Digitally Controlled Procedure for Assembling Fully Drawn Paper-Based Electroanalytical Platforms

A simple, reliable, and low-cost fabrication method is proposed here for assembling paper-based electrochemical devices (PEDs) using a commercial desktop digitally controlled plotter/cutter, together with ordinary writing tools. Permanent markers (tips of 1 mm) were used to create effective hydrophobic barriers on paper, while micromechanical pencils (mounting 4B graphite leads, 0.5 mm in diameter) were adopted for automatically drawn precise reference, counter, and working carbon electrodes. Fabrication parameters, such as writing pressure and speed, were first optimized, and the electrochemical performance of these devices was then evaluated by using potassium hexacyanoferrate(II) as redox probe. The good interdevice reproducibility (4.8%) displayed by the relevant voltammetric responses confirmed that this strategy can be profitably adopted to easily assemble paper-based electrochemical devices in a highly flexible manner. The simplicity of the instrumentation used and the low cost of each single device (about $0.04), together with the speed of fabrication (about 2 min), are other important features of the proposed strategy. Finally, to confirm the effectiveness of this prototyping method for the analysis of real samples and rapid controls, PEDs assembled by this simple approach were successfully exploited for the analysis of vitamin B₆ in food supplements.