Abstract
Abstract A typical neuron consists of a cell body (soma), dendrites, and an axon. Axon is a long process extending from soma of a neuron and plays important roles in establishing the neuron-target connection and signal transmission. On the other hand, due to their limited capability of regeneration, injury to the axons of central neurons frequently leads to incurable neural disorders, such as spinal injury. Here, we have developed a compartmentalized device by using a composite membrane consisting of a PCTE (polycarbonate) and PDMS (polydimethylsiloxane) membrane and various protein components. The PCTE membrane is ~8 µm in thickness and contains pores of an average diameter of 1μm. Placed underneath the PCTE membrane is a layer of PDMS of 500 μm in thickness and contains holes of 100 µm in diameter that open to the two surfaces. The PCTE membrane is coated with poly-L-lysine, the the holes of PDMS membrane are filled with ECM (Extracellular matrix) plus laminin. This composite membrane is placed between two chambers. Cells dissociated from rat embryonic hippocampi are then plated onto the PCTE membrane. After ~ 2 weeks in vitro, the cell bodies and glial cells remain on the surface of PCTE membrane, and only axons can penetrate through the composite membrane to the opposite side. The advantages of this device include (1) the diffusion of small molecules across this composite membrane is limited, (2) the axons on the PDMS side of the composite membrane could be observed continuously under microscopy, and (3) a second population of cells can be grown on the PDMS membrane surface. This device could be used for the high-throughput screening for drugs affecting (1) synaptogensis, (2) axonal growth and (3) axon regeneration. This device could also be used to study the molecular basis of synaptogenesis, synaptic regulation and trafficking in axons.