Hydrothermal Synthesis and Electrophoretic Deposition of MgO/HAp Coatings on Titanium for Implant Applications

Abstract

Introduction: Conventional hydroxyapatite (HAp) coatings improve bone implant integration but lack intrinsic antibacterial activity, limiting their performance in infected environments. Magnesium doping of HAp (MgOHAp) offers dual functionality by enhancing osteogenesis and providing antimicrobial effects.

Aim: This study aimed to synthesize MgOHAp coatings on titanium substrates via hydrothermal synthesis followed by electrophoretic deposition (EPD), and to evaluate their structural, mechanical, and biological properties for dental implant applications.

Materials and Methods: MgOHAp powders were prepared using  co-precipitation route and deposited on acid-etched titanium substrates by optimized EPD. The coatings were characterized by FE-SEM, EDX, and FTIR to assess morphology, composition, and bonding. Mechanical performance was determined by adhesion strength, nanoindentation, and wear testing. Biological evaluations included antioxidant  assay, hemocompatibility, cytocompatibility, osteogenic differentiation (ALP activity, Alizarin Red staining), and antibacterial efficacy against S. aureus and P. aeruginosa.

Results: The coatings displayed flower-like nanosheet clusters with uniform composition (Ca/P ratio ~1.67, Mg 1.8–2.1%). Strong interfacial bonding (Ti–O peaks), uniform thickness (~15 ± 2 µm), high adhesion (>28 MPa), hardness (3.5 ± 0.4 GPa), and low friction coefficients (0.22–0.24) confirmed stability. Biologically, MgOHAp showed <3% hemolysis, >95% cell viability, 1.6-fold upregulated ALP activity, and enhanced mineralization. Antioxidant activity reached 48% scavenging at 60 mg equivalents, while antibacterial testing revealed inhibition zones of 19 mm (S. aureus) and 16 mm (P. aeruginosa).

Conclusion: MgOHAp coatings demonstrated multifunctionality osteoconductive, hemocompatible, antioxidant, and antibacterial—highlighting their promise as advanced implant surface modifications. Further in vivo studies are warranted to validate long-term stability and clinical applicability.