Controlling Cellular Behavior by Surface Design of Titanium-based Biomaterials.

Abstract

Background/aim: Titanium alloys, especially Ti₆Al₄V, are widely used in orthopedic and dental implants. Additive manufacturing has emerged as an innovative fabrication technique for titanium implants, gradually replacing traditional machining methods. A notable feature of additively manufactured medical devices is their considerable surface heterogeneity and roughness. Coating these materials to achieve physical and chemical uniformity is essential for enhancing biocompatibility. This study evaluates the combined effect of surface roughness (ranging from sub-micrometer to micrometer scale) and three nanometer-thick polyelectrolyte multilayer coatings on protein adsorption, as well as the adhesion and proliferation of normal human osteoblasts.

Materials and methods: The adhesion of human osteoblasts to various substrates (either uncoated or coated) was quantified using a lactate dehydrogenase assay and scanning electron microscopy. The surface density of adsorbed human serum albumin was analyzed by the Bradford assay.

Results: Application of polyelectrolyte multilayer coatings significantly increased the hydrophilicity of titanium substrates without altering their sub-micrometer and micrometer roughness or topography. The coatings rich in reactive amino groups were found to enhance the adsorption of human serum albumin and promote the adhesion of osteoblasts.

Conclusion: The chemical composition of the surface, particularly the presence of free primary amino groups, significantly affects cellular behavior in machined, sand-blasted, and additively manufactured titanium materials, while the impact of surface roughness appears secondary. No correlation was observed between surface hydrophilicity and protein adsorption or cell attachment.