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DNA detection with a twist
08 February 2008
US scientists have set DNA detection in a spin by exploiting one of nature's molecular motors.
- Wayne Frasch
Dynamic connection: target DNA forms part of a bridge between molecular motor F1-ATPase (bottom left) and a gold nanorod
The system's detection limit is fewer than 600 DNA molecules in solutions of femtomolar concentrations. Conventional fluorescence-based DNA detection systems have detection limits of only about five picomolar; when fewer targets are present, either multiple fluorescent molecules must be used for each target or DNA amplification, typically using the polymerase chain reaction (PCR), is needed to generate a detectable fluorescent signal. The nanorod sensing method 'avoids the problems inherent to PCR and is much faster than current assays,' said Frasch.
Ulf Landegren, an expert on DNA detection from Uppsala University, Sweden, said, 'the critical question is how the device performs under field or regular lab conditions, where PCR and its related variants have dominated so far.' Frasch admits that he has reported the results from 'clean systems', but his team is now repeating experiments using real samples.
According to the US scientists, their system lends itself to an easy kit-based protocol. But the really exciting thing, said Frasch, is that it is the first practical nanodevice that employs a molecular motor that really works.
Link to journal article
Single-molecule detection of DNA via sequence-specific links between F1-ATPase motors and gold nanorod sensors
Justin York, David Spetzler, Fusheng Xiong and Wayne D. Frasch, Lab Chip, 2008, 8, 415
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