Chitosan beads as molecularly imprinted polymer matrix for selective separation of proteins.

Two kinds of molecularly imprinted polymers were prepared using hemoglobin as the imprinting molecule, acrylamide as the functional monomer, chitosan beads and maleic anhydride-modified chitosan beads as matrixes, respectively. Static adsorbing experimental results showed that an equal class of adsorption was formed in the imprinted polymers and the adsorption equilibrium constant and the maximum adsorption capacity were evaluated. Chromatographic characteristics showed that the column bedded with the hemoglobin imprinted beads could separate hemoglobin and bovine serum albumin effectively from their mixture, which indicates that the imprinted beads have very higher selectivity for hemoglobin than the non-imprinted with the same chemical composition.

Surface hydrophilic modification with well-defined glycopolymer for protein imprinting matrix.

Well-defined lactose-containing glycopolymer has been synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization with (4-cyanopentanoic acid)-4- dithiobenozoate (CAD) as chain transfer agent. The glycopolymer was introduced onto the exterior surfaces of the bovine serum albumin (BSA) imprinted polymer beads by grafting copolymerization with methyl methacrylate and ethylene glycol dimethacrylate. After alcoholysis, the hydrophilic lactose residues of glycopolymer will stretched on the surface of the MIP beads and then the hydrophilicity of the surface will be enhanced. Rebinding test shows that the glycopolymer hydrophilic modified BSA imprinted polymer presents higher performance selectivity than that of unmodified one, which means that the hydrophobic-hydrophilic balance of the imprinted polymer surface is in favor of the improvement of specific recognition property of the material.

Protein recognition onto silica particles using chitosan as intermedium substrate.

A novel molecular imprinting method was used to prepare twice-coated silica particles with specific recognition sites for hemoglobin. Chitosan was used as an intermedium to be coated on silica particles via phase inversion process, and the abundance of exposed amine groups (NH2) were active sites for introducing aldehyde groups. After hemoglobin was covalently immobilized by forming imine bonds with the aldehyde groups, acrylamide was then polymerized onto chitosan-coated silica particles to form the recognition sites. The obtained hemoglobin imprinted [molecularly imprinted polymer (MIP)] beads were characterized by FTIR spectroscopy, thermogravimetric analysis (TG), and scanning electron microscopy (SEM). The MIP particles exhibited selectively adsorption for the imprinted protein compared to the nonselectively adsorption for most of proteins of the nonimprinted (NIP) beads.

A novel solid phase for selective separation of flavonoid compounds.

A novel straightforward approach to selective separation for flavonoid compounds was reported. The solid phase material was prepared by copolymerization using allyl-bromide-modified chitosan as macromonomer, and ethylene glycol dimethacrylate as cross-linker. The material was evaluated by chromatographic analysis; it exhibited high selectivity separation for quercetin and its structural analogues using different mobile phases. The material could directly trap a specific class of compounds including quercetin and kaempferol from the hydrolyzate of Ginkgo biloba extract. These results demonstrated the possibility of direct extraction of certain constituents from herb using this material.

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.

Hemoglobin recognition by imprinting in semi-interpenetrating polymer network hydrogel based on polyacrylamide and chitosan.

Semi-interpenetrating polymer network (semi-IPN) hydrogel was prepared to recognize hemoglobin, by molecularly imprinted method, in the mild aqueous media of chitosan and acrylamide in the presence of N,N'-methylenebisacrylamide as the cross-linking agent. The hydrogel obtained has been investigated by using thermal analysis, X-ray diffraction, differential scanning calorimetry (DSC), and environmental scanning electron microscope (ESEM). Langmuir analysis showed that an equal class of adsorption was formed in the hydrogel, and the adsorption equilibrium constant and the maximum adsorption capacity were evaluated to be 4.27 g/mL and 36.53 mg/g wet hydrogel, respectively. The imprinted semi-IPN hydrogel has a much higher adsorption capacity for hemoglobin than the nonimprinted hydrogel with the same chemical composition and also has a higher selectivity for the imprinted molecule.