Growth of human endothelial cells on different concentrations of Gly-Arg-Gly-Asp grafted chitosan surface

To improve the adhesion and growth of endothelial cells on chitosan, different concentrations of cell adhesive peptide, Gly-Arg-Gly-Asp (GRGD), were photochemically grafted to its surface. After different concentrations of GRGD-SANPAH (N-Succinimidyl-6-4'-azido-2'-nitrophenylamino]-hexanoate) solutions were formed, they were grafted to chitosan surfaces by performing surface adsorption of the peptide solutions and subsequent ultraviolet (UV) irradiation to induce photoreaction. The grafted efficiency for GRGD peptide to chitosan surface was higher than 80%, as semiquantitatively analyzed by a high performance liquid chromatography (HPLC). FTIR spectra and electron spectroscopy for chemical analysis (ESCA) also confirmed that GRGD was successfully grafted to form chitosan-GRGD surfaces. For example, the composition fraction of nitrogen (N1s) for chitosan-GRGD surface grafted at 0.05 M GRGD was 6.8% instead of 3.2% for chitosan only. Human umbilical vein endothelial cells (HUVECs) adhered well and grew on different GRGD grafted concentrations of chitosan-GRGD surfaces after 36 hrs of incubation, but not on the chitosan surface. Furthermore, viability for the growth of HUVECs was increased with an increase in initial concentration of GRGD grafted chitosan-GRGD surfaces analyzed by MTT assay. In conclusion, an increased concentration of GRGD grafted on the chitosan-GRGD surface leads to more HUVECs adhered and grown on the surface.