Jie Zhang,Ningyu Chen,Yuheng Cui,Liqun Zhang,Dongmei Yue
In this study, novel 1-methylpropargyl alcohol derivatives containing leucine side groups on their side chains were successfully synthesized and polymerized using (nbd)Rh + [η 6 -C 6 H 5 B − (C 6 H 5 ) 3 ] as catalyst. Circular dichroism (CD) and ultraviolet–visible (UV–Vis) spectra revealed that the polymers took predominantly one-handed helical structures that were stable under heat. Deprotection of the t-butyloxycarboryl (Boc) groups in the homopolymers under acidic conditions produced polymers with primary amine moieties on the side chains. The polymers were soluble in aqueous medium, and turbidity test revealed that they were pH-responsive. Amino acid-based polymers were further used in the enantionselective crystallization of alanine enantiomers and l -alanine was preferably induced to crystallize with the l -leucine-based polymer.
In this work, the stepwise synthesis of interpenetrating polymer network (IPN) strategy was developed in an attempt to fabricate novel hydrogels consisting of sugarcane bagasse cellulose (SBC), carboxymethylcellulose (CMC) and poly (N-isopropylacrylamide) (PNIPAm) as a dual-responsive drug carrier. The pretreated and dissolved SBC was pre-crosslinked using epichlorohydrin in the presence of CMC, followed by in-situ free-radical polymerization of NIPAm in the presence of N,N′-Methylene-bis(acrylamide) as a crosslinking agent. The carboxyl groups in CMC and PNIPAm chains rendered the resulting hydrogel pH and thermal responsive. The results from scanning electron microscopy, infrared spectroscopy , thermogravimetric analysis and mechanical property testing demonstrated the successful formation of the IPN with proper structure and mechanical strength . The swelling experiments at different temperatures and pH showed the dual–sensibility of the hydrogels. Moreover, bovine serum albumin (BSA) was used as a model drug and loaded in the hydrogel; and the drug release behavior was revealed in phosphate buffer solution (PBS) and simulated gastric fluid (SGF). The results indicated that the dual-responsive IPN hydrogel is of great potential for the controlled release of drug.
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