Emerging Sensing and In Situ Detection Technologies for the Analysis of Extracellular Vesicle miRNAs

Liquid biopsy has received increasing attention as a new disease detection modality because of its noninvasive, simple sampling, and reproducible assay advantages. Among the markers of liquid biopsy, extracellular vesicles (EVs) are considered as promising disease biomarkers because they contain a large amount of biological information and have a significant role in physiological activities. The emergence and progression of some of these diseases are associated with miRNAs carried by EVs (EV‐miRNAs). Therefore, high‐sensitive detection of EV‐miRNAs is essential in clinical applications. A growing number of strategies, including biosensors, in situ detection methods, and microfluidics have been developed for the detection of EV‐miRNA and have been applied in the diagnosis of diseases such as cancer. This review summarizes the probes, signal amplification, and detection methods for EV‐miRNA detection, as well as the application of membrane fusion‐based in situ detection and integrated microfluidic chips for EV‐miRNA detection. The challenges of these materials and techniques in clinical diagnostic applications are also discussed.