title: Competition of bovine serum albumin adsorption and bacterial adhesion onto surface-grafted ODT: in situ study by vibrational SFG and fluorescence confocal microscopy.
abstract: The interaction of hydrophilic and hydrophobic ovococcoid bacteria and bovine serum albumin (BSA) proteins with a well ordered surface of octadecanethiol (ODT) self assembled monolayer (SAM) has been studied in different situations where proteins were either preadsorbed on ODT or adsorbed simultaneously with bacterial adhesion as in life conditions. The two situations lead to very different antimicrobial behavior. Bacterial adhesion on preadsorbed BSA is very limited, while the simultaneous exposure of ODT SAM to proteins and bacteria lead to a markedly weaker antimicrobial effect. The combination of sum frequency generation spectroscopy and fluorescence confocal microscopy experiments allow one to draw conclusions on the factors that govern the ODT SAM or BSA film interaction with bacteria at the molecular level. On the hydrophobic ODT surface, interaction with hydrophobic or hydrophilic biomolecules results in opposite effects on the SAM, namely, a flattening or a raise of the terminal methyl groups of ODT. On an amphiphilic BSA layer, the bacterial adhesion strength is weakened by the negative charges carried by both BSA and bacteria. Surprisingly, preadsorbed BSA that cover part of the bacteria cell walls increase the adhesion strength to the BSA film and reduce hydrophobic interactions with the ODT SAM. Finally, bacterial adhesion on a BSA film is shown to modify the BSA proteins in some way that change their interaction with the ODT SAM. The antimicrobial effect is much stronger in the case of a preadsorbed BSA layer than when BSA and bacteria are in competition to colonize the ODT SAM surface.
authors.affiliation: Institut des Sciences Moléculaires d'Orsay, ISMO-CNRS, Université Paris Sud, Bât. 350 91405 Orsay cedex, France. emilie.bulard@u-psud.fr
authors.forename: Emilie
authors.initials: E
authors.lastname: Bulard
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Fontaine-Aupart
authors.forename: Henri
authors.initials: H
authors.lastname: Dubost
authors.forename: Wanquan
authors.initials: W
authors.lastname: Zheng
authors.forename: Marie-Noëlle
authors.initials: MN
authors.lastname: Bellon-Fontaine
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Herry
authors.forename: Bernard
authors.initials: B
authors.lastname: Bourguignon
mesh_terms: D000327:Adsorption; D000473:Alkanes / Q000737:chemistry*; D001422:Bacterial Adhesion; D001667:Binding, Competitive; D057927:Hydrophobic and Hydrophilic Interactions; D013294:Lactococcus lactis / Q000737:chemistry*; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D013057:Spectrum Analysis / Q000379:methods; D055672:Static Electricity; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013499:Surface Properties; D013816:Thermodynamics; D014732:Vibration
chemical_list: D000473:Alkanes; D013438:Sulfhydryl Compounds; D012710:Serum Albumin, Bovine