Surface Modification of Biomedical Ti-18Zr-15Nb Alloy by Atomic Layer Deposition and Ag Nanoparticles Decoration

Abstract

Superelastic biocompatible alloys attract significant attention as novel materials for bone tissue replacement. These alloys are often composed of three or more components that lead to the formation of complex oxide films on their surfaces. For practical use, it is desirable to have a single-component oxide film with a controlled thickness on the surface of biocompatible material. Herein we investigate the applicability of the atomic layer deposition (ALD) technique for surface modification of Ti-18Zr-15Nb alloy with TiO2 oxide. It was found that a 10–15 nm thick, low-crystalline TiO2 oxide layer is formed by ALD method over the natural oxide film (~5 nm) of the Ti-18Zr-15Nb alloy. This surface consists of TiO2 exclusively without any additions of Zr or Nb oxides/suboxides. Further, the obtained coating is modified by Ag nanoparticles (NPs) with a surface concentration up to 1.6% in order to increase the material’s antibacterial activity. The resulting surface exhibits enhanced antibacterial activity with an inhibition rate of more than 75% against E.coli bacteria.

Atomic Layer Deposition of Antibacterial Nanocoatings: A Review

“…Such structures should exhibit higher adhesion. Thus, we have shown that such complex structures can be obtained in a single ALD process, which simplifies the synthesis and reduces the risk of poor adhesion of Ag nanoparticles [69] and is likely to increase interest in such structures in the future.…”

“…This process reduces the recombination of photo-induced carriers at the noble metal/semiconductor interface [67]. Typically, noble metals such as silver [30,68,69] and gold [60] are deposited as nanoparticles on pre-synthesized ALD TiO 2 . While silver has been shown to possess powerful antibacterial properties due to Ag + release, the formation of a Schottky heterojunction at the TiO 2 /Ag interface results in reduced electron-hole recombination rates.…”

“…In particular, Darwish et al studied ALD TiO 2 coating on PMMA using the denture cleanser challenge test and showed the high stability, mechanical strength, and adhesion of titanium oxide. According to Konopatsky et al [69], low adhesion is one of the main problems of noble metal-sensitized metal nanoparticle TiO 2 , as noble metals obtained via liquid phase deposition suffer from the gradual removal from the surface and reduce the efficiency of photocatalysis. In our recent work [57], we have successfully obtained similar hybrid structures of TiO 2 nanocoatings/Ag NPs using only ALD.…”

Ultrathin TiO2 Coatings via Atomic Layer Deposition Strongly Improve Cellular Interactions on Planar and Nanotubular Biomedical Ti Substrates

“…The material was tested on the mesenchymal tumor stem cell line ST-2, showing excellent osteoconductive properties. However, achieving such a thickness in ALD involves an extensive process with multiple cycles. − Nevertheless, ultrathin TiO 2 ALD coatings can effectively shade potentially poisonous elements, such as F and V, which can be detrimental to biocompatibility properties, decreasing the ALD process time. In our previous work, it was shown that ALD-modified TNT layers with 5c and 150c of TiO 2 can significantly improve the cell growth and the biocompatibility of WI-38 fibroblasts by 50%, SH-SY5Y neuroblasts by 30%, and MG-63 osteoblasts by 30% compared with the uncoated counterparts. , The comparison to Ti foils with a native and thermal oxide layer was also carried out …”