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Download fileResonant-Cantilever-Detected Kinetic/Thermodynamic Parameters for Aptamer–Ligand Binding on a Liquid–Solid Interface
journal contribution
posted on 2020-07-01, 12:33 authored by Xuefeng Wang, Yarong Cheng, Shengran Cai, Jianzhong Chen, Pengcheng Xu, Ying Chen, Haitao Yu, Tiegang Xu, Sen Zhang, Xinxin LiNucleic acid aptamers
have been widely used as recognition elements
on various biosensing interfaces, but quantitative kinetic/thermodynamic
analysis for revealing the aptamer–ligand binding mechanism,
which occurs on a liquid–solid interface, has not been realized
due to a lack of usable biophysical tools. Herein we apply a resonant
microcantilever sensor to continuously record the frequency shift
according to the binding-induced mass change on the liquid–solid
interface. The frequency-shift curve is used for tracing the reaction
process and is fitted with classic equations to calculate a set of
kinetic/thermodynamic parameters, such as rate constants (ka = 902.95 M–1 s–1, kd = 0.000141 s–1), equilibrium constants (KD = 1.55 μM),
the Gibbs free energy (ΔG° = −32.57
kJ/mol), and the activation energy (Ea = 38.03 kJ/mol) for the immobilized aptamer and free ATP. This quantitative
analysis method is label-free, calibration-free, and highly sensitive.
The kinetic/thermodynamic parameter detection method provides new
resolution to the in-depth understanding of the ligand–aptamer
interaction on the liquid–solid interface for biosensing or
lab-on-a-chip applications.