Scientists have created motors tiny enough to swim through your blood vessels and spidery enough to spin strands of polymer thread.
The microspiders – made by Ayusman Sen from Pennsylvania State University and colleagues – are spheres less than one micrometer wide, with one hemisphere of gold and one of silica.
They’re also self-propelling. How it all works (pictured):
- The team attached a Grubbs catalyst – a molecule that builds long chains of smaller molecules – to the silica side.
- When dropped into a solution containing a chemical called norbornene, the catalyst spins polymer threads from the chemical molecules. (This reaction is called polymerization, and it’s what’s going to power the micromotor.)
- When there are more unpolymerized single molecules (or monomers) around the gold side of the sphere than the silica side, you get a gradient: fluids move between the region with lots of particles and the region with fewer ones.
- When solution rushes toward the gold side, the whole sphere moves.
- The researchers were able to control the direction of the sphere’s movement by placing lumps of gel soaked in norbornene at one corner of the tank. That way, the sphere follows the trail of leached norbornene towards the gel lumps.
Sen hopes to develop versions of microspiders that can run on chemicals available in the body, such as glucose. New Scientist explains their potential uses:
In the future, more sophisticated microspiders attached to nanobots that detect chemicals secreted by damaged tissue could swim through the bloodstream, weaving a medical glue to help heal tears in vessel walls. Decorated with other micromachines and enzymes, they could swim through the circulatory system scouting out tumours, scouring plaque from vessel walls and helping the immune system battle infections.
The study was published in Angewandte Chemie last week.
Via New Scientist, Chemistry World.
Image from R.A. Pavlick et al.
This post was originally published on Smartplanet.com