Resonant-Cantilever-Detected Kinetic/Thermodynamic Parameters for Aptamer-Ligand Binding on a Liquid-Solid Interface

Area of Science:

• Biosensing
• Biophysics
• Analytical Chemistry

Background:

• Nucleic acid aptamers are key recognition elements in biosensors.
• Quantitative analysis of aptamer-ligand interactions at liquid-solid interfaces is challenging due to limited biophysical tools.

Purpose of the Study:

• To develop a quantitative method for analyzing aptamer-ligand binding kinetics and thermodynamics at liquid-solid interfaces.
• To utilize a resonant microcantilever sensor for label-free, calibration-free detection.

Main Methods:

• Employing a resonant microcantilever sensor to monitor binding-induced mass changes via frequency shifts.
• Fitting frequency-shift curves to classic equations to derive kinetic and thermodynamic parameters.

Main Results:

• Successfully calculated rate constants (ka, kd), equilibrium constants (KD), Gibbs free energy (ΔG°), and activation energy (Ea) for immobilized aptamer and ATP binding.
• Demonstrated a label-free, calibration-free, and highly sensitive detection method.

Conclusions:

• The resonant microcantilever sensor provides a novel approach for in-depth understanding of ligand-aptamer interactions.
• This method enhances biosensing and lab-on-a-chip applications by enabling quantitative kinetic/thermodynamic analysis.