In the journal Science, a new device is described that fashions nanowires into a transistor small enough to probe the interior of cells.
A Harvard press release reports that the new device is smaller than many viruses and about one-hundredth the width of the probes now used to take cellular measurements, which can be nearly as large as the cells themselves. Being so thin, these transistors are less likely to damage cells upon insertion.
“Our use of these nanoscale field-effect transistors represents the first totally new approach to intracellular studies in decades, as well as the first measurement of the inside of a cell with a semiconductor device,” says senior author Charles Lieber. “The nanoFETs are the first new electrical measurement tool for intracellular studies since the 1960s, during which time electronics have advanced considerably.”
Lieber says nanoFETs could be used to measure ion flux or electrical signals in cells, particularly neurons. The devices could also be fitted with receptors or ligands to probe for the presence of individual biochemicals within a cell.
Lieber and colleagues found that by coating the structures with the same material cell membranes are made of (phospholipid bilayer) the devices are easily pulled into a cell via membrane fusion, a process related to that used to engulf viruses and bacteria.
Lieber and his coauthors found that introducing two 120º angles into a nanowire creates a single V-shaped 60º angle, perfect for a two-pronged nanoFET with a sensor at the tip of the V. The two arms can then be connected to wires to create a current through the nanoscale transistor.