IR and UV Laser‐Induced Graphene: Application as Dopamine Electrochemical Sensors

Abstract 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.