Laser polarization induced surface structuring of 316L stainless steel and influence on biocompatibility and antibacterial performance

The paper details the biocompatibility and antibacterial investigations on polarization-dependent laser-induced periodic surface structures (LIPSS) generated on 316L stainless steel using circularly-polarized and linearly-polarized femtosecond (fs) laser pulses. Both LIPSS structures were self-sterilizing to control bacterial adhesion and colonization. LIPSS from the linearly-polarized fs laser had an antibacterial rate of 92 ± 6 % and 97 ± 3 % against Staphylococcus aureus (S. aureus), and Escherichia coli (E. coli), respectively, compared to the polished stainless-steel sample kept as control. LIPSS from circularly-polarized fs laser had an antibacterial rate of 41 ± 8 % and 85 ± 6 % against S. aureus and E. coli, respectively, compared to the polished stainless-steel sample kept as control. Further, the nanoripples generated using linearly-polarized fs-laser favored mammalian cell adhesion, proliferation, and alignment along the nanoripples. Based on the study, the LIPSS from circularly-polarized laser beam possesses antibacterial properties, while the LIPSS from linearly-polarized laser beam possesses both antibacterial and osseointegration properties.