The upshot is that the Mol-Switch project was far more successful than expected. The team's switch works with a number of DNA-based motors and can achieve incredible performance.
Specific sensors, which emit electrons, can tell if the biological motor is working, so the switch links the biological world with the silicon world of electronic signals.
Here's how it works. The team uses a microfluidics chip that includes a number of channels measured in nano-metres. The novelty of microfluidics is that it can channel liquids in laminar, or predictable, flow.
The floor of this channel is peppered with Hall-Effect sensors. The Hall Effect describes how a magnetic field influences an electric current. That influence can be measured to a high degree of accuracy. These measurements link the biological motor with the electronic signals of the silicon world.
The biological element of the device starts with a DNA molecule fixed to the floor of the microfluidic channel. This strand is held upright, like a string held up by a weather balloon, by anchoring the floating end of the DNA strand to a magnetic bead, itself held up under the influence of magnetism.
A specific type of protein, called a Restriction-Modification enzyme, provides one of the DNA motors. This type of DNA motor will only bind to a specific sequence of the DNA bases A, C, G and T. "This binding is very specific, a motor will bind only with its corresponding bases, so you can control exactly where the motor is placed on the vertical DNA strand," says Firman.
The motor is attached to the strand at the specific sequence of bases. Then the team introduces ATP, the phosphat