Application of implantable wireless biomicrosystem for monitoring nerve impedance of rat after sciatic nerve injury.
Electrical stimulation is usually applied percutaneously for facilitating peripheral nerve regeneration. However, few studies have conducted long-term monitoring of the condition of nerve regeneration. This study implements an implantable biomicrosystem for inducing pulse current for aiding nerve repair and monitoring the time-course changes of nerve impedance for assessing nerve regeneration in sciatic nerve injury rat model. For long-term implantation, a transcutaneous magnetic coupling technique is adopted for power and data transmission. For in vivo study, the implanted module was placed in the rat's abdomen and the cuff electrode was wrapped around an 8-mm sciatic nerve gap of the rat for nerve impedance measurement for 42 days. One group of animals received monophasic constant current via the cuff electrode and a second group had no stimulation between days 8-21. The nerve impedance increased to above 150% of the initial value in the nerve regeneration groups with and without stimulation whereas the group with no nerve regeneration increased to only 113% at day 42. The impedance increase in nerve regeneration groups can be observed before evident functional recovery. Also, the nerve regeneration group that received electrical stimulation had relatively higher myelinated fiber density than that of no stimulation group, 20686 versus 11417 fiber/mm   (2). The developed implantable biomicrosystem is proven to be a useful experimental tool for long-term stimulation in aiding nerve fiber growth as well as impedance assessment for understanding the time-course changes of nerve regeneration.
Department of Biomedical Engineering, National Cheng Kung University, Tainan 701, Taiwan.
Yu-Ting
YT
Li
Chih-Wei
CW
Peng
Lung-Tai
LT
Chen
Wen-Shan
WS
Lin
Chun-Hsun
CH
Chu
Jia-Jin Jason
JJ
Chen
D000818:Animals; D004567:Electrodes, Implanted; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008297:Male; D008904:Miniaturization; D018670:Monitoring, Ambulatory / Q000295:instrumentation*; D010992:Plethysmography, Impedance / Q000295:instrumentation*; D019736:Prostheses and Implants; D051381:Rats; D017208:Rats, Wistar; D020426:Sciatic Neuropathy / Q000175:diagnosis* / Q000503:physiopathology*; D013686:Telemetry / Q000295:instrumentation*