title: Impedimetric immunosensor doped with reduced graphene sheets fabricated by controllable electrodeposition for the non-labelled detection of bacteria.
abstract: A facile, sensitive and reliable impedimetric immunosensor doped with reduced graphene sheets (RGSs) and combined with a controllable electrodeposition technique was developed for the selective detection of marine pathogenic sulphate-reducing bacteria (SRB). The morphology of RGSs and the electrochemical properties of RGSs-doped chitosan (CS) nanocomposite film were investigated by atomic force microscopy, Fourier transform infrared spectroscopy, and cyclic voltammetry (CV). Electrochemical impedance spectroscopy and CV were used to verify the stepwise assembly of the sensor system. Faradic impedance spectroscopy for charge transfer for the redox probe Fe(CN)(6)(3-/4-) was done to determine SRB concentrations. The diameter of the Nyquist diagram that is equal to the charge-transfer resistance (R(ct)) increased with increasing SRB concentration. A linear relationship between R(ct) and SRB concentration was obtained in the SRB concentration range of 1.8×10(1) to 1.8×10(7) cfu/ml. The impedimetric biosensor gave a distinct response to SRB, but had no obvious response to Vibrio angillarum. It showed a high selectivity for the detection of the pathogen. Based on a combination of the biocompatibility of CS and good electrical conductivity of RGSs, a nanocomposite film with novel architecture was used to immobilize biological and chemical targets and to develop a new type of biosensor.
authors.affiliation: Key Lab of Corrosion Science, Shandong Province, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wan
authors.forename: Zhifeng
authors.initials: Z
authors.lastname: Lin
authors.forename: Dun
authors.initials: D
authors.lastname: Zhang
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.forename: Baorong
authors.initials: B
authors.lastname: Hou
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D002692:Chlamydia trachomatis / Q000302:isolation & purification*; D015169:Colony Count, Microbial / Q000295:instrumentation*; D003217:Conductometry / Q000295:instrumentation*; D004566:Electrodes; D004595:Electroplating / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006108:Graphite / Q000737:chemistry*; D007118:Immunoassay / Q000295:instrumentation*; D013194:Staining and Labeling
chemical_list: D006108:Graphite