New Worlds: A pinch of light

Science fiction turned into science fact.

By
July 18, 2010 02:11
4 minute read.
The Jerusalem Post

laboratory 311. (photo credit: Bloomberg)

Star Trek fans will remember “tractor beams” that allowed the starship Enterprise to trap and move objects. Now Tel Aviv University is turning this science fiction into science fact on a nano scale by building special laser “tweezers” for medicine, communications and harvesting energy.

The new tool, called Holographic Optical Tweezers (HOTs), use holographic technology to manipulate simultaneously up to 300 nanoparticles such as beads of glass or polymer that are too small and delicate to be handled with traditional laboratory instruments.

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The technology, also known as “optical tweezers,” could form the basis for tomorrow’s ultrafast, light-powered communication devices and quantum computers, says Dr. Yael Roichman of TAU’s school of chemistry. She’s using these tweezers to build nano structures that control beams of light, aiding in the development of anything from optical microscopes to lightfuelled computer technology, HOTs are a new family of optical tools that use a strongly-focused light beam to trap, manipulate and transform small amounts of matter. First proposed as a scientific theory in 1986 and prototyped by a University of Chicago team in 1997, holographic optical tweezers have been praised as indispensable for researching cutting-edge ideas in physics, chemistry and biology.

Roichman and her team of researchers are currently pioneering the use of optical tweezers to create the next generation of photonic devices. Made out of carefully arranged particles of materials such as silicon oxide and titanium oxide, these devices have the ability to insulate light, allowing less energy to be lost in transmission. “Our invention could increase transmission speed and save energy, which is important for long-life batteries in computers, for instance,” says Roichman.

Photons are already used in optical fibers that bring us every day services such as cable TV. But Roichman says this technology can be taken much further. In her lab, she is advancing the previous study of photonic crystals, which control and harness light, by manipulating a variety of particles to create 3D heterogeneous structures. The ability to insulate light in a novel way, preserving its potential energy, is central to this goal.

No known material can resist the flow of light, as its energy is either absorbed by, reflected off or passed through materials.

But Roichman has devised a new layering technique using special crystals – central to the creation of photonic devices – that are arranged to create a path along which light can travel. If done correctly, she says, the light is trapped along the path. She is hopeful that the ability to build these devices will transform communications, telescopic instruments and even medical technology, making them more efficient and powerful.

One medical project would track the effectiveness of antibiotics. She says improvements to optical microscopy will, for the first time, enable researchers to look at the internal processes within bacteria and see how different types of antibiotics attack them. More than that, her optical tweezers can isolate the bacteria to be studied, handling them without killing them.

ISRAELI NEUROSCIENTIST EXCELS A researcher at the Weizmann Institute of Science in Rehovot has just shared the Excellent Paper in Neuroscience award for young scientists, along with a colleague from Finland.

The award ceremony, in which each received 3,000 euros, took place during the Seventh Forum of European Neuroscience Societies (FENS) in Amsterdam. ERA-Net NEURON is an initiative of the European Commission aimed at advancing transnational European research in the field of disease-related neuroscience.

Dr. Asya Rolls received the award on her publication in PLoS Medicine (2008) for elucidating the role of scar tissue formation in spinal cord repair after injury. It has been accepted for quite some time that lack of nerve regeneration in the central nervous system is due to formation of harmful scar tissue. Rolls addressed the question of why should the body invest so much energy in scar formation after traumatic spinal cord injury (SCI) only to inhibit spinal cord repair. She showed that initial formation of the scar, and in particular a protein called CSPG, is part of an “SOS” response crucial for recovery. In fact, inhibiting the formation of CSPG at the early stages of spinal cord injury actually harms the recovery process. On the other hand, CSPG inhibition during the later subacute phase, improves functional recovery and can benefit regeneration. This study thus identified an endogenous repair mechanism of the body and may have considerable implications for the treatment of SCI.

The other recipient was Dr. Heidi Nousiainen from the Finnish National Institute for Health and Welfare. Nousiainen received her award on her publication in Nature Genetics (2008) describing and identifying the gene underlying two fatal nervous system diseases (LCCS1 and LAAHD) that are characterized by marked atrophy of spinal cord motoneurons and fetal immobility, and who are lethal already during fetal development or shortly after birth. She discovered that the disease causing gene, adding a new and important member to the increasing number of RNA processing molecules linked to neurodegenerative diseases.


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