Engineering hydroxyapatite-silver nanocomposite coating on Ti–6Al–4V alloy with bio-corrosion and antibacterial performances for orthopedic implant applications

Herein, a novel approach was developed to enhance the bio-functionality and corrosion resistance of Ti-6Al-4V implants by applying a homogeneous hydroxyapatite-silver (HA-Ag) nanostructured coating via an electrochemical deposition process. Comprehensive characterization using grazing-incidence X-ray diffraction (GIXRD) confirmed the presence of the crystalline HA phase and the integration of Ag nanoparticles. Furthermore, field-emission scanning electron microscopy (FE-SEM) with energy-dispersive X-ray spectroscopy (EDS) revealed a homogeneous elemental distribution and a dense morphology, indicating robust substrate adhesion. Contact angle measurements revealed that the HA-Ag coating significantly enhanced surface wettability, yielding a hydrophilic contact angle of 13.6°, a property known to favor cell attachment. In corrosion tests using electrochemical impedance spectroscopy (EIS) in simulated body fluid (SBF) at 37°C, the HA-Ag coating doubled the Nyquist loop diameter compared to the uncoated Ti-6Al-4V substrate, suggesting it acts as an effective barrier against Cl - ion penetration. Biocompatibility assessment via MTT assays demonstrated excellent cell viability exceeding 90%, with the HA-Ag coating outperforming pure HA. This superior performance was attributed to silver's minimal cytotoxicity and its role in promoting cellular proliferation. Consequently, these findings demonstrated that the HA-Ag coated biodegradable Ti-6Al-4V alloy significantly possessed the corrosion resistance, osseointegration potential, and antimicrobial efficacy, positioning it as a highly promising material for the development of more durable orthopedic and dental implants.