Nano-particles take shape

This week in the journal Science, researchers from the University of Delaware and Washington University in St. Louis described how they have managed to build long cylindrical nanoparticles, 1,000 times thinner than a human hair. These self-assembling molecules could have several potential uses, including delivering drugs within the body.

The scientists were working with block copolymers - synthetic molecules that contain two or more different segments bonded together . These materials are already used to make a range of materials including plastics, rubber soles for shoes, and portable "flash drive" memory sticks for computers.

The researchers took copolymers made up of different types of blocks - including one that loves water and one that hates it. So when you put them in water, the water-hating bits all group together and form structures known as micelles. Normally these kind of structures are small spheres, but the team found they were automatically forming long snake-like structures.

Darrin Pochan, one of the lead researchers, points out that the technique could help drug delivery in the body, by bundling drugs with the nanocylinders. He says "If you put little balls full of a drug into the bloodstream, the body's organs and immune system will get rid of them in around a day. But if you place the molecules into long, floppy cylinders, they may stay in the body for weeks." This could help to deliver drugs where they're needed over a sustained period of time - the goal for treatment of many types of disease, including cancer.