Abstract: Cardiac and skeletal muscle troponin I(cTnI, sTnI) were purified from human left ventricular tissue and skeletal muscle tissue by affinity chromatographic method, respectively. The specific polyclonal antibody to cTnIwas prepared by immuned pure New Zeal and rabbit with the purified cTnIand purified by nitrocellulose membrance filtration-affinity chromatography with sTnI. Aspecific immunobiosensor for cTnIwas developed by using surface plasmon resonance(SPR) biosensor with biotin as an intermediate layer and with the biotinylated-specific polyclonal antibody as capture antibody and used in a direct detection of cTnIin sera with the lowest detection limit of 2.5 μg/L. Amore sensitive sandwich immunobiosensor for cTnIwas developed by using biotinylated-specific polyclonal antibody as capture antibody(the first antibody) and polyclonal antibody as the second antibody. The sandwich immunoassay showed an excellent sensitivity of 0.5μg/Land the detection range of 0.5-20 μg/Land within-run variation of 3.5%-4.9% and between-run variation of 6.1%-7.4%. The cTnI′s in the sera of 40 healthy donors and 20 patients with acute myocardiaLInfarction(AMI) were monitored by using the sandwich immunoassay and the Lifesign MI Troponin Itest device, respectively and it was found that the coincidence of the two assays was 95%, indicating that the developed sandwich immunoassay with SPRbiosensor is suitable in clinical determination.

Key words: Cardiac troponin I, Polyclonal antibody to cardiac troponin I, Sandwich immunoassay, Surface plasmon resonance biosensor, Acute myocardiaLInfarction