Testing New Drugs With “ALS-On-A-Chip”

There is no cure for amyotrophic lateral sclerosis (ALS), a disease that gradually destroys motor neurons that control muscles and affects nearly 6,000 people in the United States yearly.

Engineers created the first 3-D human tissue model of the interface between motor neurons and muscle fibers on a microfluidic chip, which could help scientists develop and test new drugs. The neurons in the model were created using cells from either healthy subjects or ALS patients, allowing the researchers to test the efficacy of potential drugs.

Decades ago, scientists began developing tissue models of the connections between motor neurons and muscle cells, also known as neuromuscular junctions. However, these were limited to two-dimensional structures that do not fully replicate the tissue’s complex physiology.

Two years ago, they created the first version of their 3-D neuromuscular junction model. The model’s neurons and muscle fibers are housed in a microfluidic chip’s adjacent compartments. When neurons are placed in compartments, they extend long fibers called neurites that eventually attach to muscles, allowing the neurons to control their movement.

The neurons are designed so that the researchers can control their activity with light, a technique known as optogenetics. When the neurons are activated by light, the muscle fibers are wrapped around two flexible pillars, allowing the researchers to measure how much the muscle fibers contract by measuring the displacement of the pillars.

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