Enhancement of the adhesion of fibroblasts by peptide containing an Arg-Gly-Asp sequence with poly(ethylene glycol) into a thermo-reversible hydrogel as a synthetic extracellular matrix

In an effort to regulate the behavior of mammalian cell entrapped in a gel, the gels were functionalized with the putative cell-binding (-Arg-Gly-Asp-) (RGD) domain. The adhesion molecules composed of Gly-Arg-Gly-Asp-Ser (GRGDS) peptides and the cell recognition ligands were inculcated into the thermo-reversible hydrogel composed of N-isopropylacrylamide, with a small amount of succinyl poly(ethylene glycol) (PEG) acrylate (MW 2000) used as the biomimetic extracellular matrix (ECM). The GRGDS-containing p(NiPAAm-co-PEG) copolymer gel was examined in vitro for its ability to promote cell spreading and to increase the viability of the cells by introducing PEG spacers. ECM poorly adhered to hydrogel lacking adhesion molecules permitting only a 20% spread of the seeded cells after 10 days. When the PEG spacer arms, which were immobilized by a peptide linkage, had been integrated into the hydrogel, the conjugation of RGD improved cell spreading by 600% in a 10-day trial.