title: Manipulating degradation time in a N-isopropylacrylamide-based co-polymer with hydrolysis-dependent LCST.
abstract: A thermosensitive, bioresorbable and in situ gelling co-polymer, poly(N-isopropylacrylamide-co-dimethyl-gamma-butyrolactone acrylate-co-acrylic acid), was synthesized by radical co-polymerization with varying dimethyl-gamma-butyrolactone acrylate (DBA) content. The materials properties were characterized using differential scanning calorimetry, gel-permeation chromatography in conjunction with static light scattering, Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) and acid titration. The initial lower critical solution temperature (LCST) of the synthesized co-polymer is between room temperature and body temperature. With the increase of DBA content, the LCST decreases, but then increases after the ring-opening hydrolysis of the DBA side-group. The FT-IR and NMR spectra show the co-polymerization of three monomers, as well as the hydrolysis-dependent ring-opening of the DBA side-group. The addition of acrylic acid increases the initial LCST and accelerates the degradation rate of the co-polymer. An indirect cytotoxicity test indicated that this co-polymer has relatively low cytotoxicity as seen with 3T3 fibroblast cells.
authors.affiliation: The Harrington Department of Bioengineering, Center for Interventional Biomaterials, Arizona State University, Tempe, AZ 85287-9709, USA.
authors.forename: Zhanwu
authors.initials: Z
authors.lastname: Cui
authors.forename: Bae Hoon
authors.initials: BH
authors.lastname: Lee
authors.forename: Christine
authors.initials: C
authors.lastname: Pauken
authors.forename: Brent L
authors.initials: BL
authors.lastname: Vernon
mesh_terms: D016475:3T3 Cells; D000178:Acrylamides / Q000138:chemical synthesis / Q000737:chemistry*; D000818:Animals; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry*; D002470:Cell Survival; D005782:Gels / Q000737:chemistry; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013997:Time Factors
chemical_list: D000178:Acrylamides; D001672:Biocompatible Materials; D005782:Gels; D011108:Polymers; C067295:N-isopropylacrylamide