The novel device is an implant that turns touch into voltage, which is transmitted to healthy sensory nerves in accordance to the amount of pressure given to the device. (Photo credit: Tel Aviv University)
Traumatic peripheral nerve injury (TPNI) is a condition that affects many trauma patients and can lead to lifelong disabilities resulting in a reduced quality of life.
There are currently few options for restoring tactile sensation lost due to TPNI. Surgical nerve reconstruction utilizing allogeneic nerve grafts and nerve conduits is the gold standard solution. Unfortunately, nerve reconstruction can only be performed in certain circumstances, and even then, the success rate is poor.
In a recently published study in ACS Nano, Tel Aviv University researchers outlined how they developed a device they refer to as an integrated tactile triboelectric nanogenerator (TENG-IT), which can restore tactile sensation anywhere in the body damage by TPNI.
The implant is implanted beneath the skin and converts touch into voltage, which is then sent to healthy sensory nerves through cuff electrodes to activate peripheral neurons proportionately to the amount of pressure applied to the device. The implant has a limited number of components and is made of relatively inexpensive materials.
The researchers demonstrated the implants capabilities using rats with blocked distal tibial nerves. Using a Von Frey test, the rat is placed within a plexiglass box with an open bottom, standing on top of the wire mesh. Using a tip, pressure is placed on the rat’s paw from underneath. The maximum force exerted is automatically recorded by an electrical gadget when the rat raises its foot, showing that it has detected the pressure imposed.
The published paper states that the research “shows that the device elicits electrical activity in sensory neurons in vitro, and that the extent of this activity is dependent on the level of tactile pressure applied to the device. We subsequently demonstrate the TENG-IT in vivo, showing that it provides tactile sensation capabilities (as measured by a von Frey test) to rats in which sensation in the hindfoot was blocked through transection of the distal tibial nerve.”
If researched and developed enough, the TENG-IT could potentially provide a way to restore tactile feeling without the use of an external power source, as well as overcome some of the other shortcomings of present prosthetic systems.
“We tested our device on animal models, and the results were very encouraging,” said Dr. Maoz as reported in the university news release. “Next, we want to test the implant on larger models, and at a later stage implant our sensors in the fingers of people who have lost the ability to sense touch. Restoring this ability can significantly improve people’s functioning and quality of life, and more importantly, protect them from danger. People lacking tactile sensation cannot feel if their finger is being crushed, burned or frozen.”
The study was published in ACS Nano on June 17th, 2021.
Abstract. In this work, we propose, fabricate, and demonstrate the use of a triboelectric nanogenerator (TENG) as a relatively simple, self-powered, biocompatible, sensitive, and flexible device for restoring tactile sensation. We show that the device elicits electrical activity in sensory neurons in vitro, and that the extent of this activity is dependent on the level of tactile pressure applied to the device. We subsequently demonstrate the TENG-IT in vivo, showing that it provides tactile sensation capabilities (as measured by a von Frey test) to rats in which sensation in the hindfoot was blocked through transection of the distal tibial nerve. These findings point to the substantial potential of self-powered TENG-based implanted devices as a means of restoring tactile sensation.
Restoring Tactile Sensation Using a Triboelectric Nanogenerator. Iftach Shlomy, Shay Divald, Keshet Tadmor, Yael Leichtmann-Bardoogo, Amir Arami, and Ben M. Maoz ACS Nano Article ASAP DOI: 10.1021/acsnano.0c10141.