Biofilm growth on laser-induced periodic surface structures (LIPSS) of AISI 316L stainless steel

Abstract

The morphological characteristics of metallic surfaces play a crucial role in the adhesion, retention, and growth of bacteria and fungi. Laser-induced periodic surface structures (LIPSS) present potential to controlling biofilm formation on biocompatible metallic surfaces for biomedical and engineering applications. LIPSS have emerged as a promising technique for controlling biofilm formation on biocompatible metallic surfaces in various biomedical and engineering applications. This present work uniquely focuses on investigating the effects of LIPSS on AISI 316L stainless steel (AISI 316L SS) as a potential inhibitor against the adhesion of bacteria and fungi (E. coli and C. albicans, respectively) on laser-textured surfaces. Microstructural characterization through scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), roughness profiling, and X-ray diffraction (XRD) revealed morphologic alterations of the laser-treated surfaces, resulting in the formation of LIPSS with laser fluences of 2.1 J/cm² and 2.8 J/cm², line spacing approximately equivalent to the laser wavelength (532 nm), and average roughness values of 96 nm and 209 nm, respectively. The study found that LIPSS exhibited inhibitory effects against E. coli biofilm formation on laser-textured surfaces, with a noticeable enhancement in antimicrobial efficiency ranging from 30% to 43% compared to untreated surfaces. However, the antimicrobial effectiveness against C. albicans was notably lower, with marginal improvements observed under specific conditions. Thus, the results showed a complex interplay between surface morphology, microbial adhesion, and antimicrobial efficacy on laser-textured metallic surfaces. These findings underscore the dependence of the antimicrobial properties of laser-textured surfaces on the type of microorganism and laser processing parameters.

Keywords:
LIPSS; AISI 316L SS; E. coli biofilm; C. albicans biofilm; Laser-textured surface