Immobilization of ZnO nanosheets on TiO2 nanotubes electrochemically formed on Ti-6Al-4V alloy

ALEJANDRA L. MARTÍNEZ; DANIEL O. FLAMINI; SILVANA B. SAIDMAN

Buenos Aires

Congreso; 11th World Congress of Chemical Engineering (WCCE11).; 2023

World Chemical Engineering Council

In the last decades, metallic Ti and its alloys have attracted the attention of several researchers in the biomedical field. In particular, Ti-6Al-4V has been studied due to its good corrosion resistance, biocompatibility, low density and favorable mechanical properties. Despite its good characteristics, the release of the alloying ions is still of concern. It has been reported that Al and V can be released into the physiological environment and can originate health issues like osteomalacia, peripheral neuropathy and Alzheimer?s disease [1]. For this reason, different techniques have been applied to the alloy surface in order to improve its corrosion behavior. On the other hand, bacterial infection is the most frequent complication associated with implants. Therefore, it is important that the material presents an effective antibacterial activity to prevent biofilm formation. Several inorganic agents have been reported to exhibit antimicrobial properties, among them zinc is an environmentally friendly material that has low toxicity and has been tested against different microorganisms. In this work, TiO2 nanotubes (NTs) were electrochemically synthesized onto Ti-6Al-4V and then modified with ZnO nanosheets to enhance the corrosion behavior in Ringer solution and provide antibacterial activity against S. Aureus and S. Mutans. Ti-6Al-4V in the form of rods axially mounted in a Teflon holder were used as working electrodes (WE) and a large Pt sheet of 1 cm2 area was used as reference electrode. The exposed surface area of WE was 0.07 cm2. In order to form TiO2 nanotubes, the WE were immersed in a solution containing 1 M H3PO4 and 0.4 % (v/v) HF during 2 h at an applied potential of 20 V. The solution was under stirring during the anodization process. After this, the electrodes were rinsed in triply distilled water and introduced into a solution containing 0.1 M KCl and 0.1 M Zn(NO3)2 for the deposition of ZnO nanosheets. For this process, a potential of -1.1 V was applied for 1 h. After the experience, a white deposit could be observed on the Ti-6Al-4V alloy surface. The presence of ZnO was confirmed by scanning electron microscopy (SEM) and X-ray energy dispersion (EDX). After the electrodeposition process, corrosion tests were carried out in Ringer solution through different electrochemical techniques: Tafel polarization curves, linear sweep voltammetry, chronoamperometry and open circuit potential measurements. It was found that the formation of TiO2 nanotubes, together with the presence of ZnO nanosheets, shifts the corrosion potential towards nobler values, maintaining a low corrosion current density. Finally, the antibacterial capacity of the coatings was evaluated. The Kirby-Bauer method [2] was used for this purpose. The strains studied were a culture of Staphylococcus aureus and Streptococcus Mutans. The antibacterial capacity of the samples was determined considering the width of the inhibition zone around the modified surfaces. It was determined that the presence of ZnO nanosheets reduced the bacterial growth obtaining inhibition halos of 15 mm. References (Arial font, size 9 point, justified text)1.S. Rao, T. Ushida, T. Tateishi, Y. Okazaki, S. Asao, Effect of Ti, Al, and V ions on the relative growth rate of fibroblasts (L929) and osteoblasts (MC3T3-E1) cells, Biomed. Mater. Eng. 6 (1996) 79?86, https://doi.org/10.3233/BME-1996-6202.2.A.W. Bauer, W.M. Kirby, J.C. Sherris, M. Turck, Antibiotic susceptibility testing by a standardized single disk method, Am. J. Clin. Pathol. 45 (1966) 493?496 Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/5325707.