Advances in In Vitro Models of Neuromuscular Junction: Focusing on Organ‐on‐a‐Chip, Organoids, and Biohybrid Robotics

Abstract

The neuromuscular junction (NMJ) is a peripheral synaptic connection between presynaptic motor neurons and postsynaptic skeletal muscle fibers that enables muscle contraction and voluntary motor movement. Many traumatic, neurodegenerative, and neuroimmunological diseases are classically believed to mainly affect either the neuronal or the muscle side of the NMJ, and treatment options are lacking. Recent advances in novel techniques have helped develop in vitro physiological and pathophysiological models of the NMJ as well as enable precise control and evaluation of its functions. This paper reviews the recent developments in in vitro NMJ models with 2D or 3D cultures, from organ‐on‐a‐chip and organoids to biohybrid robotics. Related derivative techniques are introduced for functional analysis of the NMJ, such as the patch‐clamp technique, microelectrode arrays, calcium imaging, and stimulus methods, particularly optogenetic‐mediated light stimulation, microelectrode‐mediated electrical stimulation, and biochemical stimulation. Finally, the applications of the in vitro NMJ models as disease models or for drug screening related to suitable neuromuscular diseases are summarized and their future development trends and challenges are discussed.

AI-enhanced biomedical micro/nanorobots in microfluidics

“…The simulated in vivo -like conditions of OOC, together with the precise manipulation provided by MNRs, make it possible to perform experiments that closely mimic in vivo scenarios, providing more reliable and physiologically relevant results. 179 Singh et al presented a bacteria-propelled microswimmer utilizing the proactive locomotion and sensory characteristics of bacteria, which facilitated the active transportation and delivery of various cargoes, such as imaging constituents, genetic material, and therapeutics, to living cells. The method also may carry therapeutic gene components to live tissues in in vitro disease model systems ( e.g.…”

Advanced Cellular Models for Rare Disease Study: Exploring Neural, Muscle and Skeletal Organoids

“…All these recent studies highlight the great potential of bioengineered tissues to investigate rare diseases with human platforms, maintaining structural and microenvironment complexity combined with the ease of performing high-throughput experiments, genome editing and drug testing. The field is still largely unexplored and needs improvements in terms of reproducibility, but its potential will be further exploited by technological advancements, from organ biofabrication and drug screening platforms to biosensors and monitoring techniques to be integrated in future organ-on-a-chip systems [129,[153][154][155].…”

Leveraging Biomaterial Platforms to Study Aging-Related Neural and Muscular Degeneration

“…Microfluidic technology is particularly advantageous for the generation of compartmentalized systems, as it allows communication between the pre-and post-synaptic chambers and the production of customized arrangements that better mimic the anatomical characteristics of the NMJ. As previously mentioned, microfluidic platforms have distinctive advantages over other systems with regard to mechanical, biochemical, and electrical stimulation [309,310]. Furthermore, the observation of the nerve impulse transmission is facilitated by the transparency of the materials used in the manufacture of these organon-a-chip platforms [304].…”

“…As demonstrated by Southam et al, the generation of alternative designs allows the replication of the anatomical features of the NMJ [314]. The creation of different designs can also improve the functionality of the model by facilitating cell seeding, as is the case for open-architecture microfluidic chips, or by controlling the culture media composition in different chambers [309,317].…”