Patterning (Electro)chemical Treatment-Free Electrodes with a 3D Printing Pen

A simple fabrication method to make electrochemical sensorsisreported. The electrodes were fabricated with a commercial filamentbased on polylactic acid and carbon black (PLA/CB). They were engineeredwith a three-dimensional (3D) printing pen and poly(methyl methacrylate)template. The optimization parameters included the thickness and diametersof the electrodes. The electrode diameter was restricted by the 3Dprinting pen's nozzle dimension, and larger diameters generatedsmall cracks on the electrode surface, compromising their analyticalsignal. The electrode thickness can increase the electrical resistance,affecting their electrochemical response. The fabrication showed reproducibility(RSD = 4%). The electrode surface was easily renewed by sanding theelectrodes, making them reusable. Additionally, the proposed sensorprovided comparable electrochemical responses over traditional glassycarbon electrodes. Moreover, no (electro)chemical surface treatmentwas required for sensing applications due to the compromise betweenthe thickness and diameters of the electrodes, effectively translatingthe filaments' electrical properties to resulting materials.The electrodes' analytical performance was shown for organicand inorganic species, including paraquat, Pb2+, and caffeicacid. As proof of concept, the analytical applicability was demonstratedfor total polyphenolic quantification in tea samples. Therefore, thiswork provides an alternative to fabricating miniaturized electrodes,bringing valuable insights into PLA/CB 3D-printed sensors and openingpossibilities for designing electrode arrays. Moreover, the proposedelectrodes are promising platforms for paper-based microfluidic systems.

Automated summary

This study proposes a simple fabrication method for electrochemical sensors using a commercial filament based on polylactic acid and carbon black (PLA/CB). The electrodes were engineered using a three-dimensional (3D) printing pen and poly(methyl methacrylate) template. Optimizing parameters such as electrode thickness and diameter were important to ensure analytical signal integrity. The fabricated electrodes exhibited reproducibility, renewability, and comparable electrochemical responses to traditional glassy carbon electrodes, making them promising platforms for sensing applications including polyphenolic quantification in tea samples and designing electrode arrays for paper-based microfluidic systems.