Selective Artificial Neural Network and Stimulation by Targeted Delivery of Neuronal Cells Using Magnetically Controlled Cell-Based Cellbots

Several <i>in vitro</i> neural network models have been developed to mimic neural networks' reconstruction and interconnection to study brain function and related diseases. Traditional manufacturing methods, including two-photon polymerization, have been chosen to build sophisticated microrobots for neuronal cell delivery, but the manufacturing time to make a single microrobot has limited its practical use. Here we report various magnetically actuated cell-based microrobots (cellbots) for selective neurite alignment, neuronal connections, and/or selective stimulation. A biodegradable spherical gelatin methacrylate (GelMA) microrobot was fabricated in a flow-focusing droplet generator by shearing a mixture of GelMA, photoinitiator, and superparamagnetic iron oxide nanoparticles (SPIONs) with a mixture of oil and surfactant. Human turbinate stem cells (hNTSCs) were loaded onto the GelMA microrobot, and the hNTSC-loaded microrobot exhibited a precise rolling motion in response to an external rotating magnetic field. The microrobot was enzymatically degraded by collagenase and released hNTSCs proliferated and differentiated into neuronal cells. A stamping magnetoelectric microrobot (SMM) composed of neuron-like cell spheroids loaded with magnetoelectric nanoparticles will be also presented. The SMM allows for effective targeted delivery of cells to multiple target areas (via minimally invasive stamping with magnetic actuation) to facilitate selective neuronal differentiation through magnetoelectric (ME) stimulation. The SMMs were made using SH-SY5Y cells, and magnetoelectric nanoparticles for ME stimulation reacted to an alternating magnetic field, ensuring targeted cell differentiation. The proposed cellbots show the potential for <i>in vitro</i> cell delivery and neural experiments to understand how neurons communicate in the neural network by actively connecting neural clusters.