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  • 1.
    Andersson, Håkan S.
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Figueredo, Sharel M.
    Haugaard-Kedström, Linda M.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Bengtsson, Elina
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Daly, Norelle L.
    Qu, Xiaoqing
    Craik, David J.
    Ouellette, Andre J.
    Rosengren, K. Johan
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    The alpha-defensin salt-bridge induces backbone stability to facilitate folding and confer proteolytic resistance2012In: Amino Acids, ISSN 0939-4451, E-ISSN 1438-2199, Vol. 43, no 4, p. 1471-1483Article in journal (Refereed)
    Abstract [en]

    Salt-bridge interactions between acidic and basic amino acids contribute to the structural stability of proteins and to protein-protein interactions. A conserved salt-bridge is a canonical feature of the alpha-defensin antimicrobial peptide family, but the role of this common structural element has not been fully elucidated. We have investigated mouse Paneth cell alpha-defensin cryptdin-4 (Crp4) and peptide variants with mutations at Arg(7) or Glu(15) residue positions to disrupt the salt-bridge and assess the consequences on Crp4 structure, function, and stability. NMR analyses showed that both (R7G)-Crp4 and (E15G)-Crp4 adopt native-like structures, evidence of fold plasticity that allows peptides to reshuffle side chains and stabilize the structure in the absence of the salt-bridge. In contrast, introduction of a large hydrophobic side chain at position 15, as in (E15L)-Crp4 cannot be accommodated in the context of the Crp4 primary structure. Regardless of which side of the salt-bridge was mutated, salt-bridge variants retained bactericidal peptide activity with differential microbicidal effects against certain bacterial cell targets, confirming that the salt-bridge does not determine bactericidal activity per se. The increased structural flexibility induced by salt-bridge disruption enhanced peptide sensitivity to proteolysis. Although sensitivity to proteolysis by MMP7 was unaffected by most Arg(7) and Glu(15) substitutions, every salt-bridge variant was degraded extensively by trypsin. Moreover, the salt-bridge facilitates adoption of the characteristic alpha-defensin fold as shown by the impaired in vitro refolding of (E15D)-proCrp4, the most conservative salt-bridge disrupting replacement. In Crp4, therefore, the canonical alpha-defensin salt-bridge facilitates adoption of the characteristic alpha-defensin fold, which decreases structural flexibility and confers resistance to degradation by proteinases.

  • 2.
    Ankarloo, Jonas
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Wikman, Susanne
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Escherichia coli mar and acrAB Mutants Display No Tolerance to Simple Alcohols2010In: International Journal of Molecular Sciences, ISSN 1422-0067, E-ISSN 1422-0067, Vol. 11, no 4, p. 1403-1412Article in journal (Refereed)
    Abstract [en]

    The inducible Mar phenotype of Escherichia coli is associated with increased tolerance to multiple hydrophobic antibiotics as well as some highly hydrophobic organic solvents such as cyclohexane, mediated mainly through the AcrAB/TolC efflux system. The influence of water miscible alcohols ethanol and 1-propanol on a Mar constitutive mutant and a mar deletion mutant of E. coli K-12, as well as the corresponding strains carrying the additional acrAB deletion, was investigated. In contrast to hydrophobic solvents, all strains were killed in exponential phase by 1-propanol and ethanol at rates comparable to the parent strain. Thus, the Mar phenotype does not protect E. coli from killing by these more polar solvents. Surprisingly, AcrAB does not contribute to an increased alcohol tolerance. In addition, sodium salicylate, at concentrations known to induce the mar operon, was unable to increase 1-propanol or ethanol tolerance. Rather, the toxicity of both solvents was increased in the presence of sodium salicylate. Collectively, the results imply that the resilience of E. coli to water miscible alcohols, in contrast to more hydrophobic solvents, does not depend upon the AcrAB/TolC efflux system, and suggests a lower limit for substrate molecular size and functionality. Implications for the application of microbiological systems in environments containing high contents of water miscible organic solvents, e. g., phage display screening, are discussed.

  • 3.
    Bergström, Maria
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Ganji, Suresh
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Naidu Veluru, Ramesh
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Unelius, C. Rikard
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    N-Iodosuccinimide (NIS) in Direct Aromatic Iodination2017In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, no 22, p. 3234-3239Article in journal (Refereed)
    Abstract [en]

    N-Iodosuccinimide (NIS) in pure trifluoroacetic acid (TFA) offers a time-efficient and general method for the iodination of a wide range of mono-and disubstituted benzenes at room temperature, as demonstrated in this paper. The starting materials were generally converted into mono-iodinated products in less than 16 hours at room temperature, without byproducts. A few deactivated substrates needed addition of sulfuric acid to increase the reaction rate. Another exception was methoxybenzenes that preferentially were iodinated by NIS in acetonitrile with only catalytic amounts of TFA.

  • 4. Cheshev, Pavel
    et al.
    Morelli, Laura
    Marchesi, Marco
    Podlipnik, Crtomir
    Bergström, Maria
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Bernardi, Anna
    Synthesis and affinity evaluation of a small library of bidentate cholera toxin ligands: towards nonhydrolyzable ganglioside mimics2010In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 16, no 6, p. 1951-1967Article in journal (Refereed)
    Abstract [en]

    A small library of nonhydrolyzable mimics of GM1 ganglioside, featuring galactose and sialic acid its pharmacophoric carbohydrate residues,, was synthesized and tested. All compounds were synthesized from readily available precursors using high-performance reactions, including click chemistry protocols, and avoiding O-glycosidic bonds. Sonic of the most active molecules also feature a point of further derivatization that can be used for conjugation will, polyvalent aglycons. Their affinity towards cholera toxin was assessed by weak affinity chromatography, which allowed a systematic evaluation and selection of the best candidates. Affinity could be enhanced up to one or two orders of magnitude over the affinity of the individual pharmacophoric sugar residues.

  • 5.
    Elmlund, Louise
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Suriyanarayanan, Subramanian
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Wiklander, Jesper G.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Aastrup, Teodor
    Attana AB.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Uppsala University.
    Biotin selective polymer nano-films2014In: Journal of Nanobiotechnology, ISSN 1477-3155, E-ISSN 1477-3155, Vol. 12, article id 8Article in journal (Refereed)
    Abstract [en]

    Background: The interaction between biotin and avidin is utilized in a wide range of assay and diagnostic systems. A robust material capable of binding biotin should offer scope in the development of reusable assay materials and biosensor recognition elements. Results: Biotin-selective thin (3-5 nm) films have been fabricated on hexadecanethiol self assembled monolayer (SAM) coated Au/quartz resonators. The films were prepared based upon a molecular imprinting strategy where N, N'-methylenebisacrylamide and 2-acrylamido-2-methylpropanesulfonic acid were copolymerized and grafted to the SAM-coated surface in the presence of biotin methyl ester using photoinitiation with physisorbed benzophenone. The biotinyl moiety selectivity of the resonators efficiently differentiated biotinylated peptidic or carbohydrate structures from their native counterparts. Conclusions: Molecularly imprinted ultra thin films can be used for the selective recognition of biotinylated structures in a quartz crystal microbalance sensing platform. These films are stable for periods of at least a month. This strategy should prove of interest for use in other sensing and assay systems.

  • 6.
    Friedman, Ran
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Ctr Biomat Chem.
    Structural and computational insights into the versatility of cadmium binding to proteins2014In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 43, no 7, p. 2878-2887Article in journal (Refereed)
    Abstract [en]

    Cadmium is a highly toxic group XII metal, similar to zinc and mercury. Unlike zinc, which is one of the most common metal cofactors in biology, cadmium is highly toxic. Many Zn2+-binding proteins can bind Cd2+-ions without significantly affecting their structures. Here, the protein data bank is analysed with regard to protein-cadmium interactions, which shows that cadmium can bind to a variety of ion binding sites in proteins. Statistical analysis of Cd2+-side chain interactions is compared with a similar analysis of other ions. This analysis reveals that with regard to amino acid side-chain preference, Cd2+ is more similar to Mn2+ than to Zn2+ or Hg2+. Finally, the interaction energies of three native metal binding proteins are calculated where Cd2+ binds instead of Zn2+, Ca2+ or Cu2+. The interaction energies are decomposed into individual components whose contributions are discussed.

  • 7.
    Giovannoli, Cristina
    et al.
    Univ Turin, Italy.
    Passini, Cinzia
    Univ Turin, Italy.
    Di Nardo, Fabio
    Univ Turin, Italy.
    Anfossi, Laura
    Univ Turin, Italy.
    Baggiani, Claudio
    Univ Turin, Italy.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Affinity Capillary Electrochromatography of Molecularly Imprinted Thin Layers Grafted onto Silica Capillaries Using a Surface-Bound Azo-Initiator and Living Polymerization2018In: Polymers, ISSN 2073-4360, E-ISSN 2073-4360, Vol. 10, no 2, article id 192Article in journal (Refereed)
    Abstract [en]

    Molecularly imprinted thin layers were prepared in silica capillaries by using two different surface polymerization strategies, the first using 4,4-azobis(4-cyanovaleric acid) as a surface-coupled radical initiator, and the second, S-carboxypropyl-S'-benzyltrithiocarbonate as a reversible addition-fragmentation chain transfer (RAFT) agent in combination with 2,2-azobisisobutyronitrile as a free radical initiator. The ability to generate imprinted thin layers was tested on two different polymerization systems: (i) a 4-vinylpyridine/ethylene dimethacrylate (4VP-EDMA) in methanol-water solution with 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) as a template; and (ii) methacrylic acid/ethylene dimethacrylate (MAA-EDMA) in a chloroform solution with warfarin as the template molecule. The binding properties of the imprinted capillaries were studied and compared with those of the corresponding non-imprinted polymer coated capillaries by injecting the template molecule and by measuring its migration times relative to a neutral and non-retained marker. The role of running buffer hydrophobicity on recognition was investigated by studying the influence of varying buffer acetonitrile concentration. The 2,4,5-T-imprinted capillary showed molecular recognition based on a reversed phase mechanism, with a decrease of the template recognition in the presence of higher acetonitrile content; whereas warfarin-imprinted capillaries showed a bell-shaped trend upon varying the acetonitrile percentage, illustrating different mechanisms underlying imprinted polymer-ligand recognition. Importantly, the results demonstrated the validity of affinity capillary electrochromatography (CEC) to screen the binding properties of imprinted layers.

  • 8.
    Golker, Kerstin
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Olsson, Gustaf D.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Towards Molecular Dynamics-Based Rational Design of Polymeric Recognition Systems2010Conference paper (Refereed)
    Abstract [en]

    Molecular imprinting is a technique used to design polymeric recognition materials with selectivity for a predetermined structure. The molecular imprinting process generates cavities in the polymer matrix that are complementary in size, shape and functionality to the template-structure. The recognition properties of molecularly imprinted polymers (MIPs) are comparable to those of antibodies and enzymes, which make MIPs utilizable in a wide range of application areas including biomimetic assays and biosensors [1]. Previous studies have shown that the prepolymerization step is central for the establishment of high affinity binding sites in MIPs [2]. However, our understanding of the physical mechanisms underlying MIP formation and template recognition is still limited. With the rapid increase of computational power and the development of suitable software molecular dynamics (MD) simulation methods have become a valuable theoretical tool to aid our understanding of the molecular imprinting process, and even in the development of rational design strategies [2]. Recently the first simulation of a complete prepolymerization mixture was presented [3].

    Here we present 10 ns MD simulations of a series of all-component prepolymerization mixtures. The simulated systems were assembled with different molar ratios using the local anaesthetic bupivacaine as the template, methacrylic acid (MAA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the crosslinker, 2,2’-azobis-(2-methylpropionitrile) (AIBN) as the initiator and toluene as the solvent. The simulations were performed using the AMBER (v. 10.0 UCSF, San Francisco, CA) suite of programs (4) and the GAFF [6] force field. Molecular trajectories were evaluated with radial distribution functions and hydrogen bond analysis.

     

     

    References

    1. Alexander, C.; Andersson, H. S.; Andersson, L. I.; Ansell, R. J.; Kirsch, N.; Nicholls, I. A.; O´Mahony, J.; Whitcombe, J., J. Mol. Recognit. (2006), 19, 106-180
    2. Nicholls, I. A.; Andersson, H. S.; Charlton, C.; Henschel, H.; Karlsson, B. C. G.; Karlsson, J. G.; O´Mahony, J.; Rosengren, A. M.; Rosengren, K. J.; Wikman, S. Biosens. Bioelectron. (2009), 25, 543-552
    3. Karlsson, B. C. G.; O´Mahony, J.; Karlsson, J. G.; Bengtsson, H.; Eriksson, L. A.; Nicholls, I. A. J. Am. Chem. Soc. (2009), 131, 13297-13304
    4. Case, D. A.; Cheatham, T. E.; Darden, T.; Gohlke, H.; Luo, R.; Merz, K. M.; Onufriev, A.; Simmerling, C.; Wang, B.; Woods, R. J. Comput. Chem. (2009), 26, 1668-1688
    5. Wang, J.; Wolf, R. M.; Caldwell, J. W.; Kollman, P. A.; Case, D. A. J. Comput. Chem. (2004), 25, 1157-1174

     

  • 9.
    Golker, Kerstin
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Olsson, Gustaf D.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Towards Molecular Dynamics-Based Rational Design of Synthetic Polymer Recognition Systems2010Conference paper (Refereed)
    Abstract [en]

    Molecularly imprinted polymers (MIPs) are polymeric receptors with selectivity for a predetermined structure. The molecular imprinting process generates cavities in a synthetic polymer matrix that are complementary in size, shape and functionality to the template. MIPs exhibit recognition properties analogous to their biological counterparts, such as antibodies, and can be utilized in a wide range of application areas [1]. Nonetheless, the physical mechanisms underlying MIP formation and template recognition are still poorly understood. Molecular dynamics (MD) based computer simulations are a valuable theoretical tool which may be used to aid our understanding of the molecular imprinting process, and even for the development of rational design strategies [2]. Recently the first MD simulation of a complete prepolymerization mixture was presented [3].

    In the present work, MD simulations of a series of all-component prepolymerization mixtures were performed, using the local anaesthetic bupivacaine as the template, methacrylic acid (MAA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the crosslinker, 2,2’-azobis-(2-methylpropionitrile) (AIBN) as the initiator and toluene as the solvent. The simulated systems differed in the molar fraction of MAA. Systems were evaluated with radial distribution functions and hydrogen bond analyses. By correlating the results with the rebinding behaviour of a series of synthesized MIPs the importance of the stoichiometry between template, functional monomer and crosslinker was highlighted. The analysis of the MD simulations revealed strong competition for hydrogen bonding between the carbonyl oxygen’s of MAA and EGDMA and the amide proton of bupivacaine. Moreover, the hydrogen bonding contact between EGDMA and bupivacaine remained nearly unaffected by the varied molar fraction MAA in the different systems demonstrating the role of the crosslinker being more important as generally accepted.

     

    References

    [1]             Alexander, C.; Andersson, H. S.; Andersson, L. I.; Ansell, R. J.; Kirsch, N.; Nicholls, I. A.; O´Mahony, J.; Whitcombe, J., J. Mol. Recognit., 19, 106-180 (2006)

    [2]            Nicholls, I. A.; Andersson, H. S.; Charlton, C.; Henschel, H.; Karlsson, B. C. G.; Karlsson, J. G.; O´Mahony, J.; Rosengren, A. M.; Rosengren, K. J.; Wikman, S. Biosens. Bioelectron., 25, 543-552 (2009)

    [3]            Karlsson, B. C. G.; O´Mahony, J.; Karlsson, J. G.; Bengtsson, H.; Eriksson, L. A.; Nicholls, I. A. J. Am. Chem. Soc., 131, 13297-13304 (2009)

  • 10.
    Golker, Kerstin
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Olsson, Gustaf D.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Towards the use of molecular dynamics as a predictive tool in the design of molecularly imprinted polymers2010Conference paper (Refereed)
    Abstract [en]

    Through the rapid increase in computational power and the development of suitable software, molecular dynamics (MD) has become a promising tool for use in the development of molecularly imprinted polymers (MIPs).1 MD is a computational method based on Newtonian mechanics, which enables the simultaneous simulation of thousands of discrete molecules, and can be used to establish the states of the molecular species present in MIP-prepolymerization mixtures. As detailed understanding of the molecular basis for formation of high affinity MIP sites is still lacking and the physical mechanism underlying specific recognition is still a matter of debate, the use of MD as a tool to investigate MIP-prepolymerization mixtures is highly motivated.1 Recently the first MD simulation of an all-component prepolymerization mixture was presented, which gave a detailed picture of the underlying monomer-template interactions important for the “molecular memory” in MIPs.2

    Here, we present results obtained from a series of MD simulations representing all-component MIP/REF prepolymerization mixtures assembled with differences in stoichiometries of functional and crosslinking monomer. In these mixtures, the local anaesthetic drug bupivacaine was used as a template, methacrylic acid as the functional monomer, ethylene dimethacrylate as crosslinking monomer, 2,2’-azobis-(2-methylpropionitrile) as the initiator and toluene as the solvent. Bupivacaine complexation in each system was evaluated with radial distribution functions and hydrogen bond analyses. By correlating the results with the rebinding behaviour of a series of synthesized bupivacaine-MIPs, the relationship between the degree of crosslinking and MIP-performance was highlighted.

    [1] Nicholls, I. A.; Andersson, H. S.; Charlton, C.; Henschel, H.; Karlsson, B. C. G.; Karlsson, J. G.; O´Mahony, J.; Rosengren, A. M.; Rosengren, K. J.; Wikman, S. Biosens. Bioelectron., 25, 543-552 (2009)

    [2] Karlsson, B. C. G.; O´Mahony, J.; Karlsson, J. G.; Bengtsson, H.; Eriksson, L. A.; Nicholls, I. A. J. Am. Chem. Soc., 131, 13297-13304 (2009)

  • 11.
    Golker, Kerstin
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Rosengren, Annika M.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Uppsala University.
    A Functional Monomer Is Not Enough: Principal Component Analysis of the Influence of Template Complexation in Pre-Polymerization Mixtures on Imprinted Polymer Recognition and Morphology2014In: International Journal of Molecular Sciences, ISSN 1422-0067, E-ISSN 1422-0067, Vol. 15, no 11, p. 20572-20584Article in journal (Refereed)
    Abstract [en]

    In this report, principal component analysis (PCA) has been used to explore the influence of template complexation in the pre-polymerization phase on template molecularly imprinted polymer (MIP) recognition and polymer morphology. A series of 16 bupivacaine MIPs were studied. The ethylene glycol dimethacrylate (EGDMA)-crosslinked polymers had either methacrylic acid (MAA) or methyl methacrylate (MMA) as the functional monomer, and the stoichiometry between template, functional monomer and crosslinker was varied. The polymers were characterized using radioligand equilibrium binding experiments, gas sorption measurements, swelling studies and data extracted from molecular dynamics (MD) simulations of all-component pre-polymerization mixtures. The molar fraction of the functional monomer in the MAA-polymers contributed to describing both the binding, surface area and pore volume. Interestingly, weak positive correlations between the swelling behavior and the rebinding characteristics of the MAA-MIPs were exposed. Polymers prepared with MMA as a functional monomer and a polymer prepared with only EGDMA were found to share the same characteristics, such as poor rebinding capacities, as well as similar surface area and pore volume, independent of the molar fraction MMA used in synthesis. The use of PCA for interpreting relationships between MD-derived descriptions of events in the pre-polymerization mixture, recognition properties and morphologies of the corresponding polymers illustrates the potential of PCA as a tool for better understanding these complex materials and for their rational design.

  • 12.
    Guo, Ming
    et al.
    Zhejiang Agr & Forestry Univ, Peoples R China.
    Wang, Xiaomeng
    Zhejiang Agr & Forestry Univ, Peoples R China.
    Lu, Xiaowang
    Zhejiang Agr & Forestry Univ, Peoples R China.
    Wang, Hongzheng
    Zhejiang Agr & Forestry Univ, Peoples R China.
    Brodelius, Peter E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    alpha-Mangostin Extraction from the Native Mangosteen (Garcinia mangostana L.) and the Binding Mechanisms of alpha-Mangostin to HSA or TRF2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 9, article id e0161566Article in journal (Refereed)
    Abstract [en]

    In order to obtain the biological active compound, alpha-mangostin, from the traditional native mangosteen (Garcinia mangostana L.), an extraction method for industrial application was explored. A high yield of a-mangostin (5.2%) was obtained by extraction from dried mangosteen pericarps with subsequent purification on macroporous resin HPD-400. The chemical structure of alpha-mangostin was verified mass spectrometry (MS), nuclear magnetic resonance (H-1 NMR and C-13 NMR), infrared spectroscopy (IR) and UV-Vis spectroscopy. The purity of the obtained alpha-mangostin was 95.6% as determined by HPLC analysis. The binding of native alpha-mangostin to human serum albumin (HSA) or transferrin (TRF) was explored by combining spectral experiments with molecular modeling. The results showed that amangostin binds to HSA or TRF as static complexes but the binding affinities were different in different systems. The binding constants and thermodynamic parameters were measured by fluorescence spectroscopy and absorbance spectra. The association constant of HSA or TRF binding to alpha-mangostin is 6.4832x10(5) L/mol and 1.4652x10(5) L/mol at 298 K and 7.8619x10(5) L/mol and 1.1582x10(5) L/mol at 310 K, respectively. The binding distance, the energy transfer efficiency between alpha-mangostin and HSA or TRF were also obtained by virtue of the Forster theory of non-radiation energy transfer. The effect of alpha-mangostin on the HSA or TRF conformation was analyzed by synchronous spectrometry and fluorescence polarization studies. Molecular docking results reveal that the main interaction between amangostin and HSA is hydrophobic interactions, while the main interaction between alpha-mangostin and TRF is hydrogen bonding and Van der Waals forces. These results are consistent with spectral results.

  • 13.
    Haugaard-Kedström, Linda M.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Structure and function of relaxins2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The relaxin/insulin superfamily is a group of peptide hormones that consists of ten members in human, namely relaxins 1-3, insulin-like peptides (INSL) 3-6, insulin and insulin-like growth factors (IGF) I-II. These peptides have various functions in the body, such as regulating growth, blood glucose levels,  collagen metabolism, germ cell maturation and appetite. Misregulation of these mechanisms is associated with disease and accordingly they are of interest as potential pharmaceutical targets. Structurally the hormones are characterised by two peptide chains, A and B, which are held together by one intra A-chain and two inter chain disulfide bonds. Four different G-protein coupled receptors (GPCR) called relaxin family peptide receptor (RXFP) 1-4 have been found to respond to stimuli by different relaxin peptides. RXFP3 and RXFP4 are classic peptide ligand GPCRs, whereas RXFP1 and RXFP2 are characterised by a large extracellular leucine rich-repeat domain. Relaxin-3, which is the relaxin family ancestor, is the only relaxin peptide known to be able to bind and activate both subtypes of GPCRs, namely RXFP1, RXFP3 and RXFP4.

    The aim of this thesis was to analyse the structure-function relationship of the relaxin ligands and receptors, and to use this information to develop selective ligands for the relaxin receptors, which can be used as drug leads or pharmacological tools for investigating the physiological roles of the RXFPs.

    The 3D structures of native INSL5 and relaxin-2 were determined by solution NMR spectroscopy. The peptides showed an insulin/relaxin-like overall fold. A relaxin chimera peptide, consisting of the A-chain from INSL5 and the B-chain from relaxin-3, R3/I5, which has been shown to be selective for RXFP3 and RXFP4 over RXFP1, was also subjected to NMR studies. The R3/I5 peptide maintained an insulin/relaxin-like overall fold, and the relaxin-3 B-chain adopted a conformation identical to that in native relaxin-3, confirming that the activity of R3/I5 can be directly related to its primary sequence. Furthermore, a truncation study was undertaken to ascertain the importance of the termini for structure and function. By using the knowledge generated from the structure-function relationship, a single-chain high affinity RXFP3 selective antagonist was developed.

    In conclusion, this thesis has contributed to broaden the knowledge of the structure-function relationship of the relaxin ligands and the development of a selective RXFP3 antagonist, which is currently a drug lead for treatment of neurological disorders including stress and obesity.

  • 14.
    Henschel, Henning
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Rosengren, Annika M.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Insights into the Isomerisation Mechanism of Warfarin2010Conference paper (Refereed)
    Abstract [en]

    Warfarin is one of the most commonly used drugs in anticoagulent therapy. Notwithstanding its wide use, achieving correct dosage is often a major challenge due to its narrow therapeutic window.[1] The bioavailability of warfarin is believed to be greatly influenced by the environment-dependent composition of the ensemble of isomers present. While the different structures of warfarin have been discussed in earlier publications,[2] details of the mechanism underlying the formation of the cyclic hemiacetal (Figure 1) had not yet been investigated.

    Figure 1. Cyclization reaction of warfarin.

    Figure 2. Transition state in presence of one water molecule.

     

    We have now studied the reaction by means of density functional calculations. Comparison of results from calculations performed on the isolated warfarin molecule and in presence of water molecules (compare Figure 2) highlight the importance of intermolecular interactions in the key proton transfer step for the reaction to proceed. A viable model for the mechanism underlying the isomerisation shall be presented.

     

     

    References

    [1]             J. Ansell, J. Hirsh, L. Poller, H. Bussey, A. Jacobsen and E. Hylek, Chest, 126, 204S (2004).

    [2]            B. C. G. Karlsson, A. M. Rosengren, P. O. Andersson and I. A. Nicholls, J. Phys. Chem. B, 111,10520 (2007).

  • 15.
    Henschel, Henning
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Rosengren, Annika M.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    The Mechanistic Basis for Warfarin’s Structural Diversity and Implications for Its Bioavailability2010In: Journal of Molecular Structure: THEOCHEM, ISSN 0166-1280, Vol. 958, p. 7-9Article in journal (Refereed)
    Abstract [en]

    The anticoagulent drug warfarin exhibits chameleon-like isomerism, where the environment-dependent composition of the ensemble of structures greatly influences its bioavailability. Here, the mechanism of conversion between the major isomeric forms is studied. The dramatic differences in transition state energies, as determined by density functional calculations, highlight the necessity for the involvement of intermolecular interactions in the key proton transfer step. A viable model for the mechanism underlying the isomerization reactions is presented.

  • 16.
    Henschel, Henning
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Prosenc, Marc H.
    University of Hamburg, Germany.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences. Uppsala University.
    A Density Functional Study on the Factors Governing Metal Catalysis of the Direct Aldol Reaction2011In: Journal of Molecular Catalysis A: Chemical, ISSN 1381-1169, E-ISSN 1873-314X, Vol. 351, p. 76-80Article in journal (Refereed)
    Abstract [en]

    Density functional calculations are employed in the study of the C-C bond formation step of an aldol reaction in presence of a series of metals. Focus was placed on first row d-block metals that have been used in catalysis of direct aldol reactions. The obtained energy profiles are analysed in order to differentiate between factors governing catalysis. Results demonstrate a major influence of d-orbital occupation, and suggest some of the so far less commonly used metals as promising candidates for development of new catalytic systems.

  • 17.
    Hulteberg, Christian
    et al.
    Biofuel-Solution i Malmö AB ( Lund University/ Chemical Engineering) .
    Brandin, Jan
    Linnaeus University, Faculty of Science and Engineering, School of Engineering. Biofuel-Solution i Malmö AB.
    Method for Hydrogenating 1,2-Unsaturated Carbonylic Compounds2011Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    Disclosed is a method of hydrogenating an1,2-unsaturated carbonylic compound to obtain the corresponding saturated carbonylic compound in the presence of a palladium catalyst with heterogeneous distribution of palladium

  • 18.
    Karlsson, Björn C. G.
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Olsson, Gustaf D.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Rosengren, Annika M.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    The Effect of Warfarin’s Structural Diversity on Permeation Across a DPPC Bilayer Membrane2010Conference paper (Refereed)
    Abstract [en]

    Warfarin is an oral anticoagulant drug used to prevent thrombolic disorders such as myocardial infarction and stroke by inhibiting the active site of vitamin-K dependent epoxide reductase (VKOR) [1]. Despite being in widespread use and having a narrow therapeutic window, its mechanisms of action are not yet fully understood and incorrect warfarin dosage often leads to severe side effects. A factor limiting our understanding of warfarin’s bioavailability is warfarin’s structural diversity, which has been shown to be strongly affected by the nature of molecular environment e.g. solvent polarity and pH [2-7]. One of the major factors contributing to a drug’s biological effect is membrane transport, a process involving exposure of warfarin to environments of quite different character. Since a drug’s transport across membrane may include both active transport by carriers as well as diffusion-controlled processes, it may be envisaged that in order to fully predict warfarin’s anticoagulant effect these mechanisms must be carefully elucidated.

     

    Molecular dynamics (MD) simulations have previously been performed in order to obtain detailed information on static equilibrium as well as dynamic properties of small organic drugs in biomembranes. One of the most studied lipids in cell membrane simulations has been dipalmitoylphosphatidylcholine (DPPC) which is the most abundant phospholipid in cell membranes. Here we present lipid bilayer membrane transport properties for a series of warfarin structures previously reported in the literature using a fully solvated DPPC membrane model. Data extracted from simulations shed light on differences in membrane partioning as well as mobilities of warfarin isomers studied and a mechanism by which warfarin permeates through membranes in vivo is presented.

     

    References

    1. Landefeld, C.; Beyth, R. Am. J. Med. 1993, 95, 315-328.
    2. Karlsson, B. C. G.; Rosengren, A. M.; Andersson, P. O.; Nicholls, I. A. J. Phys. Chem. B 2007, 111, 10520-10528.
    3. Karlsson, B. C. G.; Rosengren, A. M.; Andersson, P. O.; Nicholls, I. A. J. Phys. Chem. B 2009, 113, 7945-7949.
    4. Karlsson, B. C. G.; Rosengren, A. M.; Näslund, I.; Andersson, P. O.; Nicholls, I. A. Submitted 2010.
    5. Rosengren, A. M.; Karlsson, B. C. G.; Näslund, I.; Andersson, P. O.; Nicholls, I. A. Submitted 2010.
    6. Nicholls, I. A.; Karlsson, B. C. G.; Rosengren, A. M.; Henschel, H. J. Mol. Recognit. 2010, In press.
    7. Henschel, H.; Karlsson, B. C. G.; Rosengren, A. M.; Nicholls, I. A. Submitted 2010.

     

  • 19.
    Karlsson, Björn C. G.
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Rosengren, Annika M.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Näslund, Inga
    FOI, Swedish Defence Research Agency.
    Andersson, Per Ola
    FOI, Swedish Defence Research Agency.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    A molecularly imprinted polymer-based detection of Warfarin using time resolved fluorescence spectroscopy2010Conference paper (Refereed)
    Abstract [en]

    Warfarin is a clinically important drug widely used in the treatment of thrombolic disorders e.g. myocardial infarction and stroke.1 When administered, 99% of the drug present in blood is bound to the transport protein human serum albumin (HSA).2 On account of the fact that HSA demonstrates polymorphism and warfarin has a narrow therapeutic index, careful monitoring of the effect of drug-dosage must be performed.

    Currently, warfarin’s anticoagulant effect is measured by an indirect method in which the clotting time is measured and correlated to the amount of warfarin present. As current methods for self-monitoring are limited, the development of alternative robust and more sensitive methods is desirable.

    In this study, we have developed a non-covalent molecularly imprinted polymer3 (MIP) system with selectivity for warfarin.4 The HSA-like binding properties of this MIP were established in previous efforts to develop polymers capable of HSA-like binding of warfarin.5

    In principle, the fluorophoric nature of warfarin should allow for the fluorescence spectroscopy-based detection of the drug. Recent efforts by us,6-8 using a series of theoretical and spectroscopic studies have highlighted the complex nature of warfarin. In particular, the medium dependent isomerization of this drug illustrates why spectroscopy based methods for the direct detection of the drug has not been forthcoming. Results from these studies have been used to develop a method for the in situ detection of warfarin using time resolved fluorescence spectroscopy.

    (1)      Landefeld, C.; Beyth, R. Anticoagulant-related bleeding - epidemiology, prediction and prevention. Am. J. Med. 1993, 95, 315-328.

    (2)      Yacobi, A.; Udall, J. A.; Levy, G. Comparative pharmacokinetics of coumarin anticoagulants.18 Serum-protein binding as a determinant of warfarin body clearance and anticoagulant effect. Clin. Pharmacol Ther. 1976, 19, 552-558.

    (3)      Alexander, C.; Andersson, H. S.; Andersson, L. I.; Ansell, R. J.; Kirsch, N.; Nicholls, I. A.; O'Mahony, J.; Whitcombe, M. J. Molecular imprinting science and technology: A survey of the literature for the years up to and including 2003. Journal of Molecular Recognition 2006, 19, 106-180.

    (4)      Rosengren, A. M.; Karlsson, B. C. G.; Näslund, I.; Andersson, P. O.; Nicholls, I. A. Time resolved fluorescence spectroscopic detection of the anticoagulant warfarin: A sensor-based method for direct detection in blood plasma. 2010, Submitted.

    (5)      Karlsson, B. C. G.; Rosengren, A. M.; Näslund, I.; Andersson, P. O.; Nicholls, I. A. Synthetic Human Serum Albumin Sudlow I binding site mimics. 2010, Submitted.

    (6)      Karlsson, B. C. G.; Rosengren, A. M.; Andersson, P. O.; Nicholls, I. A. The Spectrophysics of Warfarin: Implications for Protein Binding J. Phys. Chem. B 2007, 111, 10520-10528.

    (7)      Karlsson, B. C. G.; Rosengren, A. M.; Andersson, P. O.; Nicholls, I. A. Molecular Insights on the Two Fluorescence Lifetimes Displayed by Warfarin from Fluorescence Anisotropy and Molecular Dynamics Studies. J. Phys. Chem. B 2009, 113, 7945-7949.

    (8)      Nicholls, I. A.; Karlsson, B. C. G., Rosengren, A. M.. Henschel, H. Warfarin: an Environment-Dependent Switchable Molecular Probe. J. Mol. Recognit. 2010, in press.

  • 20.
    Kathiravan, Suppan
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Uppsala University.
    Cobalt Catalyzed, Regioselective C(sp(2))-H Activation of Amides with 1,3-Diynes2017In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 19, no 18, p. 4758-4761Article in journal (Refereed)
    Abstract [en]

    The development of a first row transition metal (cobalt)-based catalyst for the as yet unexplored CH activation-driven reaction of 1,3-diynes, themselves a functional class of interest in a range of application areas, to form isoquinolinonesan important structural motif in a number of biologically active substancesis presented. This versatile and inexpensive catalyst employs a covalently attached bidendate-directing group, 8-aminoquinoline. The template directs the CH activation and facilitates the synthesis of a wide range of alkynylated heterocycles under mild conditions and with excellent regioselectivity. This strategy provides a novel and efficient route to diverse heterocyclic frameworks as demonstrated by its late stage application in bisheterocycle syntheses.

  • 21.
    Kathiravan, Suppan
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Uppsala university.
    Palladium Catalyzed Vinyltrifluoromethylation of Aryl Halides through Decarboxylative Cross-Coupling with 2-(Trifluoromethyl)acrylic Acid2015In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 17, p. 1874-1877Article in journal (Refereed)
    Abstract [en]

    An efficient Pd-catalyzed stereoselective vinyltrifluoromethylation of aryl halides, through decarboxylative cross-coupling with 2-(trifluoromethyl)acrylic acid is described. The ready availability of the starting materials, the high level of functional group tolerance, and excellentE/Z selectivity make this protocol a safe and operationally convenient strategy for efficient synthesis of vinyltrifluoromethyl derivatives.

  • 22.
    Kathiravan, Suppan
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Uppsala University.
    Rhodium-Catalyzed Oxidative Perfluoroalkenylation by Carbonyl Group Directed C-H Bond Activation2014In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, no 32, p. 7211-7219Article in journal (Refereed)
    Abstract [en]

    The selective activation of C-H bonds under mild Rh-III catalytic conditions has been developed for the perfluoroalkenylation of various cyclic and acyclic aromatic ketones. This protocol uses versatile reagents and mild conditions. It requires a very low catalyst loading and has exceptional functional group tolerance as well as provides products in good to excellent yields. An application of this approach was described for the preparation of perfluoroethyl acrylate derivatives of biologically active substances.

  • 23.
    Kathiravan, Suppan
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Uppsala University.
    Rhodium(III)-catalysed aerobic synthesis of highly functionalized indoles from N-arylurea under mild conditions through C-H activation2014In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 50, no 95, p. 14964-14967Article in journal (Refereed)
    Abstract [en]

    A Rh(III) catalysed amino arylation of alkynes using copper as the terminal oxidant for regeneration of the catalytically active species under aerobic conditions is described. This novel C-H activation reaction was applied to the synthesis of a wide range of substituted indoles from N-arylureas.

  • 24.
    Marshall, D. G.
    et al.
    AgResearch Ltd, New Zealand.
    Jackson, T. A.
    AgResearch Ltd, New Zealand.
    Unelius, C. Rikard
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. New Zealand Inst Plant & Food Res Ltd, New Zealand.
    Wee, S. L.
    New Zealand Inst Plant & Food Res Ltd, New Zealand ; Univ Kebangsaan Malaysia, Malaysia.
    Young, S. D.
    AgResearch Ltd, New Zealand.
    Townsend, R. J.
    AgResearch Ltd, New Zealand.
    Suckling, D. M.
    New Zealand Inst Plant & Food Res Ltd, New Zealand ; Univ Auckland, New Zealand.
    Morganella morganii bacteria produces phenol as the sex pheromone of the New Zealand grass grub from tyrosine in the colleterial gland2016In: The Science of Nature: Naturwissenschaften, ISSN 0028-1042, E-ISSN 1432-1904, Vol. 103, no 7-8, article id 59Article in journal (Refereed)
    Abstract [en]

    Costelytra zealandica (Coleoptera: Scarabeidae) is a univoltine endemic species that has colonised and become a major pest of introduced clover and ryegrass pastures that form about half of the land area of New Zealand. Female beetles were previously shown to use phenol as their sex pheromone produced by symbiotic bacteria in the accessory or colleterial gland. In this study, production of phenol was confirmed from the female beetles, while bacteria were isolated from the gland and tested for attractiveness towards grass grub males in traps in the field. The phenol-producing bacterial taxon was identified by partial sequencing of the 16SrRNA gene, as Morganella morganii. We then tested the hypothesis that the phenol sex pheromone is biosynthesized from the amino acid tyrosine by the bacteria. This was shown to be correct, by addition of isotopically labelled tyrosine (C-13) to the bacterial broth, followed by detection of the labelled phenol by SPME-GCMS. Elucidation of this pathway provides specific evidence how the phenol is produced as an insect sex pheromone by a mutualistic bacteria.

  • 25.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Towards the Rational Design of Functional Molecularly Imprinted Polymers2010Conference paper (Refereed)
  • 26.
    Nicholls, Ian A.
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Andersson, Håkan S.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Golker, Kerstin
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Henschel, Henning
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Olsson, Gustaf D.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Rosengren, Annika M.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Shoravi, Siamak
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Wiklander, Jesper G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Wikman, Susanne
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Rational Design of Biomimetic Molecularly Imprinted Materials: Theoretical and Computational Strategies for Guiding Nanoscale Structured Polymer Development2011In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 400, p. 1771-1786Article, review/survey (Refereed)
    Abstract [en]

    In principle, molecularly imprinted polymer science and technology provides a means for ready access to nano-structured polymeric materials of predetermined selectivity. The versatility of the technique has brought it to the attention of many working with the development of nanomaterials with biological or biomimetic properties for use as therapeutics or in medical devices. Nonetheless, the further evolution of the field necessitates the development of robust predictive tools capable of handling the complexity of molecular imprinting systems. The rapid growth in computer power and software over the past decade has opened new possibilities for simulating aspects of the complex molecular imprinting process. We present here a survey of the current status of the use of in silico-based approaches to aspects of molecular imprinting. Finally, we highlight areas where ongoing and future efforts should yield information critical to our understanding of the underlying mechanisms sufficient to permit the rational design of molecularly imprinted polymers.

  • 27.
    Nicholls, Ian A.
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Andersson, Håkan S.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Golker, Kerstin
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Henschel, Henning
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Olsson, Gustaf D.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Rosengren, Annika M.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Shoravi, Siamak
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Wiklander, Jesper G.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Wikman, Susanne
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Rational molecularly imprinted polymer design: theoretical and computational strategies2013In: Molecular Imprinting: Principles and Applications of Micro- and Nanostructured Polymers / [ed] Ye, L, London: Pan Stanford Publishing, 2013, p. 71-104Chapter in book (Refereed)
  • 28.
    Nicholls, Ian A.
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Andersson, Per-Ola
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Rosengren, Annika M.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Method and apparatus for detecting pharmaceuticals in a sample2010Patent (Other (popular science, discussion, etc.))
  • 29.
    Nicholls, Ian A.
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Uppsala Univ, Dept Chem BMC, SE-75123 Uppsala, Sweden.
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Olsson, Gustaf D.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Rosengren, Annika M.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Computational Strategies for the Design and Study of Molecularly Imprinted Materials2013In: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 52, no 39, p. 13900-13909Article in journal (Refereed)
    Abstract [en]

    The need for materials with predetermined ligand-selectivities for use in sensing and separation technologies, e.g. membranes and chromatography, has driven the development of molecularly imprinted polymer science and technology. Over recent years, the need to develop robust predictive tools capable of handling the complexity of molecular imprinting systems has become apparent The current status of the use of in silica techniques in molecular imprinting is here presented, and we highlight areas where new developments are contributing to improvements in the rational design of molecularly imprinted polymers.

  • 30.
    Olsson, Gustaf D.
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Schillinger, Eric
    Sellergren, Börje
    Nicholls, Ian A.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Uppsala Univ, Dept Chem BMC, SE-75123 Uppsala, Sweden.
    Theoretical Studies of 17-beta-Estradiol-Imprinted Prepolymerization Mixtures: Insights Concerning the Roles of Cross-Linking and Functional Monomers in Template Complexation and Polymerization2013In: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 52, no 39, p. 13965-13970Article in journal (Refereed)
    Abstract [en]

    In this study, computational methods were employed in efforts to elucidate physical mechanisms underlying the ligand selectivity of polymeric sorbents produced through the molecular imprinting of 17-beta-estradiol. Previous computational and experimental studies had identified candidate systems applicable to the development of synthetic polymeric receptors for the detection and possible removal of pollutants with endocrine-disrupting properties. Here we present a series of comprehensive molecular dynamics studies of candidate molecular imprinting prepolymerization systems. The results from the studies highlight the role of the cross-linker and the importance of the interplay between functionalities of the various monomers employed in template complexation. The significance of these results for future studies is discussed.

  • 31.
    Olsson, Gustaf D.
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Shoravi, Siamak
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Wiklander, Jesper G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Mechanisms Underlying Molecularly Imprinted Polymer Molecular Memory and The Role of Crosslinker: Resolving Debate on the Nature of Template Recognition in Phenylalanine Anilide Imprinted Polymers2012In: Journal of Molecular Recognition, ISSN 0952-3499, E-ISSN 1099-1352, Vol. 25, no 2, p. 69-73Article in journal (Refereed)
    Abstract [en]

    A series of molecular dynamics simulations of prepolymerization mixtures for phenylalanine anilide imprinted co-(ethylene glycol dimethacrylate-methacrylic acid) molecularly imprinted polymers have been employed to investigate the mechanistic basis for template selective recognition in these systems. This has provided new insights on the mechanisms underlying template recognition, in particular the significant role played by the crosslinking agent. Importantly, the study supports the occurrence of template self-association events that allows us to resolve debate between the two previously proposed models used to explain this system's underlying recognition mechanisms. Moreover, the complexity of the molecular level events underlying template complexation is highlighted by this study, a factor that should be considered in rational molecularly imprinted polymer design, especially with respect to recognition site heterogeneity.

  • 32.
    Olsson, Gustaf D.
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Wiklander, Jesper G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Mechanism of Phenylalanine Anilide Molecularly Imprinted Polymer - Template Recognition: The Role of Template Dimerization2010Conference paper (Refereed)
    Abstract [en]

    It is now widely accepted that the recognition properties of a MIP are derived from molecular level events present during the prepolymerization stage.1 Studies regarding the nature and extent of template complexation during this stage should therefore yield valuable information regarding the template recognition properties of the final MIP. One method of great potential for illuminating molecular level details in this area of MIP research is molecular dynamics (MD).2 MD simulations enable studies of molecular-level events in MIP prepolymerization mixtures.

    Phenylalanine anilide (PA) is a molecule that has been extensively used as a template in a series of seminal molecular imprinting studies.3-5 In an effort to elucidate the origin to the imprinting effect, Sellergren, Lepistö and Mosbach proposed that selective high-affinity sites in the PA-MIP were based on functional monomer-template complexation of a 2:1 stoichiometry.3 In a follow-up study, Katz and Davis presented results that revealed further information regarding the origin of recognition in PA-MIPs.5 It was suggested that the template recognition sites were based on functional monomer-template complexes of 1:1 stoichiometry, and also that the formation of higher order template-template complexes has important effects on the final PA-MIP recognition properties. In light of this conjecture and several more recent studies highlighting the diversity of template complexation mechanisms in prepolymerization mixtures, have pointed at the complexity and diversity in the ensemble of complexes leading to the final “molecular memory”.

    Here we present the novel insights into the molecular basis for PA-MIP template recognition derived from a series of MD simulations of the PA-MIP prepolymerisation systems. Data support the presence of PA-PA complexes and that the most statistically prevalent stoichiometry functional monomer-PA complexes was 1:1. The role of cross-linker is also discussed. This study highlights the potential of all component MD studies for rational MIP design.

     

    (1)      Alexander, C.; Andersson, H.S.; Andersson, L.I.; Ansell, R.J.; Kirsch, N.; Nicholls, I.A.; O'Mahony, J.; Whitcombe, M.J.  Molecular imprinting science and technology: A survey of the literature for the years up to and including 2003. Journal of Molecular Recognition 2006, 19, 106-180.

    (2)      Nicholls, I.A.; Andersson, H.S.; Charlton, C; Henschel, H.; Karlsson, B.C.G.; Karlsson, J.G.; O’Mahony, J.; Rosengren, A.M.; Rosengren, J.K.; Wikman, S. Theoretical and computational stratgies for rational molecularly imprinted polymer design. Biosensors and Bioelectronics 2009, 25, 543-552

    (3)      Sellergren, B.; Lepistoe, M.; Mosbach, K.. Highly enantioselective and substrate-selective polymers obtained by molecular imprinting utilizing noncovalent interactions. NMR and chromatographic studies on the nature of recognition. Journal of American Chemical Society 1988, 110, 5853-5860

    (4)      Sellergren, B.. Molecular imprinting by noncovalent interactions: Tailor-made chiral stationary phases of high selectivity and sample load capacity. Chirality 1989, 1, 63-68

    (5)      Katz, A.; Davis, M.E. Investigations into the mechanism of molecular recognition with imprinted polymers. Macromolecules 1999, 32, 4113-4121

  • 33.
    Olsson, Gustaf D.
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Wiklander, Jesper G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Shoravi, Siamak
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    The nature and extent of interactions in phenylalanine anilide molecularly imprinted polymer prepolymerisation mixtures: a new model for the basis for ligand-selective recognition2010Conference paper (Refereed)
    Abstract [en]

    In this work, classical molecular dynamics (MD) simulations have been used to provide unique insights on the nature and extent of intermolecular interactions present in a phenylalanine anilide (PA) molecularly imprinted polymers (MIP) prepolymerization mixture.

    Molecular Imprinting is a technique for producing highly selective synthetic receptors for a predetermined molecular structure, and involves the formation of cavities in a synthetic polymer matrix that are of complementary functional and structural character to a template molecule.1 It is generally accepted that the recognition properties of a MIP is a product of the interactions between monomers and template during the prepolymerization stage. Accordingly, studies of the nature and extent of the interactions present in prepolymerization mixtures, in patricular those involving template, should yield information which can be related to the observed recognition properties of the final MIP.

    Phenylalanine anilide MIPs have been the subject of a significant number of studies aimed at producing an understanding of the mechanisms underlying the recognition processes. Interestingly, two different models have been proposed to explain the behaviour of PA-MIPs. Studies by Sellergren et al. proposed that template selectivity, was a consequence of  the presence of a functional monomer-template complexes of 2:1 stoichiometry.2 Later, however, Katz and Davis proposed an alternative model,3 where the template (PA) recognition sites in the MIP were suggested to arise from functional monomer-template complexes of 1:1 stoichiometry in combination with the presence of higher order template-template complexes.

    To resolve this conjecture, we performed a series of MD studies, the results of which demonstrated both the presence of PA-PA self association complexes, and that the most statistically prevalent monomer-PA complex stoichiometry was of a 1:1 nature, though differetn in character from that proposed by Katz and Davis.  Moreover, the role of cross-linker in forming recognition sites was apparnet in these studies, a fact not previously considered.

     

    References

    1. Alexander C, Andersson HS, Andersson LI, Ansell RJ, Kirsh N, Nicholls IA, O’Mahony J, Whitcombe MJ. Molecular imprinting science and technology: A survey of the literature for the years up to and including 2003. Journal of Molecular Recognition 2006;19:106-180
    2. Sellergren B, Lepistö M, Mosbach K. Highly enantioselective and substrate selective polymers obtained by molecular imprinting utilizing noncovalent interactions. NMR and chromatographic studies on the nature of recognition. Journal of the American Chemical Society 1988;110:5853-5860
    3. Katz A, Davis ME. Investigations into the mechanisms of molecular recognition with imprinted polymers. Macromolecules 1999;32:4113-4121

     

  • 34.
    Olsson, Gustaf D.
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Wiklander, Jesper G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Shoravi, Siamak
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    The Nature and Extent of Template-Template Complexation in Phenylalanine Anilide Molecularly Imprinted Polymers2010Conference paper (Refereed)
    Abstract [en]

    The molecular imprinting technique has received significant attention due to its utility in the production of synthetic polymeric materials with predetermined ligand recognition properties [1].

    It is generally accepted that the recognition properties of a molecularly imprinted polymer (MIP) is established during the prepolymerization stage. Previous investigations on the nature and extent of template prepolymerization complexation in a phenylalanine anilide (PA) MIP pointed at the complexity and diversity in the ensemble of complexes leading to the final “molecular memory”. In particular, conflicting models have been used to explain the observed molecular memory. Sellergren, Lepistö and Mosbach [2] proposed that selective, high-affinity sites in the final MIP were based on functional monomer-PA complexation of a 2:1 stoichiometry. Later, Katz and Davis [3] proposed that the template recognition sites arose due to a 1:1 functional monomer-template complex stoichiometry and that the effect of template dimerization is critical for the observed PA-MIP recognition properties.

    In this study, we have attempted to shed new light on this as yet unresolved conflict using a series of molecular dynamics (MD) simulations. Results demonstrated the presence of PA-PA complexes and that the most statistically prevalent stoichiometry of functional monomer-PA complexes was of 1:1.

    [1]             Alexander C, Andersson HS, Andersson LI, Ansell R, Kirsch N, Nicholls IA et al. Molecular imprinting science and technology: a survey of the literature for the years up to and including 2003, Journal of Molecular Recognition, 19, 106-180 (2006).

    [2]            Sellergren B, Lepistö M, Mosbach K. Highly enantioselective and substrate selective polymers obtained by molecular imprinting utilizing noncovalent interactions. NMR and chromatographic studies on the nature of recognition, Journal of the American Chemical Society, 110, 5853-5860 (1988).

    [3]             Katz A, Davis ME. Investigations into the mechanisms of molecular recognition with imprinted polymers, Macromolecules, 32, 4113-4121 (1999).

  • 35.
    Olsson, Gustaf D.
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Niedergall, Klaus
    Fraunhofer Inst Interfacial Engn & Biotechnol IGB, Germany..
    Bach, Monika
    Fraunhofer Inst Interfacial Engn & Biotechnol IGB, Germany ; Univ Stuttgart, Inst Interfacial Engn & Plasmatechnol IGVT, Germany.
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Linnaeus University Centre for Biomaterials Chemistry.
    Tovar, Guenter
    Fraunhofer Inst Interfacial Engn & Biotechnol IGB, Germany ; Univ Stuttgart, Inst Interfacial Engn & Plasmatechnol IGVT, Germany.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Uppsala University.
    Simulation of imprinted emulsion prepolymerization mixtures2015In: Polymer journal, ISSN 0032-3896, E-ISSN 1349-0540, Vol. 47, no 12, p. 827-830Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to develop protocols for and evaluate the use of all-atom full system molecular dynamic (MD) simulations of emulsion systems in the development of molecularly imprinted polymers (MIPs). Here, we report on the first, to the best of our knowledge, use of all-component MD studies to simulate and evaluate MIP miniemulsion prepolymerization mixtures; in this case, the mixtures used in the synthesis of a series of MIP-nanoparticles (MIP-NPs).

  • 36. O'Mahony, John
    et al.
    Moloney, Mary
    McCormack, Martin
    Nicholls, Ian A.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Mizaikoff, Boris
    Danaher, Martin
    Design and implementation of an imprinted material for the exaction of the endocrine disruptor bisphenol A from milk2013In: Journal of chromatography. B, ISSN 1570-0232, E-ISSN 1873-376X, Vol. 931, p. 164-169Article in journal (Refereed)
    Abstract [en]

    This paper describes the determination of bisphenol A (BPA) in milk samples, using a novel molecularly imprinted polymer. The imprinted polymer was developed using a rational design approach, and pre-polymerization interactions were investigated using molecular dynamics simulations and X-ray crystallography. A hydroquinone-imprinted polymer was used for solid phase extraction (SPE) clean-up of samples. BPA was quantified by high performance liquid chromatography (HPLC) and fluorescence (FLD) detection. Following validation, the method described was capable of determining bisphenol A in milk down to a limit of detection of 1.32 mu g kg(-1). The method was applied to a survey (n = 27) of commercial milk products; BPA was detected in one of the samples, at a level of 176 mu g kg(-1). Test results were confirmed by a parallel UHPLC-MS/MS analytical method. This demonstrates the utility of the hydroquinone-imprinted polymer for application to selective sample clean-up and analysis of bisphenol A in milk, avoiding possible detrimental affects associated with template bleeding and without the need for expensive or difficult-to-obtain template. (C) 2013 Elsevier B.V. All rights reserved.

  • 37.
    Oskarsson, Louise
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Söderberg, Pernilla
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Towards Phage Display-Derived Synthetic Receptors for Adenine2010Conference paper (Refereed)
    Abstract [en]

    The expression of peptides on phage coat proteins via genetic engineering was first achieved in 1985 [1] and was followed by the construction of phage display combinatorial libraries in 1990 [2].  Phage display combinatorial libraries have been used not only to find peptides that interact with various biomolecules such as receptors, antibodies, enzyme active sites, and protein surfaces, but also to find peptides with affinity for metals and plastics and with function in non-biological environments [3].

    In this study, we have challenged a cyclic heptamer phage display library with surfaces adenine functionalised surfaces with the aim of identifying peptide motifs selective for adenine. The synthesis and characterisation of surfaces, and results from phage display screening shall be presented.

     

     

    [1] Smith, G.P. Science (1985) 228, 1315-1317.

    [2] Scott, J.K.; Smith, G.P. Science (1990) 249, 386-390.

    [3] Olofsson, L.; Söderberg, P.; Ankarloo, J.; Nicholls, I.A. J. Mol. Recognit. (2008) 19, 18-25.

  • 38. Park, Kye Chung
    et al.
    McNeill, Mark
    Unelius, C. Rikard
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Oh, Hyun-Woo
    Suckling, David M.
    Characterization of olfactory receptor neurons for pheromone candidate and plant volatile compounds in the clover root weevil, Sitona lepidus2013In: Journal of insect physiology, ISSN 0022-1910, E-ISSN 1879-1611, Vol. 59, no 12, p. 1222-1234Article in journal (Refereed)
    Abstract [en]

    Antennal olfactory receptor neurons (ORNs) for pheromone and plant volatile compounds were identified and characterized in male and female clover root weevil, Sitona lepidus (Gyllenhal), using the single sensillum recording technique with five pheromone-related compounds, and 40 host and non-host plant volatile compounds. Overall, seven different types of olfactory sensilla containing specialized ORNs were identified in each sex of S. lepidus. Among them, three different types of sensilla in the males and two types in the females housed ORNs specialized for pheromone-related compounds. The ORNs in males were specialized for 4-methyl-3,5-heptanedione or one or more of four stereoisomers of 5-hydroxy-4-methyl-3-heptanone. In contrast, female sensilla did not contain ORNs sensitive to 4-methyl-3,5-heptanedione while they contained ORNs sensitive to and specialized for the stereoisomers of (4S,5S)-5-hydroxy-4-methyl-3-heptanone. In addition to the pheromone-related ORNs, four types of olfactory sensilla contained ORNs responsive to plant volatile compounds in male S. lepidus, and five types in females. Most of the ORNs identified in S. lepidus showed a high degree of specificity to specific volatile compounds although some of the active compounds showed overlapping response spectra in the ORNs across different types of sensilla. The most active plant volatile compounds were the four green leaf volatile compounds, (E)-2-hexenol, (Z)-2-hexenol, (Z)-3-hexenol and (E)-2-hexenal, and isomers of two monoterpenols, (+/-)-linalool and (+/-)-alpha-terpineol, all eliciting strong responses from relatively large numbers of ORNs in male and female S. lepidus. Our study indicates that S. lepidus has a set of highly sensitive and selective ORNs for pheromone and plant volatile compounds. Further work is needed to elucidate the behavioral implications of these findings. (C) 2013 Elsevier Ltd. All rights reserved.

  • 39. Piletsky, SA
    et al.
    Piletska, OV
    Elska, GV
    Andersson, Håkan S.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Turner, APF
    Molecularly imprinted polymers produced by template polymerisation2002Patent (Other (popular science, discussion, etc.))
  • 40.
    Rosengren, Annika M.
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Golker, Kerstin
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Wiklander, Jesper G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Identification of Solvent Properties Influencing Binding to Molecularly Imprinted Polymers2010Conference paper (Refereed)
    Abstract [en]

    In order to examine the physical mechanisms underlying molecularly imprinted polymer1 (MIP)–ligand recognition, polymers with selectivity for the local anaesthetic bupivacaine have been synthesised and their ligand-recognition characteristics examined. As several previous studies have pointed at the complexity of the rebinding characteristics and the dependence on rebinding media,2-4 we used chemometric strategies for the analysis of ligand-MIP binding in various media.5

    In a previous study we presented results from a chemometric analysis showing that rebinding of bupivacaine to the MIP in different solvent mixtures and at different temperatures follow a complicated non-linear relationship.6 The results from that analysis, motivated an investigation into the significance of the solvent physical characteristics (molecular and bulk) on rebinding properties. In this work,7 principal component analysis was employed to identify the factors with the greatest influence on binding. While the dielectric constant made a significant contribution to describing the observed binding, the influence of polarity as reflected in the Snyder polarity index was also demonstrated to also make a significant contribution. The use of solvents containing hydroxyl functionality was observed to exert unique effects on recognition. The variation in solvent influence on binding at constant dielectricity motivates more complex analyses when studying MIP-ligand recognition.

    (1)      Alexander, C.; Andersson, H.S.; Andersson, L.I.; Ansell, R.J.; Kirsch, N.; Nicholls, I.A.; O'Mahony, J.; Whitcombe, M.J. Molecular imprinting science and technology: A survey of the literature for the years up to and including 2003. Journal of Molecular Recognition 2006, 19, 106-180.

    (2)      Andersson, L.I. Efficient sample pre-concentration of bupivacaine from human plasma by solid-phase extraction on molecularly imprinted polymers. Analyst 2000, 125, 1515-1517.

    (3)      Karlsson, J.G.; Andersson, L.I.; Nicholls, I.A. Probing the molecular basis for ligand-selective recognition in molecularly imprinted polymers selective for the local anaesthetic bupivacaine. Analytica Chimica Acta 2001, 435, 57-64.

    (4)      Karlsson, J.G.; Karlsson, B.; Andersson, L.I.; Nicholls, I.A. The roles of template complexation and ligand binding conditions on recognition in bupivacaine molecularly imprinted polymers. Analyst 2004, 129, 456-462.

    (5)      Nicholls, I.A.; Andersson, H.S.; Charlton, C.; Henschel, H.; Karlsson, B.C.G.; Karlsson, J.G.; O’Mahony, J.; Rosengren, A.M.; Rosengren, K.J.; Wikman, S. Theoretical and computational strategies for rational molecularly imprinted polymer design. Biosensors and Bioelectronics 2009, 25, 543-552.

    (6)      Rosengren, A.M.; Karlsson, J.G.; Andersson, P.O.; Nicholls, I.A. Chemometric models of template-molecularly imprinted polymer binding. Analytical Chemistry 2005, 77, 5700-5705.

    (7)      Rosengren, A.M; Golker, K.; Wiklander, J.G.; Nicholls, I.A. Dielectric constants are not enough: Principal component analysis of the influence of solvent properties on molecularly imprinted polymer–ligand rebinding. Biosensors and Bioelectronics 2009, 25, 553-557.

  • 41.
    Rosengren, Annika M.
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Golker, Kerstin
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Wiklander, Jesper G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Principal component analysis of the influence of solvent properties on molecularly imprinted polymer–ligand rebinding2010Conference paper (Refereed)
    Abstract [en]

    Molecular imprinting is a technique for creating polymeric recognition materials with predetermined ligand selectivities.1 A molecularly imprinted polymer (MIP) with selectivity for the local anaesthetic bupivacaine has been synthesised in order to examine the physical mechanisms underlying MIP–ligand recognition characteristics. As rebinding characteristics has shown to be complex, we use chemometric strategies for the analysis of ligand-MIP binding in various media.2-4 The use of chemometrics simplify the selection of optimal experimental parameters as well as the extraction of significant information generated from multivariate data analysis.5

    Previously we have presented results from a chemometric analysis pointing at a complex non-linear relationship when studying binding of bupivacaine to the MIP in different solvent mixtures and at different temperatures.6 The results motivated an investigation into the significance of the solvent physical characteristics (molecular and bulk) on rebinding properties. In this work, principal component analysis was employed to identify the factors with the greatest influence on binding. While the dielectric constant made a significant contribution to describing the observed binding, the influence of polarity as reflected in the Snyder polarity index was also demonstrated to make a significant contribution. The use of solvents containing hydroxyl functionality was observed to exert unique effects on recognition. The variation in solvent influence on binding at constant dielectricity motivates more complex analyses when studying MIP-ligand recognition. Collectively, the results provided general insights concerning the complex interplay between the mechanisms controlling ligand recognition in MIPs.

     

    References

    1. Alexander, C.; Andersson, H.S.; Andersson, L.I.; Ansell, R.J.; Kirsch, N.; Nicholls, I.A.; O’Mahony, J.; Whitcombe, M.J. Journal of Molecular Recognition 2006, 19, 106-180.
    2. Andersson, L.I. Analyst 2000, 125, 1515-1517.
    3. Karlsson, J.G.; Andersson, L.I.; Nicholls, I.A. Analytica Chimica Acta 2001, 435, 57-64.
    4. Karlsson, J.G.; Karlsson, B.; Andersson, L.I.; Nicholls, I.A. Analyst 2004, 129, 456-462.
    5. Nicholls, I.A.; Andersson, H.S.; Charlton, C.; Henschel, H.; Karlsson, B.C.G.; Karlsson, J.G.; O’Mahony, J.; Rosengren, A.M.; Rosengren, K.J.; Wikman, S. Biosensors and Bioelectronics 2009, 25, 543-552.
    6. Rosengren, A.M.; Karlsson, J.G.; Andersson, P.O.; Nicholls, I.A. Analytical Chemistry 2005, 77, 5700-5705.
  • 42.
    Rosengren, Annika M.
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Golker, Kerstin
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Wiklander, Jesper G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Principal component analysis of the influence of solvent properties on molecularly imprinted polymer–ligand rebinding2010Conference paper (Refereed)
    Abstract [en]

    A molecularly imprinted polymer (MIP) is a polymeric material with selective recognition for an analyte.1 In order to examine the physical mechanisms underlying MIP–ligand recognition, polymers with selectivity for the local anaesthetic bupivacaine have been synthesised and their ligand-recognition characteristics examined. As several previous studies have pointed at the complexity of the rebinding characteristics and the dependence on rebinding media,2-4 we used chemometric strategies for the analysis of ligand-MIP binding in various media.5

    In a previous study we presented results from a chemometric analysis showing that rebinding of bupivacaine to the MIP in different solvent mixtures and at different temperatures follow a complicated non-linear relationship.6 The results from that analysis, motivated an investigation into the significance of the solvent physical characteristics (molecular and bulk) on rebinding properties. In this work, principal component analysis was employed to identify the factors with the greatest influence on binding. While the dielectric constant made a significant contribution to describing the observed binding, the influence of polarity as reflected in the Snyder polarity index was also demonstrated to also make a significant contribution. The use of solvents containing hydroxyl functionality was observed to exert unique effects on recognition. The variation in solvent influence on binding at constant dielectricity motivates more complex analyses when studying MIP-ligand recognition.

     

    References

    1. Alexander, C.; Andersson, H.S.; Andersson, L.I.; Ansell, R.J.; Kirsch, N.; Nicholls, I.A.; O’Mahony, J.; Whitcombe, M.J. Journal of Molecular Recognition 2006, 19, 106-180.
    2. Andersson, L.I. Analyst 2000, 125, 1515-1517.
    3. Karlsson, J.G.; Andersson, L.I.; Nicholls, I.A. Analytica Chimica Acta 2001, 435, 57-64.
    4. Karlsson, J.G.; Karlsson, B.; Andersson, L.I.; Nicholls, I.A. Analyst 2004, 129, 456-462.
    5. Nicholls, I.A.; Andersson, H.S.; Charlton, C.; Henschel, H.; Karlsson, B.C.G.; Karlsson, J.G.; O’Mahony, J.; Rosengren, A.M.; Rosengren, K.J.; Wikman, S. Biosensors and Bioelectronics 2009, 25, 543-552.
    6. Rosengren, A.M.; Karlsson, J.G.; Andersson, P.O.; Nicholls, I.A. Analytical Chemistry 2005, 77, 5700-5705.
  • 43.
    Rosengren, Annika M.
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Morphology studies on warfarin imprinted polymers: the significance of the degree of crosslinking on polymer performance2010Conference paper (Refereed)
    Abstract [en]

    Warfarin is an oral anticoagulant drug, used in the treatment of thrombolic disorders.1 Since the therapeutic window of warfarin is narrow, careful monitoring of the effect of drug dosage is important. To date, the effect of warfarin treatment is monitored indirectly in which the clotting time (prothrombin time) is measured. The development of an alternative method, ideally both more robust and more sensitive, for the determination of warfarin effect on blood coagulation is desirable.

    It was envisaged that a warfarin-selective synthetic antibody prepared by molecular imprinting2 could provide the basis for the development of a novel method to facilitate the direct determination of warfarin in blood, and ideally even allow correlation the extent of patient blood coagulation. A large number of factors have been shown to be important and influence molecularly imprinted polymer (MIP) performance, such as type and amount of monomer incorporated in the final MIP matrix as well as rebinding media.3,4 Recent studies on polymer composition have pointed at the influence of the choice of monomer and template on the textural properties of a MIP.5-7

    We have prepared a series of warfarin imprinted methacrylic acid ethylene dimethacrylate co-polymers, with varying degrees of crosslinking, using a non-covalent molecular imprinting strategy. Characterization of polymer morphology and MIP-ligand radioligand binding studies were performed in order to understand the molecular basis for recognition in warfarin MIPs and to optimize polymer composition. Furthermore, we conclude that polymers prepared with a high degree of cross-linking demonstrated the highest binding capacity, however this rebinding is proposed to be predominately non-specific in character. In contrast, the co-existence of specific and non-specific binding was found within polymers with meso- and macroporous size distributions. Finally, detailed investigations of warfarin-MIP rebinding revealed that the optimal polymer composition was represented by a material with a narrow population of pores (~3-4 nm), a size range similar to the diameter of warfarin (~1 nm).

    (1)      Landefeld, C.; Beyth, R. Anticoagulant-related bleeding - epidemiology, prediction and prevention. American Journal of Medicine 1993, 95, 315-328

    (2)      Alexander, C.; Andersson, H.S.; Andersson, L.I.; Ansell, R.J.; Kirsch, N.; Nicholls, I.A.; O'Mahony, J.; Whitcombe, M.J. Molecular imprinting science and technology: A survey of the literature for the years up to and including 2003. Journal of Molecular Recognition 2006, 19, 106-180.

    (3)      Kempe, H.; Kempe, M. Novel method for the synthesis of molecularly imprinted polymer bead libraries. Macromolecular Rapid Communications 2004, 25, 315-320.

    (4)      Rosengren, A.M.; Karlsson, J.G.; Andersson, P.O.; Nicholls, I.A. Chemometric models of template-molecularly imprinted polymer binding. Analytical Chemistry 2005, 77, 5700-5705.

    (5)      O'Mahony, J.; Molinelli, A.; Nolan, K.; Smyth, M.; Mizaikoff, B. Anatomy of a successful imprint: Analysing the recognition mechanisms of a molecularly imprinted polymer for quercetin. Biosensors and Bioelectronics 2006, 21, 1383-1392.

    (6)      Al Kobaisi, M.; Tate, M.; Rix, C.; Jakubov, T.; Mainwaring, D. The effect of molecular imprinting on the pore size distribution of polymers. Adsorption 2007, 13, 315-321.

    (7)      Urraca, J. L.; Carbajo, M. C.; Torralvo, M. J.; González-Vázquez, J.; Orellana, G.; Moreno-Bondi, M. C. Effect of the template and functional monomer on the textural properties of molecularly imprinted polymers. Biosensors and Bioelectronics 2008, 24, 155-161.

  • 44.
    Rosengren, Annika M.
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Näslund, Inga
    Andersson, Per Ola
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    In situ detection of warfarin using time-correlated single-photon counting.2011In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 407, no 1, p. 60-62Article in journal (Refereed)
    Abstract [en]

    Here we report on a novel method for the direct in situ measurement of specific isomeric forms of the anticoagulant warfarin using time correlated single-photon counting (TCSPC) spectroscopy in conjunction with synthetic Sudlow I binding site receptors. The method is highly robust over the clinically significant concentration range, and demonstrates the potential of the binding site mimics in conjunction with the spectroscopic strategy employed here for the determination of this important pharmaceutical in clinical or even environmental samples.

  • 45.
    Rosengren, Annika M.
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Näslund, Inga
    FOI, Swedish Defence Research Agency.
    Andersson, Per Ola
    FOI, Swedish Defence Research Agency.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Time Resolved Fluorescence Spectroscopic Detection of the Anticoagulant Warfarin: A Sensor-based Method for Direct Detection in Blood-plasma2010Conference paper (Refereed)
    Abstract [en]

    Warfarin is a clinically important drug widely used in the treatment of thrombolic disorders such as myocardial infarction and stroke [1]. When administered, 99% of the drug present in blood is bound to the transport protein human serum albumin (HSA) [2]. On account of the fact that HSA demonstrates polymorphism and warfarin has a narrow therapeutic window, careful monitoring of the effect of drug-dosage must be performed. Currently, warfarin’s anticoagulant effect is measured by an indirect method in which the clotting time is measured and correlated to the amount of warfarin present. As current methods for self-monitoring are limited, the development of alternative robust and more sensitive methods is desirable.

    Molecular imprinting is a technique for the preparation of synthetic polymeric receptors (MIPs) with selective recognition for predetermined analyte [3]. In this study [4], we have used a non-covalent MIP system with selectivity for warfarin. The HSA-like binding properties of this MIP was developed from previous attempts to develop polymers with HSA-like binding of warfarin [5].

    In principle the fluorophoric nature of warfarin should allow for the fluorescence spectroscopy-based detection of the drug. Recent efforts by us [6-8], using a series of theoretical and spectroscopic studies, have highlighted the complex nature of warfarin. In particular, the medium dependent isomerization of this drug illustrates why spectroscopy-based methods for the direct detection of the drug has not been forthcoming. Results from these studies have been used to develop a method for the in situ detection of warfarin using time correlated single photon counting (TCSPC). The application of this method for the detection of warfarin in blood is highlighted.

    References

    1. Landefeld, C.; Beyth, R. Am. J. Med. 1993, 95, 315-328.
    2. Yacobi, A.; Udall, J. A.; Levy, G. Clin. Pharmacol. Ther. 1976, 19, 552-558.
    3. Alexander, C.; Andersson, H. S.; Andersson, L. I.; Ansell, R. J.; Kirsch, N.; Nicholls, I. A.; O’Mahony, J.; Whitcombe, M. J. J. Mol. Recognit. 2006, 19, 106-180.
    4. Rosengren, A. M.; Karlsson, B. C. G.; Näslund, I.; Andersson, P. O.; Nicholls, I. A. 2010, Submitted.
    5. Karlsson, B. C. G.; Rosengren, A. M.; Näslund, I.; Andersson, P. O.; Nicholls, I. A. 2010, Submitted.
    6. Karlsson, B. C. G.; Rosengren, A. M.; Andersson, P. O.; Nicholls, I. A. J. Phys. Chem. B 2007, 111, 10520-10528.
    7. Karlsson, B. C. G.; Rosengren, A. M.; Andersson, P. O.; Nicholls, I. A. J. Phys. Chem. B 2009, 113, 7945-7949.
    8. Nicholls, I. A.; Karlsson, B. C. G., Rosengren, A. M. J. Mol. Recognit. 2010, in press.
  • 46.
    Rosengren-Holmberg, Jenny P.
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Karlsson, Jesper G.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Svenson, Johan
    Andersson, Håkan S.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Nicholls, Ian A.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Synthesis and ligand recognition of paracetamol selective polymers: semi-covalent versus non-covalent molecular imprinting.2009In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 7, p. 3148-3155Article in journal (Refereed)
    Abstract [en]

    Three molecular imprinting strategies, each based upon a series of ethylene glycol dimethacrylate (EGDMA) cross-linked co-polymers, have been used to produce materials selective for the commonly used analgesic and antipyretic agent paracetamol (p-acetaminophen or 4-acetamidophenol) (1). The polymers were synthesised using either a semi-covalent imprinting strategy based upon 4-acetamidophenyl-(4-vinylphenyl) carbonate (4) or a non-covalent strategy based on methacrylic acid (MAA) as the functional monomer, or by employing a combination of these strategies. Radioligand binding studies demonstrated low template affinity in polymers offering only a single electrostatic interaction point for recognition via the phenolic residue in the template, whereas binding was substantially increased upon the introduction of a second binding mode, namely interaction at the acetamide moiety. HPLC analyses revealed no imprinting effect in the purely semi-covalent system, and only a minor effect in the purely non-covalent systems. However, a pronounced imprinting effect was demonstrated for polymers prepared by a combination of semi-covalent and non-covalent imprinting. This study illustrates a limitation of both the non-covalent and the semi-covalent strategies when it comes to achieving imprinted selectivity for small and poorly functionalised templates such as paracetamol. Parallels with conclusions from studies with antibodies are discussed. 

  • 47. Schillinger, Eric
    et al.
    Moeder, Monika
    Olsson, Gustaf D.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Sellergren, Borje
    An Artificial Estrogen Receptor through Combinatorial Imprinting2012In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, no 46, p. 14773-14783Article in journal (Refereed)
    Abstract [en]

    Polymeric sorbents targeting endocrine-disrupting estrogen active compounds (EAC) were prepared by terpolymer imprinting using 17 beta-estradiol (E2) as template. From a group of eight functional monomers representing Bronsted acids, bases, hydrogen-bond donors and acceptors, as well as pi-interacting monomers, a terpolymer library that comprises all possible binary combinations of the functional monomers was prepared. Binding tests revealed that imprinted polymers exhibit a markedly higher affinity for E2 compared to nonimprinted polymers (NIPs) or polymers prepared by using single functional monomers. A combination of methacrylic acid (MAA) and p-vinylbenzoic acid offered a particularly promising lead polymer, displaying an imprinting factor of 17 versus 2.4 for a benchmark polymer prepared by using only MAA as functional monomer. The saturation capacities ascribed to imprinted sites were four to five times higher for this polymer compared to previously reported imprinted polymers. NMR titrations and molecular dynamics simulations corroborated these results, indicating an orthogonal preference of the two functional monomers with respect to the E2 3-OH and 17-OH groups. The optimized polymer exhibited a retentivity for EACs that correlates with their inhibitory effect on the natural receptor. By using the optimized molecularly imprinted polymers (MIPs) in a model water-purification system, they were capable of completely removing ppb levels of a small group of EACs from water. This is in contrast to the performance of nonimprinted polymers and well-established sorbents for water purification (e.g., active carbon), which still contained detectable amounts of the compounds after treatment.

  • 48.
    Shoravi, Siamak
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Olsson, Gustaf D.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Molecular dynamics study of mechanisms underlying propranolol-mip molecular memory and the role of cross-linker2010Conference paper (Refereed)
    Abstract [en]

    Fundamental studies of molecularly imprinted polymer1 (MIP) systems are necessary in order to facilitate the development of the field in general, in particular through the development of rational MIP design strategies.2 Recent efforts using molecular dynamics studies of all-component molecular imprinting systems have demonstrated the unique insights that can be obtained regarding the massive diversity of interactions present in a given system.3

    One of the most widely used templates in molecular imprinting is the beta-blocker propranolol.4-8 Its use in fundamental studies and for providing proof-of-principle cases has been motivated by a number of factors including its clinical relevance, its inherent chirality, and availability in enantiomerically pure and radio-labelled forms. Significant efforts have been made to map the molecular basis for propranolol-MIP ligand recognition, though never through the simultaneous study of all components present during polymerization.

    Here we present the first all component MD study of this system which has provided unique insights concerning, in particular the role of cross-linking agent on template complexation. Through correlations with recognition data, consequences for MIP design are proposed.

    (1)      Alexander, C.; Andersson, H.S.; Andersson, L.I.; Ansell, R.J.; Kirsch, N.; Nicholls, I.A.; O'Mahony, J.; Whitcombe, M.J. J. Mol. Recognit. 2006, 19, 106-180.

    (2)      Nicholls, I. A.; Andersson, H. S.; Charlton, C.; Henschel, H.; Karlsson, B. C. G.; Karlsson, J. G.; O´Mahony, J.; Rosengren, A. M.; Rosengren, K. J.; Wikman, S. Biosens. Bioelectron. 2009, 25, 543-552.

    (3)      Karlsson, B. C. G.; O´Mahony, J.; Karlsson, J. G.; Bengtsson, H.; Eriksson, L. A.; Nicholls, I. A. J. Am. Chem. Soc., 2009, 131, 13297-13304.

    (4)      Andersson, L.I. Anal. Chem. 1996, 68, 111-117.

    (5)      Schweitz, L.; Andersson, L.I.; Nilsson, S. Anal. Chem. 1997, 69, 1179-1183.

    (6)      Haupt, K.; Noworyta, K.; Kutner, W. Anal. Commun. 1999, 36, 391-393.

    (7)      Philip, J.Y.N.; Buchweishaija, J.; Mkayula, L.L.; Ye, L. J. Agric Food Sci. 2007, 55, 8870-8876.

    (8)      Nguyen, T.H.; Ansell, R.J. Org. Biomol. Chem. 2009, 7, 1211-1220.

     

  • 49.
    Shoravi, Siamak
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Olsson, Gustaf D.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Bexborn, Fredrik
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Abghoui, Younes
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Hussain, Javed
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Wiklander, Jesper G.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Uppsala University.
    In silico screening of molecular imprinting prepolymerization systems: oseltamivir selective polymers through full-system molecular dynamics-based studies2016In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 14, no 18, p. 4210-4219Article in journal (Refereed)
    Abstract [en]

    All-component molecular dynamics studies were used to probe a library of oseltamivir molecularly imprinted polymer prepolymerization mixtures. Polymers included one of five functional monomers (acrylamide, hydroxyethylmethacrylate, methacrylic acid, 2-(triflouromethyl)acrylic acid, 4-vinylpyridine) and one of three porogens (acetonitrile, chloroform, methanol) combined with the crosslinking agent ethylene glycol dimethacrylate and initiator 2,2'-azobis(2-methylpropionitrile). Polymers were characterized by nitrogen gas sorption measurements and SEM, and affinity studies performed using radioligand binding in various media. In agreement with the predictions made from the simulations, polymers prepared in acetonitrile using either methacrylic or trifluoromethacrylic acid demonstrated the highest affinities for oseltamivir. Further, the ensemble of interactions observed in the methanol system provided an explanation for the morphology of polymers prepared in this solvent. The materials developed here offer potential for use in solid-phase extraction or for catalysis. The results illustrate the strength of this in silico strategy as a potential prognostic tool in molecularly imprinted polymer design.

  • 50.
    Shoravi, Siamak
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Olsson, Gustaf D.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Karlsson, Björn C. G.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Uppsala University.
    On the Influence of Crosslinker on Template Complexation in Molecularly Imprinted Polymers: A Computational Study of Prepolymerization Mixture Events with Correlations to Template-Polymer Recognition Behavior and NMR Spectroscopic Studies2014In: International Journal of Molecular Sciences, ISSN 1422-0067, E-ISSN 1422-0067, Vol. 15, no 6, p. 10622-10634Article in journal (Refereed)
    Abstract [en]

    Aspects of the molecular-level basis for the function of ethylene glycol dimethacrylate and trimethylolproprane trimethacrylate crosslinked methacrylic acid copolymers molecularly imprinted with (S)-propranolol have been studied using a series of all-component and all-atom molecular dynamics studies of the corresponding prepolymerization systems. The crosslinking agents were observed to contribute to template complexation, and the results were contrasted with previously reported template-recognition behavior of the corresponding polymers. Differences in the extent to which the two crosslinkers interacted with the functional monomer were identified, and correlations were made to polymer-ligand recognition behavior and the results of nuclear magnetic resonance spectroscopic studies studies. This study demonstrates the importance of considering the functional monomer-crosslinker interaction when designing molecularly imprinted polymers, and highlights the often neglected general contribution of crosslinker to determining the nature of molecularly imprinted polymer-template selectivity.

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