Design and Synthesis of Novel Squaraine-Based Fluorescent Probe for Far-Red Detection of Chymotrypsin Enzyme

• Published in: Molecules (Basel, Switzerland) Vol. 29; no. 6; p. 1282
• Main Authors: Gupta, Shekhar, Priyanka, Mavileti, Sai Kiran, Pandey, Shyam S, Kato, Tamaki
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 14.03.2024; MDPI
• Subjects: Apoptosis; Chymotrypsin; chymotrypsin detection; Cyclobutanes; Design; Dyes; dye–peptide conjugate; Enzymes; far-red squaraine dye; fluorescence microscopy; Fluorescence Resonance Energy Transfer - methods; Fluorescent Dyes - chemistry; fluorescent peptides; Gases industry; homo-FRET; Humans; Immunoassay; Mass spectrometry; Peptides - chemistry; Phenols; Physiology; Polypeptides; Proteases; Proteins; Scientific imaging; United States; Japan; dye–peptide conjugate; far-red squaraine dye; fluorescent peptides; homo-FRET; fluorescence microscopy; chymotrypsin detection
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules29061282

Chymotrypsin, a crucial enzyme in human digestion, catalyzes the breakdown of milk proteins, underscoring its significance in both health diagnostics and dairy quality assurance. Addressing the critical need for rapid, cost-effective detection methods, we introduce a groundbreaking approach utilizing far-red technology and HOMO-Förster resonance energy transfer (FRET). Our novel probe, SQ-122 PC, features a unique molecular design that includes a squaraine dye (SQ), a peptide linker, and SQ moieties synthesized through solid-phase peptide synthesis. Demonstrating a remarkable quenching efficiency of 93.75% in a tailored H O:DMSO (7:3) solvent system, our probe exhibits absorption and emission properties within the far-red spectrum, with an unprecedented detection limit of 0.130 nM. Importantly, our method offers unparalleled selectivity towards chymotrypsin, ensuring robust and accurate enzyme detection. This pioneering work underscores the immense potential of far-red-based homo-FRET systems in enabling the sensitive and specific detection of chymotrypsin enzyme activity. By bridging the gap between cutting-edge technology and biomedical diagnostics, our findings herald a new era of enzyme sensing, promising transformative advancements in disease diagnosis and dairy quality control.