Microcantilever-based label-free thermal characterization of biomolecular affinity binding

We present a microfluidic polymer cantilever array device integrating on-chip temperature control for label-free, temperature-dependent characterization of ligand-protein binding. The microfluidic device features a parylene microcantilever array within a microchamber formed by a PDMS spacer layer and a glass slide including a patterned ITO temperature sensor. The temperature is accurately controlled by using a Peltier device combined with the in situ ITO temperature sensor following a closed-loop control algorithm. For the first time, we use this cantilever-based microfluidic device to systematically characterize the temperature-dependent binding kinetics of an aptamer sensitive to platelet-derived growth factor (PDGF) at temperatures between 19 and 37 °C. Quantitative binding properties including the association and dissociation rate constants (k_on and k_off) and equilibrium dissociation constant (K_d) are derived, which indicate significant dependencies on temperature.