Tailoring ultra-flexibility in eco-friendly conductive filaments: The use of polypropylene in the development of a 3D-printed carbon black-based electrochemical sensor

This work presents a new approach for manufacturing flexible conductive filaments using carbon black nanoparticles, polypropylene, and polylactic acid (CB-PP-PLA) to develop ready-to-use 3D printed electrochemical sensors. The filament composition is ideal for producing ultra-flexible filaments due to the presence of polypropylene, eliminating the need for a plasticizer, which allows for easier and more robust sensor printing. The filament manufacturing route is simple and accessible, without the need for solvents or expensive equipment, and can be replicated in laboratories and places with less infrastructure. As a proof of concept, 3D-printed electrochemical sensors derived from the newly developed filament were used to detect quercetin (QCT) in honey samples. The produced conductive CB-PP-PLA filaments and electrodes underwent comprehensive characterization through various morphological, spectroscopic, thermoanalytical, and electrochemical methods. The sensor exhibited a robust response to QCT, demonstrating a linear range of 2.0–80.0 μmol L⁻¹ and a detection limit of 056 μmol L⁻¹. Furthermore, the new method is eco-friendly, with low cost, and it displayed recovery values close to 100 % in analyses of fortified honey samples, indicating the absence of matrix effects.