Catch, Release, Repeat: Reversible Protein Capture in Electric Fields Using Antifouling Polymer Brushes

ABSTRACT Capturing proteins is easy since their amphiphilic nature allows them to bind to almost any surface. Because of this, releasing them is challenging since various interactions need to be considered for this. We present a simple method to reversibly adsorb proteins on stabilized electrodes. By introducing negative potentials, positively charged proteins are attracted to the electrode, in contrast to negatively charged proteins. At the open circuit potential, where the potential is removed, an antifouling polymer‐brush ensures prompt release of the captured proteins. We demonstrate our method by repeatedly capturing and releasing lysozyme at gold electrodes coated with antifouling poly(oligo[ethylene glycol]methyl ether methacrylate) brushes. Furthermore, we show how the capture and release can be tuned by the potential, polymer‐brush thickness, and salt concentration. Controlling protein adhesion and release is especially relevant in sensors, and in fields where protein fouling reduces the runtime of processes, for example, in protein separation processes used for food ingredient production, and isolation of biomedical compounds.