Topographical control of human macrophages by a regularly microstructured polyvinylidene fluoride surface

In this study we investigated the influence of surface topography on the inflammatory response of human macrophages. We generated different polyvinylidene fluoride (PVDF) surfaces including (i) a smooth surface of PVDF spherulites as a control, (ii) a randomly nanotextured surface with alumina particles, and (iii) a microstructure using laser ablation. The identical chemistry of all PVDF surfaces was demonstrated by X-ray photoelectron spectroscopy. The topography was evaluated by white light interferometry and X-profile analysis. Macrophages were cultured on the different surfaces including lipopolysaccharide (LPS) treatment as an inflammatory activator. Our results demonstrate that the microstructured surface but not the nanotexured significantly affects the activation of primary human macrophages by inducing a specific cytokine and gene expression pattern. This activation resulted in a subtype of macrophages with pro- but also anti-inflammatory properties. Interestingly, the response on the topography differed from that triggered by LPS, pointing to a different activation state of the cells. Our data clearly show that a particular topography induces an inflammatory response. This suggests that the modification of topography could influence the inflammatory potency of a biomaterial and hence could affect the biocompatibility of implants.