In recent years, various human implantable medical devices used in the clinical field have been developed. These devices include brain-machine interfaces, where a chip is implanted in the brain so people can move machines with just their thoughts, and deep brain stimulators, used to treat Parkinson’s disease and other brain disorders. However, devices implanted in the human body can provoke an immune response from surrounding tissues, and the resulting degradation in performance makes these devices difficult to use for long periods of time. If a deep brain stimulator or chip is implanted in the brain, the device may not function stably and its lifespan may be shortened due to the action of the brain’s immune cells such as microglia. This would require an additional operation to replace the device.
The Korea Institute of Science and Technology (KIST) announced a joint research effort by the research team at the Brain Science Institute, led by Dr. Il-Joo Cho and the Yonsei University research team led by Dr. Jung-Mok Seo. to develop coating technology for medical devices that will be implanted in the human body, including the brain. This technology was able to minimize tissue damage during the implantation process and inhibit the inflammatory response. In addition, the lifetime of coated devices was more than four times that of existing devices.
The technology developed includes a method of creating a thin and uniform coating of a monolayer and lubricating oil on the surface of the implantable devices. Such a coating minimizes tissue damage by reducing the friction between a device and tissue that is created when the device is implanted in the human body. In addition, coated devices have the anti-bioadhesion property, ie the prevention of the adhesion of immune cells which are activated by the immune rejection reaction on the device surface.
The research team developed a lubricant-coated nerve probe with 32 electrodes for measuring brain signals and demonstrated the reduction of immune reactions in in vivo experiments. This probe was coated with the developed technology and implanted in the rodent brain. Brain signals were successfully observed from over 90% of the electrodes immediately after implantation. The number of signals was twice that obtained with uncoated neural probes. In addition, the observation of brain tissue confirmed that the tissue damage that generally occurs during implantation was minimized. The signal amplitude of uncoated probes decreased over time due to the adhesion of immune cells to the probe surface. In contrast, the coated probe showed the anti-bioadhesive property. It stably measured brain signals for four months, four times the life of uncoated probes.
Dr. Cho and Dr. Seo stated that “the coating technology developed on human implantable devices can be applied not only to the brain but also to other parts of the body, and the technology can significantly extend the life of such devices.” In addition, they said that “this technology should also contribute to faster commercialization by significantly increasing the replacement cycle of implantable medical devices for humans.”
Source:
National Research Council for Science and Technology
Journal reference:
Lee, Y., et al. (2021) A Lubricated Non-Immunogenic Neural Probe for Minimizing Acute Insertion Trauma and Long-Term Signal Recording. Advanced science. doi.org/10.1002/advs.202100231.
