Synergistic surface modification of zirconia nanotubes with silver and hydroxyapatite for enhanced early-stage...

Implant surfaces with multifunctional capabilities that can simultaneously facilitate host cell adhesion and proliferation while minimizing bacterial attachment are essential for the long-term success of an implant. In this study, we present a strategy to improve the early-stage cytocompatibility of silver-modified zirconia nanotubes, a key step to optimizing the surface of zirconia nanotubes to achieve potential dual functionality, by co-modification with silver and hydroxyapatite (Hap) nanoparticles. A novel and straightforward strategy to partially coat zirconia nanotubes (ZrNT) with Hap nanoparticles in a manner that still preserves an accessible nanotubular morphology was introduced. The surface morphology and chemical composition were characterized using SEM, XPS, and ToF-SIMS combined with principal component analysis. Protein adsorption studies reveal that coating with Hap enhances fibronectin adsorption, and the detection of RGD-related fragments via ToF-SIMS provides an analytical approach for fibronectin identification. Biological assays confirmed that the increased fibronectin adsorption due to Hap coating translates to significantly improved osteoblast adhesion and proliferation. Furthermore, incorporating Hap nanoparticles onto silver-modified ZrNT helped mitigate silver-induced cytotoxicity, thereby improving cytocompatibility. These modifications illustrate a simple yet effective approach toward enhancing the biological performance of these Ag-modified zirconia nanotubes and advance the design towards multifunctional, cytocompatible implant interfaces.