Highly Adherent Parylene-C Coatings with Nanostructuring for Enhanced Cell Adhesion and Growth.

Parylene-C is a frequently used polymeric thinfilm coating in medical applications and is known for its excellent biocompatibility and flexible deposition process. However, its use in long-term implants is limited due to its poor adhesion to metals in liquid environments. In this work we present a strategy to anchor Parylene-C to medical grade titanium (Ti) by means of nanostructuring the Ti substrates surface prior to Parylene coating. We observe that, after aging in physiological salt solution for 3 days, Parylene coating lose their adhesion to bare titanium surfaces. However, the Parylene films deposited on nanostructured Ti surfaces retain full adhesion, even after aging them in the same solution for 10 days. Additionally, we demonstrate that combining nanostructured surfaces with very thin Parylene coatings provides the additional benefit of accelerating cell proliferation. Nanostructured surfaces showed cell proliferation without the typically required oxygen plasma treatment. Combining plasma treatment and nanostructuring further improved proliferation performance over smooth Parylene surfaces.