Amperometic Immunosensor for Myeloperoxidase in Serum
A novel amperometic immunosensor for the determination of myeloperoxidase(MPO) in human serum was developed by modifying Nafion film on the glassy carbon electrode(GCE),then thionine and colloidal gold were immobilized by static electricity and covalent bonding self-assembly. And then the antibody of MPO(anti-MPO) was absorbed on the surface of nano-gold monolayer. Finally,Horseridesh peroxidase(HRP) blocked the non-specific adsorption site on the electrode,meanwhile,the signal of response current was amplified. Experiment results showed that the good linear relations between peak current and concentration of MPO were established in the range of 2.5-100 μg/L. The detection limit was 1.4 μg/L and the response time reached 95% of the steady-state current in less than 30 s. The RSD values(n=20) of intra-batch and inter-batch were less than 2.9% and 4.2%,respectively. The stability of electrode was excellent,after having been surveyed 10 times in 30 days,the average value of response current began declining to 85.6% of the initial measurement. The influence of this immunosensor was investigated in terms of concentration of antibody,concentration of substrate,pH,temperature and other interferents. Correlation analysis showed that there was significant correlation between the method of immunosensor and ELISA in 40 clinical samples(r=0.9971,p0.0001). The proposed immunosensor for MPO is used for estimating the risk of aardiovascular disease.