Biological Influence of Nano-coating Modification on Biomedical Surfaces

Objectives: A challenge in the biomedical area is to develop biomaterials with improved tissue integration properties while at the same time could inhibit bacterial colonization, to avoid device-associated infections. The aim of this study was to analyze the influence of a surface nano-modification on the biological cell behavior of bacterial and mesenchymal stem cells
Methods: Medical grade stainless steel substrates (SS) and SS surfaces modified with an amorphous titanium oxide nano-coating (ss-aTiO) were tested and compared with microstructured titanium substrates (SLA). The surface characterization of all substrates included the analysis of the surface roughness and topography, water contact angle measurements, and chemical composition. Bacterial adhesion and biofilm formation of two device-related pathogens S. aureus and S. epidermidis were analyzed. In addition, the adhesion and biofilm formation of a consortium model of seven anaerobic species representatives of the normal oral microbiota was also tested. Meanwhile, mesenchymal stem cell differentiation and protein production in microenvironment were assessed by gene expression and immune assays, respectively.
Results: Results show that the ss-aTiO nano-coating decrease the bacterial adhesion and biofilm formation of S. aureus and S. epidermidis compared with the titanium SLA surfaces. In contrast, the consortium of oral anaerobic bacteria showed less sensitivity to the ss-aTiO nano-coating, since similar patterns of colonization were observed on the titanium SLA surfaces. On the other hand, the nano-modification on the SS surfaces showed the potential to regulate stem cell behavior trough osteoblastic phenotype and favors a microenvironment associated with osseointegration around modified biomedical surfaces.
Conclusions: In this study we demonstrate that is possible to influence the biological behavior of micro-structured SS medical grade substrates by the nanomodification of an amorphous titanium oxide nano-coating (ss-aTiO), specifically on biofilm formation and mesenchymal stem cell behavior.