posted on 2019-03-15, 18:19authored byJiahui Wang, Hao Wang, Nitish V. Thakor, Chengkuo Lee
Muscle
function loss can result from multiple nervous system diseases
including spinal cord injury (SCI), stroke, and multiple sclerosis
(MS). Electrical muscle stimulation is clinically employed for rehabilitative
and therapeutic purpose and typically requires mA-level stimulation
current. Here, we report electrical muscle stimulation, which is directly
powered by a stacked-layer triboelectric nanogenerator (TENG) through
a flexible multiple-channel intramuscular electrode. This multiple-channel
intramuscular electrode allows mapping of motoneurons that is sparsely
distributed in the muscle tissue and thus enables high efficiency
TENG muscle stimulation, although the short-circuit current of the
TENG is only 35 μA. With a stimulation efficiency matrix, we
find the electrical muscle stimulation efficiency is affected by two
factors, namely, the electrode-motoneuron position, and the stimulation
waveform polarity. To test whether it is a universal phenomenon for
electrical stimulation, we then further investigate with the conventional
square wave current stimulation and confirm that the stimulation efficiency
is also affected by these two factors. Thus, we develop a self-powered
direct muscle stimulation system with a TENG as power source and waveform
generator, and a multiple-channel intramuscular electrode to allow
motoneuron mapping for stimulation efficiency optimization. We believe
such self-powered system could be potentially used for rehabilitative
and therapeutic purpose to treat muscle function loss.