3D Pen: A low-cost and portable tool for manufacture of 3D-printed sensors

3D printing has been revolutionizing the development of electrochemical devices. Here, 3D pens are proposed for sensor manufacturing as a simpler instrumentation than 3D printers (Fused deposition modeling) for the first time. To illustrate this approach, sensors containing a single working electrode and three-electrode-integrated were manufactured using a 3D pen, which extruded a conducive composite of carbon black (CB) and polylactic acid (PLA) inside molds created into a copper board. After polishing and an electrochemical activation (EA) in NaOH solution, the 3D-pen-printed sensors showed electrochemical responses comparable to glassy carbon electrode for model analyzes. The electrode surface (before and after EA) was characterized by scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The manufacture reproducibility of the 3D-pen-printed electrodes was similar to those fabricated in a 3D printer (RSD < 20 % vs 8 %; n = 10). Such sensors are very stable (robust) over time and in acid/basic electrolytes. The analytical feasibility was evaluated for the simultaneous detection of Cd(II) and Pb(II) by anodic stripping voltammetry, paracetamol by batch injection analysis with amperometric detection and ascorbic acid by square wave voltammetry. The cost per device is very low ( < US$ 0.10), once the fabrication requires negligible amounts of conducive filaments and simple apparatus. 3D pen is a promising tool for sensors development in anywhere, due to its portability and low-price (around US$ 15). Moreover, sensors may be developed over common substrates (not 3D-printed), dispensing the acquisition of a 3D printer or the need of knowledge in modeling/slicing softwares.