Silver oxide‐containing hydroxyapatite coating supports osteoblast function and enhances implant anchorage strength in rat femur

Abstract

Antibacterial silver with hydroxyapatite (Ag-HA) is a promising coating material for imparting antibacterial properties to implants. We previously reported that 3% (w/w) silver with HA (3% Ag-HA) has both antibacterial activity and osteoconductivity. In this study, we investigated the effects of Ag-HA on the in vitro osteoblast function and the in vivo anchorage strength and osteoconductivity of implants. Production of the osteoblast marker alkaline phosphatase, but not cytotoxicity, was observed in cells of the osteoblast cell line MC3T3-E1 cultured on the 3% Ag-HA-coated surface. These results were similar to those observed with silverfree HA coating. In contrast, a significant high level of cytotoxicity was observed when the cells were cultured on a 50% Ag-HA-coated surface. The anchorage strength of implants inserted into the femur of Sprague-Dawley (SD) rats was enhanced by coating the implants with 3% Ag-HA. On the 3% Ag-HA-coated surface, both metaphyseal and diaphyseal areas were largely covered with new bone and had adequate osteoconductivity. These results suggest that 3% Ag-HA, like conventional HA, promotes osteogenesis by supporting osteoblast viability and function and thereby contributes to sufficient anchorage strength of implants. Application of 3% Ag-HA, which combines the osteoconductivity of HA and the antibacterial activity of silver, to prosthetic joints will help prevent postoperative infections. ß

Atomic Layer Deposition of a Silver Nanolayer on Advanced Titanium Orthopedic Implants Inhibits Bacterial Colonization and Supports Vascularized de Novo Bone Ingrowth

“…More specifically, we examined the growth of SAOS‐2 cells (an osteoblasts‐like human cell line) on scaffolds between 6 and 48 h following culture and show ultrastructural evidence of cell survival and adherence, in addition to an MTT assay confirming cell population viability on both Ti‐only and Ti/Ag scaffolds. Our findings are consistent with both human SAOS‐2 cell and mouse osteoblast cells (MC3T3‐E1) grown on silver‐nanoparticle‐coated titanium surfaces . However, in vitro responses can be cell type specific as high concentrations of labile Ag‐containing surface coatings are known to be toxic to human fetal osteoblasts .…”

“…By 12 weeks' postimplantation, there is clear evidence of bone and vascular remodeling within the porous structure of Ti‐only and Ti/Ag scaffolds, including Volkmann's canals with attendant capillaries—features that are characteristic of mature bone growth . In addition, 2D light microscopic examination of thick histological sections and 3D X‐ray computed microtomographic reconstructions revealed excellent bone ingrowth in both Ti‐only and Ti/Ag scaffolds, similar to that described for rats implanted with titanium coated with either silver‐oxide‐doped hydroxyapatite or silver‐impregnated nanotubes …”

“…The majority of studies examining the antimicrobial potential of silver for dental/orthopedic applications rely on dissolution of Ag particles from either cements or surface coatings for titanium. These studies generally report a >2 log‐fold increase in microbicidal activity, although silver particles are highly mobile and potentially toxic, with their tissue accumulation characteristics being largely unexplored .…”

“…The majority of approaches for dissolution of Ag + or Cu ions for antimicrobial applications is directed toward localized release via gradual solubilization. Although localized release of Ag‐nanoparticles via dissolution achieves excellent antimicrobial effects in vitro and in vivo, this approach is associated with increased silver levels in both serum and systemic organs in addition to evidence of toxicity.…”

Silver-Containing Hydroxyapatite Coating Reduces Biofilm Formation by Methicillin-ResistantStaphylococcus aureusIn Vitro and In Vivo

“…Accordingly, Eto et al reported that 3% Ag-HA supported viability and function of osteoblasts, as well as anchorage strength. In pull-out tests using rat femurs, there were no significant differences between 3% Ag-HA and HA, whereas 50% Ag-HA required less force [36]. Therefore, we speculate that orthopaedic implants coated with 3% Ag-HA will have low silver toxicity while maintaining antibiofilm activity of silver, combined with the good osteoconductivity of HA.…”