Functionalized Biocompatible Poly(N-vinyl-2-caprolactam) With pH-Dependent Lower Critical Solution Temperature Behaviors

摘要

Functionalized temperature- and pH-sensitive poly(N-vinyl-2-caprolactam) (PVCL) polymers are prepared by copolymerizing monomers of N-vinyl-2-caprolactam (VCL) and a VCL derivative, 3-(tert-butoxycarbonyl)-N-vinyl-2-caprolactam (TBVCL). Different molar compositions are studied, with the functional monomer at 9 and 14 mol%, respectively, (COOH-PVCL9 and COOH-PVCL14). Sharp, complete, and reversible phase transitions of the copolymers with little hysteresis are shown to be pH-dependent, with cloud points ranging from 35 to 44 °C for COOH-PVCL9, and 29 to 64 °C for COOH-PVCL14, upon pH change from 2.0 to 7.4. Cytotoxicity assay demonstrates that the functionalized PVCL copolymers are biocompatible with NIH/3T3 up to 2 mg mL−1. Such new PVCL-based water soluble copolymers with tunable properties could be useful in a variety of biomedical applications.