Nanotechnology increasingly plays a significant role in vaccine development. As vaccine development orientates toward less immunogenic "minimalist" compositions, formulations that boost antigen effectiveness are increasingly needed. The use of nanoparticles in vaccine formulations allows not only improved antigen stability and immunogenicity, but also targeted delivery and slow release. A number of nanoparticle vaccines varying in composition, size, shape, and surface properties have been approved for human use and the number of candidates is increasing. However, challenges remain due to a lack of fundamental understanding regarding the in vivo behavior of nanoparticles, which can operate as either a delivery system to enhance antigen processing and/or as an immunostimulant adjuvant to activate or enhance immunity. This review provides a broad overview of recent advances in prophylactic nanovaccinology. Types of nanoparticles used are outlined and their interaction with immune cells and the biosystem are discussed. Increased knowledge and fundamental understanding of nanoparticle mechanism of action in both immunostimulatory and delivery modes, and better understanding of in vivo biodistribution and fate, are urgently required, and will accelerate the rational design of nanoparticle-containing vaccines.

Lipid nanoparticles have attracted significant interests in the last two decades, and have achieved tremendous clinical success since the first clinical approval of Doxil in 1995. At the same time, lipid nanoparticles have also demonstrated enormous potential in delivering nucleic acid drugs as evidenced by the approval of two RNA therapies and mRNA COVID‐19 vaccines. In this review, an overview on different classes of lipid nanoparticles, including liposomes, solid lipid nanoparticles, and nanostructured lipid carriers, is first provided, followed by the introduction of their preparation methods. Then the characterizations of lipid nanoparticles are briefly reviewed and their applications in encapsulating and delivering hydrophobic drugs, hydrophilic drugs, and RNAs are highlighted. Finally, various applications of lipid nanoparticles for overcoming different delivery challenges, including crossing the blood–brain barrier, targeted delivery, and various routes of administration, are summarized. Lipid nanoparticles as drug delivery systems offer many attractive benefits such as great biocompatibility, ease of preparation, feasibility of scale‐up, nontoxicity, and targeted delivery, while current challenges in drug delivery warrant future studies about structure–function correlations, large‐scale production, and targeted delivery to realize the full potential of lipid nanoparticles for wider clinical and pharmaceutical applications in future.

Progress towards the integration of technology into living organisms requires power devices that are biocompatible and mechanically flexible. Aqueous zinc ion batteries that use hydrogel biomaterials as electrolytes have emerged as a potential solution that operates within biological constraints; however, most of these batteries feature inferior electrochemical properties. Here, we propose a biocompatible hydrogel electrolyte by utilising hyaluronic acid, which contains ample hydrophilic functional groups. The gel-based electrolyte offers excellent anti-corrosion ability for zinc anodes and regulates zinc nucleation/growth. Also, the gel electrolyte provides high battery performance, including a 99.71% Coulombic efficiency, over 5500 hours of long-term stability, improved cycle life of 250 hours under a high zinc utilization rate of 80%, and high biocompatibility. Importantly, the Zn//LiMn₂O₄ pouch cell exhibits 82% capacity retention after 1000 cycles at 3 C. This work presents a promising gel chemistry that controls zinc behaviour, offering great potential in biocompatible energy-related applications and beyond.