Designing electroactive biointerface for spatiotemporal control of cell attachment and release

In this paper, we demonstrate the use of individually addressable microelectrodes for cell sorting and cell micropatterning applications. Microelectrodes were modified with cell adhesive or non-adhesive molecules and then electrically stimulated to selectively adsorb or desorb proteins and/or mammalian cells. The switching of the surface properties was achieved by the electrochemical desorption of protein-functionalized thiols and poly(ethylene glycol) PEG silane from gold and indium tin oxide (ITO) electrodes respectively. The thiol surfaces were modified with anti-CD4 antibodies and used to capture T-cells. Upon electrical activation of the microelectrodes, both the antibodies and the T-cells were removed from the specific locations on the substrate. In addition, ITO electrodes were modified with cellresistive PEG silane which was later electrochemically desorbed to make the surface adhesive to proteins or cells. This technique was employed to pattern two different cell types on the same substrate.