This study presents a surface‑modification strategy that imparts three key functions—osteoconductivity, antibacterial activity, and osteogenesis promotion—to titanium widely used in orthopedic and dental implants.
Fabrication process
Alkali treatment
NaOH soaking generated a layered sodium titanate layer.
Ion exchange & heat treatment
Sodium ions were replaced with Ca²⁺ and Sr²⁺, followed by firing at 600 °C to create a calcium‑deficient calcium titanate (CD‑CT) layer.
Simultaneous Sr/Ag incorporation
Immersion in a pH 4 solution containing Sr(NO₃)₂ and AgNO₃ produced a dense (~1 µm) coating enriched with osteogenic Sr²⁺ and broadly antibacterial Ag⁺.
Performance highlights
Bioactivity: Spontaneous formation of bone‑like apatite occurred in simulated body fluid within three days.
Antibacterial efficacy: Against E. coli, bacterial survival dropped by 5.9 log orders.
Controlled Sr release: A cumulative 1.29 ppm Sr²⁺ was released over 14 days without inhibiting proliferation of MC3T3‑E1 pre‑osteoblasts.
Structure & durability: Raman and XPS confirmed Sr/Ag solid‑solution in the CD‑CT phase, and scratch testing showed high adhesion strength (~ 40 mN), adequate for clinical loads.
Unlike conventional hydroxyapatite plasma‑spray coatings, which may dissolve over time and invite infection, this purely chemical–thermal method forms a uniform, multifunctional layer that penetrates deep into pores and the titanium substrate itself. By integrating direct bone bonding, infection control, and stimulation of bone remodeling, the coating holds great promise for enhancing the long‑term success of next‑generation hip stems and dental implants.