title: Electrochemical displacement sensor based on ferrocene boronic acid tracer and immobilized glycan for saccharide binding proteins and E. coli.
abstract: Pathogens such as viruses and bacteria use their envelope proteins and their adhesin lectins to recognize the glycan residues presented on the cell surface of the target tissues. This principle of recognition is used in a new electrochemical displacement sensor for the protein concanavalin A (ConA). A gold electrode was first modified with a self-assembled monolayer of a thiolated mannose/OEG conjugate and a ferrocene boroxol derivative was pre-assembled as reporter molecule onto the mannose surface. The novel tracer molecule based on a 2-hydroxymethyl phenyl boronic acid derivative binds even at neutral pH to the saccharides which could expand the application towards biological samples (i.e., urine and feces). Upon the binding of ConA, the tracer was displaced and washed away from the sensor surface leading to a decrease in the electrochemical signal. Using square wave voltammetry (SWV), the concentration of ConA in the sample solution could be determined in the dynamic concentration range established from 38nmolL(-1) to 5.76µmolL(-1) with a reproducible detection limit of 1µgmL(-1) (38nmolL(-1)) based on the signal-to-noise ratio (S/N=3) with fast response of 15min. The new reporter molecule showed a reduced non-specific displacement by BSA and ribonuclease A. The sensor was also successfully transferred to the first proof of principle for the detection of Escherichia coli exhibiting a detection limit of approximately 6×10(2)cells/mL. Specificity of the displacement by target protein ConA and E. coli was demonstrated since the control proteins (i.e., BSA and RNaseA) and the control E. coli strain, which lack of type 1 fimbriae, were ineffective.
authors.affiliation: Fraunhofer Institute for Biomedical Engineering IBMT, Am Mühlenberg 13, 14476 Potsdam, Germany.
authors.forename: Decha
authors.initials: D
authors.lastname: Dechtrirat
authors.affiliation: Fraunhofer Institute for Biomedical Engineering IBMT, Am Mühlenberg 13, 14476 Potsdam, Germany. Electronic address: nenad.gajovic@web.de.
authors.forename: Nenad
authors.initials: N
authors.lastname: Gajovic-Eichelmann
authors.affiliation: Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Wojcik
authors.affiliation: Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany.
authors.forename: Laura
authors.initials: L
authors.lastname: Hartmann
authors.affiliation: Fraunhofer Institute for Biomedical Engineering IBMT, Am Mühlenberg 13, 14476 Potsdam, Germany.
authors.forename: Frank F
authors.initials: FF
authors.lastname: Bier
authors.affiliation: Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Straße 24-25, 14476 Potsdam, Germany. Electronic address: fschell@uni-potsdam.de.
authors.forename: Frieder W
authors.initials: FW
authors.lastname: Scheller
mesh_terms: D000327:Adsorption; D058491:Bacterial Load / Q000295:instrumentation*; D015374:Biosensing Techniques / Q000295:instrumentation*; D001897:Boronic Acids / Q000737:chemistry; D003208:Concanavalin A / Q000032:analysis* / Q000737:chemistry; D003217:Conductometry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D004926:Escherichia coli / Q000302:isolation & purification* / Q000378:metabolism*; D005296:Ferrous Compounds / Q000737:chemistry; D008358:Mannose / Q000737:chemistry; D000075163:Metallocenes; D011134:Polysaccharides / Q000737:chemistry*; D011485:Protein Binding
chemical_list: D001897:Boronic Acids; D005296:Ferrous Compounds; D000075163:Metallocenes; D011134:Polysaccharides; D003208:Concanavalin A; D008358:Mannose; C004998:ferrocene
keywords: Concanavalin A; Displacement; Escherichia coli; Ferrocene benzoboroxol biosensor; Ferrocene boronic acid; Self-assembled monolayer