Growth of human endothelial cells on photochemically grafted Gly-Arg-Gly-Asp (GRGD) chitosans.

To improve ECs adhesion and growth on chitosan, cell adhesive peptide Gly-Arg-Gly-Asp (GRGD) was photochemically grafted to its surface. Grafting 0.025 M of GRGD-SANPAH (N-Succinimidyl-6-[4'-azido-2'-nitrophenylamino]-hexanoate) solutions to chitosan and tripolyphosphate anhydrous crosslinked chitosan (chitosan-TPP) surfaces was performed by surface adsorption of the peptide and subsequent ultraviolet (UV) irradiation for photoreaction. FTIR spectra and electron spectroscopy for chemical analysis (ESCA) confirmed that GRGD was successfully grafted to form chitosan-GRGD surfaces (e.g., the composition fraction of nitrogen (N(1s)) for chitosan-GRGD surface was 5.2% instead of 3.2% for chitosan only). Moreover, the grafting efficiencies for 0.025 M of GRGD to chitosan and chitosan-TPP surfaces were about 83% and 53%, semi-quantitatively analyzed by an HPLC. Human umbilical vein ECs were well adhered and grew on chitosan-GRGD and chitosan-TPP-GRGD surfaces after 36 h of incubation but not chitosan and chitosan-TPP ones. Moreover, the viability for the growth of ECs on the chitosan-GRGD and chitosan-TPP-GRGD surfaces analyzed by MTT assay also confirmed the efficacy of the GRGD immobilization. In conclusion, the chitosan-GRGD and chitosan-TPP-GRGD surfaces were prepared by a photochemical technique that could enhance the adhesion and growth of ECs on those surfaces for further applications for tissue engineering.