There are many therapeutic agents against cancer, but until now we have not had an efficient delivery system. A delivery mechanism that is capable of bringing multiple therapeutic agents directly into specific cancer cells where they can perform different tasks.

A therapeutic agent against cancer needs to accomplish the following tasks:
- It needs to recognize the cancer cell;
- Must gain access to the cancer cell;
- It needs to destroy the cancer cell;
- It must be able to be tracked through the body so that the cancer can be located and follow up treatment given if necessary.

Nanotechnology promises to do all these.

But our nano technology has to be mobile within our body. We must have moving parts so that we can open valves to release therapeutic agents or relocate to a new destination where the potential cancer cells exist.

Chemists use nanotechnology to create nano motors capable of powering miniature robots or mechanisms to deliver therapeutic agent to the right places.

One such system is currently being developed at UCLA. The simple operation of the device is shown on the right. Electron excitation by light causes a ring structured molecule to move to a new position and back again. This is analogous to the piston system found in car motors.