Near-field electrospinning (NFES) technique and charges. The IBS team achieved precise control of the layer-by-layer nanofiber deposition by just adding salt to the polymer solution. Optical images of the 3D printed nanofibers were prepared with solutions made of: (i) only polymer poly(ethylene oxide) (PEO), (ii) PEO and salt and using a conducting platform, and (iii) PEO and salt using an insulating platform. In (i), the nanostructure is not well aligned, because the deposited fibers have a weak positive surface charge, but adding salt increases the conductivity of the starting solution and the attraction between the nanofiber jet and the deposited fibers. An insulating plate made of silica reduced the effect, confirming the hypothesis. Thanks to this technique, IBS researchers constructed nanowalls with the desired height and number of layers.