A 3D-impedimetric immunosensor based on foam Ni for detection of sulfate-reducing bacteria
ABSTRACT A 3D-immunosensor based on simple and efficient trapping platform (foam Ni) combining with adsorption of gold nanoparticles and specific recognition of biological/chemical molecular has been reported for detection of sulfate-reducing bacteria (SRB) using electrochemical impedance spectroscopy (EIS). The impedance spectra were also used to characterize the successful construct and stepwise modification of the impedimetric immunosensors. This results show that a linear relationship between electron-transfer resistance (Rct) values and the logarithm of the SRB concentrations was obtained for the SRB concentration range of 2.1 × 101–2.1 × 107 cfu/ml. Additionally, the fabricated immunosensor shows a high selectivity against other bacteria.
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ABSTRACT: The development of a rapid, sensitive, specific method for the foodborne pathogenic bacteria detection is of great importance to ensure food safety and security. In recent years impedimetric biosensors which integrate biological recognition technology and impedance have gained widespread application in the field of bacteria detection. This paper presents an overview on the progress and application of impedimetric biosensors for detection of foodborne pathogenic bacteria, particularly the new trends in the past few years, including the new specific bio-recognition elements such as bacteriophage and lectin, the use of nanomaterials and microfluidics techniques. The applications of these new materials or techniques have provided unprecedented opportunities for the development of high-performance impedance bacteria biosensors. The significant developments of impedimetric biosensors for bacteria detection in the last five years have been reviewed according to the classification of with or without specific bio-recognition element. In addition, some microfluidics systems, which were used in the construction of impedimetric biosensors to improve analytical performance, are introduced in this review.Sensors 12/2012; 12(3):3449-71. · 2.05 Impact Factor
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ABSTRACT: This work presents a novel specific detection method for sulfate-reducing bacteria (SRB) based on sulfuration conversion from ZnO arrays to ZnS arrays. The sulfuration process was conducted in two steps. First, ZnO@ZnS intermediate nanocomposite arrays were formed by the sulfuration reaction between ZnO and sulfide, which is the characteristic enzymatic metabolism product of SRB. Next, unconverted ZnO cores were washed away in ammonia buffer solutions, leaving ZnS arrays on the surface of ITO substrates. The array conversion process can be used for SRB detection because the final state of ZnS arrays was highly related with the amount of accumulated sulfide, which was decided by the initial concentration of SRB. Electrochemical impedance spectroscopy has been used to optimize experimental conditions and detect SRB in aqueous solutions. This SRB detection method based on arrays conversion from ZnO to ZnS can avoid the use of biological recognition elements, which are expensive and easy to lose specific recognizing abilities. In addition, compared with the widely used MPN method which would take up to 15 days to accomplish the detection process, the proposed method can shorten the detection time greatly.Sensors and Actuators B Chemical 05/2013; 181:274–279. · 3.84 Impact Factor
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ABSTRACT: This work presents the synthesis of bacteria-mediated bioimprinted films for selective bacterial detection. Marine pathogen sulfate-reducing bacteria (SRB) were chosen as the template bacteria. Chitosan (CS) doped with reduced graphene sheets (RGSs) was electrodeposited on an indium tin oxide electrode, and the resulting RGSs-CS hybrid film served as a platform for bacterial attachment. The electrodeposition conditions were optimized to obtain RGSs-CS hybrid films with excellent electrochemical performance. A layer of nonconductive CS film was deposited to embed the pathogen, and acetone was used to wash away the bacterial templates. Electrochemical impedance spectroscopy was performed to characterize the stepwise modification process and monitor the SRB population. Faradic impedance measurements revealed that the charge transfer resistance (R(ct)) increased with increased SRB concentration. A linear relationship between ΔR(ct) and the logarithm of SRB concentration was obtained within the concentration range of 1.0×10(4)cfumL(-1) to 1.0×10(8)cfumL(-1). The impedimetric sensor showed good selectivity towards SRB based on size and shape. Hence, selectivity for bacterial detection can be improved if the bioimprinting technique is combined with other bio-recognition elements.Biosensors & Bioelectronics 08/2012; 39(1):282-8. · 6.45 Impact Factor