The creation of a viable biosensor using living cells and semiconductor devices has been thwarted by a variety of technical glitches. In theory, cells can be attached close to the “gate” region of field-effect transistors, which generate currents in the presence of small local voltage changes. However, cultured cells keep their distance both from one another and from their supportive substrate, limiting the size of the measurable voltage differential. In this issue, Peter Fromherz and his colleagues (see p. 121) partially overcome this particular problem. They transfected HEK293 cells with recombinant maxi-K channels, and then grew these on a silicon-coated, field-effect transistor. The large currents mediated by these channels created a voltage differential sufficiently large to be detected by the transistor. Most intriguing, the ion channels became concentrated at the cell–silicon interface, suggesting that further molecular manipulations to enhance the density of channels at the “gate” might enhance the signal-to-noise ratio of this device (see also p. 114).