Antibacterial properties of Ag/TiO2/PDA nanofilm on anodized 316L stainless steel substrate under illumination by a normal flashlight

Abstract

The demand of medical materials for rapid and efficient elimination of bacteria has seen a dramatic surge over the past few years. In this study, antibacterial nanofilms with reactive oxygen species were generated by photocatalysis. To prepare these nanofilms, Ag and amorphous TiO 2 nanoparticles decorated on polydopamine (PDA) were coated on three-dimensional (3D) nanopore arrays, which was fabricated on a substrate of anodized stainless steel. All the antibacterial tests were conducted with a household flashlight, which may be considered as a practical approach for antibacterial materials. The photoelectrochemical property of the 3D Ag/TiO 2 /PDA nanofilm on 316L stainless steel (Ag/TiO 2 /PDA SS) was about 15 times higher than that of the annealed Ag/ TiO 2 /PDA SS, and consequently, it exhibited higher antibacterial activity. The enhanced photoelectrochemical property is attributed to the successful separation of electrons (amorphous TiO 2 ) and holes (Ag nanoparticles). Further, when a plate containing 3D Ag/TiO 2 /PDA SS was irradiated with visible light just for 10 min, it immediately destroyed the bacteria in 10 6 CFU/mL without any bacterial colony. After five weeks, there were still no bacterial colonies in the plate corresponding to Ag/TiO 2 /PDA SS under visible light, while Ag/TiO 2 / PDA SS in dark had a negligible effect on the bacteria, i.e., the antibacterial mechanism through direct contact and ion dissolution was not efficient. The excellent antibacterial properties of 3D Ag/TiO 2 /PDA SS illuminated by flashlight provides an efficient, facile, and cost-effective technique for the development of antibacterial medical materials to meet the increasing demand of eliminating bacterial infections.

Recent Advances in a Polydopamine-Mediated Antimicrobial Adhesion System

“…PDA, as transformation interface, could support the photocatalytic mechanism to generate some ROS such as hydroxyl radical, hydrogen peroxide, and superoxides, which could cause bacterial inactivation. The study supported the future aspect of intermediate PDA layer as a favorable antibacterial coating on a wide variety of substrates such as plastic glass and metal alloy ( Wen et al, 2020 ). Yuan et al (2019) designed a functional MoS 2 /PDA–Arg–Gly–Asp–OH coating on Ti implants to inhibit in situ bacterial infection and mend osseointegration.…”

Effects of sintering temperature and particle size on permeability of functionally gradient composite porous materials prepared by hanging slurry process

“…A great diversity of porous materials can help us solving these problems as above effectively [1][2][3][4][5]. Especially the functionally gradient composite porous materials, which have the characterization of different pore sizes and porosity gradient comparing with the homogeneous porous materials, have become one of hot spots research in recent years according to the weakness of single porous materials [6][7][8][9]. By virtue of different structures and functions on those porous materials mentioned earlier, which can ensure the smaller pore size on the basis of a large filtration flux, show greatly improving the filtering accuracy and filtering efficiency in the process of filtration and separation.…”