The Biocompatibility of Silver and Nanohydroxyapatite Coatings on Titanium Dental Implants with Human Primary Osteoblast Cells

Silver nanoparticles (Ag NPs) are antimicrobial, with potential uses in medical implants, but Ag NPs alone can
also be toxic to mammalian cells. This study aimed to enhance the biocompatibility of Ag NP-coated titanium
dental implants with hydroxyapatite (HA) applied to the surface. Ti6Al4V discs were coated with Ag NPs, Ag NPs
plus HA nanoparticles (Ag + nHA), or Ag NPs plus HA microparticles (Ag + mHA). The stability of coatings was
explored and the biocompatibility with primary human osteoblasts over 7 days. Results showed that Ti6Al4V
discs were successfully coated with silver and HA. The primary particle size of nHA and mHA were
23.90 ± 1.49 nm and 4.72 ± 0.38 μm respectively. Metal analysis showed that underlying silver coatings remain stable in DMEM culture media, but the presence of FBS in the media caused some initial (clinically beneficial) release of dissolved silver. With additions of HA, osteoblasts were adherent, had normal morphology,
negligible lactate dehydrogenase (LDH) leak, and showed alkaline phosphatase (ALP) activity. Cell viability was
around 70% throughout the Ag + nHA treatment. Overall, the implants coated with Ag + nHA maintained a
higher degree of biocompatibility compared to those coated with Ag + mHA, or Ag NPs alone, suggesting the
former has a benefit for clinical use.