Poly(D,L-lactic acid)-block-(ligand-tethered poly(ethylene glycol)) copolymers as surface additives for promoting chondrocyte attachment and growth.

The poly(D,L-lactic acid)-block-(ligand-tethered poly(ethylene glycol)) copolymer was explored to engineer poly(D,L-lactic acid) (PLA) material to promote chondrocyte attachment and growth. The poly(D,L-lactic acid)-block-poly(ethylene glycol) copolymer (PLE) was synthesized by a coupling reaction between PLA and poly(ethylene glycol) (PEG) (M(n) 1000, 2000, and 4000 respectively), with the use of 4,4'-methylenediphenyl diisocyanate (MDI). Then the PLE was activated by methyl sulfonyl chloride and the amino acids or arginine-glycine-aspartic acid tripeptide (RGD) was attached, which was verified by the ninhydrin-UV method. The modified PLA films were simply prepared by blending PLA with PLE derivatives. ATR-FTIR, XPS, contact angle, and AFM results clearly showed that the PEG chain stably enriched on the surface of PLE-modified PLA films. The chondrocyte cytocompatibility test showed the modified PLA films could significantly improve chondrocyte attachment and proliferation.