title: Synthesis and fabrication of a degradable poly(N-isopropyl acrylamide) scaffold for tissue engineering applications.
abstract: Biodegradable poly(N-isopropyl acrylamide) (polyNIPAM) hydrogels with controlled molecular weight of the parent polymer and its degradation products were synthesized by atom transfer radical polymerization in the presence of a polycaprolactone-based di-chlorinated macroinitiator and polycaprolactone dimethacrylate. The phase transition temperature, swelling, hydrolytic degradability, and mechanical properties at 25 and 37°C were explored. A cytocompatibility study showed good NIH3T3 cell response over 5 days culture on the surface of the hydrogels, demonstrated by a consistent increase in cell proliferation detected by an Alamar Blue assay. MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] results suggested that the hydrogels and their degradation products in the concentration range of 1-25 mg/mL were not cytotoxic to NIH3T3 cells. A sphere-templating technique was utilized to fabricate biodegradable polyNIPAM scaffolds with monodisperse, pore size. Scaffolds with pore diameter of 48 ± 6 μm were loaded with A-10 smooth muscle cells and then warmed to 37°C entrapping cells in pores approximately 40 μm in diameter, a size we have found to be optimal for angiogenesis and biointegration. Due to their degradable nature, tunable molecular weight, highly interconnected morphology, thermally controlled monodisperse pore size, and temperature-induced volume expansion-contraction, the polyNIPAM-based scaffolds developed in this work will be valuable in tissue engineering.
authors.affiliation: University of Washington, Department of Bioengineering, Seattle, Washington 98195, USA.
authors.forename: Anna
authors.initials: A
authors.lastname: Galperin
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Long
authors.forename: Shai
authors.initials: S
authors.lastname: Garty
authors.forename: Buddy D
authors.initials: BD
authors.lastname: Ratner
mesh_terms: D000178:Acrylamides / Q000737:chemistry*; D000180:Acrylic Resins; D000818:Animals; D008422:Materials Testing; D051379:Mice; D041681:NIH 3T3 Cells; D011108:Polymers / Q000737:chemistry*; D023822:Tissue Engineering; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D000178:Acrylamides; D000180:Acrylic Resins; D011108:Polymers; C052970:poly-N-isopropylacrylamide