A cardiac tissue-specific binding agent of troponin I.

A fluorescently labeled, biphenylalanine-rich peptide was identified as a should be cardiac troponin I-specific binding agent with preferential staining affinity to myocardium tissues and extremely low staining to other stromal components. Fluorescence images demonstrate that this new peptide is an excellent contrast agent useful for examining troponin I structural distribution and expression density within heart tissue sections. It provides a clear contrast between myocardial cells and the surrounding collagen matrix.