Surface modification of stainless steel for enhanced antibacterial activity

Benčina, Metka (author), Rawat, Niharika (author), Paul, Domen (author), Kovač, Janez (author), Iglič, Aleš (author), Junkar, Ita (author)

Stainless-steel grade 316L is widely used in medical and food processing applications due to its corrosion resistance and durability. However, its inherent lack of antibacterial properties poses a challenge in environments requiring high hygiene standards. This study investigates a novel surface modification approach combining electrochemical anodization and nonthermal plasma treatment to enhance the antibacterial efficacy of SS316L. The surface morphology, roughness, chemical composition, and wettability of the modified surfaces were systematically analyzed using Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), X-ray Photoelectron Spectroscopy (XPS), and water contact angle (WCA) measurements. SEM revealed the formation of tunable nanoporous structures with pore diameters ranging from 100 to 300 nm, depending on the applied anodizing voltage (40 and 60 V). AFM measurements demonstrated that surface roughness varied significantly with anodizing voltage, from 4.3 ± 0.4 nm at 40 V to 15.0 ± 0.6 nm at 60 V. XPS analysis confirmed the presence of Cr$_2$O$_3$, a key oxide for corrosion resistance, and revealed increased oxygen concentration after plasma treatment, indicating enhanced surface oxidation. Wettability studies showed that plasma treatment changed the surfaces to superhydrophilic, with WCAs below 5°. Antibacterial efficacy against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was significantly improved, with plasma-treated samples exhibiting up to 92% reduction in bacterial adhesion. These results demonstrate that the combined anodization and plasma treatment process effectively enhances the antibacterial and surface properties of SS316L, making it a promising strategy for applications in medical and food processing industries.

• Language: English
• Keywords: stainless-steel grade, nonthermal plasma treatment, antibacterial efficacy, anodization, bacteria, plasma, surface roughness, X-ray photoelectron spectroscopy
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FE - Faculty of Electrical Engineering; MF - Faculty of Medicine
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: Str. 13361−13369
• Numbering: Vol. 10, iss. 13
• PID: 20.500.12556/RUL-168483
• UDC: 621.7+621.9
• ISSN on article: 2470-1343
• DOI: 10.1021/acsomega.4c11424
• COBISS.SI-ID: 230771203
• Publication date in RUL: 15.04.2025

Record is a part of a journal

• Title: ACS omega
• Shortened title: ACS omega
• Publisher: American Chemical Society
• ISSN: 2470-1343
• COBISS.SI-ID: 525873945

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P2-0082
• Name: Tankoplastne strukture in plazemsko inženirstvo površin

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: J3-3074
• Name: Inovativni postopki obdelave površin za napredne lastnosti medicinskega jekla