Electric field distribution analysis for the design of an electrode system in a 3D neuromuscular junction microfluidic device

Electrical stimulation (ES) highly influences the cellular microenvironment, affecting cell migration, proliferation and differentiation. It also plays a crucial role in tissue engineering to improve the biomechanical properties of the constructs and regenerate the damaged tissues. However, the effects of the ES on the neuromuscular junction (NMJ) are still not fully analyzed. In this context, the development of a specialized microfluidic device combined with an ad-hoc electrical stimulation can allow a better investigation of the NMJ functionality. To this aim, we performed an analysis of the electric field distribution in a 3D neuromuscular junction microfluidic device for the design of several electrode systems. At first, we designed and modeled the 3D microfluidic device in order to promote the formation of the NMJ between neuronal cells and the muscle engineered tissue. Subsequently, with the aim of identifying the optimal electrode configuration able to properly stimulate the neurites, thus enhancing the formation of the NMJ, we performed different simulation tests of the electric field distribution, by varying the electrode type, size, position and applied voltage. Our results revealed that all the tested configurations did not induce an electric field dangerous for the cell vitality. Among these configurations, the one with cylindrical pin of 0.3 mm of radius, placed in the internal position of the neuronal chambers, allowed to obtain the highest electrical field in the zone comprising the neurites.