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| A Micro Amperometric Immunosensor Based on MEMS |
| Bian Chao; Xu Yuan-yuan; Sun Hong-guang; Zhang Hong; Chen Shao-feng; Xia Shan-hong |
| State Key Lab of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing 100080, China |
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Abstract A micro amperometric immunosensor is fabricated to detect human IgG based on MEMS. The Pt electrode is deposited on silicon wafer with the sensitive area of 1 mm2. A micro reacting pool is made of SU-8 polymer and several microlitre reagent was needed. Polypyrrole is electropolymerized on the electrode to transfer the electron between the electrode and the enzyme. Glutaraldehyde is used to bind the antibody on polypyrrole. Human IgG is specifically recognized by goat anti-human IgG and horseradish peroxidase (HRP) conjugated goat anti-human IgG in sandwich way. Human IgG is scaled by detecting the current from the catalyzed reaction between HRP and H2O2. With the working potential of -0.3V, the immunosensor displayed a good linear dose–response behavior for human IgG concentrations between 5 and 255ng/ml.A low detection limit of 5ng/ml and 3-minute response time are achieved. This micro amperometric immunosensor has many advantages such as fast response time, low detection limit, little reagent, micro bulk and easy integration with IC.
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Received: 16 March 2005
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2006, Vol. 28 
