Immobilization of RGD to < 1 1 1 > silicon surfaces for enhanced cell adhesion and proliferation.

The ability of biomaterial surfaces to regulate cell behavior requires control over surface chemistry and microstructure. One of the greatest challenges with silicon-based biomedical microdevices such as those recently developed for neural stimulation, implantable encapsulation, biosensors, and drug delivery, is to improve biocompatibility and tissue integration. This may be achieved by modifying the exposed silicon surface with bioactive peptides. In this study, Arg-Gly-Asp (RGD) peptide conjugated surfaces were prepared and characterized. The effect of these surfaces on fibroblast adhesion and proliferation was examined over 4 days. Silicon surfaces coupled with a synthetic RGD peptide, as characterized with X-ray photoelectron spectroscopy and atomic force microscopy, display enhanced cell proliferation and bioactivity. Results demonstrate an almost three-fold greater cell attachment! proliferation on RGD immobilized surfaces compared to unmodified (control) silicon surfaces. Modulating the biological response of inorganic materials such as silicon will allow us to design more appropriate interfaces for implantable diagnostic and therapeutic silicon-based microdevices.