title: Synthesis, characterization, and in vitro cell culture viability of degradable poly(N-isopropylacrylamide-co-5,6-benzo-2-methylene-1,3-dioxepane)-based polymers and crosslinked gels.
abstract: Poly(N-isopropylacrylamide-co-5,6-benzo-2-methylene-1,3-dioxepane) (poly(NIPAAm-co-BMDO)) was synthesized by atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain transfer (RAFT) polymerization. Using UV-vis spectroscopy, the lower critical solution temperature (LCST) of poly(NIPAAm) and poly(NIPAAm-co-BMDO) copolymers were measured, varying with respect to the amount of incorporated BMDO. This material is degradable and possesses a LCST above room temperature and below body temperature, making it a potential candidate for use as an injectable tissue engineering scaffold to enhance fracture repair. ATRP and RAFT enabled preparation of polymers with control over molecular weight up to M(n) = 50,000 g/mol and M(w)/M(n) < 1.2. Degradation studies were performed in basic solution and in complete Dulbecco's modified Eagle medium. The cytotoxicity of the material and its degradation products were analyzed by in vitro cell culture analyses, including cytotoxicity live/dead and CyQUANT cell proliferation assays. Crosslinked scaffolds with degradable units within the polymer backbone and at the crosslinking sites were prepared using an ester-containing diacrylate crosslinker. Furthermore, incorporation of a GRGDS peptide sequence improved cell attachment to the gels. Controlled/living radical polymerization techniques allow for precise control over macromolecular structure and are poised to become powerful tools for tissue engineering scaffold synthesis.
authors.affiliation: Center for Macromolecular Engineering, Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Siegwart
authors.forename: Sidi A
authors.initials: SA
authors.lastname: Bencherif
authors.forename: Abiraman
authors.initials: A
authors.lastname: Srinivasan
authors.forename: Jeffrey O
authors.initials: JO
authors.lastname: Hollinger
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Matyjaszewski
mesh_terms: D000178:Acrylamides / Q000138:chemical synthesis* / Q000737:chemistry* / Q000378:metabolism; D000180:Acrylic Resins; D000818:Animals; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D049109:Cell Proliferation; D002470:Cell Survival; D002478:Cells, Cultured; D003432:Cross-Linking Reagents / Q000737:chemistry; D017102:Fracture Healing; D005782:Gels / Q000138:chemical synthesis* / Q000737:chemistry* / Q000378:metabolism; D006016:Glycolates / Q000737:chemistry; D008422:Materials Testing; D051379:Mice; D015394:Molecular Structure; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry* / Q000378:metabolism; D023822:Tissue Engineering / Q000295:instrumentation; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D000178:Acrylamides; D000180:Acrylic Resins; D001672:Biocompatible Materials; D003432:Cross-Linking Reagents; D005782:Gels; D006016:Glycolates; D011108:Polymers; C031149:glycolic acid; C052970:poly-N-isopropylacrylamide; D011092:Polyethylene Glycols