Pyramid array substrates for biomedical studies

Abstract

Cellular reactions to structured surfaces are the subject of intense studies in biomedical research, e.g., for implant technology. Substrates with well-defined structures in relevant materials such as titanium (Ti) are required for these investigations. The pyramidal arrays presented here offer very sharp edges and tips, which appeared to be the main adhesion spots in our earlier cell-surface-interaction studies. Using an etch process based on anisotropic etching of silicon in alkaline solution, the shape of the pyramids is strictly determined by the crystal structure of silicon, while the height as well as the pitch of the pyramids can be precisely controlled and, therefore, be varied in a systematic fashion. Being made from silicon nitride with a thin cover layer of titanium, they offer mechanical stiffness, inertness to all chemicals used in the cell experiments, and a high degree of biocompatibility.