Circular compartmentalized microfluidic platform: Study of axon-glia interactions.

We describe a compartmentalized circular microfluidic platform that enables directed cell placement within defined microenvironments for the study of axon-glia interactions. The multi-compartment platform consists of independent units of radial microchannel arrays that fluidically isolate somal from axonal compartments. Fluidic access ports punched near the microchannels allow for direct pipetting of cells into the device. Adjacent somal or axonal compartments can be readily merged so that independent groups of neurons or axons can be maintained in either separate or uniform microenvironments. We demonstrate three distinct modes of directed cell placement in this device, to suit varying experimental needs for the study of axon-glia interactions: (1) centrifugation of the circular platform can result in a two-fold increase in axonal throughput in microchannels and provides a new technique to establish axon-glia interactions; (2) microstencils can be utilized to directly place glial cells within areas of interest; and (3) intimate axon-glia co-culture can be attained via standard pipetting techniques. We take advantage of this microfluidic platform to demonstrate a two-fold preferential accumulation of microglia specifically near injured CNS axons, an event implicated in the maintenance and progression of a number of chronic neuroinflammatory and neurodegenerative diseases.