A single-step fabrication approach for development of antimicrobial surfaces

In recent years, the increasing incidence of healthcare-associated infections and overuse of antibiotics have led to high demand for antimicrobial-coated medical devices. Silver nanoparticles (AgNPs) have attracted tremendous attention as a subject of investigation due to their well-known antibacterial properties. However, current physical and chemical synthesis methods for AgNPs are costly, time-consuming and not eco-friendly. For the first time, this paper proposes a novel single-step fabrication approach, named StruCoat, to generate antimicrobial AgNPs coated microstructures through hybridizing subtractive laser ablation and additive chemical deposition processes. This new approach can offer antimicrobial micro-structured silver coatings for medical devices such as surgical tools and implants. The StruCoat approach is demonstrated on 316 L stainless steel specimens structured by using nanosecond pulsed laser, while AgNPs are decomposed and coated on these microstructures from the micro drops of silver nitrate solution simultaneously generated by an atomizer. According to the experimental results, silver nitrate with a molarity of 50 mmol and jet to the stainless steel machined at 14 W are the best-operating conditions for chemical decomposition of drops of silver nitrate solution in this research and results in AgNPs with a mean size of 480 nm. Moreover, an investigation of the material microstructures of stainless steel surfaces processed by StruCoat shows significant reduction of material grain size (81% reduction compared to that processed by normal laser machining) which will help improve the fracture toughness and strength of the specimen. Antimicrobial testing also demonstrated that specimens processed by StruCoat exhibited excellent antibacterial properties with 86.2% reduction in the surface attachment of Staphylococcus aureus compared to the smooth surface. Overall, this study has shown StruCoat is a potential approach to prepare antimicrobial surfaces.