Electrochemical Sensors Used In Immunoassay

In this theisis, electrochemical sensors for applications in immunodetection are studied. The details are as follows.1. New structure of multi-channel integrated electrochemical sensor on chip.Base on the micro-electrode electrochemical theory and immunoassay requirements, a novel-structured electrochemical sensor array with five disk working electrodes, one arc counter electrode and one reference electrode was designed. The effect of the arc corresponding to different working electrodes and different size working electrode were studied. We found the optimal design of the electrochemical sensor with the radius of working electrode, radius and radian of arc ring of 500μm, 200μm and 3π/2, respectively. Oxidation peak current reached 2.14μA.2. Electrode with nano-structured surfaceBased on the theory of Au and Cu intense diffusion at high temperature, a nano-structured gold electrode was fabricated by annealing under different temperature and time period. When the scale of the nano structure was 100～200nm, and. the peak current of the electrode increased 0.5μA compared to the bare electrode with the same area. And the increasing rate of peak currents vs. the square root of scan rate was linear, which showed a good current characteristic of Faraday. The slope of the fitting line was 9.1935 with a correlation of 0.9992. The bare electrode had a smaller fitting slope of 8.4633. The bigger slope of the nano structured electrode vs. scan rate indicated a higher sensitivity.3. Electrode with surface modification of carbon nano-materialsUsing SAM self-assembly method, SGNF (Stacked graphene nanofibers) were modified to form SGNF/SAM/Au electrode. Electrochemical characterization of showed that SGNF/SAM/Au electrode had a larger peak current than Au electrode and Graphite/SAM/Au electrode. For SGNF/SAM/Au electrode, the increasing rate of peak current along with the square root of scan rate was linear, shown a great current characteristic of Faraday. The slope of the fitting line was 10.638 with a correlation of 0.9968. The biggest slope of electrode modified with nano materials vs. scan rate indicated the highest sensitivity.