Well-defined lactose-containing polymer grafted onto silica particles

Reversible addition-fragmentation chain transfer (RAFT) polymerization of 2-O-meth-acryloyloxyethoxyl-(2,3,4,6-tetra-O-acetyl-beta-D-galactopyranosyl)-(1-4)-2,3,6-tri-O-acetyl-beta-D-glucopyranoside (MAEL) was performed directly in CHCl3 solutions using cumyl dithiobenzoate (CDB) as the chain transfer agent to give well-defined glycopolymers. The chemical composition and structure of the glycopolymer were characterized by 1HNMR, FTIR, and SEC. The living glycopolymer chains were subsequently grafted onto gamma-methacryloxypropyl-trimethoxy (MPTMS) modified silica particles. The acetyl groups of the poly(MAEL) grafted onto the silica gel particles were converted to the hydroxyl groups with CH3ONa/CH3OH, thus obtaining silica gel particles modified with well-defined lactose-carrying polymer.     

Functional polymer brushes via surface-initiated atom transfer radical graft polymerization for combating marine biofouling

Dense and uniform polymer brush coatings were developed to combat marine biofouling. Nonionic hydrophilic, nonionic hydrophobic, cationic, anionic and zwitterionic polymer brush coatings were synthesized via surface-initiated atom transfer radical polymerization (SI-ATRP) of 2-hydroxyethyl methacrylate, 2,3,4,5,6-pentafluorostyrene, 2-(methacryloyloxy)ethyl trimethylammonium chloride, 4-styrenesulfonic acid sodium and N,N'-dimethyl-(methylmethacryloyl ethyl) ammonium propanesulfonate, respectively. The functionalized surfaces had different efficacies in preventing adsorption of bovine serum albumin (BSA), adhesion of the Gram-negative bacterium Pseudomonas sp. NCIMB 2021 and the Gram-positive Staphylococcus aureus, and settlement of cyprids of the barnacle Amphibalanus amphitrite (=Balanus amphitrite). The nonionic hydrophilic, anionic and zwitterionic polymer brushes resisted BSA adsorption during a 2?h exposure period. The nonionic hydrophilic, cationic and zwitterionic brushes exhibited resistance to bacterial fouling (24?h exposure) and cyprid settlement (24 and 48?h incubation). The hydrophobic brushes moderately reduced protein adsorption, and bacteria and cyprid settlement. The anionic brushes were least effective in preventing attachment of bacteria and barnacle cyprids. Thus, the best approach to combat biofouling involves a combination of nonionic hydrophilic and zwitterionic polymer brush coatings on material surfaces.     

Functional polymer brushes via surface-initiated atom transfer radical graft polymerization for combating marine biofouling

Dense and uniform polymer brush coatings were developed to combat marine biofouling. Nonionic hydrophilic, nonionic hydrophobic, cationic, anionic and zwitterionic polymer brush coatings were synthesized via surface-initiated atom transfer radical polymerization (SI-ATRP) of 2-hydroxyethyl methacrylate, 2,3,4,5,6-pentafluorostyrene, 2-(methacryloyloxy)ethyl trimethylammonium chloride, 4-styrenesulfonic acid sodium and N,N′-dimethyl-(methylmethacryloyl ethyl) ammonium propanesulfonate, respectively. The functionalized surfaces had different efficacies in preventing adsorption of bovine serum albumin (BSA), adhesion of the Gram-negative bacterium Pseudomonas sp. NCIMB 2021 and the Gram-positive Staphylococcus aureus, and settlement of cyprids of the barnacle Amphibalanus amphitrite (=Balanus amphitrite). The nonionic hydrophilic, anionic and zwitterionic polymer brushes resisted BSA adsorption during a 2 h exposure period. The nonionic hydrophilic, cationic and zwitterionic brushes exhibited resistance to bacterial fouling (24 h exposure) and cyprid settlement (24 and 48 h incubation). The hydrophobic brushes moderately reduced protein adsorption, and bacteria and cyprid settlement. The anionic brushes were least effective in preventing attachment of bacteria and barnacle cyprids. Thus, the best approach to combat biofouling involves a combination of nonionic hydrophilic and zwitterionic polymer brush coatings on material surfaces.     

Molecular imprinting of proteins and other macromolecules resulting in new adsorbents

When the model protein bovine serum albumin (BSA) was dissolved in a concentrated aqueous solution of the multifunctional ligand L-malic acid, the solution was lyophilized, and the solid residue thoroughly washed with tetrahydrofuran to extract malic acid, then the resultant ("imprinted") protein was capable of binding 26.4 +/-0.9 mol equivalents of the ligand in anhydrous ethyl acetate. The nonimprinted BSA (i.e., that prepared in the same manner apart from the absence of malic acid) bound less then one-tenth of that amount under identical conditions. Furthermore, both imprinted and nonimprinted BSA exhibited little binding of L-malic acid in water. The imprinted BSA retained its "memory" for the ligand in ethyl acetate even after a prolonged incubation under vacuum; dissolution in water, however, eliminated the imprinted protein's binding capacity. The BSA imprinted with L-malic acid displayed affinity for this ligand not only in ethyl acetate but also in many other anhydrous solvents. It was found that the higher the solvent's propensity to form hydrogen bonds, the lower the protein-ligand binding in it, thus pointing to hydrogen bonds as the driving force of this binding. Studies with completely or partially cleaved BSA, with other globular proteins, glutathione, and poly(L-aspartic acid) revealed that the critical requirement for the imprintability is the presence of a sufficiently long polymeric chain. Moreover, many hydrogen-bond-forming macromolecules other than proteins, such as dextrans and their derivatives, partially hydrolyzed starch, and poly(methacrylic acid), also could be imprinted for subsequent binding in ethyl acetate. The mechanism of imprinting and binding inferred from these experiments involves a multipoint hydrogen bonding in water of each ligand molecule with two or more sites on the polymeric chain, thereby folding a segment of the latter into a cavity around the ligand; following lyophilization and extraction of the ligand, the cavities remain in organic solvents (but not in water) and give rise to ligand binding. This conclusion is supported by the results of binding of numerous malic acid analogs and related ligands to BSA imprinted with L-malic acid. Finally, BSA imprinted with malic acid was used as a selective adsorbent for a chromatographic separation of an equimolar mixture of maleic and acrylic acids in ethyl acetate.     

Protein osmotic pressure and the state of water in frog myoplasm

We measured the osmotic pressure of diffusible myoplasmic proteins in frog (Rana temporaria) skeletal muscle fibers by using single Sephadex beads as osmometers and dialysis membranes as protein filters. The state of the myoplasmic water was probed by determining the osmotic coefficient of parvalbumin, a small, abundant diffusible protein distributed throughout the fluid myoplasm. Tiny sections of membrane (3.5- and 12-14-kDa cutoffs) were juxtaposed between the Sephadex beads and skinned semitendinosus muscle fibers under oil. After equilibration, the beads were removed and calibrated by comparing the diameter of each bead to its diameter measured in solutions containing 3-12% Dextran T500 (a long-chain polymer). The method was validated using 4% agarose cylinders loaded with bovine serum albumin (BSA) or parvalbumin. The measured osmotic pressures for 1.5 and 3.0 mM BSA were similar to those calculated by others. The mean osmotic pressure produced by the myoplasmic proteins was 9.7 mOsm (4 degrees C). The osmotic pressure attributable to parvalbumin was estimated to be 3.4 mOsm. The osmotic coefficient of the parvalbumin in fibers is approximately 3.7 mOsm mM(-1), i.e., roughly the same as obtained from parvalbumin-loaded agarose cylinders under comparable conditions, suggesting that the fluid interior of muscle resembles a simple salt solution as in a 4% agarose gel.     

Capacitated acrosome-intact mouse spermatozoa bind to Sepharose beads coated with functional neoglycoproteins

Capacitated acrosome-intact mouse spermatozoa bind to the egg's extracellular coat, the zona pellucida (ZP), in a carbohydrate-mediated receptor-ligand manner. The tight irreversible binding of the opposite gametes triggers a signal transduction pathway resulting in the exocytosis of acrosomal contents (i.e., induction of the acrosome reaction [AR]). Previously, we demonstrated that a hexose (mannose) and two amino sugars (N-acetylglucosamine and N-acetylgalactosamine), when covalently conjugated to bovine serum albumin (BSA) (functional neoglycoproteins, ngps), mimicked mZP3 and induced the AR [Biol. Reprod. 60 (1999) 94-101]. To further elucidate the specificity of sperm-ngp interaction and the mZP3 mimicking role of the functional ngps, we have examined binding of the mouse spermatozoa to Sepharose 4B beads coated with the functional and non-functional ngps as well as BSA, ovalbumin (OVA), or asialofetuin (ASF). A significantly greater number of capacitated acrosome-intact spermatozoa bound to the beads coated with functional ngps than the beads coated with non-functional ngps, BSA, OVA, or ASF. The binding was temperature-sensitive and was highest when the sperm-bead assay was carried out at 37 degrees C. Blocking of in vitro capacitation, by including calmodulin antagonists in the incubation medium, prevented sperm from binding to the beads. Furthermore, inclusion of free sugars (mannose, N-acetylglucosamine, or N-acetylgalactosamine) in the binding assay, either individually or as a mixture, inhibited sperm-bead binding in a concentration-dependent manner. Taken together, our data provide evidence strongly suggesting that binding of capacitated spermatozoa to the ngp-coated Sepharose beads is specific. The beads that mimic zona-intact eggs provide an excellent tool for examining pharmacological effects of reagents that alter the sperm function. In addition, the immobilized ngp(s) will be useful as an affinity medium to isolate the sperm surface receptor(s) that recognize and bind to the sugar residues.     

Exploring structural change of protein bovine serum albumin by external perturbation using extrinsic fluorescence probe: spectroscopic measurement, molecular docking and molecular dynamics simulation

Structural modification through binding interaction of plasma protein bovine serum albumin (BSA) with an extrinsic charge transfer fluorophore 5-(4-dimethylamino-phenyl)-penta-2,4-dienoic acid (DMAPPDA) and its response to external perturbation due to interactions with surfactant sodium dodecyl sulphate (SDS) have been explored at physiological pH by steady state absorption, emission, fluorescence anisotropy, red edge excitation shift, far-UV circular dichroism and time resolved spectral measurements in combination with Molecular Docking and Molecular Dynamics (MD) simulation. Interaction of the probe with BSA is reflected by a small change in protein secondary structure with fluorescence enhancement and blue shift of probe emission. Molecular docking studies revealed that the probe binds to the hydrophobic cavity of sub-domain IIA of BSA. The distance for energy transfer from the tryptophan of BSA to the bound DMAPPDA measured by Fluorescence Resonance Energy Transfer is in good agreement with the molecular docking results. MD simulation predicts stabilization of the complex with respect to the bare molecule. Interaction of BSA and SDS with DMAPPDA supports the movement of the probe from hydrophilic free water region to a more restricted hydrophobic zone inside the protein.     

Copolymers including L-histidine and hydrophobic moiety for preparation of nonbiofouling surface

A new type of copolymer composed of l-histidine (ampholyte) and n-butyl methacrylate (hydrophobic moiety) was developed for the preparation of nonbiofouling surfaces. The copolymer adsorbed onto resin surfaces and made the surface very hydrophilic. The hydrophilization effect was higher than that of bovine serum albumin (BSA). When polystyrene surfaces were coated with the copolymer, both the nonspecific adsorption of protein and the adhesion of cells were significantly reduced in comparison with BSA coating. The newly synthesized polymer is a new and useful candidate for the preparation of nonbiofouling surfaces.     

Fabrication of a surface imprinted hydrogel shell over silica microspheres using bovine serum albumin as a model protein template

Surface imprinting is an effective approach to improve the template transfer efficiency in applications of molecularly imprinted polymers as biosensors and separation materials. In this paper, we tried to fabricate a surface imprinted hydrogel over silica microspheres for selective recognition of bovine serum albumin by covalent immobilization of a water-soluble UV sensitive initiator onto the surface of silica beads. The polymerization was initiated by UV radiation with N-[3-(dimethylamino)propyl]methacrylamide and N-isopropylacrylamide as the functional monomer and assistant monomer, respectively, and a thin coat of stimuli-responsive hydrogel yielded over the silica gels. The surface imprinted hydrogels exhibited specific affinity toward the template protein with an association constant (K_a) of 2.2 × 10⁵ L mol⁻¹ and a maximum binding capacity (Q_max) of 27.3 mg g⁻¹ in Tris–HCl buffer (pH 7.0). The rebinding and desorption kinetics of the surface imprinted hydrogels were determined and proven to be extremely fast (about 1 min compared to 3 h for the previously prepared bulk imprinted hydrogel). Besides, the hydrogel-silica core-shell particles inherit both the stimuli-responsive property of the hydrogel and the good mechanical strength of the silica beads based on the on-line evaluation with high-performance liquid chromatography. The above comprehensive merits of the obtained surface imprinted hydrogel suggest the presented approach an attractive and broadly applicable way of developing biosensors and high-performance protein separation materials.     

Molecular imprinting in monolayer surfaces

A comprehensive report on molecularly imprinted monolayers (MIMs) is presented, but does not include bulk-polymer thin film coatings on surfaces, inorganic surface imprinting, polymer grafting and layer-by-layer methods. Due to difficulties in imprinting large molecules and obtaining fast binding responses with traditional network polymer materials, MIMs have been developed with the aim of enhancing mass-transfer of analytes in imprinted materials. Three approaches to MIM fabrication have been developed with respect to the formation of the pre-organized template-matrix complex. In the first approach, the molecular binding sites are formed in a monolayer on a glass or gold surface. The second approach uses a template-macromolecule complex to form binding sites in the solution phase that are immobilized onto a surface; and the third approach transfers an imprinted Langmuir film onto a gold surface. Mass transfer in these MIMs in most cases is on the order of minutes, and both small and large molecules (proteins) have been imprinted.     

Synthesis of various glycopolymer architectures via RAFT polymerization: from block copolymers to stars

Well-defined linear poly(acryloyl glucosamine) (PAGA) exhibiting molar masses ranging from 3 to 120 K and low polydispersities have been prepared via reversible addition-fragmentation chain transfer polymerization (RAFT) in aqueous solution without recourse to protecting group chemistry. The livingness of the process was further demonstrated by successfully chain-extending one of these polymers with N-isopropylacrylamide affording narrow dispersed thermosensitive diblocks. This strategy of polymerization was finally extended to the preparation of glycopolymer stars from Z designed non-water-soluble trifunctional RAFT agent. After the growth of very short blocks of poly(hydroxyethyl acrylate) ((-)DP(n)(branch) = 10), AGA was polymerized in aqueous solution in a controlled manner affording well-defined 3-arm glycopolymer stars.     

A low-serum medium with BSA and ferrous sulfate for the production of tissue plasminogen activator by human embryo lung cells

A low-serum medium containing bovine serum albumin (BSA) was investigated with respect to the growth of and tissue plasminogen activator (TPA) production by human embryo lung (HEL) cells on microcarrier beads and in collagen gel. BSA and ferrous sulfate were chosen as substitutes for fetal calf serum (FCS) through a simple screening test involving many substances. The growth promoting effects of BSA and ferrous sulfate were independent of each other and from the FCS concentration. Though BSA inhibited initial cell attachment to the carrier surface, it did promote the growth of cells attached to microcarrier beads. Cells grown on microcarrier beads in the low-serum medium containing BSA, ferrous sulfate and 3% FCS produced an amount of TPA similar to that produced by ones grown in the 10% FCS medium. Although cells on the dish surface did not grow at all on serum-free media containing BSA and ferrous sulfate, cells in the collagen gel were able to grow slightly on the serum-free medium. Cells grown on the low-serum medium in collagen gel produced more TPA over a long period than those in the microcarrier beads using the low-serum medium. The optimum concentration of proteose peptone in the TPA production medium for the collagen gel culture was similar to that for the dish surface culture.     

Nucleation of calcium oxalate crystals on an imprinted polymer surface from pure aqueous solution and urine

Calcium oxalate (CaOx) is the most common component of human kidney stones. Heterogeneous nucleation is regarded as the key mechanism in this process. In this study, we have used an imprinted 6-methacrylamidohexanoic acid/divinylbenzene co-polymer as a biomimetic surface to nucleate CaOx crystal formation. The polymer was imprinted with either calcium oxalate monohydrate (COM) or dihydrate (COD) template crystals. These were washed out of the polymer, which was then immersed in various test solutions. The test solutions were an aqueous solution of calcium chloride and sodium oxalate, artificial urine and a sample of real urine. Crystals that formed on the polymer surface were characterized by X-ray powder diffraction, Fourier transform infrared spectroscopy, atomic absorption spectroscopy and scanning electron microscopy. Results showed that in the aqueous solution the COM-imprinted polymer induced the nucleation of COM. The COD-imprinted polymer induced only trace amounts of COD crystallization, together with larger quantities of COM. In artificial and real urines, COM also specifically precipitated on the COM-imprinted surface. The results show that, at least to some extent, the imprinted polymers direct formation of their morphologically matched crystals. In the case of COD, however, it appears that either rapid hydrate transformation of COD to COM occurs, or the more stable COM polymorph is directly co-precipitated by the polymer. Our results support the hypothesis that heterogeneous nucleation plays a key role in CaOx stone formation and that the imprinted polymer model could provide an additional and superior diagnostic tool for stone researchers to assess stone-risk in urine.Abbreviations COD calcium oxalate dihydrate - COM calcium oxalate monohydrate - COT calcium oxalate trihydrate - dvb divinylbenzene - 6-maaha 6-methylacrylamidohexanoic acid     

New strategy in glycopolymer synthesis. Preparation of antigenic water-soluble poly(acrylamide-co-p-acrylamidophenyl beta-lactoside).

Stereospecific phase-transfer-catalyzed glycosidation of acetobromolactose 3 with p-nitrophenoxide gave the peracetylated 1,2-trans-beta-D-4-nitrophenyl lactoside 4. Functionalization of 4 into an N-acryloyl monomer was achieved by catalytic transfer hydrogenation of the nitro group, followed by N-acryloylation of the resulting amino group, on both O-acetyl-protected and unprotected disaccharides. Copolymerization of 4-acrylamidophenyl beta-lactoside (9) with acrylamide, initiated by ammonium persulfate, afforded a water-soluble carbohydrate copolymer (glycopolymer). The antigenicity of the new polymer was demonstrated by agar gel diffusion with Arachis hypogaea (peanut) and Ricinus communis (castor bean) lectins. Quantitative precipitation and enzyme linked lectin assays (ELLA) were also performed with peanut lectin.     

Synthetic cinchonidine receptors obtained by cross-linking linear poly(methacrylic acid) derivatives as an alternative molecular imprinting technique

A molecular imprinting approach to construct synthetic receptors was examined, wherein a linear pre-polymer bearing functional groups for intermolecular interaction with a given molecule is cross-linked in the presence of the molecule as a template, and subsequent removal of the template from the resultant network-polymer is expected to leave a complementary binding site. Poly(methacrylic acid) (PMAA) derivatized with a vinylbenzyl group as a cross-linkable side chain was utilized as the pre-polymer for the molecular imprinting of a model template, (-)-cinchonidine. Selectivity of the imprinted polymer was evaluated by comparing the retentions of the original template, (-)-cinchonidine and its antipode (+)-cinchonine in chromatographic tests, exhibiting a selectivity factor up to 2.4. By assessment of the imprinted polymers in a batch mode, a dissociation constant at 20 degrees C for (-)-cinchonidine was estimated to be K (d) = 2.35 x 10(-6) M (the number of binding sites: 4.54 x 10(-6) mol/g-dry polymer). The displayed affinity and selectivity appeared comparable to those of an imprinted polymer prepared by a conventional monomer-based protocol, thus showing that the pre-polymer, which can be densely cross-linked, is an alternative imprinter for developing template-selective materials. (-)-Cinchonidine-imprinted polymers were prepared and assessed using the pre-polymers bearing different densities of the vinylbenzyl group and different amounts of the cross-linking agent to examine the appropriate density of the cross-linking side chain that was crucial for developing the high affinity and selectivity of the imprinted polymers.     

Detection of Salmonella by indicator agar media and PCR as affected by alfalfa seed homogenates and native bacteria

AIMS: To investigate and prevent the undesirable effect of native bacteria and alfalfa seed homogenates on detection of Salmonella in alfalfa seeds by indicator agar media and polymerase chain reaction (PCR). METHODS AND RESULTS: The relative sensitivity of five indicator agar media, including modified semisolid RV (MSRV), xylose-lysine-Tergitol 4 (XLT4), Hektoen enteric agar (HEA), brilliant green agar (BGA) and bismuth sulphite agar (BSA), for detection of Salmonella in the presence of a large number of native bacteria from alfalfa seeds was examined. The detection limit as measured by the ratio between the numbers of native bacteria and Salmonella was estimated to be 10(6) to 1 for MSRV and 10(3) to 1 for XLT4, HEA, BGA or BSA. Presence of alfalfa seed homogenates markedly reduced the sensitivity of Salmonella detection by PCR. The minimal number of Salmonella detectable by PCR was determined to be 1-10 and 100-1000 CFU in the absence and presence of seed homogenate, respectively. Application of anti-Salmonella immunomagnetic beads permitted detection of 2-5 CFU of heat-injured cells in 25 g of seeds within 24 h by PCR. CONCLUSIONS: The MSRV medium is more sensitive than other indicator agars for detecting a small number of motile Salmonella in samples containing a large number of native bacteria. Application of immunomagnetic beads eliminates the PCR-inhibitory activity of seed homogenates and improves the detection of Salmonella in inoculated seeds. SIGNIFICANCE AND IMPACT: The results generated from this study will aid the seed distributors, sprout growers and public health officials to identify and recall the Salmonella-contaminated seed lots to be used for sprout production.     

Imprinted polymer layer for recognizing double-stranded DNA

A method of preparing a thin polymer layer able to recognize double-stranded DNA (dsDNA) was developed by using 2-vinyl-4,6-diamino-1,3,5-triazine (VDAT) as a functional monomer for creating a DNA-imprinted polymer. The formation of hydrogen bonds between VDAT and A-T base pairs in dsDNA was confirmed by measuring the effects of VDAT on the melting point and the NMR and CD spectra of dsDNA. An imprinted polymer that can recognize dsDNA of the verotoxin gene was prepared by polymerizing VDAT, acrylamide, a crosslinking agent, and the template verotoxin dsDNA on a silanized glass surface. The specificity of this polymer layer for binding verotoxin dsDNA was investigated by using fluorescent-labelled dsDNAs. The fluorescence intensity of the polymer layer after binding verotoxin dsDNA was twice as high as after binding oligo(dG)-oligo(dC), indicating that verotoxin dsDNA was preferentially bound to the polymer imprinted with verotoxin dsDNA. The kinetics of verotoxin dsDNA binding to the imprinted polymer were analyzed by surface plasmon resonance measurements. The dissociation constant (KD) was low, of the order of 10(-9)M.     

High biological activity of a recombinant protein immobilized onto polystyrene

The adsorption characteristics of glutathione S-transferases (GST) genetically fused with polystyrene (PS)-binding peptides (PS-tags) on PS plates with increase in hydrophilicity were studied to clarify the mechanisms of the specific interaction between the PS-tag-fused protein and PS plates. GST fused with the PS-tag PS19 (RAFIASRRIKRP) preferentially interacted with hydrophilic PS plates, even in the presence of high concentrations of competitors such as Tween 20 and BSA. Both basic and aliphatic amino acids in the PS-tags were involved in the specific interaction of PS-tags with the surface of the hydrophilic PS plate. Genetic fusion of the PS19 variants, PS19-4 (RAIARRIRR) and PS19-6 (RIIIRRIRR), further improved the immobilization yield of GST in the presence of a high concentration of the competitor BSA (50 mg/mL). The PS19-6 peptide specifically interacted with the surfaces of various hydrophilic PS plates, especially in the presence of Tween 20. Higher remaining activity was detected on all of the hydrophilic PS plates immobilized with GST-PS19-6 in comparison with those with wild-type GST and GST-PS19, and the remaining activity was further increased by the addition of Tween 20 in the adsorption state. The PS19-6 peptide developed in this study is therefore very useful as an affinity tag that can immobilize a target protein directly onto various hydrophilic PS supports with high remaining activity.     

Synthesis of imprinted beads by aqueous suspension polymerisation for chiral recognition of antihistamines

A novel non-stabilised aqueous suspension polymerisation methodology for the preparation of spherical molecularly imprinted polymers is described with chlorpheniramine (CP), d-chlorpheniramine (d-CP), brompheniramine (BP) and d-brompheniramine (d-BP) as the templates, respectively. Using this rapid and simple technique, controlled polymer beads in the low micron range with narrow size distributions were generated by photo-polymerisation. The use of agitation speed as a method of controlling bead size distribution was demonstrated. Enantioselective properties of the imprinted beads were examined and the polymers prepared using d-chlorpheniramine and d-brompheniramine were capable of discriminating between the enantiomers of the template. Cross-selectivity studies were performed by batch rebinding with the influence of template size and functional group orientation of analytes on the recognition properties of the imprinted polymers investigated. Physical characteristics of all polymers were studied by nitrogen sorption porosimetry, particle size analysis and scanning electron microscopy (SEM) in order to gain an insight into the role of such properties on retention behaviour.     

Regulation of cell adhesion signaling by synthetic glycopolymer matrix in primary cultured hepatocyte

Control of cell-matrix interactions is a central principle for the design of biomaterial in tissue engineering. In this study, we evaluated a synthetic glycopolymer, which is recognized by the asialoglycoprotein receptor (ASGPR) expressed on the surface of hepatocytes, as an artificial matrix to regulate integrin-mediated signaling. The phosphorylation of focal adhesion kinase was restricted in hepatocytes cultured on the glycopolymer compared with fibronectin. In addition, there was no reorganization of cytoskeleton-related proteins such as actin filaments, microtubules, and vinculin in hepatocytes cultured on the glycopolymer. DNA synthesis and cyclin D1 expression were suppressed in hepatocytes grown on the glycopolymer as compared with those grown on fibronectin and collagen. The data suggest that the glycopolymer will be a good artificial matrix to regulate integrin-mediated signaling and cell growth through the unique ASGPR-carbohydrate interaction.