Molecular motors inch closer

A Florida scientist claims to have made the first "nanomotor" from a single molecule of DNA (deoxyribonucleic acid), bringing the prospect of microscopic motors that could change manufacturing and medicine a step closer to reality.

The chemically-powered motor, so small that hundreds of thousands could fit on a pinhead, curls up and extends like an inchworm. Although DNA motors have been created before, they have needed several different DNA molecules, making them less efficient and more difficult to control. "Compared to other DNA motors, our nanomotor is more practical," says its developer, Weihong Tan, a chemistry professor at the University of Florida.

The first applications for DNA motors are starting to emerge in the form of biosensors that can detect a piece of DNA that may be related to a disease, and could help to diagnose cancer. Later, these motors could play an active role in clinical treatment by being injected into cancer patients, along with drugs. The motors would attach the drugs to the membrane of cancerous cells, and prevent them from attaching to non-cancerous cells, thus reducing the debilitating effects of chemotherapy.

Some researchers believe that nanomotors could also be used in "test-tube manufacturing" which involves building structures from tiny atomic or molecular components.

Tan and a colleague confirmed that their molecular motor was working by attaching a light-emitting molecule to one end and a light-quenching molecule to the other end. When the motor extended, separating the emitter from the quencher, the light went on. When it curled up, the light went out.

Tan says it is difficult to predict when nanomotors will become practical tools. The next step in his research is to coax his nanomotor to move a tiny particle from one place to another, thus demonstrating that it can perform a potentially useful task.