In efforts that can improve studies of biological objects and the construction of nanotech materials, researchers at the University of California-Berkeley have invented "optoelectronic tweezers," a new way of controlling nanometer-scale objects. The research will be presented at the upcoming CLEO/QELS meeting in Baltimore.
In the design, the researchers reflect light from a digitally controlled array of mirrors, sending the light through a magnifying lens, and then into a sandwich of semiconductor planes, creating (at the interface between two of the planes) as many as 15,000 traps that can be addressed separately. In each of the traps, objects such as biological cells can be studied.
Optoelectronic tweezers, which use optical energy to create powerful electric forces in carefully prescribed places, differ from ordinary optical tweezers, which use optical energy to create mechanical forces that can push things around, helping to make the technique potentially easier for laboratories to implement.
According to Berkeley's Aaron Ohta, the optoelectronic approach uses much less power than optical tweezers and doesn't need to be as carefully focused. In recent months the Berkeley group has had some success in using their locally controlled electric fields to manipulate the positions of tiny nanorods (100 nanometers in diameter and 1-50 microns long). The rods are suspended in a thin layer of water by sound waves and then transferred to the tweezer apparatus. Ohta says that the lateral-field optoelectronic device will possibly be used to place rods for the sake of building 3-D circuitry or for positioning oblong-shaped cells or cell protrusions with micron-level precision.
Source: Optical Society of America
Related stories:
Optoelectronic tweezers to round up cells, microparticles
Rounding up wayward cells and particles on a microscope slide can be as difficult as corralling wild horses on the range, particularly if there's a need to separate a single individual from the group.
But now, a new device developed by University of California, Berkeley, engineers, and dubbed an "optoelectronic tweezer," will enable researchers to easily manipulate large numbers of single cells and particles using optical images projected onto a glass slide coated with photoconductive materials.
Tweezers Trap Nanotubes by Color
Singled-walled carbon nanotubes are graphene sheets wrapped into tubes, and are typically made up of various sizes and with different amounts of twist (also known as chiralities). Each type of nanotube has its own electronic and optical properties. Physicists at Osaka University in Japan used colored light to selectively manipulate different types of carbon nanotubes. They found that some of nanotubes displayed a tendency to cluster at the focal area of a focused laser beam.
E. coli discovery could lead to new antibacterial target
Northeastern University scientists have discovered a new and unique DNA binding property of a protein in E. coli. Penny J. Beuning, Assistant Professor in the Department of Chemistry and Chemical Biology, spent the last two years researching double and single-stranded DNA binding of E. coli DNA polymerase III alpha protein and notes that her findings have potential for developing a new antibacterial target.
Sewing DNA thread with lasers, hooks and microbobbins
(PhysOrg.com) -- Japanese scientists have made a micro-sized sewing machine to sew long threads of DNA into shape. The work published in the Royal Society of Chemistry journal
Lab on a Chip demonstrates a unique way to manipulate delicate DNA chains without breaking them.
Molecular motor works by detecting minute changes in force
Researchers at the University of Pennsylvania School of Medicine discovered that the activity of a specific family of nanometer-sized molecular motors called myosin-I is regulated by force. The motor puts tension on cellular springs that allow vibrations to be detected within the body. This finely tuned regulation has important implications for understanding a wide variety of basic cellular processes, including hearing and balance and glucose uptake in response to insulin. The findings appear in the most recent issue of
Science.
Using a light touch to measure protein bonds
MIT researchers have developed a novel technique to measure the strength of the bonds between two protein molecules important in cell machinery: Gently tugging them apart with light beams.
The Particle Whisperers
As many parents know, it's often easier to keep your kids under control by exerting less authority rather than more. A child who fidgets uncontrollably in a confining booster seat, for example, may be perfectly content on a plain old chair.
Scientists obtain first direct observations of protein-synthesis mechanism
Research by UC Santa Cruz molecular biologist Harry Noller and his collaborators has led to the first direct observations of the mechanism for protein synthesis in living cells. Their new findings on ribosomes, the protein-making molecular machines in all cells, are featured on the cover of the April 3, 2008, issue of the international science journal
Nature.