This image collection depicts the use of biocompatible 3D-printed materials to study the process of myelination, or wrapping of membranes around neuronal axons in the central nervous system, by oligodendrocyte cells. The process of myelination is involved in a myriad of disorders for which no therapies have been successfully developed. Understanding causes and potential treatments of disorders characterized by incomplete myelin production or myelin degeneration are particularly challenging due to a lack of predictive preclinical tools. Using these Artificial Axons, we can stimulate and quantify oligodendrocyte myelination in a well-defined environment that recapitulates key physical, mechanical and chemical properties of central nervous cells and tissues.