A cleverly designed silicon chip developed by researchers at the University of California (Berkeley, CA) may soon give biologists precise control over cell electroporation. Using standard silicon fabrication techniques, the researchers created a chip with a microscopic hole capable of holding a single mammalian cell as part of an electrical circuit. The cell behaves as a diode in the circuit, allowing current to flow at the specific voltage that causes pores to open in the cell membrane. The ability to monitor electroporation in real time in a single cell should allow scientists to exert precise control on the introduction of novel genes, proteins, and other macromolecules. Since individual cells in a population differ in their responses to electricity, current electroporation techniques are often inefficient. Though the initial work, reported in Biomedical Microdevices (3, 145–150, 2000), involved manually drawing each cell into the hole in the chip, a commercially useful device might electroporate cells in a continuously flowing stream. In addition, it could be “the first step to building complex circuitry that incorporates the living cell,” says Boris Rubinsky, senior author on the paper. Cells implanted on chips could ultimately be used to administer precise doses of therapeutic proteins, build complex biocomputers, or test novel pharmaceutical compounds in automated high-throughput screening systems.