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Protein-imprinted polyacrylamide (PAM)-grafted calcium alginate (CaA) microspheres were synthesized via free-radical grafting polymerization with potassium persulfate and sodium bisulfite as initiators. FTIR, 13C-NMR and SEM were used for characterization. Swelling behaviors were studied and it was found that modified calcium alginate (CaA) microspheres possessed larger swelling degree than calcium alginate, because grafted hydrophilic PAM side chains contributed to more water absorption. Moreover, the durability of the swollen samples was improved for the modified microspheres. Compared with calcium alginate microspheres, modified calcium alginate samples exhibited higher absorption capacity (approximately, 13.1 and 10.3 mg/g) for MIPs in single and binary protein solution. The rebinding selectivity of CaA-g-PAM microspheres (approximately, 2.7) was higher than that of calcium alginate (CaA) microspheres (approximately, 1.5) in binary protein solution. It was suggested that the introduction of PAM side chains was beneficial for the specific recognition of protein. [ABSTRACT FROM AUTHOR]

Bovine serum albumin imprinted polyethylene glycol 600 (PEG600) grafted Calcium alginate (CaA) hydrogel microspheres were prepared and characterized. The adsorption and recognition properties of PEG600 grafted calcium alginate (CaA- g-PEG600) microspheres were evaluated and the results showed that the crosslinking structure of CaA- g-PEG600 microspheres exerted an obvious effect on the adsorption capacity and imprinting properties for bovine serum albumin. The adsorption isotherms and recognition properties indicated that the imprinted modified microspheres had excellent rebinding affinity toward target proteins and the imprinting efficiency varied according to PEG600 grafting degree. The adsorption capacity and the imprinting factor were 5.5 mg g and 3.6, respectively. Adsorption kinetics of CaA- g-PEG600 microspheres in accordance with the molecular weight between crosslinks ( Mc) was investigated and the structural influence on protein selective rebinding was discussed. Furthermore, the binary solution separation performance of CaA- g-PEG600 microspheres with different Mc was investigated by selective binding bovine serum albumin from protein mixture solution. [ABSTRACT FROM AUTHOR]

Vinyl group capped urethane acrylate (UA) was prepared with diisocyanate (IPDI), hydroxyethyl methacrylate (HEMA) and dimethylolpropionic acid (DMPA). The UA was grafted onto sodium alginate via free-radical polymerization with KPS/Na 2 SO 3 as initiator and then crosslinked by Ca 2+ . Grafted polymers (UA- g- CaA) were characterized by FT-IR, SEM, TGA, XRD and tension gauge. The swelling behavior was also investigated. It is found that urethane acrylate grafted calcium alginate possesses lower swelling degree and is improved in thermal stability as well as mechanical performance. The reason is that hydrophobic urethane acrylate provides alginate with physical crosslinking and forms partial crystal regions. The optimum condition for synthesis of UA- g- CaA with lower swelling degree is that weight percentage of initiator to monomer is 0.8%, mass ratio of reductant to oxidant is 0.45:1, monomer concentration is 0.0385 mol/L and grafting reaction temperature is 55 °C. [ABSTRACT FROM AUTHOR]

Polyurethane grafted calcium alginate hydrogel microspheres intended for bovine serum albumin imprinting were prepared and characterized. The grafting modification was performed prior to the assembling of protein template with hydrogel, which was advantageous to maintain protein conformation and construct more accessible imprinted sites. It was found that the imprinted hydrogel had higher affinity to template molecules after modification. Investigations of grafting ratio influence on specific rebinding and competitive properties indicated that grafted side chains were beneficial to the selective recognition of protein. [ABSTRACT FROM AUTHOR]

Abstract: With the aim of improving the performance of calcium alginate (Ca-Alg) hydrogel, a small quantity (5% of dry mass of sodium alginate) of hydroxyethyl cellulose (HEC) was used to associate sodium alginate to form interpenetrating networks (IPNs). Swelling results and mechanical stability tests showed that the formation of IPNs considerably restrained dried samples from swelling in 0.9% sodium chloride aqueous solution and reinforced the mechanical strength of microspheres. For emulsion droplets as template, microscopy showed that the original emulsion templating method employed in preparation of macroporous Ca-Alg microspheres was also applicable in the IPNs system. As for bovine serum albumin molecules as template, Alg/HEC microspheres showed a better recognition effect than that of Ca-Alg microspheres. The reduced network mesh size and strengthened cross-linkages in IPNs are responsible for these results. [Copyright &y& Elsevier]

Abstract: Calcium phosphate/alginate hybrid polymer microspheres with bovine serum albumin (BSA) embedded and coated on the surface were prepared with sodium alginate (SA) and (NH4)2HPO4 by using CaCl2 as the gelling agent in an inverse suspension. The morphology and pore structure of imprinted hybrid polymer microspheres was observed by optical microscopy, ESEM, TEM and SEM. Infrared spectrum analysis demonstrated that new hybrid components were produced in the polymer microspheres. Rebinding dynamic and thermodynamic behaviors of the two imprinted microspheres were evaluated, resulting in a higher BSA affinity for imprinted microspheres relative to non-imprinted ones. The factors influencing the imprinting efficiency (IE) of imprinted microspheres were also studied, including the concentration of CaCl2, template content and pH in rebinding solution, etc. All the results indicated that the surface imprinted microspheres exhibited better imprinting efficiency and higher rebinding capacity. Selectivity tests showed that the imprinted beads exhibited good recognition properties for the template protein versus others. [Copyright &y& Elsevier]