Development of a surface plasmon resonance-based immunosensor for the rapid detection of cardiac troponin I

The concentration of cardiac troponin I (cTnI) in blood is an important marker for heart muscle cell damage. A surface plasmon resonance (SPR)-based immunosensor was devised for the rapid and specific detection of cTnI. It was constructed by crosslinking a monoclonal antibody P-II-13, which was generated against a loop region (aa 84-94) of cTnI protein as an epitope peptide, onto a chemically modified thin gold film. The performance of the sensor was examined with respect to the SPR signal intensity versus cTnI concentration. The signal intensity was directly correlated with the cTnI concentration in the range of 0-160 μg/l. The sensor signal was saturated when the concentration of cTnI approached 660 μg/l with the SPR intensity of 172 RU. The lower detection limit of the sensor was 68 ng/l cTnI, which was comparable to ELISA-based commercial cTnI detection systems.