Influence of poly(ethylene oxide)-based copolymer on protein adsorption and bacterial adhesion on stainless steel: Modulation by surface hydrophobicity

• Pseudomonas adhesion on stainless steel (SS) was studied using a modified flow cell.
• XPS was used to quantify adsorption of PEO–PPO–PEO and of a model protein.
• PEO–PPO–PEO prevents bacterial adhesion on hydrophobized SS, not on native SS.
• Prevention of bacterial adhesion is linked with inhibition of protein adsorption.
• Surface hydrophobicity influences PEO–PPO–PEO efficiency via adlayer structure.

The aim of the present work is to study the adhesion of Pseudomonas NCIMB 2021, a typical aerobic marine microorganism, on stainless steel (SS) substrate. More particularly, the potential effect on adhesion of adsorbed poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO–PPO–PEO) triblock copolymer is investigated. Bacterial attachment experiments were carried out using a modified parallel plate flow chamber, allowing different surface treatments to be compared in a single experiment. The amount of adhering bacteria was determined via DAPI staining and fluorescence microscopy. X-ray photoelectron spectroscopy (XPS) was used to characterize the surface chemical composition of SS and hydrophobized SS before and after PEO–PPO–PEO adsorption. The adsorption of bovine serum albumin (BSA), a model protein, was investigated to test the resistance of PEO–PPO–PEO layers to protein adsorption. The results show that BSA adsorption and Pseudomonas 2021 adhesion are significantly reduced on hydrophobized SS conditioned with PEO–PPO–PEO. Although PEO–PPO–PEO is also found to adsorb on SS, it does not prevent BSA adsorption nor bacterial adhesion, which is attributed to different PEO–PPO–PEO adlayer structures on hydrophobic and hydrophilic surfaces. The obtained results open the way to a new strategy to reduce biofouling on metal oxide surfaces using PEO–PPO–PEO triblock copolymer.