A project to create amphiphilic smart dust.

(Try saying that quickly five times.)

Roland Piquepaille caught word of a smart dust project at UC San Diego. Apparently they’ve created silicon chips that are amphiphilic– i.e., they’re attracted to water on one side, and repelled by it on the other– and thus can detect and isolate oil or other impurities:

When added to water, the “dust” will align with the hydrophilic side facing the surface of the water and the hydrophobic side facing toward the air. If a drop of an oily substance is added to the water, the dust surrounds the drop with the hydrophobic side facing inward. In addition to this alignment, which will occur in the presence of any substance that is insoluble in water, a slight color change occurs in the hydrophobic mirror. The degree of this color change depends on the identity of the insoluble substance. The color change occurs as some of the oily liquid enters the tiny pores on the hydrophobic side of the silicon particle….

[T]he dual-sided particles have the additional benefit of being able to collect at a target and then self-assemble into a larger, more visible reflector that can be seen from a distance. “The collective signal from this aggregate of hundreds or thousands of tiny mirrors is much stronger and more easily detected than that from a single mirror,” [graduate student Jamie Link] points out. “The tendency of these particles to clump together will therefore enable us to use this technology for remote sensing applications.”

It sounds like an elegant little technology, though I’m not sure from the press release whether it’s “smart dust” the way that Kris Pister’s “smart dust” is smart: reactive, yes, but not using a little tiny computer. Still, it sounds cool.

There’s another interesting thing here. There are have been groups influenced by biomimicry who’ve been working on harnessing amphiphilic molecules in self-assembly and drug delivery, but this is the first example I’ve heard of the phenomenon being reproduced in a technology.

[via Smart Mobs]