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Archive - Mar 22, 2010

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Nanotech Research May Ultimately Lead to Retinal Implants

Researchers at Tel Aviv University are making progress in work to merge retinal nerve cells with electrodes in the hope of someday being able to create retinal implants for people. But that goal is quite a ways off, said research leader Dr. Yael Hanein. Until then, her team’s current invention might be used by drug developers investigating new compounds or formulations to treat delicate nerve tissues in the brain. "We're working to interface man-made technology with neurons” Dr. Hanein said. "It can be helpful in in vitro and in in vivo applications, and provides an understanding of how neurons work so we can build better devices and drugs," she said. Her group has developed a spaghetti-like mass of nano-sized (one-millionth of a millimeter) carbon tubes, and using an electric current has managed to coax living neurons from the brains of rats to grow on this man-made structure (see image, courtesy of Tel Aviv University). The growth of living cells on the nano substrate is a very complicated process, Dr. Hanein said, but the cells adhere well to the structure, fusing with the synthetic electrical and physical interface. Using the new technology developed in Dr. Hanein's laboratory, graduate student Mark Shein has been observing how neurons communicate and work together. "We are attempting to answer very basic questions in science," Dr. Hanein explained. "Neurons migrate and assemble themselves, and using approaches we've developed, we are now able to 'listen' to the way the neurons fire and communicate with one another using electrical impulses. Listening to neurons 'talking' allows us to answer the most basic questions of how groups of nerves work together. If we can investigate functional neuronal networks in the lab, we can study what can't be seen or heard in the complete brain, where there are too many signals in one place."

Blocking miRNA Might Aid Healing of Chronic Wounds

New results indicate that targeting a specific microRNA (miR-210) with a drug that could be used topically on the skin might offer new strategies for treating chronic wounds, which are sometimes fatal and cost the U.S. health-care system an estimated $25 billion annually. Ohio State University researchers have discovered, in a new animal study, that the presence of miR-210 in wounds with limited blood flow lowers the production of a protein (E2F3) that is needed to encourage skin cells to grow and close over the wound. In a parallel experiment using human skin cells, the researchers silenced the miR-210 with an experimental drug and saw E2F3 protein levels rise. The skin cells multiplied as a result. The research involved wounds that are ischemic, that is, they heal very slowly or are in danger of never healing because they lack blood flow and oxygen at the wound site. These types of wounds affect approximately 6.5 million patients each year, and are common complications of diabetes, high blood pressure, obesity, and other conditions characterized by poor vascular health. "When blood supply is inadequate, many things are deficient at the wound site, including oxygen. That leads to a condition called hypoxia," said Dr. Chandan Sen, senior author of the study. "We have shown that hypoxia induces miR-210, which actually blocks the ability of the cells to proliferate, a step necessary for the wound-closure process.” This research was published online on March 22, 2010 in PNAS. [Press release] [PNAS abstract]