A review: Research progress of SERS-based sensors for agricultural applications

Surface-enhanced Raman scattering/spectroscopy (SERS) is now being extensively employed as a non-destructive and highly sensitive analytical tool, especially in the detection of various trace chemicals. With the increasing demand for online food quality and safety inspection, SERS has also attracted more and more attention in agricultural applications, including quality assessment of agricultural products, monitoring of crop growth, screening of plant seeds, as well as safety control of varieties of food including fruit and vegetable. A comprehensive understanding of the recent progress in both research and application of SERS-based sensors in these aspects is highly required. This review focuses on diversified strategies for fabrication of effective SERS substrates for SERS sensors, including flexible SERS substrates, reusable SERS substrates, selective SERS substrates for specific targets, and microfluidic SERS-based sensors, and also effective solutions to practical tasks from different aspects, with the discussion of features of different SERS-based sensors and their applications in agriculture and related fields. SERS-based sensors provide extraordinary convenience in sample preparation and instrument operation, exhibiting special advantages over many traditional methods in terms of detection throughput, cost, efficiency, universality, automation, and portability. Currently, researchers are striving to develop advanced SERS sensing techniques in agriculture by making use of modern technology, including nanomaterial/nanostructure fabrication, automation, mobile communication, machine learning, and artificial intelligence. We expect that portable and smart/intelligent advanced SERS-based sensors specifically designed for various situations and scenarios of agricultural purposes will be more widely applied in the future.