To realize RNA interference (RNAi) therapeutics, it is necessary to deliver therapeutic RNAs (such as small interfering RNA or siRNA) into cell cytoplasm. A major challenge of RNAi therapeutics is the endosomal entrapment of the delivered siRNA. In this study, we developed a family of delivery vehicles called Janus base nanopieces (NPs). They are rod-shaped nanoparticles formed by bundles of Janus base nanotubes (JBNTs) with RNA cargoes incorporated inside via charge interactions. JBNTs are formed by noncovalent interactions of small molecules consisting of a base component mimicking DNA bases and an amino acid side chain. NPs presented many advantages over conventional delivery materials. NPs efficiently entered cells via macropinocytosis similar to lipid nanoparticles while presenting much better endosomal escape ability than lipid nanoparticles; NPs escaped from endosomes via a “proton sponge” effect similar to cationic polymers while presenting significant lower cytotoxicity compared to polymers and lipids due to their noncovalent structures and DNA-mimicking chemistry. In a proof-of-concept experiment, we have shown that NPs are promising candidates for antiviral delivery applications, which may be used for conditions such as COVID-19 in the future.

Nanotechnology platforms, such as nanoparticles, liposomes, dendrimers, and micelles have been studied extensively for various drug deliveries, to treat or prevent diseases by modulating physiological or pathological processes. The delivery drug molecules range from traditional small molecules to recently developed biologics, such as proteins, peptides, and nucleic acids. Among them, proteins have shown a series of advantages and potential in various therapeutic applications, such as introducing therapeutic proteins due to genetic defects, or used as nanocarriers for anticancer agents to decelerate tumor growth or control metastasis. This review discusses the existing nanoparticle delivery systems, introducing design strategies, advantages of using each system, and possible limitations. Moreover, we will examine the intracellular delivery of different protein therapeutics, such as antibodies, antigens, and gene editing proteins into the host cells to achieve anticancer effects and cancer vaccines. Finally, we explore the current applications of protein delivery in anticancer treatments.

A variety of engineered nanoparticles, including lipid nanoparticles, polymer nanoparticles, gold nanoparticles, and biomimetic nanoparticles, have been studied as delivery vehicles for biomedical applications. When assessing the efficacy of a nanoparticle-based delivery system, in vitro testing with a model delivery system is crucial because it allows for real-time, in situ quantitative transport analysis, which is often difficult with in vivo animal models. The advent of tissue engineering has offered methods to create experimental models that can closely mimic the 3D microenvironment in the human body.

Although co-delivery of small-molecule drugs and siRNAs is a promising platform strategy for combination therapy, current delivery systems fail to achieve efficient endosomal escape, limiting cytosolic siRNA bioavailability and therapeutic efficacy. Conventional lipid nanoparticles (LNPs) can co-encapsulate chemotherapeutics and siRNA, but their poor endosomal escape results in suboptimal siRNA bioavailability. Here, we report a novel type of sphere-like nanoparticle (SNP) platform for co-delivery of siRNA and small-molecule drugs that overcomes these limitations. In this system, doxorubicin (DOX) is intercalated within a Janus base nanotube (JBNt) structure, while siRNA is encapsulated through electrostatic interactions, enabling stable co-packaging. Notably, SNPs exhibit significantly enhanced endosomal escape compared with lipid nanoparticles, leveraging JBNt’s endosomal escape, attributable to its distinct proton-sponge-mediated buffer capacity, consequently promoting efficient, coordinated cytosolic delivery of both cargos. In a proof-of-concept study, SNP-mediated co-delivery of Multidrug Resistance 1 gene (MDR1/ABCB1)-targeting siRNA and DOX was associated with effective gene silencing and enhanced apoptosis in cancer cells, tumor spheroids, and murine ovarian tumor xenograft models. Collectively, these findings deliver proof-of-concept evidence for SNPs as a promising co-delivery platform for RNA and chemotherapeutics to overcome chemoresistance and improve anticancer efficacy.