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Label-free fluorescence assay for thrombin based on unmodified quantum dots.
Lijun Li1, Hui Lin1, Chunyang Lei1
1State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Yuelu shan, Changsha, Hunan 410082, PR China.
Biosensors & Bioelectronics
|November 19, 2013
Summary
This study introduces a novel biosensor using cadmium telluride quantum dots (CdTe QDs) for rapid and sensitive detection of thrombin and its inhibitors. The biosensor offers high sensitivity and specificity in biological samples.
Area of Science:
- Biomedical Engineering
- Nanotechnology
- Biochemistry
Background:
- Thrombin plays a critical role in hemostasis and thrombosis, making its accurate measurement essential for diagnostics and drug development.
- Existing methods for thrombin detection often lack the sensitivity, speed, or specificity required for high-throughput screening.
- Developing novel biosensors is crucial for advancing the field of coagulation diagnostics and therapeutic monitoring.
Purpose of the Study:
- To develop a novel, sensitive, and high-throughput biosensor for detecting thrombin activity and inhibition.
- To utilize the aggregation behavior of unmodified cadmium telluride quantum dots (CdTe QDs) as a detection mechanism.
- To demonstrate the applicability of the biosensor in biological matrices like blood serum.
Main Methods:
- Utilized unmodified cadmium telluride quantum dots (CdTe QDs) whose fluorescence is quenched upon aggregation.
- Employed a cationic substrate peptide that induces QD aggregation, with thrombin hydrolysis releasing peptides that stabilize QDs and restore fluorescence.
- Employed fluorescence spectroscopy, transmission electron microscopy (TEM), and dynamic light scattering (DLS) to elucidate the quenching mechanism.
Main Results:
- The biosensor demonstrated sensitive detection of thrombin in the range of 10-100 μU/mL with a limit of detection (LOD) of 1.5 μU/mL.
- The method showed high sensitivity and specificity in both buffer and human blood serum samples.
- Successfully detected thrombin inhibitor hirudin within a concentration range of 2-30 μU/mL (LOD of 0.21 μU/mL).
Conclusions:
- The developed CdTe QD-based biosensor provides a rapid, sensitive, and specific platform for thrombin and its inhibitor detection.
- The approach offers potential for high-throughput screening in diagnostic and pharmaceutical applications.
- The methodology can be extended for the detection of other proteases and their inhibitors using unmodified CdTe QDs.
