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

Abstract

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.

Keywords: ALP, Alkaline Phosphatase; APH, Anodization-Cyclic Precalcification-Heat Treatment; Ag2O NPs, Silver Oxide Nanoparticles; AgNPs, Silver Nanoparticles; Anodization; BIC, Bone-Implant Contact; Bioassays; CAGR, Compound Annual Growth Rate; CT, Computed Tomography; DMF, Dimethylformamide; DMSO, Dimethyl Sulfoxide; DRI, Drug-Releasing Implants; E. Coli, Escherichia Coli; ECs, Endothelial Cells; EG, Ethylene Glycol; Electrochemistry; FA, Formamide; Fe2+, Ferrous Ion; Fe3+, Ferric Ion; Fe3O4, Magnetite; GEP, Gene Expression Programming; GO, Graphene Oxide; HA, Hydroxyapatite; HObs, Human Osteoblasts; HfO2 NTs, Hafnium Oxide Nanotubes; IMCs, Intermetallic Compounds; LEDs, Light emitting diodes; MEMS, Microelectromechanical Systems; MONs, Mixed Oxide Nanotubes; MOPSO, Multi-Objective Particle Swarm Optimization; MSCs, Mesenchymal Stem Cells; Mixed oxide nanotubes; NMF, N-methylformamide; Nanomedicine; OPC1, Osteo-Precursor Cell Line; PSIs, Patient-Specific Implants; PVD, Physical Vapor Deposition; RF, Radio-Frequency; ROS, Radical Oxygen Species; S. aureus, Staphylococcus Aureus; S. epidermidis, Staphylococcus Epidermidis; SBF, Simulated Body Fluid; TiO2 NTs, Titanium Dioxide Nanotubes; V2O5, Vanadium Pentoxide; VSMCs, Vascular Smooth Muscle Cells; XPS, X-ray Photoelectron Spectroscopy; ZrO2 NTs, Zirconium Dioxide Nanotubes; hASCs, Human Adipose-Derived Stem Cells.