Surface phenomena of hydroxyapatite film on the nanopore formed Ti-29Nb-xZr alloy by anodization for bioimplants

Nano-hydroxyapatite coated TiO2 nanotubes on Ti-19Zr-10Nb-1Fe alloy promotes osteogenesis in vitro

Titanium and titanium alloys have broad applications in orthopedic implants due to their excellent mechanical properties and biocompatibility. The biological activity of the metallic implants can be improved by implementing a nano-hydroxyapatite (nano-HA) coating, while it is still challenging to synthesize uniform and stable nano-HA on the metallic materials. The characterization results confirmed that the nanotube array with a diameter of 87 ± 21 nm and a length of 8.1 ± 1.3 μm is achieved by using double anodic oxidation, and then microsphere-like nano-HA crystals are formed on the TiO₂ nanotube arrays. Through X-ray diffraction (XRD) and Fourier Transform Infrared Spectrometer (FT-IR) analysis, it is determined that the chemical composition of the coating is hydroxyapatite. in vitro cell experiments, compared to the TZNF metal surface, the TZNF-NTs/HA is beneficial to the proliferation and adhesion of osteoblasts, and the activity of ALP was 6.93 ± 0.47 DEA unit and the content of OCN was 7.04 ± 0.51 ng/L. In terms of the expression of osteogenic gene information as osterix, osteopontin, and osteonectin, the mRNA levels of TZNF-NTs/HA were 2.6-fold, 1.6-fold, and 4.3-fold higher than that of TZNF samples, respectively, at 14 days. The results suggested that the introduction of nano-HA improves osteoblast differentiation and local factor production, as well as indicates the potential for improved implant osseointegration.

Mixed oxide nanotubes in nanomedicine: A dead-end or a bridge to the future?

Nanomedicine has seen a significant rise in the development of new research tools and clinically functional devices. In this regard, significant advances and new commercial applications are expected in the pharmaceutical and orthopedic industries. For advanced orthopedic implant technologies, appropriate nanoscale surface modifications are highly effective strategies and are widely studied in the literature for improving implant performance. It is well-established that implants with nanotubular surfaces show a drastic improvement in new bone creation and gene expression compared to implants without nanotopography. Nevertheless, the scientific and clinical understanding of mixed oxide nanotubes (MONs) and their potential applications, especially in biomedical applications are still in the early stages of development. This review aims to establish a credible platform for the current and future roles of MONs in nanomedicine, particularly in advanced orthopedic implants. We first introduce the concept of MONs and then discuss the preparation strategies. This is followed by a review of the recent advancement of MONs in biomedical applications, including mineralization abilities, biocompatibility, antibacterial activity, cell culture, and animal testing, as well as clinical possibilities. To conclude, we propose that the combination of nanotubular surface modification with incorporating sensor allows clinicians to precisely record patient data as a critical contributor to evidence-based medicine.