Graphene-Coated Surface Plasmon Resonance Interfaces for Studying the Interactions between Bacteria and Surfaces

Abstract

A variety of physical and chemical parameters are of importance for adhesion of bacteria to surfaces. In the colonization of mammalian organisms for example, bacterial fimbriae and their adhesins not only seek particular glycan sequences exposed on diverse epithelial linings, they also enable the bacteria to overcome electrostatic repulsion exerted by their selected surfaces. In this work, we present a new technique based on simplified model systems for studying the adhesion strength of different Escherichia coli strains. For this purpose, gold-based surface plasmon resonance (SPR) interfaces were coated with thin films of reduced graphene oxide (rGO) through electrophoretic deposition. The rGO matrix was post-modified with polyethyleneimine (PEI), poly(sodium 4-styrenesulfonate) (PSS), mannose, and lactose through π-stacking and/or electrostatic interactions by simple immersion of the SPR interface into their respective aqueous solutions. The adhesion behaviors of one uropathogenic and two enterotoxigenic Escherichia coli clinical isolates, that each express structurally characterized fimbrial adhesins, were investigated. It was found that the UTI89 cystitis isolate that carries the mannose-binding FimH adhesin was most attracted to the PEI- and mannose-modified surfaces, whereas the att25 diarrhoeal strain with the N-acetylglucosamine-specific F17a-G adhesin disintegrated the lactose-modified rGO. The highly virulent 107/86 strain interacted strongly with the PSS-modified graphene oxide, in agreement with the polybasic surroundings of the ABH blood group-binding site of the FedF adhesin, and showed a linear SPR response in a concentration range between 1 × 10(2) and 1 × 10(9) cfu/mL.

“Click” Chemistry on Gold Electrodes Modified with Reduced Graphene Oxide by Electrophoretic Deposition

“…The development of these approaches depends on having robust graphene-coated interfaces at hand. Next to drop-casting and spin-coating of reduced graphene oxide (rGO) suspensions onto electrical interfaces, electrophoretic deposition (EPD) has been shown to be an effective technique for manipulating graphene oxide (GO) suspensions with the aim of producing graphene-related films [9][10][11][12][13]. The ability of EPD to be applied to different materials and to control the thickness of the deposits has been well known for a decade [14,15].…”

Reduced graphene oxide/polyethylenimine based immunosensor for the selective and sensitive electrochemical detection of uropathogenic Escherichia coli

“…In a recent work by our group, we have studied the influence of the chemical composition and charge of graphene-gold interfaces on the adhesion strength of different E. coli strains through surface plasmon resonance (SPR) measurements [24].…”

Nanotechnology-Based Surface Plasmon Resonance Affinity Biosensors forIn VitroDiagnostics

“…Graphene and metal nanoparticles (MNPs) show the most suitable characteristics for sensor chip modifications. Graphene coating improves the change of the refractive index at the interface graphene/gold sensor chip, thus modifying the SPR signal associated with the thin metal surface [10]. Metal nanoparticles, in particular, gold and silver nanoparticles (AuNPs or AgNPs), displaying a localized surface plasmon resonance (LSPR), are widely used to enhance the SPR response [11, 12].…”