Electrophoretic deposition of monticellite nanoparticles on Ti implants for bone replacements: Physicochemical characteristics and in vitro biological assessments

This study investigates the use of Monticellite nanoparticles as a bioactive coating for titanium implants to enhance their biological properties. Monticellite was synthesized via the sol-gel method and reduced to the nanoscale through ball milling. Optimal electrophoretic deposition conditions were achieved by dispersing nanoparticles in ethanol at different acidic pH levels. The coating process resulted in improved zeta potential and particle size uniformity, and subsequent sintering produced a durable and bioactive layer. Characterization techniques, including SEM, AFM, XRD, and FTIR, confirmed the structural integrity, surface roughness, and chemical stability of the coatings. Thermal analysis (TGA/DTA) indicated a significant weight loss (∼67 %) during heating, attributed to the removal of organic and inorganic components, with crystallization occurring around 600 °C. XRD analysis demonstrated the formation of a single-phase Monticellite structure after calcination at 1200 °C, with a crystallite size of 28.93 nm. AFM analysis revealed a nano-rough surface with Sa = 9 ± 2 nm, supporting improved protein adsorption and osteoblast adhesion. The coating thickness measured ∼20 μm, with a porous structure facilitating cell attachment and nutrient transport. The microhardness test showed a hardness value of 424.5 ± 12.7 HV, balancing mechanical integrity with bioactivity. Biological assessments demonstrated significant improvements in osteoblast adhesion, proliferation, and alkaline phosphatase (ALP) activity. MTT assay results showed enhanced cell viability, particularly at a 1:16 dilution, supporting optimal bioactivity and controlled ion release. ALP activity increased significantly by day 4 and 7, indicating the coated samples promoted early osteoblast differentiation. Degradation and bioactivity tests in simulated body fluid (SBF) and Hank's balanced salt solution (HBSS) confirmed controlled ion release and apatite formation. The degradation rate was 0.11–0.12 mg/day in SBF and 0.03 mg/day in HBSS, with SEM and EDX analysis showing increased phosphorus uptake and apatite formation after 3 days. These findings suggest that Monticellite coatings enhance osteoconductivity and osteoinductivity while maintaining mechanical stability. Monticellite, when used as a composite with other bioceramics in proportions below 50 %, offers an optimal balance of bioactivity and degradation control, making it a promising candidate for orthopedic and dental implant applications.