Nucleic acid-based drugs against emerging zoonotic viruses

Hollow Nanomaterials in Advanced Drug Delivery Systems: From Single- to Multiple Shells

Hollow-structured nanomaterials (HSNMs) have attracted increased interest in biomedical fields, owing to their excellent potential as drug delivery systems (DDSs) for clinical applications. Among HSNMs, hollow multi-shelled structures (HoMSs) exhibit properties such as high loading capacity, sequential drug release, and multi-functionalized modification and represent a new class of nanoplatforms for clinical applications. The remarkable properties of HoMS-based DDS can simultaneously satisfy and enhance DDSs for delivering small molecular drugs (e.g., antibiotics, chemotherapy drugs, and imaging agents) and macromolecular drugs (e.g., protein/peptide- and nucleic acid-based drugs). First, the latest research advances in delivering small molecular drugs are summarized and highlight the inherent advantages of HoMS-based DDSs for small molecular drug targeting, combining continuous therapeutic drug delivery and theranostics to optimize the clinical benefit. Meanwhile, the macromolecular drugs DDSs are in the initial development stage and currently offer limited delivery modes. There is a growing need to analyze the deficiency of other HSNMs and integrate the advantages of HSNMs, providing solutions for the safe, stable, and cascade delivery of macromolecular drugs to meet vast treatment requirements. Therefore, the latest advances in HoMS-based DDSs are comprehensively reviewed, mainly focusing on the characteristics, research progress by drug category, and future research prospects.

Nucleolin-targeted Extracellular Vesicles as a Versatile Platform for Biologics Delivery to Breast Cancer

Small interfering RNAs (siRNA)/microRNAs (miRNA) have promising therapeutic potential, yet their clinical application has been hampered by the lack of appropriate delivery systems. Herein, we employed extracellular vesicles (EVs) as a targeted delivery system for small RNAs. EVs are cell-derived small vesicles that participate in cell-to-cell communication for protein and RNA delivery. We used the aptamer AS1411-modified EVs for targeted delivery of siRNA/microRNA to breast cancer tissues. Tumor targeting was facilitated via AS1411 binding to nucleolin, which is highly expressed on the surface membrane of breast cancer cells. This delivery vesicle targeted let-7 miRNA delivery to MDA-MB-231 cells in vitro as confirmed with fluorescent microscopic imaging and flow cytometry. Also, intravenously delivered AS1411-EVs loaded with miRNA let-7 labeled with the fluorescent marker, Cy5, selectively targeted tumor tissues in tumor-bearing mice and inhibited tumor growth. Importantly, the modified EVs were well tolerated and showed no evidence of nonspecific side effects or immune response. Thus, the RNAi nanoplatform is versatile and can deliver siRNA or miRNA to breast cancer cells both in vitro and in vivo. Our results suggest that the AS1411-EVs have a great potential as drug delivery vehicles to treat cancers.