Custom-formulated MWCNT inks for scalable fabrication of flexible screen-printed electrodes

Screen-printing technology enables mass production of disposable electrochemical sensors on diverse substrates, such as ceramic, paper and polymer films. Two fully custom conductive inks-multi-walled carbon nanotube (MWCNT) and MWCNT/Prussian blue (PB)-together with a lab-made Ag paste was formulated for scalable printing of flexible screen-printed electrodes (SPEs) on cellulose and acetate substrates. Prior to printing, the inks were first characterized by scanning electron microscopy/x-ray diffraction/Fourier transform infrared spectroscopy and then optimized for shear-thinning rheology and high conductivity. The resulting SPEs exhibited diffusion-controlled behavior and good reproducibility. As a practical demonstration, SPEs printed on office paper detected bisphenol A in tap water with a limit of detection (LOD) of 0.084µM with a sensitivity of 1.3µA · mM^-1· cm^-2. In addition, SPEs with PB showed a linear amperometric response to H₂O₂with an LOD of 5.3µM (R²of 0.95). These results highlight a low-cost, scalable fabrication strategy for SPEs with applications in environmental monitoring and point-of-care testing, especially in resource-limited settings.