Recent progress on biosensors for detection of circulating miRNA biomarkers

Circulating miRNAs are a class of non-coding endogenous RNAs found in body fluids which typically consist of 19-24 nucleotides in length. The abnormal expression of miRNAs has been demonstrated to be associated with severe human diseases. Aiming to provide valuable insights for the further development of reliable miRNA detectors for disease early diagnosis and treatment, this work systematically summarizes the latest advancements in signal amplification strategies for miRNA analysis, based on nanomaterials, nucleic acids, enzymes, and CRISPR/Cas system. The emerging techniques for detecting circulating miRNAs in human body fluids over the past decade are highlighted, including electrochemical, optical, and dual-mode biosensors. Furthermore, the challenges of trace miRNA detection in complex samples and the development prospects of miRNA biosensors are also discussed.