Scientists at Harvard University have fashioned nanowires into a type of V-shaped transistor small enough to probe the interior of cells. The device, described in Science, is smaller than many viruses and about 1/100th the width of the probes currently used to take cellular measurements. The technology represents a marked improvement over bulkier probes, which can damage cells upon insertion and reduce the accuracy or reliability of data. “Our use of these nanoscale field-effect transistors, or nanoFETs, represents the first totally new approach to intracellular studies in decades [and] the first measurement of the inside of a cell with a semiconductor device,” says senior author Charles M. Lieber, PhD, professor of chemistry at Harvard.
Lieber and colleagues say nanoFETs could be used to measure ion flux or electrical signals in cells — particularly neurons. The devices also could be fitted with receptors or ligands to probe for the presence of individual biochemicals within a cell. Aside from their size, two features allow for easy insertion of nanoFETs into cells. First, Lieber and colleagues found that by coating the structures with a phospholipid bilayer — the material found in cell membranes — the devices are easily pulled into a cell via membrane fusion, the same process used to engulf viruses and bacteria. Secondly, introducing triangular “stereocenters” — essentially, fixed 120-degree joints — into nanowires in the proper orientation creates a single V-shaped 60-degree angle, enabling the construction of a two-pronged nanoFET with a sensor at the tip of the V. The two arms then can be connected to wires to create a current through the nanoscale transistor.
Source: Biology News Net
Posted September 1st, 2010 under Tech Transfer
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