Generic High-Capacity Electrochemical Capture and Release of Proteins by Polyelectrolyte Brushes

Capture and release of proteins by an electrical signal is of general interest but methods have proven difficult to develop. We present a polyelectrolyte brush electrode with high-capacity (several µg/cm2 ) for protein immobilization that captures and releases proteins by an electrochemical potential. The electrochemical potential produces an interfacial pH gradient that enables rapid and tunable switch of the interaction between the polyelectrolyte brush and proteins on-demand. Key to our solution is an electrochemically inert aryl anchor between the polyelectrolytes and the electrode, which enables multiple capture-release cycles (without any regeneration step) and minimal degradation of the electrode. For all proteins tested we observed complete release by electrochemistry. In addition to proteins, the electrode could successfully immobilize and release liposomes suggesting additional applicability within the field of biomedicine and drug delivery. Importantly the electrode retained its functions when exposed to serum suggesting it can be used in a biological environment. We predict that this technology will be highly useful for protein purification and in biomedical devices.