Pyrene-Based Amphiphilic Fluorescent Probe as a Versatile Optical Platform for Cardiac Biomarker Detection: From...

A pyrene-linked sugar amphiphilic probe (1) was developed as a versatile optical sensor for detecting myoglobin (Mb) and cytochrome c (Cyt c), biomarkers of myocardial infarction and apoptosis. The probe (10 μM) exhibited emission maxima at 378, 396, and 417 nm and showed selective quenching for heme proteins, with ∼12-fold reduction for Cyt c and ∼8-fold for Mb, accompanied by a visible blue-to-black color change. Stern-Volmer constants were 1.52 × 10⁶ M^-1 (Cyt c) and 0.68 × 10⁶ M^-1 (Mb), with detection limits of 1.816 and 1.568 mg/L, respectively. Mechanistic studies revealed hydrophobic interactions, PET-driven quenching, and perturbation of protein secondary structures. The probe retained sensitivity in 10% serum, enabled visual gel-to-sol transition in hydrogels, and offered onsite detection via TLC strips. It was also biocompatible (>90% cell viability) and effective in live HeLa cells. The ability to sensitively detect Mb and Cyt c is crucial for early diagnosis of cardiac injury and apoptosis-related disorders, offering significant clinical impact. Docking studies revealed stronger cavity binding in myoglobin and solvent-exposed, electrostatically driven binding in cytochrome c, explaining its greater fluorescence quenching in water.