Comparison between RGD-peptide-modified titanium and borosilicate surfaces

The use of synthetic peptides containing adhesive sequences, such as the Arg-Gly-Asp (RGD) motif, represents a promising strategy to control biological interactions at the cell-material interface. These peptides are known to improve the tissue-material contact owing to highly specific binding to cellular membrane receptors known as integrins, thereby promoting the adhesion, migration and proliferation of cells. The peptides were coupled to borosilicate glass and titanium surfaces using silanisation chemistry. A tryptophan residue was incorporated into the amino acid sequences of selected peptides to facilitate the detection of the covalently bound peptides. Successful peptide immobilisation was proven by fluorimetric measurements. The confocal imaging analysis suggests a homogeneous distribution of the immobilised peptide across the biomaterial surface. In vitro cell proliferation assays were employed to compare the adhesion potentials of the well-known RGD-containing peptides GRGDSP, GRADSP and RGDS to the three peptides designed by our group. The results demonstrate that the RGD sequence is not necessarily required to enhance the adhesion of cells to non-biological surfaces. Moreover, it is shown that the number of adhering cells can be increased by changes in the peptide hydrophobicity. Changes in the cytoskeleton are observed depending on the type of RGD-peptide modification.