A review of printed electrochemical sensors for pesticide sensing applications

An electrochemical sensor (ECS) is one that converts the electrode-analyte interaction/chemical reaction events into detectable electrochemical signals that can be exploited for analyte detection. This review paper provides a perspective on electrochemical sensors for pesticide detection through a comprehensive literature study on diverse pesticide classes for different environmental contexts. Moreover, this review covers the fundamental working principles of ECS and their performance efficacy in terms of parameters such as sensitivity, selectivity, and practical utility. It also presents different sensing strategies incorporated with ECS for pesticide detection, with a particular focus on printed ECS and the various printing techniques in use for their fabrication. The review also discusses a wide range of active/functional nanomaterials used either directly as printed electrodes or deposited onto conventional electrodes. The printed sensors and sensor arrays provide the promise of the handling of small analyte volumes (from a few microlitres or less), which increases detection sensitivity due to a higher surface-to-volume ratio. The integration of printed electrodes with optical transparency and flexibility of both the electrodes and the substrates has resulted in the development of printed transparent flexible ECS (PTFECS). The development of ECS in the areas of electrode composition, printing-based fabrication, flexible/rigid geometry, surface modification type, and electrode optical transparency is paving the way for efficient pesticide detection and environmental monitoring. Moreover, their applications in environmental monitoring and food safety are addressing the UN’s 2030 Sustainable Development Goals to enhance lives. The review also provides future directions, especially towards the development of PTFECS and its applications.