Electrostatic Actuation Based Modulation of Interaction Between Protein and DNA Aptamer

Abstract

The need to design nanoscale, sensitive and flexible biotic-abiotic interface keeps increasing. The essential issue is how to facilitate biological signal transmission and modulation through controllable external stimuli. This requires a thorough understanding of the binding and dissociation process between bio-molecules under the stimuli. The purpose of this study is to demonstrate the binding and dissociation behavior between the anti-coagulation protein thrombin and single-stranded DNA aptamer with application of electrical fields. Micro-contact printing was utilized to prepare compositionally patterned gold specimen with adjacent regions covered with alkanethiol and DNA aptamer molecules, then thrombin molecules were injected into the system to form the binding pair with aptamer. Different electrical field potentials were applied to the nanoscale structure by a three-electrode electrochemical cell. Due to the negatively charged nature of aptamer DNA strands, positive electrical field can trigger a large bending-down conformational transition of the aptamer, thus can break the bonds between binding pair. Through Atomic Force Microscopy, height of the pattern was measured and the difference of height under different potentials can show the binding state of the pair. We can propose a method to actuate and modulate the dissociation behavior between thrombin and aptamer through the external electrostatic stimuli.