Antibacterial effect on microscale rough surface formed by fine particle bombarding

Abstract

Fine particle bombarding (FPB) is typically utilized to modify metal surfaces by bombarding them with fine particles at high-speed. The diameters of the particles range from several to tens of micrometers. FPB forms fine microscale concavities and convexities on a surface. As FPB-treated surfaces are widely used in the food industry, the influence of bacteria on their surface must be considered. In this study, we examined the antibacterial activity of microscale rough surfaces formed by FPB. We applied FPB to a stainless-steel surface and evaluated the antibacterial effect of FPB-treated surfaces based on JIS Z 2801 (a modified test method from ISO 22196:2007). Our results indicated that the FPB-treated surfaces (FPB-1 (avg. pitch: 0.72 µm) and FPB-2 (avg. pitch: 3.56 µm)) exhibited antibacterial activity both against Escherichia coli and Staphylococcus aureus. Graphical Abstract

Mechanism of antibacterial property of micro scale rough surface formed by fine-particle bombarding

“…In our previous study [ 14 ], we confirmed that FPB-treated surfaces with microscale roughness exhibited antibacterial performance against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ). Nanopillar surfaces induced membrane damage in bacteria, whereas FPB-treated surfaces with a strong antibacterial effect were affected by a concavity that matched the size of a bacterium.…”

“…Reports indicate that the wettability of a surface with a nanopillar structure is related to the viable cell rate [ 21–23 ]. In our previous study [ 14 ], we found that the lower the WCA, the higher the antibacterial performance, with the number of bacteria adhering to the sample surface increasing with decreasing WCA owing to the hydrophilic cell membrane [ 24–27 ]. We evaluated the wettability of the FPB-treated test pieces by measuring their water contact angles (WCAs) using a contact angle meter (DMo-701, Kyowa Interface Science, Japan) with 1.5 μL of purified water droplets.…”

In vitro study of bacterial adhesion and biofilm growth on fresh, frozen, or decellularized human bone grafts

“…Historically, porous materials have also been considered to be more favourable to the development of infections than non-porous ones [30]. However, this assumption is now in doubt, particularly with the discovery of the antibacterial effect produced by modifying the surface structure of materials on micro-and nanometric scales [31,32].…”