The ability to image and quantify growth properties of axons and dendrites (growth rate, length, fasciculation, retraction etc.) in microfluidic devices is superior over more traditional methods [17,28]. Moreover, microfluidic devices are well suited for studying interactions of neurons with their target cells or with glial cells. Neuron-glia co-culture devices provide means for studying CNS axon-glia interaction, such as neuron-oligodendrocyte signaling during myelination [29]. In a microfluidic neuron-oligodendrocyte coculture device with cell-reservoir immersed electrodes, constant electrical stimulation was shown to increase myelination of axonal segments [30]. Acetylcholine receptor clustering during neuromuscular synaptogenesis was studied using differentiated myotubes and laminar flow of agrin in microfluidic devices [31]. Combination of microfluidic chips with actuators, such as pneumatically or hydraulically controlled valves, for fine control of neuron-to-neuron connectivity provides another interesting approach for studying synaptogenesis in vitro [32].
