World's Smallest Transistor Radio

Scientists at the University of Illinois have built the world's smallest transistor radio according the Early Online Edition of the Proceedings of the National Academy of Sciences released January 29, demonstrating the first practical application of a carbon nanotube technology developed last year.

"These results indicate that nanotubes might have an important role to play in high-speed analog electronics..." said Founder Professor John Rogers of Illinois' Materials Sciences and Engineering program in a press release from Illinois. Rogers is also is a researcher at the Beckman Institute and at the university's Frederick Seitz Materials Research Laboratory.

Bacteria Used to Build Semiconducting Nanotubes

Nanodevices produced by bacteria? Chips made from microbes? If the work in progress at the University of California, Riverside and Gwangju Institute of Science and Technology in Korea bears fruit, "bugs in a jar" could be creating the building blocks for micrcochips and other devices that could use nanotubes as parts of their structures.

Neural Growth Initiated Using Nanotech

Researchers at Georgia Tech have developed a scaffolding technology that could lead to hope for people with nerve damage by promoting the growth of new connections between neurons in the brain, with potential treatments for common neurodegenerative disorders as well as brain and central nervous system injuries.

The methodology, reported in the December 11 issue of Advanced Materials, shows that by lacing a series of polymer scaffolds with acetylcholine that nerve growth could be promoted to make new connections with adjacent brain cells.

“Regeneration in the central nervous system requires neural activity, not just neuronal growth factors alone, so we thought a neurotransmitter might send the necessary signals,” said Yadong Wang in a press release from Georgia Technical Institute, assistant professor in the Coulter Department of Biomedical Engineering at Georgia Tech and Emory University, and principal investigator of the study.

The team led by Wang developed a new biodegradable polymer with a flexible backbone, which they laced with acetylcholine, one of the most common neurotransmitters found in the central nervous system. Neurotransmitters are the chemical “signals” used in the central nervous system to send messages from one cell to another. The scaffold of polymers were added to damaged nerves and studied in a test tube environment, and found to have grown new neurites (the connecting sections of neurons).

Damaged neurons rarely spontaneously grow new neurites in adults, and have difficulty penetrating scar tissue formed by an injury. Wang and his team are hopeful that this methodology will lead to a means of bridging the gap between damaged neurons, and lead to therapies for both brain injuries and neurological disorders.

Common neurological disorders are Alzheimer’s Disease, Huntington’s Disease, and Parkinson Disease. Most neurological disorders involve either the breakage of connections between neurons, or a short circuit in the pathway between them. By bridging these gaps, or creating new connections, scientists are hopeful to develop a cure, or at least an effective therapy to relieve their symptoms.

The team is continuing its work, expanding the scope and studying how the neurites and neurotransmitters interact with the polymer, and looking at potential surgical implantations. “This polymer and approach aren’t limited to nerve regeneration though, they can probably be used for other neurodegenerative disorders as well,” Wang said.

Work was funded by a combination of grants from Georgia Tech, the National Science Foundation, and the National Institutes of Health. Christiane Gumera, a graduate student under Wang’s supervision, co-authored the paper in Advanced Materials.

Nanoscaled Ink Tech Developed

Researchers at the University of Illinois have created a major breakthrough in creating nanostructures, and will potentially effect everything from water purification to electronics manufacture and the creation of photonic crystals.

A trio of researchers, Eric Duoss, Mariusz Twardowski, and Jennifer Lewis created the breakthrough technology which currently can create structures as small as 225 nanometers, with their goal to create structures as small as 100 nanometers. The technique permits the creation of complex 3-dimensional structures, but at the nanoscale.

The researchers’ created a new family of sol-gel inks, which eliminates the need for a coagulation reservoir that is necessary in other techniques. This makes it possible to robotically place the metallic inks in complex layers on a substrate, in the open air. The technology uses a ‘direct-write’ technique dispensing the ink in a filament, using a tip just 1 micron across, or 1/100^th the size of a human hair.

Current manufacture of electronic circuits requires careful etching and deposition of ceramo-metallic substances within the etches to build microcircuits, and that technology is rapidly approaching its limits in scaling. The possibility with the sol-gel process is to directly write the circuits onto the substrate, eliminating the painstaking etching and templating process. The etching and templating process creates impurities that can cause up to one in ten of the manufactured microcircuits to be unusable and end up as trash.

One of the demonstrated uses was creating a weave of densely packed, finely shaped material, which may be suitable as a filtration substrate. Because of the level of complexity and control, the layers could be created so literally only a specifically-shaped molecule could pass through leaving ultra-pure materials on the other side.

Another application the researchers are excited about is the creation of photonic crystals. At the scales at which they are working, they can literally block all but a very specific wavelength of light, as well as potentially finding methods for creating technology for controlling the flow of light within a system. Science fiction may be meeting reality, as fans of Star Trek: The Next Generation recall the blips of light within the android Data, in which the data flow was photonic.

Details of the research were recently published in the journal Advanced Materials. Work was conducted at the university’s Frederick Seitz Materials Research Laboratory at the Urbana-Champaign campus. Funding in part came from a grant from the U.S. Department of Defense.

Light-Powered Chips on the Horizon?

A pair of researchers at the Massachusetts Institute of Technology have developed a theory to use light to control and power “smart” microchips capable of adapting to different wavelengths and changing their behavior. If successful in their further research, they expect advances in telecommunications, remote sensing, and a variety of other photonic applications.

Postdocs Peter Rakich and Milos Popovic of MIT's Research Laboratory of Electronics presented their results in the November issue of Nature Photonics. Co-authors were Marin Soljacic, assistant professor of physics; and Erich Ippen, the Elihu Thomson Professor of Electrical Engineering and professor of physics. Work was funded in part by the Army Research Office through MIT's Institute for Soldier Nanotechnologies.

Rakich and Popovic believe they have found a means to use the miniscule energy caused by light bouncing off a surface to power nano-scale motors and machines embedded on a microchip. The devices would be able to self-adapt to the wavelengths of light, and react differently based on input. Current microchips are limited to an “on-off” state and are not capable of adjusting to conditions around them.

Their next step is to build a device to prove their theory has practical application. If successful, the team will have developed one of the first micro-electro-mechanical systems, a microscopic device with ‘eyes’ and ‘ears’ and able to function as a self-contained system. Such devices have widespread applications, from medical telemetry to cell phones, and handheld sensors with military and security applications. The United States Army is pursuing a ‘smart’ uniform for combat soldiers, and looking at being able to remotely monitor soldier’s condition as well as location.

By combining light as the means of transmitting information, the limits imposed by wiring would be eliminated, which include problems with heat dispersal caused by the ‘friction’ created when electrons flow throw a conductor, allowing devices to be constructed on an even smaller scale than currently possible. It also would pave the way for putting sensors in locations difficult, or impossible, for wiring or fiber optics to be placed.

Researchers all over the country have been working on various photonic devices, with the goal of switching from electrical conductivity in microchips to light. A recent development at the University of Illinois created a means for polarizing and limiting light to a single wavelength.

In a press release from MIT, Popovic said "Our objective now is to develop a variety of light-powered micro- and nanomachines with unique capabilities enabled by this technology. But the first step will be to demonstrate the concept in practice."

New Water Treatment Potential from Mimicking Kidney

Researchers at the University of Illinois (Urbana-Champaign campus) have taken the first step toward creating a membrane for moving water, and nothing but water, by mimicking the action found in kidneys. If they are successful in scaling up the size, their method promises to be at least 10-times more effective at desalinization and water purification than current methods, a critical technology for areas with poor water supplies, or in semiarid coastal regions.

Researchers in the lab of Mark Clark, professor of civil and environmental engineering and in Basil, Switzerland took a close look at how kidneys so effectively transported water via their membranes, and created a biomimetic membrane based on the Aquaporin Z protein extracted from E. coli bacteria. A biomimetic compound is one that mimics the behavior of a biological system.

“We took a close look at how kidneys so efficiently transport water through a membrane with aquaporins, and then we found a way to duplicate that in a synthetic system,” said Manish Kumar, a graduate research assistant at the U. of I., and the paper’s lead author in a press release from Illinois.

The researchers created the biomimetic membrane by using a polymer permeable to water, and before they could close into a vesicle, inserting and encapsulating the Aquaporin Z.

Another potential use for the new polymer is for drug transport, since it only selectively permits compounds to pass through. “By varying the amount of Aquaporin Z, we can vary the membrane’s permeability,” Kumar said, “which could be very useful for drug-delivery applications.”

One of the advantages that the biomimetic polymer has over biological membranes is strength and durability. Both features are critical for the potential use in water purification and desalinization, in which significant pressures are applied to current reverse-osmosis filters in order to purify water at a usable rate.

Currently the membranes only exist as microscopic vesicles, and additional work lies ahead to create larger-scale membranes for practical applications. Additional testing and tweaking to the structure of the membrane should also lead to greater control of permeability according to Kumar.

The paper has been accepted for publication in the Proceedings of the National Acadamies of Science, and is scheduled to appear in the Early Online Edition November 30. Co-authors also include research professor Julie Zilles at the U. of I., and chemistry professor Wolfgang Meier and doctoral student Mariusz Grzelakowski, both at the University of Basel in Switzerland.

New Cancer Therapy Being Developed at U of Michigan

A team of researchers at the University of Michigan have announced they have found a new weapon in the fight against cancer, and as a side note shows a need to preserve natural environments.

An interdisciplinary team led by David Sherman and Janet Smith of Michigan’s Life Sciences Institute studies uses for toxins found in and around coral reefs to fight cancer. They were looking how a common family of proteins, found in a broad variety of life, from microorganisms to humans, are made, looking at more than 60 steps necessary for the complex proteins formation.

One of the toxins under close scrutiny is curacin A, derived in 1994 by William Gerwick of the University of California, San Diego from a Caribbean coral-reef cyanobacterium, L. majuscula. Lab studies have shown that curacin A may be effective in treating colon kidney and breast cancer.

What the team found was that the commonly occurring GNAT protein complex, which has long been linked to gene regulation, hormone synthesis, and antibiotic resistance in bacteria, was the important first catalyst in the synthesis of curacin A. Sherman’s team published the blueprint for the steps in synthesizing curacin A in 2004, but until now did not understand the purpose of GNAT in that process.

With the methods derived from the research, the team is hopefully it will be able to more rapidly reverse engineer the processes organisms have evolved over the ages, and also find ways to tweak the naturally occurring substances so they are even more effective in fighting cancer.

"It's a totally new function for these GNAT enzymes," Sherman said in a press release from the University of Michigan. "Decoding these biosynthetic pathways is like trying to understand a series of hieroglyphics," he said. "And this GNAT discovery is like finding the Rosetta stone."

Another issue that this research brings into the spotlight is the fast-dwindling reef habitats in which these drugs are being discovered. One of the most famous compounds derived from research into marine toxins is AZT, used in the treatment of HIV and AIDS.

Mark Spalding, lead author of the United Nation’s atlas of coral reefs told the BBC in 2001 that “Less than 10% of an estimated 1-2 million reef species have been identified.” Researchers looking at medical uses of compounds found in coral reefs have so far located a dozen that are in clinical or pre-clinical trials.

The group’s finding was published in the journal Science on November 9.