Abstract: A method for the controlled release of an agent (e.g., a biomolecule or nanoparticle) into a specified environment, includes the steps of: (a) providing an electrode or array of electrodes, (b) functionalizing the electrode's surface by introducing to it a molecule or molecules (e.g., thiols on a gold electrode) that chemically bond on the electrode surface and form themselves into a self-assembled monolayer (c) attaching or linking said agent to the molecules through a chemical (e.g., using a coupling group such as amine) or electrostatic (e.g., when the agent is DNA) linkage, and (d) electrochemically releasing the agent from the electrode surface.