(696f) Novel Star Multifucntional Polylactide-Co-Glycolides as Injectable in-Situ Crosslinkable Macromers

Poly(lactide-co-glycolide) (PLGA) is the most widely used resorbable polymer in biomedical applications but PLGA can not be crosslinked in situ, requiring an invasive surgical procedure for implantation. To reduce invasiveness of the implantation procedure, in-situ crosslinkable macromers like poly(anhydrides), poly(propylene fumarate), and polyurethanes have been developed but the crosslinking reaction requires the use of toxic crosslinking agents to accelerate the rate of in-situ hardening which is not compatible with encapsulated cells and proteins. Our laboratory has developed novel functionalized star PLGA macromer using dipentaerythritol, tripentaerythritol, and pentaerythritol ethoxylate family of compounds. These acrylate functionalized ultra-low molecular weight star PLGA liquid macromers crosslink in the absence of toxic crosslinking agents like methacrylic anhydride or N-methyl-2-pyrrolidinone. The macromer can be crosslinked by photopolymerization or redox iniation without any diluent to produce crosslinked networks with >300 MPa modulus or it can be crosslinked with the addition of water for cell encapsulation applications. More importantly, the crosslinked networks exhibit linear degradation characteristics from 4-12 weeks depending on the ratio of lactide to glycolide in the macromer and the extent of crosslinking. This novel macromer is potentially useful as an injectable in-situ crosslinkable scaffold in minimally invasive procedures for skeletal tissue engineering.