Analyte-activable probe for protease based on cytochrome C-capped Mn: ZnS quantum dots

Area of Science:

• Biomedical Engineering
• Materials Science
• Analytical Chemistry

Background:

• Quantum dots (QDs) offer unique optical properties for biosensing.
• Developing sensitive and selective protease detection methods is crucial for early disease diagnosis.
• Existing methods often involve complex post-synthesis modifications.

Purpose of the Study:

• To develop a novel, one-pot synthesized sensor for protease detection.
• To integrate analyte recognition and signal quenching during QD synthesis.
• To create a turn-on luminescence assay for improved sensitivity and reduced background.

Main Methods:

• Synthesis of phosphorescence-attenuated Mn-doped ZnS QDs with cytochrome C (Cyt C) as a ligand.
• Utilizing the enzymatic digestion of Cyt C by protease to activate QD luminescence.
• Label-free and activable sensing formats were explored.
• Evaluation of sensor selectivity and differentiation of active/inactive serine proteases.
• Determination of trypsin in cell lysates.

Main Results:

• Successfully synthesized Mn-doped ZnS QDs with inherent phosphorescence quenching by Cyt C.
• Demonstrated a turn-on luminescence response upon protease-induced digestion of Cyt C.
• Achieved high selectivity for proteases over other proteins.
• Differentiated between active and inactive serine proteases.
• Obtained a low limit of detection (2 nM) for trypsin, relevant for clinical samples.
• Successfully detected trypsin in human pancreatic cancer cell lysates.

Conclusions:

• The developed sensor format offers a simplified, sensitive, and selective approach for protease detection.
• The turn-on luminescence mechanism effectively reduces background noise.
• This QD-based sensor shows significant potential for early clinical diagnosis, particularly in oncology.
• The one-pot synthesis strategy streamlines sensor preparation.