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Laser‐induced graphene (LIG) is inexpensive, fast, and easy to produce when compared to many other forms of graphene. Within the biosensing field, LIG electrodes are most often produced via infrared (IR) laser irradiation of polyimide sheets. Nevertheless, the usage of ultraviolet (UV) laser to produce LIG provides advantages in terms of sensor miniaturization because of its inherently higher scribing resolution. Yet, studies on the electrochemical performance of UV LIG, its relation with morphological and structural aspects as well as its comparison with IR LIG are still lacking. This work shows that both LIGs present swift electron transfer kinetics constituting excellent electrodes for electroanalysis. Extreme sensitivities of 93 and 58 µA µm−1 cm−2 at physiologically relevant dopamine (DA) concentrations are found for IR and UV LIG, respectively. Such sensitivities and good selectivity are achieved in the presence of physiologically relevant concentrations of ascorbic and uric acids, contrasting to the related literature employing IR LIG where such interferents are below the physiological range. Despite providing lower sensitivity, UV LIG is still an excellent material for DA biosensors, with the above‐mentioned advantages in terms of miniaturization. To our knowledge, these are among the highest sensitivities reported for voltammetric measurement of DA using carbon‐based materials. [ABSTRACT FROM AUTHOR]

Carbon-based electrodes have demonstrated great promise as electrochemical transducers in the development of biosensors. More recently, laser-induced graphene (LIG), a graphene derivative, appears as a great candidate due to its superior electron transfer characteristics, high surface area and simplicity in its synthesis. The continuous interest in the development of cost-effective, more stable and reliable biosensors for glucose detection make them the most studied and explored within the academic and industry community. In this work, the electrochemistry of glucose oxidase (GOx) adsorbed on LIG electrodes is studied in detail. In addition to the well-known electroactivity of free flavin adenine dinucleotide (FAD), the cofactor of GOx, at the expected half-wave potential of −0.490 V vs. Ag/AgCl (1 M KCl), a new well-defined redox pair at 0.155 V is observed and shown to be related to LIG/GOx interaction. A systematic study was undertaken in order to understand the origin of this activity, including scan rate and pH dependence, along with glucose detection tests. Two protons and two electrons are involved in this reaction, which is shown to be sensitive to the concentration of glucose, restraining its origin to the electron transfer from FAD in the active site of GOx to the electrode via direct or mediated by quinone derivatives acting as mediators. [ABSTRACT FROM AUTHOR]