Thermoreversible Hydrogels from RAFT-Synthesized BAB Triblock Copolymers: Steps toward Biomimetic Matrices for Tissue Regeneration super([dagger])

• Published in: Biomacromolecules Vol. 9; no. 2; pp. 481 - 486
• Main Authors: Kirkland, Stacey E, Hensarling, Ryan M, McConaughy, Shawn D, Guo, Yanlin, Jarrett, William L, McCormick, Charles L
• Format: Journal Article
• Language: English
• Published: 01.01.2008
• ISSN: 1525-7797; 1526-4602
• DOI: 10.1021/bm700968t

Narrowly dispersed, temperature-responsive BAB block copolymers capable of forming physical gels under physiological conditions were synthesized via aqueous reversible addition fragmentation chain transfer (RAFT) polymerization. The use of a difunctional trithiocarbonate facilitates the two-step synthesis of BAB copolymers with symmetrical outer blocks. The outer B blocks of the triblock copolymers consist of poly(N- isopropylacrylamide) (PNIPAM) and the inner A block consists of poly(N,N- dimethylacrylamide). The copolymers form reversible physical gels above the phase transition temperature of PNIPAM at concentrations as low as 7.5 wt % copolymer. Mechanical properties similar to collagen, a naturally occurring polypeptide used as a three-dimensional in vitro cell growth scaffold, have been achieved. Herein, we report the mechanical properties of the gels as a function of solvent, polymer concentration, and inner block length. Structural information about the gels was obtained through pulsed field gradient NMR experiments and confocal microscopy.