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We have developed a novel nitric oxide (NO) cellular biosensor based upon the immobilization of red blood cells (RBCs) onto nanometer‐size colloidal gold that is attached to an electrochemically pretreated glassy carbon electrode via the bridging of an ethylenediamine monolayer. The biosensor has been characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), and electrochemistry. The immobilized RBCs display an excellent electrocatalytic response to nitric oxide. The electrocatalytic currents are proportional to the NO concentration in the range from 1.0×10–8 to 1.0×10–6 M and the detection limit is as low as 5.0×10–9 M (S/N=3). Furthermore, the biosensor is very stable and relatively free of potential interference. [ABSTRACT FROM AUTHOR]

An electrochemical immunosensor has been constructed by the self-assemble technique and studied by the AC impedance and potential method respectively. The change of the surface impedance shows that the antibody can be assembled on the electrode surface and recognize the antigen. The gold nanoparticles are not only used to immobilize the CRP antibody, but also can amplify the potential response. The immunosensor responds to antigen in the linear range from 5 to 25 µg/mL and can meet the needs of clinical assay. [ABSTRACT FROM AUTHOR]