Investigation of a FRET immunosensor technique for the detection of cardiac troponin T and I

Cardiac troponin T and I are sensitive and specific markers for myocardial infarction. A novel optical biosensor technique is being investigated to detect cardiac troponin T and troponin I utilizing the distance-dependent chemical transduction method of fluorescence resonance energy transfer (FRET). The FRET process requires two fluorophores, termed the donor and the acceptor. When in close proximity, the donor absorbs energy from the excitation source and nonradiatively transfers the energy to the acceptor, which in turn, emits fluorescent energy. The fluorophores are conjugated to either a troponin I antibody-Protein G complex or a troponin T anti body-Protein A complex. A conformational change occurs in the antibody-protein complex during binding of the specific analyte, resulting in a detectable change in fluorescence. Insolution tests were performed to demonstrate the FRET technique. A statistically significant change in fluorescence occurred in the presence of specific troponin T and troponin I antigens. The technique detected both troponin T and troponin I antigens at a concentration level of 27 nM. The results demonstrated the feasibility of the FRET immunosensor technique to detect troponin T and troponin I.