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6 Headlines Implant offers hope for people with spinal injuries At the University of Auckland medical school, Dr Bruce Harland and a small team of PhD students and collaborators have developed a tiny electrical implant, no bigger than the tip of a finger, that is showing promising results in treating spinal cord injury (SCI). There are just over 200 SCIs in New Zealand each year, around four per week. About two-thirds are traumatic, resulting in paraplegia or tetraplegia. And there is no cure. “This is exciting work because it’s close to being something that can be deployed,” says Dr Harland, estimating they are 7 to 10 years away from a human-ready device, which in the world of medical research, is very soon. The bioelectronic implant works by emitting electrical pulses to stimulate damaged nerve cells to regenerate. The idea is not new, but until now, the technology to do it safely did not exist. Electrical treatment for SCI was tried by an American group more than 30 years ago. It had some success, reaching clinical trials in humans. “But it fell over because they put current through large metal electrodes attached to muscle nearby the spinal cord. There was too much risk of toxic by-products or burning the tissue,” says Dr Harland. “Our approach is to use an implant made of a biocompatible material called polyimide. It's a very thin plastic, only eight microns thick. It's like Sellotape but without the sticky bit.” “Tiny electrodes and connecting tracks are spun inside the plastic by our collaborators in Germany.” The electrodes are made from a cutting-edge material called iridium oxide, allowing much safer stimulation. “We position the implant underneath the spine’s protective membrane, so the electrodes sit directly on the spinal cord and deliver very low amplitude current to create an electric field to encourage growth across the injury site.” The Neurological Foundation has funded the project for the past two years, allowing the team to achieve some important breakthroughs in the device’s development. “We’ve successfully implanted the device in rodents without pain or distress and kept it in place for three months. That's the length of time needed if you're going to try regenerative treatment,” Dr Harland says. “We were also the first in the world to record spinal cord electrical activity in an awake and freely moving animal using this device,” Dr Harland adds, an achievement that has sparked worldwide interest. “It allowed us to view spinal neural activity in ways that had never been seen before.” This milestone is hugely significant. It means the device has applications as a diagnostic tool; it could be used to verify improvements after a treatment; or to map the extent of injured tissue. “The recordings are also exciting as they could provide new information about how the spinal cord functions.” While Dr Harland trained as a neuroscientist, the project is based in the School of Pharmacy, where the device is also being tested to deliver drugmolecules directly into the central nervous system. The tiny devices with ENORMOUS POTENTIAL Implantable medical devices are set to revolutionise future treatments for neurological conditions and injuries. Major technological advances in the last two decades, such as new materials, more powerful computers and the miniaturisation of batteries and electronics, has resulted in a surge of medical research projects exploring the potential of implantable devices. These devices have enormous potential to both treat neurological disorders, and record nerve cell activity. And while it takes significant time and money before a wireless device can be safely implanted in a human body, some are moving tantalisingly close to clinical trials. "...the exciting thing about this is it's being done in New Zealand. It's right at the cutting edge of science. Our small team has achieved as much as multi- million-dollar international research consortiums.”