title: Microfluidic device for the formation of optically excitable, three-dimensional, compartmentalized motor units.
abstract: Motor units are the fundamental elements responsible for muscle movement. They are formed by lower motor neurons and their muscle targets, synapsed via neuromuscular junctions (NMJs). The loss of NMJs in neurodegenerative disorders (such as amyotrophic lateral sclerosis or spinal muscle atrophy) or as a result of traumatic injuries affects millions of lives each year. Developing in vitro assays that closely recapitulate the physiology of neuromuscular tissues is crucial to understand the formation and maturation of NMJs, as well as to help unravel the mechanisms leading to their degeneration and repair. We present a microfluidic platform designed to coculture myoblast-derived muscle strips and motor neurons differentiated from mouse embryonic stem cells (ESCs) within a three-dimensional (3D) hydrogel. The device geometry mimics the spinal cord-limb physical separation by compartmentalizing the two cell types, which also facilitates the observation of 3D neurite outgrowth and remote muscle innervation. Moreover, the use of compliant pillars as anchors for muscle strips provides a quantitative functional readout of force generation. Finally, photosensitizing the ESC provides a pool of source cells that can be differentiated into optically excitable motor neurons, allowing for spatiodynamic, versatile, and noninvasive in vitro control of the motor units.
authors: Department of Mechanical Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA.
authors: Sebastien G M
authors: SG
authors: Uzel
authors: Department of Biological Engineering, MIT, Cambridge, MA 02139, USA.; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
authors: Randall J
authors: 0000-0002-2914-7052
authors: RJ
authors: Platt
authors: Department of Biology, MIT, Cambridge, MA 02139, USA.
authors: Vidya
authors: V
authors: Subramanian
authors: Department of Biological Engineering, MIT, Cambridge, MA 02139, USA.
authors: Taylor M
authors: TM
authors: Pearl
authors: Department of Biological Engineering, MIT, Cambridge, MA 02139, USA.
authors: Christopher J
authors: 0000-0002-8261-2371
authors: CJ
authors: Rowlands
authors: Department of Mechanical Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA.
authors: Vincent
authors: V
authors: Chan
authors: Department of Biology, MIT, Cambridge, MA 02139, USA.
authors: Laurie A
authors: LA
authors: Boyer
authors: Department of Mechanical Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA.; Department of Biological Engineering, MIT, Cambridge, MA 02139, USA.; BioSystems and Micromechanics (BioSyM) IRG, Singapore-MIT Alliance for Research and Technology, Singapore, Singapore.
authors: Peter T C
authors: PT
authors: So
authors: Department of Mechanical Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA.; Department of Biological Engineering, MIT, Cambridge, MA 02139, USA.; BioSystems and Micromechanics (BioSyM) IRG, Singapore-MIT Alliance for Research and Technology, Singapore, Singapore.
authors: Roger D
authors: RD
authors: Kamm
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques; D002454:Cell Differentiation; D002478:Cells, Cultured; D000075402:Channelrhodopsins; D018920:Coculture Techniques; D015870:Gene Expression; D017930:Genes, Reporter; D066298:In Vitro Techniques; D056656:Lab-On-A-Chip Devices; D051379:Mice; D009046:Motor Neurons / Q000166:cytology / Q000502:physiology*; D000066450:Mouse Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism; D009119:Muscle Contraction / Q000235:genetics; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000502:physiology*; D009469:Neuromuscular Junction / Q000502:physiology*; D023822:Tissue Engineering
chemical_list: D000075402:Channelrhodopsins
keywords: Microfluidics; neuromuscular junctions; optogenetics; tissue engineering