title: Graphene-interfaced electrical biosensor for label-free and sensitive detection of foodborne pathogenic E. coli O157:H7.
abstract: E. coli O157:H7 is an enterohemorrhagic bacteria responsible for serious foodborne outbreaks that causes diarrhoea, fever and vomiting in humans. Recent foodborne E. coli outbreaks has left a serious concern to public health. Therefore, there is an increasing demand for a simple, rapid and sensitive method for pathogen detection in contaminated foods. In this study, we developed a label-free electrical biosensor interfaced with graphene for sensitive detection of pathogenic bacteria. This biosensor was fabricated by interfacing graphene with interdigitated microelectrodes of capacitors that were biofunctionalized with E. coli O157:H7 specific antibodies for sensitive pathogenic bacteria detection. Here, graphene nanostructures on the sensor surface provided superior chemical properties such as high carrier mobility and biocompatibility with antibodies and bacteria. The sensors transduced the signal based on changes in dielectric properties (capacitance) through (i) polarization of captured cell-surface charges, (ii) cells' internal bioactivity, (iii) cell-wall's electronegativity or dipole moment and their relaxation and (iv) charge carrier mobility of graphene that modulated the electrical properties once the pathogenic E. coli O157:H7 captured on the sensor surface. Sensitive capacitance changes thus observed with graphene based capacitors were specific to E. coli O157:H7 strain with a sensitivity as low as 10-100 cells/ml. The proposed graphene based electrical biosensor provided advantages of speed, sensitivity, specificity and in-situ bacterial detection with no chemical mediators, represents a versatile approach for detection of a wide variety of other pathogens.
authors.affiliation: Sabanci University Nanotechnology Research and Application Center, Orta Mah., 34956 Istanbul, Turkey.
authors.forename: Ashish
authors.initials: A
authors.lastname: Pandey
authors.affiliation: Faculty of Engineering and Natural Science, Sabanci University, Orhanli, Tuzla, 34956 Istanbul, Turkey.
authors.forename: Yasar
authors.initials: Y
authors.lastname: Gurbuz
authors.affiliation: Sabanci University Nanotechnology Research and Application Center, Orta Mah., 34956 Istanbul, Turkey.
authors.forename: Volkan
authors.initials: V
authors.lastname: Ozguz
authors.affiliation: Sabanci University Nanotechnology Research and Application Center, Orta Mah., 34956 Istanbul, Turkey. Electronic address: javed@sabanciuniv.edu.
authors.forename: Javed H
authors.initials: JH
authors.lastname: Niazi
authors.affiliation: Sabanci University Nanotechnology Research and Application Center, Orta Mah., 34956 Istanbul, Turkey. Electronic address: anjum@sabanciuniv.edu.
authors.forename: Anjum
authors.initials: A
authors.lastname: Qureshi
mesh_terms: D055910:Antibodies, Immobilized / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation*; D004867:Equipment Design; D004927:Escherichia coli Infections / Q000382:microbiology*; D019453:Escherichia coli O157 / Q000302:isolation & purification*; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology; D005517:Foodborne Diseases / Q000382:microbiology; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D056656:Lab-On-A-Chip Devices; D057230:Limit of Detection; D008839:Microelectrodes; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure
chemical_list: D055910:Antibodies, Immobilized; D006108:Graphite
keywords: Biochip; Biosensors; Dielectric; E. coli O157:H7; Foodborne pathogen; Graphene