Noy’s work, described this week in the Proceedings of the National Academy of Sciences, opens new avenues because it makes the nanowires more like cells, says Yi Cui, assistant professor of materials science and engineering at Stanford University. With Charles Lieber, a chemist at Harvard University, Cui has made silicon nanowires into very sensitive sensors by coating the nanowires with antibodies. The sensors could, for example, detect blood proteins characteristic of cancer. Noy’s work, Cui says, “is a really creative way to integrate a transistor with a cell membrane.” By coating the nanowires, Noy can take advantage of everything that biological cell membranes have to offer, including the ability to sense and respond to voltage changes, as well as ions, proteins, and other biomolecules. This range of functionality can’t be achieved with antibodies, says Cui.
Next, Noy plans to develop more-sophisticated nanowire-hybrid devices. So far, each device has been equipped with only one type of ion channel, which limits the complexity of the functions they can carry out. (Biological cells are coated with many different membrane proteins.)
The researchers will also begin testing the devices’ interactions with living cells. Other researchers, including Peidong Yang at the University of California, Berkeley, and Harvard’s Lieber, have used bare silicon nanowires to interface with neurons, stem cells, heart cells, and other tissues. They’ve shown that the nanowires can send and receive electrical signals with very high spatial resolution, even within single cells. Noy’s initial work remains a proof of concept.