Single neuron capture and axonal development in three-dimensional microscale hydrogels

Autapse is an unusual type of synapse generated by a neuron on itself. The ability to monitor axonal growth of single neurons and autapse formation in three-dimensions (3D) may provide fundamental information relating to many cellular processes, such as axonal development, synaptic plasticity and neural signal transmission. However, monitoring such growth is technically challenging due to the requirement for precise capture and long-term analysis of single neurons in 3D. Herein, we present a simple two-step photolithography method to efficiently capture single cells in microscale gelatin methacrylate hydrogel rings. We applied this method to capture and culture single neurons. The results demonstrated that neural axons grew and consequently formed axonal circles, indicating that our method could be an enabling tool to analyze axonal development and autapse formation. This method holds great potential for impact in multiple areas, such as neuroscience, cancer biology, and stem cell biology.