Figure 1

Three techniques for isolation of axons in neuronal cell culture. (A) The Campenot chamber is a Teflon ring placed on a layer of silicon grease on top of regular cell culture dish or glass coverslip. Dissociated peripheral neurons such as dorsal root ganglion cells are placed in the middle reservoir. NGF placed in the axonal chambers attracts axons to grow through the silicon grease layer while the cell somas are restricted to the middle reservoir. (B) Microfluidic devices are typically microfabricated from PDMS. The two cell reservoirs are connected via microgrooves (typically appr. 3–10 μm width and hight, >450 μm in length). Axons grow through the microgrooves while somas and dendrites are limited in the cell reservoirs. Many types of neurons including central neurons can be grown in microfluidic devices. (C) Individual neurons can be cultured to create directed neuronal networks using the low-melting agar etching technique. Glass coverslip is coated with a 50 nm-thick indium-tin iodide (ITO) layer below the agar. ITO allows highly localized photo-thermal etching of agar with a 1064-nm infrared laser beam. Based on observed initial axon growth, microchannels can be opened to connect individual neurons to form simple networks. The panel C is reproduced from [7].