carbon nanotubes , graphene , graphite , or even nanodiamond derivatives in an amount sufficient to fabricate percolation conductive paths (see Fig. ). Such a procedure makes a 3D printout an attractive electrode material. Moreover, 3DP fits perfectly into the circular economy and integrates emerging Industry 4.0 technologies . This will enable moving away from the concept of waste and the linear take-make-waste model and replacing it with the 6R model based on the principles of reduce, reuse, recycle, recover, redesign, and remanufacture . Since material extrusion is one of the few technologies that supports multi-material 3DP, combining conductive and insulating materials into more complex architectures makes it possible to build electronic components , electrochemical cells , and more. A three-electrode 3DP electrochemical cell (3DPEC) printed using a two-material extruder was presented in the work , where it was used to detect cadmium, lead, uric acid, and midazolam maleate ions. Katseli and his research team created dual-extruder printed systems in which the measurement cell was printed from conductive PLA composite and later on ABS composite . Both devices were used to analyse pharmaceutical and environmental samples. Measuring cells with electrodes produced by other authors in one printing process were used for the detection of dopamine , ascorbic acid , hydrazine oxidation , or ephedrine detection . Li et al.'s freedom to design the shape led to the fabrication of a fully functional 3DP flow cell, used to analyse pharmaceuticals in biological fluids and produced results as good as conventionally used systems.