MIT engineers develop mircrofluidic
chip that’s bridging the gap between nerves and muscles
Orange County, CA - August 15th 2016 - Researchers have been finding ways to stimulate the neuromuscular junction, where nerve and muscle meet, since the 70’s, but in unnatural laboratory environments. The goal of MIT engineers was to make this connection in an environment less like a Petri dish and more like the human body. That means a complex, three-dimensional environment, sometimes dived by large distances.
The chip itself is small and filled with millimeter-sized compartments that act as a natural separation between the nerve and muscle cells that are placed within in them. Even when separated, the cells are still close enough for continued cell to cell signaling and nutrient supply. The device is then filled with gel to give it three dimensions.
The neurons placed inside of the device were genetically modified to respond to light, a process called optogenetics. When researchers observed that an axon had made a connection, they shined light on the neuron and watched as the muscle contracted. By shining a precise light onto a specific neuron, they are able to stimulate the cells. Spontaneous muscle twitches that happened after light was applied were a confirmation that the α-bungarotoxin added did not alter the contractility of the myocytes.
Using the optogenetics method is much more precise than the previous method of using electrodes, which can stimulate other cells unintentionally because of the small size of the chip. The device can also be used to calculate the mechanical force of the muscle contraction it is creating. By constructing two small, flexible pillars that muscle fiber can wrap around, when the muscle contracts, the pillars squeeze together, creating a displacement that is measurable.
One of the authors, Roger Kamm, said the chip has the ability to act as a testing ground for drugs that treat neuromuscular disorders like amyotrophic lateral sclerosis (ASL). The chip could be customized for each individual patient by taking pluripotent cells from a patient with a neuromuscular disorder and creating a whole system that represents them. The size of the chip will allow the system to be infinitely replicated to implement as many drug and therapy trials possible without putting the actual patient at risk. This will maximize the outcome of finding the best course of action for a specific patient to take.
