Small RNAs are a class of non-coding RNA with a length of 20~24 nt that regulate target genes through RNA-RNA interaction. Small RNAs have become a hot spot in the research and development of new drugs due to their wide range of targets and the ability to regulate the expression of pathogenic genes in multiple ways. The research and development of small RNA drugs depend on the acquisition of RNA raw materials. Based on this, three small RNA synthesis methods including chemical synthesis, in vitro transcription and in vivo biosynthesis were summarized. Four small RNA biosynthesis technologies including siRNA expressed by si-RNA-binding protein, rRNA scaffold, tRNA scaffold and modified tRNA scaffold were mainly introduced. It proposed that the use of hybrid tRNA scaffold can produce recombinant small RNA on a large scale by biological fermentation, which has the advantages of high activity, low cost, natural modification and high safety,and provides an alternative source for clinical RNA drug raw materials. In addition, 14 kinds of small RNA drugs approved by the American Food and Drug Administration (FDA) as well as the latest research progress of small RNA drugs in research were summarized. The challenges and future development directions of small RNA drugs were analyzed. This review is helpful to deepen the understanding of small RNA synthesis technology and small RNA drug research progress.

small RNA synthesis; small RNA drugs; RNA therapy; recombinant small RNA