Tunable protein and bacterial cell adsorption on colloidally templated superhydrophobic polythiophene films

A facile approach for enabling or inhibiting the adsorption of protein and adhesion of bacterial cells on a potential-induced reversibly wettable polythiophene film is described. The superhydrophobic polymeric surface was first prepared by a two-step process that combines the layering of polystyrene (PS) latex particles via a Langmuir-Blodgett (LB)-like technique followed by cyclic voltammetric (CV)-electrodeposition of polythiophene from a terthiophene ester monomer. The polythiophene conducting polymer coating enabled control of the wettability of the surface by simply changing its redox property via potential switching. The influence of morphology on this switching behavior is also described. The wettability in return controls the adsorption of protein and adhesion of bacterial cells. For instance, the undoped polythiophene film, which is superhydrophobic, inhibits the adhesion of fibrinogen proteins and Escherichia coli (E. coli) cells. On the other hand, the doped film, which is hydrophilic, leads to increased attachment of both protein and bacteria. Unlike most synthetic antiwetting surfaces, the as-prepared superhydrophobic coating is nonfluorinated. It maintains its superhydrophobic property at a wide range of pH (pH 1-13) and temperature (below -10 °C and between 4 and 80 °C). Moreover, the surface demonstrated self-cleaning properties at a sliding angle as low as 3° ± 1. The proposed methodology and material should find application in the preparation of smart or tunable biomaterial surfaces that can be either resistant or susceptible to proteins and bacterial cell adhesion by a simple potential switching.