Direct Toner Printing: A Versatile Technology for Easy Fabrication of Flexible Miniaturized Electrodes

We reported here three simple, low cost and easy to accomplish strategies for the fabrication of microelectrodes and other conductive patterns using ordinary office laser-printers. In this work, toner patterns were directly printed onto the flexible substrate, acting as a mask to create the intended conductive design. To highlight the versatility of such technology, toner-printed patterns were employed in two diverse ways: one in which the patterned toner had the exact design of the electrode and other employing a reverse toner-printed pattern. The first one was used for the adaptation of the well-known printed circuit board (PCB) fabrication technique, but using direct toner printing (DTP) in an already conductive flexible substrate. The second was employed for the two remaining strategies: one based on the deposition of conductive film, followed by lift-off process; and another based on drop-casting of a conductive ink into the formed toner cavities, followed by thermal cure. As proof-of-concept, all three DTP strategies were used for the fabrication of miniaturized gold electrodes in polyimide substrate, and electrochemical performance of each obtained electrode was evaluated by cyclic voltammetry. Insights about DTP technology, alignment issues, advantages, limitations and resolution of each presented approach were provided. Finally, direct toner printing showed to be a simple, affordable and quite promising technology for the fabrication of low cost point-of-care electrochemical devices using flexible platforms.