Biomimetic Synthesis of Fluorogenic Quantum Dots for Ultrasensitive Label-Free Detection of Protease Activities

: A biomimetic quantum dot synthesis-based strategy for ultrasensitive label-free detection of protease activities is reported. A dithiol peptide substrate can be activated by the protease through cleavage to form monothiol peptides, which then triggers QD growth and generates a photoluminescence signal readout. As low as 0.8 nM trypsin can be detected directly in buffer and serum and 4 pM trypsin can be detected via trypsinogen amplification with high signal to background ratios.