Nanomotor Created from DNA Molecule

Originally Published MDDI June 2002

R&D DIGEST

For some years, researchers have speculated on the potential of molecular-scale motors in healthcare applications such as delivering drugs or performing medical procedures within the patient's body. Although such motors' practical application remains years in the future, University of Florida (UF; Gainesville) researchers have made an important step in their development by creating a nanomotor from a single DNA molecule. According to Weihong Tan, the lead researcher, the motor curls up and extends like an inchworm.

Tan emphasizes that this is not the first DNA motor, but that it is the first to be built from a single molecule instead of several different DNA molecules. "The new design has a much higher energy conversion efficiency. The motor is much more powerful in doing work. The new design has also made the preparation, application, and manipulation easier than before," says Tan.

Such nanomotors are expected to play an active role in clinical treatment. In such applications, according to Tan, the technology could "combine recognition, delivery, and treatment or diagnosis together in the same nanodevice, like a nanoparticle." Such devices, for example, could be injected in addition to drugs intended to treat cancer cells or tumors, according to Tan. He explains that when the drugs reach the disease site, the nanomotors would make the drug molecules attach and stick to the cancer cell membrane. He emphasizes that the motors' precision would enable them to prevent the drugs from attaching to noncancerous molecules or healthy parts of the body.

Although nanoscale motors had previously been created from multiple strands of DNA, Tan believes that nanomotors created in such a fashion have certain limitations. He explains that they can be difficult to control because the pieces are so tiny. He adds that each DNA strand requires an energy source, which also reduces the motors' efficiency. With just one DNA strand, the UF nanomotor is easier to control and more efficient, Tan says.

The researcher explains that the new DNA motor was synthesized by attaching a light-emitting organic molecule to one end and a light-quenching molecule to the other. When the strand extended, separating the quencher and emitter, the light went on. When it curled up, the light went out.

Tan says the next step in his research is to coax his nanomotor to move a tiny particle from one place to another, demonstrating that it can perform a potentially useful task. The researcher explains that several challenges remain in developing the technology. One obstacle is to find "easy ways to turn the motor on and off without physically adding a biological solution." Tan adds, "We are working on similar motors which will convert photon or electrical energy into mechanical energy for doing work.

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