New ‘smart’ material could help tap medical potential of tissue-penetrating light

Scientists at the University of California, San Diego Skaggs School Pharmacy and Pharmaceutical Sciences report development and successful initial testing of the first practical “smart” material to use a form of light that can penetrate four inches into the human body, for use in diagnosing diseases and engineering new human tissues in the lab. They used near-infrared (NIR) light (just beyond what humans can see), which penetrates through the skin and almost four inches into the body. Low-power NIR does not damage body tissues. However, current NIR-responsive smart materials require high-power NIR light, which could damage cells and tissues.

They developed a new smart polymer (plastic). Hit with low-power NIR, the material breaks apart into small pieces that appear to be nontoxic to surrounding tissue. They could put the polymer in an implantable hydrogel, which is a water-containing flexible material used for tissue engineering and drug delivery. A hydrogel with the new polymer could release medications or imaging agents when hit with NIR. “To the best of our knowledge, this is the first example of a polymeric material capable of disassembly into small molecules in response to harmless levels of irradiation,” say the researchers.

A practical "smart" material that may supply the missing link in efforts to medically use a form of light that can penetrate four inches into the human body (credit: University of California, San Diego)

Ref.: Nadezda Fomina, et al., Low Power, Biologically Benign NIR Light Triggers Polymer Disassembly, Macromolecules, 2011; 44 (21): 8590 [DOI: 10.1021/ma201850q]

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‘Wearable robot’ arm improves performance of brain-controlled device

The performance of a brain-machine interface designed to help paralyzed subjects move objects with their thoughts is improved with the addition of a robotic arm that provides sensory feedback, a new study from the University of Chicago finds.

Devices that translate brain activity into the movement of a computer cursor or an external robotic arm have already proven successful in humans. But in these early systems, vision was the only tool a subject could use to help control the motion.

Adding a robot arm that provided kinesthetic information about movement and position in space improved the performance of monkeys using a brain-machine interface in a study published today in The Journal of Neuroscience. Incorporating this sense may improve the design of “wearable robots” to help patients with spinal cord injuries, researchers said.

Aided by a robotic exoskeleton, a monkey can hit the target faster and more directly 

(Hatsopoulos, et al. The Journal of Neuroscience)

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A Terminator-style contact-lens display

Bringing us a step closer to a Terminator-style augmented-reality display, University of Washington engineers have constructed an experimental contact lens with a single-pixel embedded light-emitting diode (LED) and tested it in a rabbit.

The LED lights up when it receives energy from a remote radio frequency transmission, picked up by an antenna around the edge and collected via a silicon power harvesting and radio integrated circuit.

Single-pixel wireless contact lens display (credit: University of Washington/Journal of Micromechanics and Microengineering)

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Awareness in Vegetative Patients

Three brain injury patients diagnosed as being in a vegetative state—meaning they do not respond to their environment—may actually be conscious. Using EEG (electroencephalography) to measure their brain activity, researchers found that the patients could follow simple commands.

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