Researchers at Quantum Logic Devices, in Texas, US, constructed the detector by modifying an existing transistor design. This features a 5-nanometre-wide gold particle flanked by three electrodes.
Currently label DNA molecules using fluorescence, but that can take around 24 hours to produce a result. The new detector can detect a piece of DNA in less than 30 minutes. The detector would be ideal for diagnosing viruses quickly.
It can detect a single matching sequence. Sample purity becomes important, if you've got one bit of crud in there it could interfere.
The team at Quantum Logic Devices are currently developing a chip containing thousands of individual quantum dot transistors, manufactured using conventional semiconductor technologies. These could keep track of levels of combinations of genes in a biological sample