Directional Growth of Human Neuronal Axons in a Microfluidic Device with Nanotopography on Azobenzene-Based Material

Axonal dysfunction and degeneration are important pathological features of central nervous system (CNS) diseases and traumas, such as Alzheimer's disease, traumatic brain injury, ischemic stroke and spinal cord injury. Engineered microfluidic chips combined with human pluripotent stem cell (hPSC)-derived neurons provide valuable tools for targeted in vitro research on axons to improve understanding of disease mechanisms and enhance drug development. Here, a polydimethylsiloxane (PDMS) microfluidic chip integrated with a light patterned substrate is utilized to achieve both isolated and unidirectional axonal growth of hPSC-derived neurons. The isolation of axons from somas and dendrites and robust axonal outgrowth to adjacent, axonal compartment, is achieved by optimized cross-sectional area and length of PDMS microtunnels in the microfluidic device. In the axonal compartment, the photoinscribed nanotopography on a thin film of azobenzene-containing molecular glass efficiently guides the growth of axons. Integration of nanotopographic patterns with a compartmentalized microfluidic chip creates a human neuron-based model that supports superior axonal alignment in an isolated microenvironment. The practical utility of the chip by studying oxygen-glucose deprivation-induced damage for the isolated and aligned axons is demonstrated here. The created chip model represents a sophisticated platform and a novel tool for enhanced and long-term axon-targeted in vitro studies.