This work presents a novel procedure involving the sequential chemical treatment to generate reduced graphene oxide (rGO) within 3D-printed polylactic acid (PLA) electrodes and their potential applications for sensing and biosensing. A new configuration of a compact all-3D-printed electrochemical device containing the three electrodes is presented, in which the working electrode was treated to generate rGO within PLA (rGO-PLA) after treatment within NaBH4. The rGO-PLA electrodes presented a notable current increase for the redox probe ferrocene-methanol in comparison with the same surface treated by dimethylformamide immersion. Also, the electrochemical impedance spectroscopic data that presented the lowest resistance to electron transfer for the proposed electrode. The electrochemical experiments were in accordance with Raman spectra and surface roughness obtained by atomic force microscopy images. As proofs-of-concept, the rGO-PLA electrode was applied for serotonin determination in synthetic urine using differential-pulse voltammetry with a limit of detection of 0.032 μmol L-1. Also, the second application involved the fabrication of a tyrosinase-based biosensor capable of determining catechol in natural water samples with a limit of detection of 0.26 μmol L-1. Based on both applications, the 3D-printed rGO-PLA showed to be an excellent platform for sensing and biosensing purposes.
Keywords: 3D-electrodes; Biosensor; Phenol; Reduced graphene oxide.
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