Responses of fibroblasts and glial cells to nanostructured platinum surfaces

Abstract

The chronic performance of implantable neural prostheses is affected by the growth ofencapsulation tissue onto the stimulation electrodes. Encapsulation is associated withactivation of connective tissue cells at the electrode’s metallic contacts, usually made ofplatinum. Since surface nanotopography can modulate the cellular responses to materials,the aim of the present work was to evaluate the ‘in vitro’ responses of connective tissuecells to platinum strictly by modulating its surface nanoroughness. Using molecular beamepitaxy combined with sputtering, we produced platinum nanostructured substratesconsisting of irregularly distributed nanopyramids and investigated their effect on theproliferation, cytoskeletal organization and cellular morphology of primary fibroblasts andtransformed glial cells. Cells were cultured on these substrates and their responses tosurface roughness were studied. After one day in culture, the fibroblasts were moreelongated and their cytoskeleton less mature when cultured on rough substrates. This effectincreased as the roughness of the surface increased and was associated with reduced cellproliferation throughout the observation period (4 days). Morphological changesalso occurred in glial cells, but they were triggered by a different roughness scaleand did not affect cellular proliferation. In conclusion, surface nanotopographymodulates the responses of fibroblasts and glial cells to platinum, which may be animportant factor in optimizing the tissue response to implanted neural electrodes.