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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Fingertip Microscope Can Peek Inside a Moving Animal

An inexpensive microscope about the size of a gumdrop could allow scientists to peer into the inner workings of living, moving animals much more easily. The device is small and light enough—it weighs less than two grams—to be mounted atop a rodent's head, where it can capture the activity of up to 200 individual brain cells as the animal explores its environment. The device could help scientists learn how the brain directs movement.

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Reconstructing Visual Experiences from Brain Activity Evoked by Natural Movies

Using functional Magnetic Resonance Imaging (fMRI) and computational models, UC Berkeley researchers have succeeded in decoding and reconstructing people’s dynamic visual experiences – in this case, watching Hollywood movie trailers.

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An Objective Way to Measure Pain

Researchers found that by pairing functional MRI (fMRI) with a machine-learning algorithm, they could detect specific patterns of brain activity that predicted whether someone was experiencing pain or not.

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Word association with brain scans

In an effort to understand what happens in the brain when a person reads or considers such abstract ideas as love or justice, Princeton researchers have for the first time matched images of brain activity with categories of words related to the concepts a person is thinking about. The results could lead to a better understanding of how people consider meaning and context when reading or thinking.

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