Antimicrobial and antiviral properties of stainless steel enhanced by controlled silver nano-island deposition: A safe and sustainable by design approach

Stainless steel (SS), particularly SS316L, is extensively utilised across industries, from consumer products to biomedical applications, due to its superior mechanical and chemical properties. However, in critical settings such as healthcare, maintaining contamination-free surfaces is essential to reduce microbial and viral transmission. This study introduces a multifunctional approach by leveraging the antimicrobial potential of silver (Ag) nano-islands deposited on SS316L substrates. By varying the Ag coating thickness from 2.7 nm to 45.5 nm, a transition from discrete nano-islands to a continuous layer was achieved, influencing surface morphology and functionality. The formation of Ag nano-islands reduced surface hydrophilicity by 57% and increased surface roughness by 50%, enabling a controlled release of Ag ions and nanoparticles. This controlled release mechanism provides potent antimicrobial and antiviral effects with minimal silver usage, eliminating the need for full surface coverage. Stability tests confirmed that the nano-islands remained intact, retaining antimicrobial efficacy over time, proportional to the amount of Ag deposited. This Safe and Sustainable by design (SSbD) based nano-island approach offers a cost-effective, scalable, and efficient solution for antimicrobial surface modification, achieving significant microbial and viral inhibition while minimising silver use. Additionally, the user-activated release mechanism enhances surface longevity, presenting a sustainable and safe strategy for high-touch antimicrobial surfaces.