Electrochemical synthesis of poly(methylene blue) on PLA-CB conductive 3D printer filament and its electrochemical activity towards the sensitivity of uric acid

The following study describes the electropolymerization of phenothiazine methylene blue (MB) monomer on conductive 3D printer filaments made of polylactic acid doped carbon black (PLA-CB). Poly(methylene blue) (PMB) thin layers were successfully synthesized on PLA-CB electrodes using various electrochemical techniques, including cyclic voltammetry (CV), chronopotentiometry (CP), and chronoamperometry (CA). The threshold values required to initiate the polymerization process were found to be 470 mV and 10 µA.cm ˗2 for the potentiostatic and galvanostatic modes respectively. Afterward, microscopic and spectroscopic characterization by SEM, Raman, as well as, XPS confirmed the successful modification of the PLA-CB surface with a thin layer of saccharin counter ions-doped PMB. The modified electrode PMB/PLA-CB was then tested for its ability as an electrochemical sensor for uric acid. The analysis conducted by cyclic voltammetry and differential pulse voltammetry (DPV) demonstrated a faster rate for electron transfer, consequently, uric acid can be electrochemically oxidized at a high number of active sites. The modified conductive 3D printer filament tested in the present study can be considered a promising sensor, not only for uric acid but also for other analytes contained in pharmaceuticals and biological samples.