Influence of the Surface Topography of Stainless Steel on Bacterial Adhesion

TLDR

Bacterial adhesion on stainless steel can cause microbially induced corrosion or serve as a chronic source of contamination. The study examined how the surface topography of AISI 304 stainless steel influences the extent and patterns of adhesion of four bacterial species from three phyla with diverse physicochemical traits. The authors fabricated five surface finishes with Ra values from 0.03 to 0.89 µm and used interaction‑energy calculations and micro‑geometry analysis to confirm how surface roughness governs bacterial adhesion. Adhesion was lowest at Ra = 0.16 µm, with smoother and rougher surfaces showing higher adhesion; the 0.7 µm scratches aligned three strains, and rougher surfaces with wider scratches allowed more bacteria to adhere in non‑parallel orientations, whereas the smoothest surface produced random bacterial orientation.

Abstract

Bacterial adhesion on stainless steel may cause problems such as microbially induced corrosion or represent a chronic source of microbial contamination. The investigation focussed on how the extent and patterns of four bacterial species comprising three different phyla and a broad variety of physicochemical characteristics was influenced by the surface topography of AISI 304 stainless steel. Five types of surface finish corresponding to roughness values R a between 0.03 and 0.89 w m were produced. Adhesion of all four bacteria was minimal at R a =0.16 w m, whereas smoother and rougher surfaces gave rise to more adhesion. This surface exhibited parallel scratches of 0.7 w m, in which a high proportion of bacteria of three of the strains aligned. Reduced overall adhesion was attributed to unfavorable interactions between this surface and bacteria oriented other than parallel to the scratches. Interaction energy calculations and considerations of micro-geometry confirmed this mechanism. Rougher surfaces exhibiting wider scratches allowed a higher fraction of bacteria to adhere in other orientations, whereas the orientation of cells adhered to the smoothest surface was completely random.