Engineering Cortical Networks: An Open Platform for Controlled Human Circuit Formation and Synaptic Analysis In vitro

Neuronal circuits are complex networks formed by specific neuron connections across brain regions. Understanding their development is key to studying circuit-related dysfunctions in brain diseases. Human-induced pluripotent stem cell (iPSC) models aid in this research but lack precise architecture, limiting insights into neuronal interactions and activity-dependent processes. Microfluidic technologies offer structural control but are restricted by closed systems that hinder 3D integration, scalability, and cell retrieval. To address these limitations, we developed an open cortical network platform integrating iPSC-derived cortical neurons with bioengineering techniques. Using a polydimethylsiloxane (PDMS)-based microgroove topography and a cell plating guide, we created neuronal nodes for controlled circuit assembly. This design enables large-scale functional cortical circuits without physical barriers, allowing optogenetic control of neural activity and flexible network modifications, including cellular composition, neurite directionality, and synapse formation. The open design facilitates neuronal material accessibility, supporting multi-level analyses such as proteomics. This platform serves as a powerful tool for investigating neuronal network development and function, offering new opportunities to study both normal and pathological states, including molecular changes linked to connectivity loss in brain diseases.