Hydrogels as Suitable miRNA Delivery Systems: A Review

The use of miRNA in therapeutics has, since its discovery in 1993, attracted tremendous attention, and research in this area has progressed rapidly. Since the advent of RNA interference (RNAi), much about the nucleic acid siRNA has been elucidated. At the same time, no miRNA-based drugs have passed phase II clinical trials. A significant obstacle to miRNA-based drug development is the ease of degradation and relatively short half-life in vivo of miRNA. Hydrogels are networks of cross-linked polymer chains with the ability to 'swell'. They have shown remarkable capabilities that improve the properties of other researched carriers. In combination with miRNA modification strategies and inorganic carriers, hydrogel systems show promise for sustained miRNA delivery and the development of novel miRNA-based drugs. Although hydrogel systems have been reported recently, the focus has been predominantly on their wound-healing properties, with a dearth of information on their nucleic acid carrier abilities. This paper focuses more on the latest advancements in developing hydrogels as a carrier system, emphasizing the delivery of miRNA. This review will cover the methods of hydrogel fabrication, efforts for sustained miRNA release, biomedical applications, and future prospects.