Combining sandblasting and pink anodisation of Ti implants as a promising method for improving fibroblast adhesion and immune response

Abstract

This study examined the effect of combining the sandblasting and anodising of titanium alloys used in implants on the cell response and protein adsorption patterns. The titanium samples were divided into four groups depending on the surface treatment: machining (MC), pink anodisation (PA), sandblasting (MC04) and a combination of the last two (MC04 + PA). Their physicochemical properties were analysed by SEM/EDX, Raman, contact angle measurements and profilometry. In vitro responses were examined using human gingival fibroblastic (HGF) cells and THP-1 macrophages. Cytokine secretion, macrophage adhesion and gene expression were measured by ELISA, confocal microscopy and RT-PCR. Cell adhesion and collagen secretion were evaluated in HGF cultures. The adsorption of immune and regenerative proteins onto the surfaces was assessed employing nLC-MS/MS. MC04 + PA surfaces exhibited a change in the roughness, chemical composition and hydrophilicity of the material, showing more elongated HGF cells and a considerable increase in the area of cells exposed to the MC04 + PA surfaces. Moreover, cells cultured on MC04 + PA generally showed a reduction in the expression of proinflammatory genes (TNF-α, MCP-1, C5, NF-kB and ICAM-1) and an increase in the secretion of anti-inflammatory cytokines, such as IL-4. These results correlated with the proteomic data; we found preferential adsorption of proteins favouring cell adhesion, such as DSC1 and PCOC1. A considerable reduction in the adsorption of immunoglobulins and proteins associated with acute inflammatory response (including SAA4) was also observed. The study highlights the potential advantages of MC04 + PA surface treatment to modify dental implant abutments; it enhances their compatibility with soft tissues and reduces the inflammatory response.