Surface and biomolecular forces of conducting polymers

In this review, we provide insight into the surface forces of conducting polymers, a class of intelligent materials that offer unique strategies for controlling biomolecular interactions in wide-ranging biomedical applications. Critical to the success of these applications is that the polymer interface is exposed to biological fluids whose interactions are controlled through the polymer surface chemistry and electrochemical switching of the surface properties. There is, however, little known about the intermolecular and surface forces that govern these interactions. Therefore, the purpose of this review is to more closely examine the forces that mediate interactions with biological entities, including forces such as van der Waals, electrostatic, hydrophobic, and hydrogen bonding. We introduce relevant surface properties such as surface energy and surface potential, and demonstrate how they manifest as forces. In particular, we highlight the emerging use of Atomic Force Microscopy for directly measuring these forces at the single molecule level; a unique capability that is enabling deconvolution of complex biomolecular interactions with conducting polymers. Finally, we provide an overview of biomolecular interactions, namely model proteins and DNA, and conclude by discussing a growing area of interest; the spatio-temporal and reversible control of biomolecular forces via electrical stimulation.