Fig. 2

Schematic representation of a biomaterials-based delivery system. The motor neuron, skeletal muscle, and neuromuscular junction (NMJ) contribute to a complete neuromuscular functional unit. The motor neuron axon branches as it comes into contact with the skeletal muscle to form a single NMJ with each individual muscle fiber. At the motor neuron terminal, Ach is released from the synaptic vesicles into the synaptic cleft where it binds to its receptors in the motor endplate to trigger muscle contraction. Injectable hydrogels with encapsulated stem cells and/or growth factors can be used to achieve controlled release into the area of tissue damage. ACh, acetylcholine; Mito, mitochondrion