Surface plasma treatment (Ar/CF4) decreases biofouling on polycarbonate surfaces

The purpose of this study was to examine the impact of hydrophobicity, surface chemistry and topography on bacterial and microalgal adhesion. To this end, the effects of surface plasma treatments (argon (Ar) and tetrafluorocarbon (CF4)) of polycarbonate substrates on bioadhesion were investigated in vitro. Surfaces were characterized by goniometry, atomic force microscopy and X-ray photoelectron spectroscopy. Two marine bacterial strains, a hydrophobic Pseudoalteromonas sp. 5M6 and a hydrophilic Paracoccus sp. 4M6, and two microalgae (Cylindrotheca closterium and Porphyridium purpureum) involved in marine biofouling were selected. Their adhesion onto the substrates was observed and quantified using confocal laser scanning microscopy-microfluidic flow cells. It was demonstrated that the combination of three parameters - namely, surface energy, fluorination and nanotopography - significantly decreases the adhesion of three microorganisms out of four (Pseudoalteromonas sp. 5M6, C. closterium and P. purpureum), whereas one parameter on its own is insufficient.