Modification of oligo(poly(ethylene glycol) fumarate) macromer with a GRGDpeptide for the preparation of functionalized polymer networks

A novel macromer, oligo(poly(ethylene glycol) fumarate) (OPF), was synthesi zed by the reaction between poly(ethylene glycol) (PEG) of molecular weight 1000 (PEG 1.0K) and fumaryl chloride. The oligo(PEG fumarate) (OPF 1.0K) w as modified with a peptide known to modulate cellular functions, Gly-Arg-Gl y-Asp (GRGD), after being activated with 4-nitrophenyl chloroformate (NPC). The determined yield of the GRGD modification in 0.1 M sodium bicarbonate buffer of pH 8.3 was 83% as determined by NMR measurements. The OFF 1.0K an d the OFF 1.0K modified with GRGD were cross-linked with an unsaturated bio degradable polyester, poly(propylene fumarate) (PPF), by photopolymerizatio n. The cross-linked PPF was characterized by Fourier transform infrared (FT -IR) spectroscopy and contact angle measurements. The equilibrium contact a ngle of water on the cross-linked PPF surface decreased with the incorporat ion of OFF 1.0K and the OFF 1.0K modified with GRGD. The results suggest th at the OFF macromer can be used for the preparation of functionalized netwo rks incorporating cell adhesion specific sequences.