Nanomotor from DNA Strand

Phrogger writes "Nanomotors have been built from multiple DNA strands before this but this is the first to be built from a single strand. Said to be more practical, this holds wonderful promise for treating diseases such as cancer."

Comments

Sensor function of DNA nanomotors

[nucal]

In my opinion, calling these things nanomotors is a bit of a misnomer, since they are really undergoing cycles of melting (to cause the hairpinning) and reannealing (to straighten the DNA strand). But, this melting cycle can do work to move things around - which is the strict definition of a motor. Will these things work as a drug targeting strategy for cancer cells? Maybe someday, but that's a long ways off until the problem of inducing specific DNA melting in vivo is solved (a non-trivial issue).

On the other hand, the sensor function seems to be more practical right now. Any type of hybridization strategy requires and interaction between the target and the "test" sample from some source (cancer cell, crime scene evidence, etc.) to generate a signal. Most of the current technologies require processing the sample to add a detectable marker, either radioactivity or fluorescence, which is then detected when it binds to the target stuck to some matrix.

For DNA nanomotors to act as a sensor, sample DNA would bind to the DNA target to interfere with motor function - I'm guessing to leave it in a semi-melted state. One key here is that the DNA nanomotor has the detection method built into the target - since when the DNA melts, the fluorescence is emitted (e.g. through resonance energy transfer - RET). Having the detector in the target eliminates a lot of sample processing steps and so increases the sensitivity of detection. Adding motor function may enable this to be linked to some sort of electronic relay - further increasing sensitivity.

The real advance here is that by doing this with a single DNA strand it is much easier to engineer a "detector" sequence into the nanomotor than it would be if multiple strands are required for different steps in motor function.