Origin of nanomechanical cantilever motion generated from biomolecular interactions

Generation of nanomechanical cantilever motion from biomolecular interactio ns can have wide applications, ranging from high-throughput biomolecular de tection to bioactuation, Although it has been suggested that such motion is caused by changes in surface stress of a cantilever beam, the origin of th e surface-stress change has so far not been elucidated. By using DNA hybrid ization experiments, we show that the origin of motion lies in the interpla y between changes in configurational entropy and intermolecular energetics induced by specific biomolecular interactions. By controlling entropy chang e during DNA hybridization, the direction of cantilever motion can be manip ulated. These thermodynamic principles were also used to explain the origin of motion generated from protein-ligand binding.