Electrochemical Biosensing Based On One Dimensional Nanomaterial

Nanomaterials have been widely used in a great amount of fields, such as biosensor,environment, clinic diagnosis and biology, because of their unique physical and chemicalproperties, such as large specific surface area, good chemical stability, biocompatibility, andstrong adsorption capacity which can provide a friend micro-environment to maintain thebiomolecules’ biological activity. The main work of this paper is focus on the preparation ofnanomaterials, construction of the sensing interface and their applications in electrochemicalanalysis. The details are summarized as follows:(1) An electrochemical sensor of Pb2+was constructed by modifing carbon nanotubes onthe glassy carbon electrode. Pb2+was accumulated at-1.0V in the form of Pb; and thenstripped by differential pulse voltammetry at-0.58V. The carbon nanotubes can significantlyenhance the detection signal of Pb2+. The amount of carbon nanotubes, pH and supportingelectrolyte were optimized. Under the optimized experimental conditions, a linear range of0.005to1μg/mL was obtained with the detection limit of0.005μg/mL. The reliability wasinvestigated with satisfactory recovery from95.4to105.5%for real samples. Thereproducibility was investigated with a RSD of1.69%for six measurements. The developedPb2+sensor based on carbon nanotubes possesses advantages such as simple fabrication, fastresponse, low detection limit, good anti-interferential ability and reproducibility.(2) Chitosan nanotubes array (CNTA) has been obtained for the first time byelectrodepositing with the aid of a porous polycarbonate (PC) template. The proposed CNTAis applied to fabricate a sandwich-type electrochemical immunosensor with human IgG as amodel analyte. The characteristics of the sensing surface were studied by scanning electronmicroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The CNTAshows good biocompatibility, stability with large specific area and controlled dimension. Theconcentration and incubation time of the immobilized antibody were optimized. Under theoptimized experimental conditions, a linear range of1to1000ng/mL was obtained with thedetection limit of0.37ng/mL. The developed immunosensor based on CNTA possessesadvantages such as simple fabrication, fast response, good anti-interferential ability andreproducibility.(3) The gold nanowire array has been synthesized by electrodeposition with the aid of aporous polycarbonate (PC) membrane template. Based on self assemble of CS2and SPA on the proposed gold nanowire array, a bio-affinity sensing interface was prepared and applied infabricating an immunosensor, with human IgG as a model analyte. The characteristics of thesensing surface were studied by electrochemical impedance spectroscopy. The gold nanoarrayshowed good biocompatibility, electroconductivity and large specific surface area. Theconcentration and incubation time of goat anti-hIgG antibody and pH value were optimized.Under the optimized experimental conditions, a linear range of0.1to2500ng/mL wasobtained with the detection limit of0.05ng/mL. The proposed sensing surface would beuseful for potential applications in electrochemical immunosensor.