Impedimetric aptasensors: Emerging tools for sensitive detection in health, food, and environmental monitoring

Electrochemical impedance spectroscopy (EIS)-based aptasensors combine the high selectivity of aptamers as biorecognition elements with the label-free, sensitive, and noninvasive measurement capabilities of EIS. Owing to these features, they have recently attracted considerable attention, offering a wide range of applications from the early diagnosis of numerous biomarkers in the field of healthcare to food safety and environmental analysis. In this review, the fundamental principles of impedimetric aptasensors are discussed, and studies published over the last two years in the fields of health, food, and environment are comprehensively examined. In this context, recent original research on the development of aptasensors for the detection of various analytes including cancer biomarkers, viral and bacterial pathogens, mycotoxins, antibiotic residues, hormones, and heavy metals has been analyzed in detail. Moreover, recent findings supporting the applicability of these aptasensors in complex biological (e.g. serum, plasma, saliva, urine), food (e.g. milk, fruit juice, cereal products), and environmental (e.g. wastewater, river water) sample matrices have been summarized. Additionally, key application-oriented challenges such as optimization of surface chemistry for aptamer immobilization, minimization of matrix effects, sensor surface stability, repeatability/reproducibility, multiplex detection, and integration into portable platforms have been thoroughly discussed. Furthermore, innovative solutions that could facilitate the transition of this technology into clinical and field applications, as well as future perspectives regarding commercialization, have been presented. In this regard, it is emphasized that impedimetric aptasensors possess strong potential not only at the laboratory scale but also as powerful tools for real-world diagnostic and monitoring applications.