Nanostructured Zirconia (ZrO2): from Anodization to potential bio-medical implants

Surfaces in the sub-micron range benefit by maximizing the surface area to volume ratio. Conventional bulk materials such as metal monoliths can be transformed into nanostructured metal-oxides via electrochemical anodization. These metal-oxide surfaces have successfully been modified to elicit surface functionality via facile application of self-assembled monolayers (SAM).^[1] Especially in the biomedical field, multi-functional materials are being explored for prosthetics and diagnostic prognosis suited for implant coatings, where they potentially can serve as drug reservoirs and simultaneously enhance the implant acceptance.^[2] In this work, we develop zirconium-oxide nanostructures and shed light on the role of the type of functionalization strategy, such as immersion in bulk solution (BI) and micro-contact printing (μCP) used to impart specific surface-modification. Zirconia nanotubes (ZrNTs) were evaluated for the influence on the extent of achievable hydrophobic-effect as a function of application techniques and were assessed for their storage capacities augmented by modified surface reactivity via dye-release experiments aimed to simulate drug-release behaviour. The use of sequential functionalization strategies via BI and μCP bears a ‘proof of principle’ to create bi-functionalized nanostructures that are able to demonstrate multi-molecule and multi-depth modifications.^[3] Such nanotubular reservoirs developed on the implant surface would be capable of facilitating developmental strategies towards controlled multi-drug release models that can even elicit, sequential release of drugs to limit clotting, inhibit infection and ultimately promote healing. Additionally, zirconia nanostructures were quantified on their acellular ability- extent of biomineralization and cellular viability- in-vitro cytotoxicity tests and stability in relation to morphology.

References

1. Wetting behavior of zirconia nanotubes, RSC Adv., 2021, https://doi.org/10.1039/D1RA04751E

2. Drug Release from Thermo‐Responsive Polymer Brush Coatings to Control Bacterial Colonization and Biofilm Growth on Titanium Implants, Adv. Healthc. Mater., 2021, https://doi.org/10.1002/adhm.202100069.

3. Functionalization strategies to facilitate multi-depth, multi-molecule modifications of nanostructured oxides for triggered release applications, Surf. Sci., 2022, https://doi.org/10.1016/j.susc.2022.122024.