Electrochemically programmed release of biomolecules and nanoparticles

The controlled release of molecules or nanoparticle conjugates is an important tool for a wide range of applications in science and engineering. Here we demonstrate electrochemically programmed release of biomolecules and nanoparticles immobilized on patterned gold electrodes using the thiol-gold linkage. This technique exploits the reductive desorption of self-assembled monolayers and allows both spatially controlled release and regeneration of small molecules (e.g., drugs), biopolymers (e.g., peptides, proteins, DNA), protein assemblies (e.g., viruses), and nanoparticles (e.g., particle-DNA conjugates). Fluorescence microscopy is used to image the release of avidin and nanoparticles in phosphatebuffered saline and to determine the kinetics of desorption. We also demonstrate that the electrodes can be regenerated using the same conjugation scheme.