strömberg, Tomas
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Inverse Monte Carlo method in a multilayered tissue model for diffuse reflectance spectroscopy2012In: Journal of Biomedical Optics, ISSN 1083-3668, Vol. 17, no 4, 047004- p.Article in journal (Refereed)
    Abstract [en]

    Model based data analysis of diffuse reflectance spectroscopy data enables the estimation of optical and structural tissue parameters. The aim of this study was to present an inverse Monte Carlo method based on spectra from two source-detector distances (0.4 and 1.2 mm), using a multilayered tissue model. The tissue model variables include geometrical properties, light scattering properties, tissue chromophores such as melanin and hemoglobin, oxygen saturation and average vessel diameter. The method utilizes a small set of presimulated Monte Carlo data for combinations of different levels of epidermal thickness and tissue scattering. The path length distributions in the different layers are stored and the effect of the other parameters is added in the post-processing. The accuracy of the method was evaluated using Monte Carlo simulations of tissue-like models containing discrete blood vessels, evaluating blood tissue fraction and oxygenation. It was also compared to a homogeneous model. The multilayer model performed better than the homogeneous model and all tissue parameters significantly improved spectral fitting. Recorded in vivo spectra were fitted well at both distances, which we previously found was not possible with a homogeneous model. No absolute intensity calibration is needed and the algorithm is fast enough for real-time processing.

  • 48.
    Fu, Le
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Andersson, Martin
    Unosson, Erik
    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.
    Engqvist, Håkan
    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.
    Influence of alkali metal additives on phase transition of translucent ZrO2/SiO2 glass ceramics prepared by a sol-gel method2015In: European Cells and Materials, ISSN 1473-2262, E-ISSN 1473-2262, Vol. 29, no S1, 10- p.Article in journal (Refereed)
  • 49.
    Fu, Le
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Andersson, Martin
    Unosson, Erik
    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.
    Engqvist, Håkan
    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.
    Influences of alkali metals additives on phase transition of translucent ZrO2/SiO2 glass ceramic prepared by sol-gel method2015Conference paper (Refereed)
  • 50.
    Fu, Le
    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.
    Wu, Chengtie
    Grandfield, Kathryn
    McMaster University.
    Chang, Jiang
    Engqvist, Håkan
    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.
    Spark plasma sintering consolidated transparent ZrO2- SiO2 glass ceramic containing nano-sized ZrO2 spheres2016Conference paper (Refereed)
1234 1 - 50 of 186
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