One of the main challenges in making labs-on-a-chip
is finding ways to control and mix tiny amounts of liquids.
Researchers from the University of California at San Diego are
using minuscule silicon particles to carry out these tasks.
The researchers' have modified their previously developed smart
dust by trapping magnetic iron oxide nanoparticles within the silicon
particles. The particles are chemically coated so that they adhere to
water on one side, and repel water on the other side.
The chemical coating causes the silicon particles to surround
water droplets, and the dust changes color depending on the chemicals
it is in contact with. This allows the researchers to identify chemicals
encased by the smart dust. The magnetic properties makes it possible to
move the particles -- and the droplets they are surrounding -- using a
The silicon particles are 50 to 100 microns in diameter, which
is one-tenth to one-twentieth of a millimeter.
The researchers demonstrated the system by filling and draining
droplets and by combining two droplets to carry out a chemical reaction.
The system makes it possible to work with small amounts of chemicals,
and can be automated, making it possible to carry out many reactions simultaneously,
according to the researchers.
The method could be used practically in two to five years, according
to the researchers. The work appeared in the November 7, 2004 issue of
For pure nanotubes add
Solar cell doubles as
Pure silicon laser debuts
toughens nanotube fiber
hydrogen on ice
Smart dust gets magnetic
carry big currents
View from the High Ground Q&A
How It Works
News | Blog
Buy an ad link