Medicine has been tackling the problem of nerve reconstruction and brain
plasticity for many years. These are areas of research in which the latest
advances have given new hope that one day it will be possible to heal lesions
hitherto considered definitive. Recently, researchers have developed a
conductive hydrogel that could help repair certain nerve damage.
Injuries to peripheral nerves -- tissues that transmit bioelectrical signals
from the brain to the rest of the body -- often result in chronic pain,
neurologic disorders, paralysis or disability. Now, researchers have developed
a stretchable conductive hydrogel that could someday be used to repair these
types of nerves when there's damage. They report their results in ACS Nano.
Injuries in which a peripheral nerve has been completely severed, such as a
deep cut from an accident, are difficult to treat. A common strategy, called
autologous nerve transplantation, involves removing a section of peripheral
nerve from elsewhere in the body and sewing it onto the ends of the severed
one.
However, the surgery does not always restore function, and multiple
follow-up surgeries are sometimes needed. Artificial nerve grafts, in
combination with supporting cells, have also been used, but it often takes a
long time for nerves to fully recover. Qun-Dong Shen, Chang-Chun Wang,
Ze-Zhang Zhu and colleagues wanted to develop an effective, fast-acting
treatment that could replace autologous nerve transplantation. For this
purpose, they decided to explore conducting hydrogels -- water-swollen,
biocompatible polymers that can transmit bioelectrical signals.
The researchers prepared a tough but stretchable conductive hydrogel
containing polyaniline and polyacrylamide. The crosslinked polymer had a 3D
microporous network that, once implanted, allowed nerve cells to enter and
adhere, helping restore lost tissue. The team showed that the material could
conduct bioelectrical signals through a damaged sciatic nerve removed from a
toad. Then, they implanted the hydrogel into rats with sciatic nerve
injuries.
Two weeks later, the rats' nerves recovered their bioelectrical properties,
and their walking improved compared with untreated rats. Because the
electricity-conducting properties of the material improve with irradiation
by near-infrared light, which can penetrate tissues, it could be possible to
further enhance nerve conduction and recovery in this way, the researchers
say.
Reference:
Mei Dong, Bo Shi, Dun Liu, Jia-Hao Liu, Di Zhao, Zheng-Hang Yu, Xiao-Quan
Shen, Jia-Min Gan, Ben-long Shi, Yong Qiu, Chang-Chun Wang, Ze-Zhang Zhu,
Qun-Dong Shen. Conductive Hydrogel for a Photothermal-Responsive
Stretchable Artificial Nerve and Coalescing with a Damaged Peripheral
Nerve. ACS Nano, 2020; DOI:
10.1021/acsnano.0c05197