Pre-adsorption of serum albumin on biomaterial surfaces modulates bacteria-surface interactions and alters bacterial physiological responses

When a biomedical device is implanted into the body, its surface initially encounters biological fluids, resulting in the natural adsorption of various host proteins. This protein-adsorbed layer alters the inherent properties of the biomaterial surface and plays a crucial role in interactions between the implant and bacteria. Here, we investigated the influence of an adsorbed layer of albumin, the most abundant blood protein, on the adhesion and biofilm formation of three different bacterial strains: <i>Staphylococcus aureus</i>, <i>Staphylococcus epidermidis</i>, and <i>Pseudomonas aeruginosa</i>. We found that the effect of a serum albumin layer on bacterial adhesion was strain-dependent. Albumin pre-adsorption reduced the initial attachment of <i>S. aureus</i> and <i>S. epidermidis</i> to PDMS surfaces but had no impact on <i>P. aeruginosa</i>. However, with prolonged incubation, albumin-coated surfaces significantly promoted <i>P. aeruginosa</i> attachment and biofilm formation. Additionally, this biofilm alteration was associated with reduced macrophage-mediated bacterial clearance. Proteomic analysis further revealed significant physiological changes in <i>P. aeruginosa</i> upon exposure to albumin-coated surfaces compared to uncoated controls. These alterations were particularly associated with molecular pathways involved in surface colonization, including <i>quorum sensing</i>, motility, adhesion, and biofilm formation. These findings suggest that serum albumin adsorption not only affects the initial adhesion of bacteria but also modifies their adaptive responses upon contact with the biomaterial surface. This study provides a deeper understanding of the complex bacteria-surface interactions, contributing to the development of future strategies for preventing implant-associated infections.