Dual aptamer-immobilized surfaces for improved affinity through multiple target binding in potentiometric thrombin...

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Analytical Chemistry

Background:

• Thrombin detection is crucial for diagnosing and monitoring various medical conditions.
• Existing biosensors often face limitations in sensitivity, specificity, and cost-effectiveness.
• Developing label-free and reagent-less biosensors is a key goal in diagnostics.

Purpose of the Study:

• To develop a novel potentiometric biosensor with enhanced affinity and specificity for thrombin.
• To investigate the impact of dual aptamer immobilization strategies on sensor performance.
• To optimize aptamer probe configuration for multivalent binding and improved detection limits.

Main Methods:

• Fabrication of a label-free, reagent-less potentiometric biosensor surface.
• Immobilization of two distinct DNA aptamers targeting different thrombin epitopes in parallel or serial configurations.
• Optimization of aptamer probe spacer and linker lengths for molecular recognition.
• Incorporation of a sulfobetaine-based self-assembled monolayer (SAM) for antifouling properties.
• Surface characterization using techniques to confirm aptamer density and SAM alignment.
• Thrombin sensing via potentiometry and analysis using the Langmuir adsorption model.

Main Results:

• Dual aptamer immobilization significantly improved thrombin affinity compared to single aptamer surfaces.
• The optimized dual aptamer biosensor achieved a limit of detection of 5.5 nM for thrombin.
• Fine control over aptamer probe structure enabled efficient multivalent binding of thrombin.
• The antifouling SAM effectively prevented non-specific adsorption, enhancing sensor specificity.
• The developed sensor demonstrates improved dissociation constants (Kd) for thrombin.

Conclusions:

• The dual aptamer-based potentiometric biosensor offers a sensitive and specific method for label-free thrombin detection.
• Optimized aptamer probe design and immobilization are critical for achieving multivalent binding and high affinity.
• This approach provides an affordable strategy for enhancing the sensitivity of potentiometric biosensors for detecting low concentrations of biomolecules.
• The developed sensor technology holds promise for advancements in clinical diagnostics and biomolecular analysis.