ABSTRACT
The presence of hierarchical suppressive pathways in the immune system combined with poor delivery efficiencies of adjuvants and antigens to antigen-presenting cells are major challenges in developing advanced vaccines. The present study reports a nanoadjuvant constructed using aluminosilicate nanoparticles (as particle templates), incorporating cytosine-phosphate-guanosine (CpG) oligonucleotides and small-interfering RNA (siRNA) to counteract immune suppression in antigen-presenting cells. Furthermore, the application of a metal-phenolic network (MPN) coating, which can endow the nanoparticles with protective and bioadhesive properties, is assessed with regard to the stability and immune function of the resulting nanoadjuvant in vitro and in vivo. Combining the adjuvanticity of aluminum and CpG with RNA interference and MPN coating results in a nanoadjuvant that exhibits greater accumulation in lymph nodes and elicits improved maturation of dendritic cells in comparison to a formulation without siRNA or MPN, and with no observable organ toxicity. The incorporation of a model antigen, ovalbumin, within the MPN coating demonstrates the capacity of MPNs to load functional biomolecules as well as the ability of the nanoadjuvant to trigger enhanced antigen-specific responses. The present template-assisted fabrication strategy for engineering nanoadjuvants holds promise in the design of delivery systems for disease prevention, as well as therapeutics.
ABSTRACT
Recently, zeolitic imidazolate frameworks (ZIFs) composites have emerged as promising precursors for synthesizing hollow-structured N-doped carbon-based noble-metal materials with diverse structures and compositions. Here, a strong/weak competitive coordination strategy is presented for synthesizing high-performance electrocatalysts with hollow features. During the competitive coordination process, the cubic zeolitic-imidazole framework-8 (Cube-8)@ZIF-67 with core-shell structures are transformed into Cube-8@ZIF-67@PF/POM with yolk-shell nanostructures employing phosphomolybdic acid (POM) and potassium ferricyanide (PF) as the strong chelator and the weak chelator, respectively. After calcination, the hollow Mo/Fe/Co@NC catalyst exhibits superior performance in both oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). Interestingly, the Mo/Fe/Co@NC catalyst exhibits efficient electrocatalytic performance for Zn-air batteries (ZABs), with a high power density (≈150 mW cm-2) and superior cycling life (≈500 h) compared to commercial platinum/carbon (Pt/C) and ruthenium dioxide (RuO2) mixture benchmarks catalysts. In addition, the density functional theory further proves that after the introduction of Mo and Fe atoms, the adsorption energy with the adsorption intermediates is weakened by adjusting the d-band center, thus weakening the reaction barrier and promoting the reaction kinetics of OER. Undoubtedly, this study presents novel insights into the fabrication of ZIFs-derived hollow structure bifunctional oxygen electrocatalysts for clean-energy diverse applications.
ABSTRACT
Crystalline metal-organic frameworks (MOFs) have garnered extensive attention owing to their highly ordered porous structure and physicochemical properties. However, their practical application often requires their integration with various substrates, which is challenging because of their weakly adhesive nature and the diversity of substrates that exhibit different properties. Herein, we report the use of amorphous metal-phenolic network coatings to facilitate the growth of crystalline MOF coatings on various particle and planar substrates. Crystalline MOFs with different metal ions and morphologies were successfully deposited on substrates (13 types) of varying sizes, shapes, and surface chemistries. Furthermore, the physicochemical properties of the coated crystalline MOFs (e.g., composition, thickness) could be tuned using different synthesis conditions. The engineered MOF-coated membranes demonstrated excellent liquid and gas separation performance, exhibiting a high H2 permeance of 63200â GPU and a H2/CH4 selectivity of 10.19, likely attributable to the thin nature of the coating (~180â nm). Considering the vast array of MOFs available (>90,000) and the diversity of substrates, this work is expected to pave the way for creating a wide range of MOF composites and coatings with potential applications in diverse fields.
ABSTRACT
Small molecules, including therapeutic drugs and tracer molecules, play a vital role in biological processing, disease treatment and diagnosis, and have inspired various nanobiotechnology approaches to realize their biological function, particularly in drug delivery. Desirable features of a delivery system for functional small molecules (FSMs) include high biocompatibility, high loading capacity, and simple manufacturing processes, without the need for chemical modification of the FSM itself. Herein, we report a simple and versatile approach, based on metal-phenolic-mediated assembly, for assembling FSMs into nanoparticles (i.e., FSM-MPN NPs) under aqueous and ambient conditions. We demonstrate loading of anticancer drugs, latency reversal agents, and fluorophores at up to ~80 % that is mostly facilitated by π and hydrophobic interactions between the FSM and nanoparticle components. Secondary nanoparticle engineering involving coating with a polyphenol-antibody thin film or sequential co-loading of multiple FSMs enables cancer cell targeting and combination delivery, respectively. Incorporating fluorophores into FSM-MPN NPs enables the visualization of biodistribution at different time points, revealing that most of these NPs are retained in the kidney and heart 24â h post intravenous administration. This work provides a viable pathway for the rational design of small molecule nanoparticle delivery platforms for diverse biological applications.