Junyou Wang

Colloidal gels are three-dimensional networks formed by nanoparticles, which have attracted great attention for applications in tissue engineering and regenerative medicine due to their excellent viscoelastic properties. Usually, they are formed by attractive electrostatic interactions between oppositely charged particles. However, high ionic strength of physiological fluids may disrupt the networks by screening electrostatic interactions resulting in gel instability, thereby limiting practical applicability. Herein, we report the fabrication of novel colloidal gels stabilized by host-guest interactions between gelatin nanoparticles functionalized with either β-cyclodextrin or adamantane as building blocks. These host-guest stabilized colloidal gels exhibit repeatable self-healing capability (∼100%) in NaCl solutions of high ionic strength similar to physiological fluids (150 mM), surfactant solutions and cell culture medium. Furthermore, these gels are cytocompatible and promote proliferation and migration of HUVECs and L929 cells. Consequently, this work provides a promising new strategy for extending biomedical applicability of colloidal gels.

Cationic nanogels are efficient polymeric vectors for siRNA delivery but often raise toxicity concerns. To address this efficacy-toxicity trade-off, we present a charge-mixed nanogel platform that reconciles high delivery potency with excellent biocompatibility. Specifically, a library of cationic nanogels was synthesized with precise control over charge composition, size, and cross-linking degree, enabling systematic investigation of their effects on delivery performance and toxicity. Our findings reveal that delivery efficiency is cooperatively modulated by charge, size, and cross-linking degree, whereas toxicity reduction is primarily achieved by diluting the positive charge density through incorporation of anionic units. The established structure-activity relationship identified an optimal formulation comprising 80% cationic and 20% anionic monomers, with a hydrodynamic radius of approximately 83 nm and a cross-linking degree of 20% using a disulfide-based cross-linker. This design enables intracellular glutathione-responsive dissociation and efficient siRNA release. The engineered charge-mixed nanogels demonstrate potent gene silencing (83.0%) and antitumor efficacy (84.3%), alongside notably reduced cellular and systemic toxicity. Collectively, this work provides rational design principles for cationic nanocarriers and establishes a promising vector platform that effectively overcomes the efficacy-toxicity dilemma for advanced siRNA therapeutics.

Restoring the tumor suppressor PTEN (phosphatase and tensin homolog) offers a promising therapeutic strategy for nonsmall cell lung cancer (NSCLC). In particular, mRNA-based therapy provides a compelling alternative to small molecules and DNA-based gene therapy, combining high specificity with an excellent safety profile. However, its clinical translation hinges on the development of safe and efficient delivery systems. In this study, we present a rationally designed diblock copolymer that mediates highly effective PTEN mRNA delivery both in vitro and in vivo. The copolymer consists of a stealth PEG block and a cationic binding block, with precisely engineered 3-acrylamidophenylboronic acid (AAPBA) and N-(3-dimethylaminopropyl) methacrylamide (DMAPMA) units. Following optimization of the PEG chain length, the structure PEG45-b-P(AAPBA21-co-DMAPMA18) achieved a critical balance of delivery properties, leading to enhanced cellular uptake, facilitated endosomal escape, and enabled mRNA release for protein translation. When further functionalized with folic acid (FA), the copolymer successfully restored PTEN expression and inhibited tumor growth (81.0% relative to the PBS control group) in vivo, with no significant toxicity observed under the tested conditions. We anticipate that this block copolymer-based PTEN mRNA delivery platform could provide a promising new approach for the treatment of NSCLC.

Polyion complex (PIC) vesicles represent a promising platform for protein therapeutics delivery, yet balancing extracellular stability with intracellular degradability remains challenging. Herein, we present a ligand-engineering strategy to fabricate dual-functional PIC vesicles. The design centers on a disulfide bridged bis-dipicolinic acid ligand, L₂(S-S), which chelates with Gd³⁺ at a stoichiometric ratio of 1:3 to form anionic branched coordination polymers. These polymers coassemble with cationic PEG₁₁₃-b-PMETAC₇₃ diblock copolymers, creating uniform vesicles capable of in situ protein loading while preserving their structure and bioactivity. The branched architecture ensures extracellular stability of the vesicle and effective cargo shielding. However, upon cellular internalization, the high intracellular glutathione concentration triggers the reductive cleavage of disulfide bonds, leading to rapid polymer degradation, vesicle disassembly, and subsequent cytoplasmic protein release. Notably, while both GSH-responsive and nonresponsive vesicles facilitated efficient cytosolic delivery, only the degradable vesicles induced significant tumor suppression, underscoring the critical role of cytoplasmic protein release for therapeutic efficacy. This ligand-engineering approach resolves the stability-degradability paradox and provides a general design principle for intelligent protein delivery systems.

Cationic polymers, while widely used for therapeutic delivery of biomacromolecules, are constrained by a fundamental trade-off between efficacy and cytotoxicity. We report a mixed anionic-cationic nanogel platform that overcomes this limitation through cooperative regulation of charge and structure. By copolymerizing cationic and anionic monomers at programmed ratios, we precisely tune the net positive charge, substantially reducing toxicity without compromising delivery efficiency. The cross-linked network of the nanogel provides a stable yet open architecture, enabling siRNA loading both on interior and surface sites. When a nanogel particle is loaded with siRNA, deposition of serum proteins occurs largely on its surface, thereby both preserving the integrity of the encapsulated siRNA and maintaining the colloidal stability of the delivery vehicle. To ensure intracellular release of RNA, we incorporate redox-responsive cross-linkers that trigger nanogel disassembly in the reducing cytosolic environment. This dual charge-and-structure engineering strategy enables effective siRNA delivery with minimized adverse effects, and can be generalized to other charge-mixed systems and macromolecular cargoes. Our work thus provides a versatile solution to a long-standing challenge in cationic vector design, with broad implications for therapeutic nucleic acid delivery.

Cationic polymers have been applied widely for siRNA delivery, yet most of the conventional linear or branched polymers make RNA polyplexes with poor serum stability and low delivery efficacy. We here propose cationic nanogels as a better alternative and demonstrate their advantages for siRNA delivery. Using a recently developed electrostatic-templated polymerization method, we synthesized a series of cationic nanogels with precisely controlled chemical composition, size, and cross-linking degree, enabling the systematic exploration of structure-performance relationships for nanogel-mediated siRNA delivery. We show that the nanogels, with their stable 3D structure, offer both surface and interior sites for siRNA loading depending on the N/P ratio. At high N/P ratios, siRNA binds primarily to the interior sites of the nanogels, which provide enhanced protection against competing serum proteins and facilitate efficient cellular uptake. Furthermore, the chemical composition, size, and degree of cross-linking of the nanogels cooperatively influence siRNA loading and cellular uptake. The optimal formulation, poly(vinylbenzyl trimethylammonium chloride) (PVBTMA) nanogel, incorporates a strong charge group and a hydrophobic phenyl spacer that facilitate siRNA loading and cellular uptake, respectively. With an optimal size of 107 nm and 5% cross-linking, PVBTMA nanogel achieves superior siRNA internalization compared to widely used transfection agents like Lipofectamine 3000 and branched PEI_25k. Finally, when loaded with tumor-specific gene silencer siPLK1, the PVBTMA nanogel facilitates superior gene silencing in vitro and effectively inhibits tumor growth in vivo. Our findings clarify the distinct advantages of cationic nanogels as carriers for siRNA delivery and highlight their promising potential for therapeutic applications.