Electrodeposition of Calcium Polyphosphate on Ti-6Al-4V Substrates for Rapid Osseointegration in Orthopedic Applications.

Total hip arthroplasty (THA) is a widely performed surgical procedure that relieves pain and restores mobility in patients with degenerative hip disease. The cementless orthopedic implants have gained popularity in THA due to reduced stress shielding compared with cemented fixation; they also face higher revision rates largely due to aseptic loosening and instability. Calcium polyphosphate (CPP) is a bioactive inorganic polymer that promotes osteogenic activity and has the potential to enhance implant osseointegration. However, limited methods exist for producing strong, uniform CPP coatings on metallic orthopedic implants due to high manufacturing costs and complex surface geometries. This study introduces an electrophoretic deposition (EPD) approach to fabricate uniform CPP coatings on Ti-6Al-4V substrates cost-efficiently and achieves high mechanical adhesion and improved biocompatibility. The CPP-coated samples exhibit an interfacial adhesion strength of above 17 MPa, higher than the FDA guideline requirement. In vitro simulated body fluid immersion evaluations demonstrate rapid apatite formation within 3 days and a degradation rate below 8.3 mg cm-2 over 5 days, indicating a good biocompatibility for orthopedic applications. Collectively, these results demonstrate that EPD-derived CPP coatings offer strong adhesion, controlled degradation rate, and rapid osseointegration, supporting the potential to improve long-term biological fixation of cementless orthopedic implants cost-effectively.