Framework nucleic acids: a promising vehicle for small molecular cargos.

Framework nucleic acids (FNAs), which are a series of self-assembled DNA nanostructures, are highly versatile tools for engineering intelligent molecular delivery vehicles. Owing to their precise and controllable design and construction, excellent programmability and functionality, as well as favorable intercalation between DNA and small molecules, FNAs provide a promising approach for small molecule delivery. This review discusses the advantages, applications, and current challenges of FNAs for the delivery of small molecular cargo. First, the physicochemical and biological properties that make FNAs favorable for the transport of small molecules are introduced. Thereafter, the classification of loaded cargos and the mechanism of combination between small molecules and FNAs are summarized in detail, and recent research on FNA-based delivery systems and their applications are highlighted. Finally, the challenges and prospects of FNA nanocarriers are discussed to advance their exploitation and clinical adoption.