Cytocompatibility and early osseointegration of nanoTiO₂-modified Ti-24 Nb-4 Zr-7.9 Sn surfaces

This study aimed to evaluate the cytocompatibility and early osseointegration of Ti-24 Nb-4 Zr-7.9 Sn (Ti-2448) surfaces that were modified with a nanoscale TiO₂ coating. The coating was fabricated using a hydrothermal synthesis method to generate nanoTiO₂/Ti-2448. The surface characteristics of the samples were evaluated using scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray diffraction (XRD). The cytotoxicity of the fabricated nanoTiO₂/Ti-2448 was determined using MTT assays. The proliferation and alkaline phosphatase (ALP) activity of MC3T3-E1 osteoblasts cultured on nanoTiO₂/Ti-2448 were compared with those cultured on Ti-2448. Disk-shaped implants were placed in Wistar rats. The histological sections were stained with haematoxylin and eosin (HE), and the histocompatibility was analysed at 4 and 12 weeks post-implantation. Cylindrical implants were embedded in Japanese white rabbits, and the histological sections were stained with HE and anti-TGF-β1 to evaluate the histocompatibility and early osseointegration at 4, 12 and 26 weeks post-implantation. NanoTiO₂/Ti-2448 exhibited a rougher surface than did Ti-2448. NanoTiO₂/Ti-2448 was determined to be non-cytotoxic. More osteoblasts and higher ALP activity were observed for nanoTiO₂/Ti-2448 than Ti-2448 (p < 0.05). Few inflammatory cells were detected around nanoTiO₂/Ti-2448, and the expression of TGF-β1 on nanoTiO₂/Ti-2448 peaked at earlier time than that on Ti-2448. The results indicate that the cytocompatibility and early osseointegration were enhanced by the nanoTiO₂ coating. - Highlights: • The cytocompatibility of nanoTiO2/Ti-2448 is first reported in our work. • The early osseointegration of nanoTiO2/Ti-2448 is first reported in our work. • We evaluate the biocompatibility of nanoTiO2/Ti-2448 by in-vitro and in-vivo tests