Innovative Ti_1–xNb_xN–Ag Films Inducing Bacterial Disinfection by Visible Light/Thermal Treatment

Abstract

This study presents innovative TiNb N-Ag films obtained by a suitable combination of low-energy and high-energy sputtering leading to bacterial inactivation. The bacterial inactivation kinetics by the TiNbN layers was drastically enhanced by the addition of 6-7% Ag and proceeded to completion within 3 h after the film autoclaving. By X-ray photoelectron spectroscopy (XPS), the samples after autoclaving presented in their upper layers TiO, NbO and AgO with a surface composition of TiNbNAg. Surface potential/pH changes in the TiNb N-Ag films were monitored during bacterial inactivation. Surface redox processes during the bacterial inactivation were detected by XPS. The diffusion of Ag in the TiNb N-Ag films was followed at 50 and 70 °C pointing. The beneficial thermal treatment points out to the bifunctional bacterial inactivation properties of these films and their potential application in healthcare facilities. Interfacial charge transfer (IFCT) under light irradiation between AgO, NbO and TiO is suggested consistent with the data found during the course of this study. The TiO/NbO lattice mechanism is discussed in the framework of the Verwey's controlled valence model. The surface properties of the TiNb N-Ag films were investigated by X-ray diffraction, atomic force microscopy, and scanning electron microscopy.

Electrophoretic Deposition and Characteristics of Chitosan–Nanosilver Composite Coatings on a Nanotubular TiO2 Layer

“…Bacterial inactivation may occur via two different actions: at the direct contact of bacteria with nanosilver at the interface or by the interaction of bacteria and the silver ions that appear during the dissolution of nanosilver [57][58][59]. The present results did not support either hypothesis, but the direct contact of silver ions and bacteria in solution seems more probable, as the antibacterial efficiency followed the silver release.…”

“…Moreover, the reference dose for allowable oral exposure of Ag, as defined by the US EPA (United States Environmental Protection Agency) is 0.005 mg of Ag/kg of body mass per day and, considering the maximum Ag release rate determined here, the maximum daily allowable consumption of Ag will not be exceeded in an average adult [56]. Bacterial inactivation may occur via two different actions: at the direct contact of bacteria with nanosilver at the interface or by the interaction of bacteria and the silver ions that appear during the dissolution of nanosilver [57][58][59]. The present results did not support either hypothesis, but the direct contact of silver ions and bacteria in solution seems more probable, as the antibacterial efficiency followed the silver release.…”

Update on Interfacial Charge Transfer (IFTC) Processes on Films Inactivating Viruses/Bacteria under Visible Light: Mechanistic Considerations and Critical Issues

“…The virus inactivation depends on the UV-A intensity and irradiation time. Titanium dioxide photocatalysis under UV light can inactivate 4-log 10 influenza virus within a short time at extremely low doses of UV-A (0.01 mW/cm 2 ) [21,22].…”

In Vitro Corrosion and Wear Investigation of Multifunctional TiAlMoN Sputtered Coatings on Cold-Sprayed SS316L

“…Magnetron sputtering is a highly recommended technique for depositing various industrial coatings. , It contributes to a wide application range, including wear-resistant, hard, corrosion-resistant, oxidation-resistant, and decorative coatings with specific optical or electrical properties. It is often used to improve the performance and extend the lifetime of different components such as cutting tools, aircraft fasteners, and proton exchange membrane fuel cells. − Transition metal nitride films have shown good corrosion resistance, high hardness, and excellent electrical conductivity. − Among them, titanium nitride is widely used in manufacturing cutting tools, orthopedic implants, stamping tools, and bearings and as a decorative material. , Many researchers have found that TiN coatings are usually characterized by high tribological performance during friction by forming a solid lubricant. − Therefore, combining TiN coatings with other elements (e.g., Al, Mo, Cr, etc.) presents a remarkable improvement in the hardness and wear resistance.…”