ENHANCING THE BIOCOMPATIBILITY OF 3D PRINTED TITANIUM IMPLANTS BY MICROPLASMA SPRAYING OF HYDROXYAPATITE COATINGS

Abstract

The growing demand for durable and biologically functional orthopedic implants has stimulated the development of surface-modification strategies capable of improving tissue integration while limiting bacterial colonization. In this study, porous Ti6Al4V scaffolds produced by additive manufacturing were functionalized with hydroxyapatite (HAP) using robotic microplasma spraying, and their biological performance was evaluated in comparison with gas-abrasive-treated Ti6Al4V surfaces. Surface morphology and elemental composition were examined by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDX). Cytocompatibility was assessed using rat bone marrow-derived mesenchymal stem cells, with metabolic activity quantified by the Alamar Blue assay, while antibacterial performance was evaluated against Escherichia coli. HAP deposition markedly altered the interaction of the titanium surface with both mammalian and bacterial cells. The coated scaffolds supported greater MSC metabolic activity and more extensive cellular attachment than the uncoated Ti6Al4V reference, with cell viability increasing by 56%. At the same time, E. coli proliferation was suppressed, with bacterial growth approximately 30% lower after 15 h of incubation. These findings demonstrate that microplasma-deposited HAP can provide additively manufactured titanium scaffolds with a favorable combination of cytocompatibility and resistance to bacterial growth. The integration of additive manufacturing with controlled plasma-based surface functionalization therefore represents a promising approach for the development of porous titanium implants with improved biological performance.