Real-time and label-free analyte detection in a flow-through mode using immobilized fluorescent aptamer/quantum dots...

Area of Science:

• Biotechnology
• Nanotechnology
• Analytical Chemistry

Background:

• Development of specific biosensors for real-time detection of unlabeled analytes is crucial.
• Existing methods may lack specificity or real-time flow-through capabilities.
• Aptamer-based molecular switches offer potential for high specificity detection.

Purpose of the Study:

• To design and develop a miniature flow cell biosensor with designer specificity for real-time, flow-through detection of unlabeled analytes.
• To utilize aptamer/quantum dot molecular switches for fluorescence-based detection.
• To demonstrate the sensor's capability for detecting specific toxins like Botulinum Neurotoxin A and Ricin Toxin A chain.

Main Methods:

• A miniature flow cell with an aptamer/quantum dot modified quartz window was designed.
• Aptamer complexes were engineered as molecular switches to release fluorescent labels upon analyte interaction, causing fluorescence decrease.
• The sensor was tested for specificity and repeated detection of target analytes at a flow rate of 60µl/min.

Main Results:

• The biosensor demonstrated specific and repeatable detection of Botulinum Neurotoxin A and Ricin Toxin A chain.
• Sensitivity was found to be comparable to other real-time detection methods.
• The potential for multi-specific sensing was explored, and the design's flexibility for altering sensor specificity was highlighted.

Conclusions:

• Surface-bound aptamer sensing is feasible for flow-through analyte detection.
• The developed system provides a valuable tool for real-time surface fluorescent studies.
• The aptamer-based biosensor design is adaptable for detecting various environmental or clinical targets.