Scientists used silicon nanowires to create hairpin-shaped conducting transistors that are smaller than a typical virus. The transistors are able to float freely inside the cells and "listen in" on crucial biological functions.

When put to the test inside cultured chicken heart cells, the transistors recorded changes in the cells' heartbeat-driving electrical output.

The new device is surprisingly noninvasive, said study leader Charles Lieber, a nanoscientist at Harvard University.

That's because the wires were coated with cell membrane, so that target cells were enticed to fuse the wires with their own membranes and "suck" the wires inside naturally, Lieber said.

(Related: "New Needle So Tiny It 'Injects' Meds Into Cell Organs.")

The nanowire method also eliminates the need for needle-like insertions, which