jaws snatch cells
Technology Research News
The human circulatory system is full of
what are essentially micro machines -- red blood cells that carry oxygen,
platelets that stop wounds from leaking, and white blood cells that engulf
One branch of microelectromechanical
systems (MEMS) research is aimed at figuring out ways to make and
control inorganic machines as small as some of nature's biological constructions.
In that vein, researchers from Sandia National Laboratories have produced
a set of tiny, silicon micro jaws that can open and close rapidly to trap
and release red blood cells one at a time.
The device demonstrates that it will eventually be possible to puncture
and inject substances into single cells, said Jay Jakubczak, a senior
manager of MEMS science and technology at Sandia National Laboratories.
This will be useful for studying interactions within and among cells,
The tiny teeth could eventually be used to isolate, manipulate and gain
information about microscopic particles in many different environments,
said Jakubczak. "Overall, this technology... may have impact in the areas
of drug discovery, drug delivery, prosthetics, vision, and hearing," said
The jaws are about 20 microns wide, contain five upper and five lower
teeth, and are powered by an engine that measures 100 by 100 microns.
A red blood cell is about five microns in diameter, and a human hair about
75 microns in diameter.
The lower jaw of the microdevice resides in a tiny channel flowing with
red blood cells immersed in liquid. The upper teeth slide back and forth
across the channel, trapping and releasing a red blood cell about every
tenth of a second.
The researchers made the device and channel using the same silicon wafers
and lithographic processes used to make computer chips. This means many
of the tiny machines can be stamped out on a single silicon wafer, making
their manufacture relatively inexpensive. To make chips, manufacturers
deposit layers of metal, semiconductor and insulator in certain patterns
on the silicon wafers, then etch material away to fashion features.
More complicated microfluidics machines can also be constructed this way,
according to Jakubczak. "The big impact of a technology such as this is
that many functions needed in a fluidic system can be integrated onto
a single silicon chip -- pumps, valves, actuators, electrodes, channels,
mixers -- [and] these microfluidics silicon chips can be manufactured
in silicon wafer fabrication facilities like the ones used today to make
One key to the prototype's success is that the microchannel is made from
silicon nitride, which is both transparent and an electrical insulator.
This makes it easier to track what is happening in the channel by taking
advantage of the transparency to use optics, and the insulation properties
to use electrical and magnetic fields to analyze and manipulate the contents
of the channel without shorting out the chip.
The next step is to get the microteeth to actually puncture the cells
to allow them to absorb substances, said Jakubczak. "Though not demonstrated
to date, these microteeth would roughen the cellular membrane of individual
cells, making it possible for molecules of interest to be inserted through
the cell. These molecules would be present in the channel with the cells
or might be inserted through hollow capillaries in the microteeth themselves,"
If Sandia is able to use the technique to make a device that successfully
injects substances into cells, it would pave the way for doing so on a
much larger scale and at much lower cost than is possible today, said
Jakubczak. Current techniques for introducing chemicals into cells include
using electricity to break down cell walls, which kills many cells, and
manually puncturing cells with very fine pipettes, which is a labor-intensive
The tiny teeth could also be used to manipulate individual nanoparticles
within cells, said Jakubczak. "You might envision an array of micron-sized
electrical probes that when activated can cause nanoparticles to separate
by their particular electronic charge," he said.
The device could find applications in the research community within the
next three to five years and in commercial products within five to ten
years, according to Jakubczak.
Jakubczak's research colleagues were Murat Okandan, Paul Galambos and
Sita Mani of Sandia National Labs. The research was funded by Sandia.
Timeline: 3-10 years
TRN Categories: Microfluidics and BioMEMS
Story Type: News
Related Elements: None
Neurons battle to a draw
Quantum crypto gear shrinks
Toy shows bare bones
Tiny jaws snatch cells
Plastic mix helps
Research News Roundup
Research Watch blog
View from the High Ground Q&A
How It Works
News | Blog
Buy an ad link