gms | German Medical Science

Surface topography, surface energy and hydrophobicity are important biophysical properties influencing the functionality and biocompatibility of electrical implants. The aim of this study was that would create a functionalized surface to decrease the post-operative connective tissue growth.

Using micro spikes produced by fs-laser in silicon. Additional this silicon spike structure was used as a mask for silicone molding. A ns-laser was used to procuce the randomized micro structure in silicone. These structured surfaces were then analyzed by SEM (Scanning electron microscopy), SPM (Scanning probe microscopy) and contact angle measurements before cell culturing.

All the laser induced micro structures showed a hydrophobic surface. The hydrophobicity was stable over a period of 3 weeks. In vitro experiments demonstrated a reduced fibroblast growth on the silicon spike structure compared to the unstructured silicon surface. The fibroblasts had an round morphology on the spikes in contrast to the their characteristic spindle-shape on unstructured silicon surface. Also on the ns-laser induced silicone micro structure the fibroblast growth rate was also reduced compared to the unstructurese silicone material. In contrast the fibroblasts showed normal cell growth on the moldes silicone structure as well as on unstructured silicone.

Both laser structuring methods create a stable hydrophobic micro structured surface. Additional experiments will be performed to analyze the long term properties, so that just long term stable structures would be included in the implant manufacturing process.