Johns Hopkins researchers have devised a way to use a brief burst of electricity to release biomolecules and nanoparticles from a tiny gold launch pad. The technique could someday be used to dispense small amounts of medicine on command from a chip implanted in the body. The method also may be useful in chemical reactions that require the controlled release of extremely small quantities of a material.

For their experiments, the researchers used gold electrodes, each as thin as a single strand of human hair, fabricated through the same photolithography techniques used to make computer chips.

To tether each useful molecule to this surface, the team used a long chain of hydrocarbon molecules. At one end, the tether was anchored to the electrode by a gold-sulfur bond. At the other end was the biomolecule they wished to release on command. The researchers then sent a brief, mild pulse of electricity through wires attached to each electrode. The current caused the bond between the sulfur atoms and the gold platform to break, setting free the tethered molecule.

In theory, the researchers said, this technique could be incorporated into a biocompatible implant chip that would release medicine inside a patient on command.

Source: Johns Hopkins University news release