A new material developed by researchers at the Technion and the University of Chicago is expected to optimize medical treatments and accelerate the use of renewable energies
A new material developed in joint research at the Technion and the University of Chicago paves the way forRehabilitation of damaged nerve tissue and pacing by a light source external to the body. The general concept: the light projected into the body (infrared) will damage the sheet of the new material, and this will activate the damaged nerve tissue or the heart. The research published in Nature Materials was led by Dr. Hami Rotenberg from the Faculty of Biomedical Engineering at the Technion and Prof. Buzhi Tian from the University of Chicago.
Nerve tissues are the biological platform that conducts information between areas of the body. Most of them are found in the two control centers of the central nervous system: the brain and the spinal cord. Branching off from the central nervous system is the peripheral nervous system, which controls many aspects of activity, including muscle activation and the transmission of sensory information.
Damage to the peripheral nervous system can lead to limitations such as paralysis, numbness and chronic pain. Nerve tissues in this system can undergo regeneration, but this is slow and limited. However, certain medical interventions may allow some rehabilitation of them.
One of the solutions for treating damaged nerves is electrical stimulation (stimulation), the effectiveness of which has been demonstrated in many studies. The problem is that this method usually involves performing an invasive procedure that can damage the body's tissues.
The development presented by Dr. Rotenberg Nature Materials may eliminate the use of inserting electrodes. Technion and University of Chicago researchers have produced a new, semi-conducting material in the form of a flexible, ultra-thin sheet that interfaces well with biological tissues. The idea demonstrated in the article is the use of this sheet to wrap the damaged nerve tissue, or in the case of cardiac pacing - wrapping the heart itself. This step will be carried out as part of the analysis that is necessary anyway in case of such injuries.
"Our development is a photovoltaic material, meaning a material that converts light energy into electrical energy that affects the nerve tissue," explains Dr. Rotenberg. "In the article we demonstrate the effectiveness of the new material in two different contexts - Heart rate and activation of the peripheral nervous system . In the context of heart treatments, for example, the use of such a sheet can speed up rehabilitation after surgery and eliminate the use of a temporary electrode inserted into the heart. Since the sheet we developed is made of a silicone-based material, which breaks down in the body without any toxic effect, there is no need for an additional surgical operation to remove it from the body."
The uniqueness of the material developed by the researchers is that it is a very unusual semiconductor, which has a property that is not usually found in a single material: a p-n junction interface, or diode.
Here is a brief explanation: Semiconductors are based on energy gaps that determine their level of conductivity. They are usually made of N-type materials, which contribute an electron to the material, and P-type materials, which take an electron from the material; The connection between the two materials creates an efficient interface called a p-n junction, which is the building block of electronic devices and solar cells.
The connection between the two materials Different It is a very complex technological challenge, hence the importance of the discovery presented in the new article: a diode made only of P-type, and the junction is made of normal silicon, and porous silicon!
Dr. Rotenberg says that the new material was created in an unplanned way. "I accidentally used metal tweezers in the lab that provide iron ions for the process - something I didn't plan would happen. The iron ions were used as a catalyst to create the nano holes on the surface of the silicon."
According to Dr. Rotenberg, the new material is Therapeutic window which allows the medical team to influence the patient's body tissues from the outside. Even outside the medical field, the new development is expected to contribute greatly to various applications, for example in the field of renewable energies. Since renewable energy sources such as the sun are volatile, i.e. they do not operate at constant power throughout the day, energy storage becomes a major challenge in promoting the use of these energies. One of the trends in this context is the production of hydrogen by breaking down water with the power of solar radiation, this is because the hydrogen produced is a storable source of energy. Dr. Rotenberg appreciates and hopes that the new material he developed with his colleagues will accelerate the development of more advanced and efficient solar devices.
In the video: an isolated heart contracting spontaneously. On the wall of the heart you can see the silicon sheet on the right. By projecting light onto the sheet it is possible to change the heart rate in case of a rhythm problem. In a similar way, it is possible to influence limb movements using pulses of light. As mentioned, the intention is to use infrared light that penetrates through the body's tissues, however, in the video, visible (green) light is used to demonstrate the mechanism of action.
