Highly Porous Crosslinkable PLA-PNB Block Copolymer Scaffolds

Poly(lactic acid) (PLA)-block-poly(norbornene) (PNB) copolymers which bear photocrosslinkable cinnamate side-chains are synthesized by combining the ring-opening metathesis polymerization (ROMP) of norbornenes with the ring-opening polymerization (ROP) of lactides. Highly porous 3D scaffolds with tunable pore sizes ranging from 20 to 300 mu m are fabricated through liquid-solid phase separation. Scaffolds with an average pore size around 250 mu m, which are under investigation as bone grafting materials, are reproducibly obtained from freeze-drying 5% w/v benzene solutions of PLA-b-PNB copolymers at -10 degrees C. As a demonstration of the impact of photocrosslinking of cinnamate side-chains, scaffolds are exposed to UV radiation for 8 h.. resulting in a 33% increase in the compressive modulus of the polymeric scaffold. The foams and the methodology described herein represent a new strategy toward polymeric scaffolds with potential for use in regenerative medicine applications.