In this paper, graphene oxide (GO) was modified in-situ on an electrochemical electrode array for attachment of protein. GO suspension made from natural graphite flakes was directly dip-coated onto the Au working electrodes. Detected by cyclic voltammetry, the peak current of GO on Au electrode increased by 1 � as compared with bare gold electrode. Modified graphgene oxide (MGO) with stable active esters was formed by in-situ modifying GO with N -ethyl-N' -(3 -dimethy laminopropy 1) carbodiimide hydrochloride (EDAC)/ N-hydroxysuccinimide (NHS). MGO was ready for protein attachment. An immune sensor chip (GO-antigen) was prepared by tuberculosis (TB) antigens bound with MGO. The peak of CV curve of GO-antigen increased by about �1.·tA as compared with that of MGO, however, after the GO-antigen reaction with the antibody, the peak of the current decreased 41lA. Such results showed potential applications of the immunosensor.

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In this paper, a novel-structured electrochemical sensor array with five disk working electrodes, one arc counter electrode and one reference electrode is introduced. The array is fabricated by micro-electro-mechanical system (MEMS) technology. The radii of the disk working electrodes are 400 Pm and 500 Pm while the distance between the working electrodes and counting electrode is 100 Pm. The counter electrode is composed of difference arc rings. The radian of the arc rings ranges from S to 11S/6 while the radius ranges from 100 Pm to 200Pm for different chips. The arrays are characterized by cyclic voltammetry in the presence of the redox probe ferrocenemethanol (FcM). It is found that the peak current has a biggest value between 3S/2 and 5S/3 at the same radius of arc rings. The peak current increases along with the increasing of the radius of the arc rings. For working electrode in same size, the best design has the peak current 35% higher than the smallest peak current. An optimal design of the high sensitivity electrochemical sensor is found.