ACS Appl Mater Interfaces. 2025 Jan 29;17(4):6095-6102. doi: 10.1021/acsami.4c20214. Epub 2025 Jan 14. Hydrogen Bonding-Driven Adaptive Coacervates as Protocells Abstract Coacervation based on liquid-liquid phase separation (LLPS) has been widely used for the preparation of artificial protocells and to mimic the dynamic organization of membrane-free organelles. Most complex synthetic coacervates are formed through electrostatic interactions but cannot withstand high ionic strength conditions (>0.1 M). Alternative components and driving forces are highly desired for the formation of natural organelles to overcome the drawbacks of traditional coacervates. Herein, hydrogen bonding-driven adaptive coacervates are reported via the complexation of poly(ethylene glycol) (PEG) and tannic acid (TA). The LLPS behavior of these adaptive coacervates is dependent on the concentration and mass ratio of PEG and TA, which can be used to tune the size of coacervates ranging from 70 nm to 10 μm as well as the morphology of isotropic particles and hollow capsules. Coacervates are stable at high ionic concentrations up to 1 M and can serve as protocells to mimic cellular behaviors including metabolism (e.g., nutrient uptake), phagocytosis, and membrane fusion. The reported approach provides a platform for the rational design of hydrogen bonding-driven coacervates with controllable size and morphology, offering potential applications in protocell construction and therapeutic delivery. Keywords: coacervates; hydrogen bonding; poly(ethylene glycol); polyphenol; protocells. Product: 8-arm PEG-OH

Nat Biomed Eng. 2025 Aug;9(8):1320-1334. doi: 10.1038/s41551-025-01373-0. Epub 2025 Mar 28. Generation of tolerogenic antigen-presenting cells in vivo via the delivery of mRNA encoding PDL1 within lipid nanoparticles Abstract Tolerogenic antigen-presenting cells (APCs) are promising as therapeutics for suppressing T cell activation in autoimmune diseases. However, the isolation and ex vivo manipulation of autologous APCs is costly, and the process is customized for each patient. Here we show that tolerogenic APCs can be generated in vivo by delivering, via lipid nanoparticles, messenger RNA coding for the inhibitory protein programmed death ligand 1. We optimized a lipid-nanoparticle formulation to minimize its immunogenicity by reducing the molar ratio of nitrogen atoms on the ionizable lipid and the phosphate groups on the encapsulated mRNA. In mouse models of rheumatoid arthritis and ulcerative colitis, subcutaneous delivery of nanoparticles encapsulating mRNA encoding programmed death ligand 1 reduced the fraction of activated T cells, promoted the induction of regulatory T cells and effectively prevented disease progression. The method may allow for the engineering of APCs that target specific autoantigens or that integrate additional inhibitory molecules. Product: SM-102

Nat Commun. 2025 May 20;16(1):4700. doi: 10.1038/s41467-025-60040-9. Freezing induced incorporation of betaine in lipid nanoparticles enhances mRNA delivery Abstract Lipid nanoparticles (LNPs) are key non-viral carriers for mRNA vaccines and therapeutics, but the inherent instability of mRNA necessitates sub-zero storage with cryoprotectants (CPAs) to prevent freeze-induced LNP aggregation and compromised mRNA delivery. Here we show that ice formation during freezing concentrates CPAs with LNPs in the remaining liquid-a phenomenon known as freeze concentration. This creates a steep concentration gradient of CPAs across the lipid membrane that drives passive CPAs diffusion into LNPs. By leveraging this process, we developed betaine-based CPAs that both preserve the stability of LNP and enter LNP during freeze-thaw. The incorporated betaine enhances endosomal escape and boosts mRNA delivery of LNP. In female mice, betaine-loaded LNPs elicit stronger humoral and cellular immune responses, providing dose-sparing advantages. These findings highlight freeze concentration as a promising LNP formulation strategy and underscore the role of CPA as active modulators of LNP structure and function. Product: lipids for LNP

Mol Ther Nucleic Acids. 2025 Feb 12;36(2):102485. doi: 10.1016/j.omtn.2025.102485. eCollection 2025 Jun 10. Enhancing mRNA translation efficiency by introducing sequence optimized AU-rich elements in 3' UTR via HuR anchorage Abstract mRNA technology holds immense promise as an innovative therapeutic approach with applications spanning infectious disease vaccines, cancer immunotherapy, protein replacement, and gene editing. However, practical use of mRNA has been hindered by challenges such as low cellular stability and transient protein expression. For addressing these, we propose a novel strategy to optimize mRNA sequences, particularly in the untranslated region, by inserting adenylate/uridylate-rich elements (AU-rich elements) to enhance stability and protein expression. Our investigation revealed that integrating AU-rich elements between the open reading frame (ORF) and the 3' untranslated region (3' UTR) significantly enhances RNA stability compared with other insertion sites. We identified cytoplasmic Human antigen R (HuR) as an essential RNA-binding protein responsible for promoting mRNA stability and translation, confirmed through HuR knockdown experiments and pull-down assays between AU-rich elements and HuR. Through rational design, we optimized the sequence of natural AU-rich elements and identified the essential "AUUUA" element, which, with certain repeats, can increase protein expression up to 5-fold. To demonstrate the universality of AU-rich element sequences in enhancing mRNA translation, we switched the coding proteins from luciferase to EGFP, mCherry, and ovalbumin (OVA), finding that both natural and engineered AU-rich element sequences amplify the expression of these proteins. In conclusion, leveraging the functionalities of RNA-binding proteins and the natural regulation of RNA stability in the untranslated region represents a novel strategy to enhance mRNA pharmacokinetics in the cytoplasm, expanding the potential applications of mRNA in therapeutic drugs. Keywords: 3′ UTR rational design; AU-rich elements; HuR; MT: Oligonucleotides: Therapies and Applications; RNA stability; RNA-binding proteins; mRNA vaccines; sequence optimization. Product: lipids for LNP

ACS Nano. 2025 Dec 16;19(49):41803-41815. doi: 10.1021/acsnano.5c15619. Epub 2025 Dec 4. Engineering of Metal-Organic Networks as Band-Aid for the Repair of Osteoporotic Bone Fractures Abstract The treatment of osteoporotic bone fractures remains a critical challenge due to the dysregulated bone remodeling microenvironment characterized by excessive osteoclastic resorption, impaired osteogenic differentiation, angiogenic dysfunction, and chronic inflammation. In this work, we engineered a metal-organic network as a bone repair "band-aid" by integrating poly(ethylene glycol)-alendronate (PEG-ALN) conjugates with bioactive epigallocatechin gallate (EGCG), zinc, and calcium ions into a multifunctional scaffold. This design leverages the synergistic effects of anti-inflammatory and antioxidant properties of EGCG with the balancing osteogenic and osteoclastic functions of ALN, zinc, and calcium ions. In vitro studies demonstrated that the band-aid significantly enhanced the proliferation and differentiation of osteoblasts while promoting endothelial cell migration and tubule formation, indicating the robust osteogenic and angiogenic potential. In vivo evaluations in an osteoporotic bone fracture model revealed accelerated bone regeneration and improved microvascularization while maintaining a balanced immune response to prevent chronic inflammation. Mechanistically, the band-aid modulated macrophage polarization toward a pro-regenerative M2 phenotype and suppressed excessive osteoclast activity, thereby restoring the osteogenic-osteoclastic equilibrium. This study not only provides a therapeutic implant for osteoporotic bone repair but also proposes a strategy for designing immunomodulatory scaffolds that target the pathological bone microenvironment. Keywords: bone repair; metal−organic networks; osteoporosis; polyphenols; tissue engineering. Product: 8-arm-PEG-NHS

J Phys Chem Lett. 2025 Apr 17;16(15):3874-3878. doi: 10.1021/acs.jpclett.5c00825. Epub 2025 Apr 10. Double-Helix Duality: Rods Bow, Toroids Wow in the Nuclease Arena Abstract Utilizing polyion complexation, the formation of rod-like DNA condensates is driven by the intrinsic rigidity of supramolecular plasmid DNA. Upon interaction with polycationic block copolymers of poly(ethylene glycol)-polylysine (PEG-PLys), these macromolecules undergo a regular self-folding process, during which double-stranded DNA (dsDNA) transitions into single-stranded DNA (ssDNA) at the kinked junctions. Our investigations, employing transmission electron microscopy (TEM), unprecedentedly reveal the absence of a PEG coating at these critical junctions, rendering them susceptible to nuclease degradation. This finding underscores the critical necessity for comprehensive PEG encapsulation in the engineering of robust gene delivery constructs. In stark contrast to the anisotropic rod-like condensates, our novel isotropic toroidal DNA condensates, characterized by comprehensive PEG shielding and a self-spooling mechanism that preserves dsDNA integrity, exhibit a marked enhancement in enzymatic stability (nearly 30-fold greater). Their favorable condensation process also confers superior transcriptional potential, positioning these toroidal condensates as promising platforms for the next generation of gene delivery systems. Product: mPEG-NH2

Proc Natl Acad Sci U S A. 2024 Oct 29;121(44):e2406434121. doi: 10.1073/pnas.2406434121. Epub 2024 Oct 22. CXCL13 promotes broad immune responses induced by circular RNA vaccines Abstract Antibody responses induced by current vaccines for influenza and SARS-CoV-2 often lack robust cross-reactivity. As hubs where diverse immune cells converge and interact, the alterations in the immune microenvironment within lymph nodes (LNs) are intricately linked to immune responses. Herein, we designed a lipid nanoparticle (LNP) loaded with circular RNA (circRNA) and targeted to LNs, in which CXCL13 was directly integrated into antigen-encoding circRNA strands. We demonstrated that CXCL13 alters the transcriptomic profiles of LNs, especially the upregulation of IL-21 and IL-4. Meanwhile, CXCL13 promotes the formation of germinal center and elicits robust antigen-specific T cell responses. With the codelivery of CXCL13 and the antigen, CXCL13 enhances cross-reactive antibodies against influenza virus and SARS-CoV-2, achieving protection against both homologous and heterologous influenza virus challenges in a mouse model. Notably, the targeted modification of LNP surfaces with antibodies helps address some of the challenges associated with lyophilized LNP vaccines, which is crucial for the long-term storage of LNP-circRNA vaccines. Overall, the circRNA-based antigen-CXCL13 coexpression system developed herein provides a simple and robust platform that enhances the magnitude and breadth of antibody responses against multiple viral glycoproteins, highlighting the potential utility of CXCL13 in inducing broad immune responses. Keywords: CXCL13; SARS-CoV-2; broadly cross-reactive antibodies; circRNA vaccine; influenza virus. Product: SM-102

Adv Healthc Mater. 2025 Mar;14(6):e2403865. doi: 10.1002/adhm.202403865. Epub 2025 Jan 2. Coacervate-Derived Assembly of Poly(ethylene glycol) Nanoparticles for Combinational Tumor Therapy Abstract Coacervates have garnered significant attention as potential drug carriers. However, the instability resulting from their intrinsic membrane-free nature restricts the application of coacervates in drug delivery. Herein, the engineering of poly(ethylene glycol) nanoparticles (PEG NPs) is reported using coacervates composed of PEG and polyphenols as the templates, where PEG is subsequently cross-linked based on different chemistries (e.g., thiol-disulfide exchange, click chemistry, and Schiff base reaction). The reported assembly strategy avoids the template removal process and the resultant PEG NPs exhibit excellent stability in the physiological environment compared to coacervates. The presence of polyphenols in PEG NPs enables the loading of various cargos including metal ions (i.e., Ru, Gd, Mn, Fe) and drug molecules (i.e., doxorubicin), which demonstrates their promise in magnetic resonance imaging and combinational tumor therapy. This work provides a promising strategy to promote the development of coacervate-derived NPs as a drug delivery system for biomedical applications. Keywords: coacervates; drug delivery; nanoparticles; poly(ethylene glycol); self‐assembly. Product: 8-arm PEG-NH2HCl (HG)