Axons-on-a-Chip for Mimicking Non-Disruptive Diffuse Axonal Injury underlying Traumatic Brain Injury

Diffuse axonal injury (DAI) is the most severe pathological feature of traumatic brain injury. However, how primary axonal injury is induced by mechanical stress and whether it could be mitigated remain unknown, largely due to the resolution limits of medical imaging approaches. Here we established an Axon-on-a-Chip (AoC) model for mimicking DAI and investigating its early cellular responses. By integrating computational fluid dynamics and microfluidic techniques, DAI was observed for the first time during mechanical stress, and a clear correlation between stress intensity and severity of DAI was elucidated. This AoC was further used to investigate the dynamic intracellular changes occurring simultaneously with stress, and identified delayed local Ca2+ surges escorted rapid disruption of periodic axonal cytoskeleton during the early stage of DAI. Compatible with high-resolution live-microscopy, this model hereby provides a versatile system to identify early mechanisms underlying DAI, offering a platform for screening effective treatments to alleviate brain injuries.