Aptamer functionalized microcantilever sensors for cocaine detection

Area of Science:

• Biosensing and Nanotechnology
• Analytical Chemistry
• Molecular Recognition

Background:

• Cocaine detection is crucial for forensic and clinical applications.
• Existing detection methods often lack sensitivity or require complex sample preparation.
• Aptamers offer specific molecular recognition capabilities for biosensor development.

Purpose of the Study:

• To develop and characterize a microcantilever-based surface stress sensor for cocaine detection.
• To utilize cocaine-specific aptamers as receptor molecules for enhanced specificity.
• To evaluate the sensor's performance, including sensitivity, dynamic range, and reusability.

Main Methods:

• A microcantilever array functionalized with cocaine-specific aptamers was employed.
• An interferometric technique measured differential displacement due to cocaine-aptamer binding.
• Surface stress changes were analyzed across a range of cocaine concentrations (25–500 μM).
• Regeneration was achieved through reversible thermal denaturation of the aptamer.

Main Results:

• The sensor exhibited a proportional response to cocaine concentration in the range of 25–100 μM, with surface stress increasing from 11 to 26 mN/m.
• A lower dependence of surface stress on aptamer/cocaine complex coverage was observed at concentrations above 100 μM.
• A lowest detectable threshold of 5 μM cocaine was estimated based on a sensitivity of 3 mN/m.
• The aptamer-functionalized sensor demonstrated successful regeneration and reusability.

Conclusions:

• The developed microcantilever sensor effectively detects cocaine using aptamer recognition.
• The sensor shows promise for sensitive and reusable cocaine monitoring.
• This approach offers a viable platform for developing advanced biosensors for small molecule detection.