Why does SLIPS inhibit P.aeruginosa initial adhesion in static condition?

Slippery liquid-infused porous surfaces (SLIPSs) have distinguished themselves in inhibiting bacteria attachment and biofilm development in static conditions. However, underlying antifouling mechanisms, especially from gene level in bioinformatics, is still lacking. In this work, we investigated the initial attachment difference of Pseudomonas aeruginosa PAO1 on polydimethylsiloxane (PDMS) surface and the infused silicone slippery surface (i-PDMS). RNA sequencing (RNA-seq) was used to investigate the differences in the expression of PAO1 gene on elastomer surface during initial adhesion before and after oil injection. Compared with PDMS, bacterial attachment on i-PDMS was remarkably decreased 98.0 ± 0.7 % within 10 mins. And the antifouling ability of i-PDMS significantly outperformed PDMS throughout the entire culture period of PAO1 (14 days) in static conditions. RNA-seq reveals that the down-regulated PA1382 of PAO1 in bulk near the i-PDMS surfaces may inhibit bacterial initial adhesion. PA1382 gene encodes type II secretion outer membranes (OM) secretin, also known as type II secretion system (T2SS) protein GspD, which is involved in regulating the opening or closing of exoprotein channels, influencing bacterial adhesion and biofilm formation by controlling the secretion of toxins or effectors. Our findings provide a deeper understanding of the mechanism by which SLIPS inhibits initial bacterial adhesion.