**4. Conclusions**

An ideal method for detecting intracellular miRNA should possess high throughput, high specificity, high detection sensitivity, wide detection range, and low detection cost. To achieve this goal, a variety of miRNA detection methods have been developed, but there are many shortcomings, and the technology needs to be improved. The additionally introduced nanomaterials is self-aggregated and enriched in different tissues in a complex living environment. Hybridization probe assay lacks signal amplification capabilities. SDA, HCR, and CHA need to avoid high background signal caused by probe leakage. DNAzyme-mediated assays usually require exogenous cofactors to initiate signal amplification. Therefore, EDC and CRISPR-mediated assays are the most promising detection methods of miRNA *in vivo* in the future. The establishment of an ideal miRNA detection technology still needs the efforts of scientists and the continuous progress of related science and technology.
