The new implant will return the ability to walk to the paralyzed
Swiss researchers from the Federal Polytechnic School of Lausanne managed to restore the ability to walk to rats with spinal injuries using a combination of electrical and chemical stimuli. The application of this technique in clinical practice implies the introduction of multifunctional implants into the human body, which could be on the surface of the spinal cord for a long time without causing irritation and tissue damage.
This became possible thanks to the e-Dura implant developed by the authors, which is a small device capable of simultaneously emitting electrical impulses and releasing pharmacological preparations. At the same time, its mechanical properties practically do not differ from the mechanical properties of living tissue.
According to the developers, they managed to overcome the barrier that suspended progress in the development of so-called "surface implants". Earlier versions of such devices could not be located directly on the surface of the brain or spinal cord for a long time under the protective shell of the nervous system, known as the dura mater (Latin dura mater). When moving or stretching the nervous tissue, it rubbed against solid devices, which led to the development of inflammation, scar formation and rejection. The flexibility and extensibility of the new implant minimizes all these undesirable manifestations.
The researchers tested a prototype device on paralyzed rats by implanting it under the dura mater of the spinal cord of animals. A rehabilitation protocol consisting in the combined effects of electrical and chemical stimulation was applied to the rats. The results demonstrated not only the biocompatibility of the implant, which did not cause any adverse reactions for two months, but also its ability to restore the animals' ability to walk after several weeks of training.
The e-Dura implant is a very complex device. Its creation became possible thanks to the joint work of specialists in various fields, including materials science, electronics, neuroscience, medicine and programming.
The implant base made of silicon oxide is covered with stretchable electrodes. Their elasticity is provided by notches on strips of gold with the addition of an innovative composite material, which includes microgranules of silicon oxide and platinum. Such electrodes can deform in any direction while maintaining optimal electrical conductivity. And finally, microfluidic channels penetrating the implant ensure the delivery and release of pharmacological drugs – in this case, neurotransmitters – that resuscitate damaged nerve cells.
The e-Dura implant can also be used to monitor brain-generated electrical impulses in real time. During the experiments, the researchers were able to register the intentions of animals with a high degree of accuracy before they were embodied in movements.
The developers believe that the potential application of the new implant is huge. For example, it can be used for epilepsy, Parkinson's disease, as well as in the treatment of chronic pain. The researchers plan to start conducting clinical trials of e-Dura in the foreseeable future and prepare for the commercialization of the device.
Article by Ivan R. Minev et al. Electronic dura mater for long-term multimodal neural interfaces is published in the journal Science.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of Ecole Polytechnique Federale de Lausanne:
Neuroprosthetics for paralysis: an new implant on the spinal cord.
14.01.2015