Sangyong Jon

Lipid nanoparticles (LNPs) are clinically validated platform for the delivery of small interfering RNA (siRNA) therapeutics. However, conventional LNPs typically consist of multiple lipid components, which complicates formulation optimization and limits compositional flexibility. Furthermore, efficient delivery of siRNA to extrahepatic tissues, including solid tumors, remains a major challenge. To address these limitations, we developed a class of ionizable cholesterol derivatives by conjugating biocompatible dimethylated amino acids to cholesterol through a cleavable linker, thereby integrating the structural role of cholesterol and the pH‐responsive ionization of ionizable lipids into a single molecule. Five i‐Chol derivatives were synthesized and formulated into LNPs, which demonstrated efficient siRNA encapsulation and delivery in cancer cells. The resulting siRNA@i‐Chol LNPs exhibited uniform particle size and near‐neutral surface charge, indicating favorable physicochemical properties for systemic administration. Notably, phenylalanine‐based cholesterol LNPs (Phe‐Chol LNPs) loaded with siRNA targeting kinesin spindle protein (KIF11) achieved the most potent in vitro gene knockdown in PC3 prostate cancer cells and induced significant dose‐dependent antitumor activity in a xenograft model without observable systemic toxicity. Collectively, this study establishes a simplified i‐Chol LNP platform that maintains high siRNA delivery efficiency to solid tumors and provides a versatile framework for further LNP engineering and scalable manufacturing.

Reactive oxygen species (ROS) are key biomarkers of oxidative stress in the tumor microenvironment (TME), yet their non‐invasive, real‐time visualization remains challenging. Here, we present biotinylated PEGylated bilirubin nanobubbles encapsulating perfluoropentane gas (bt‐PEG‐BR@PFP) as ROS‐responsive contrast agents for dual‐modality ultrasound (US) and magnetic resonance imaging (MRI). Upon ROS exposure, the bilirubin shell undergoes oxidative degradation, leading to nanobubble fusion and signal amplification in both US and T ₂ *‐weighted MRI. In vitro, biotin‐mediated cellular uptake and ROS‐induced fusion were validated in A549 cancer cells. In vivo, intratumoral injection of bt‐PEG‐BR@PFP into dual‐tumor xenografts led to a >3.7‐fold increase in US signal intensity in ROS‐high A549 tumors compared to ROS‐low DU145 tumors, which was abolished by the ROS scavenger N‐acetylcysteine. Following systemic administration, the nanobubbles accumulated selectively in A549 tumors through biotin‐mediated targeting and produced ∼50‐fold higher US signal than in DU145 tumors. In contrast, the clinical agent SonoVue showed no such tumor selectivity and ROS‐responsive signal enhancement. MRI studies revealed a time‐dependent signal drop only in A549 tumors treated with bt‐PEG‐BR@PFP, consistent with ROS‐mediated nanobubble fusion. These results highlight bt‐PEG‐BR@PFP as a promising and clinically translatable platform for non‐invasive, dual‐modality imaging of tumor oxidative stress, with potential utility in various ROS‐associated pathologies.

Human adipose‐derived stem cells (hADSCs) possess immunomodulatory and multipotent properties, making them attractive candidates for regenerative therapies. However, conventional tissue culture plate (TCP)‐based 2D adherent cultures or widely used ultra‐low attachment (ULA) spheroid systems often compromise differentiation potential and therapeutic efficacy of hADSCs. Here, we report a synthetic polymer matrix, poly‐Z, that enables the formation of hADSC spheroids with significantly enhanced biological functions. Compared to ULA or TCP culture systems, poly‐Z‐cultured hADSC spheroids exhibited improved cell viability, enriched extracellular matrix deposition, elevated pluripotency marker expression, and superior tri‐lineage differentiation capacity. Notably, poly‐Z spheroids displayed a distinct immunomodulatory signature characterized by significantly elevated secretion of indoleamine‐pyrrole 2,3‐dioxygenase (IDO) and prostaglandin E2 (PGE2), and showed enhanced in vivo persistence after transplantation. In mouse models of acute colitis and acetaminophen‐induced liver injury, poly‐Z‐cultured hADSC spheroids markedly alleviated inflammation, reduced tissue damage, and modulated pro‐ and anti‐inflammatory cytokine levels more effectively than ULA or TCP‐derived cells. These findings establish the poly‐Z matrix as a potent 3D culture platform that enhances the functional and therapeutic potential of hADSCs for clinical applications.

Single-chain variable fragments (scFvs) antibodies are used in diagnostic and therapeutic biopharmaceuticals. However, its production is limited due to insoluble expression and lack of a universal purification ligand. Here, we report a novel two-in-one protein tag, termed CSQ-tag, utilizing a calsequestrin (CSQ) protein to enable the soluble expression and calcium-dependent purification for scFvs. The CSQ-tag enhanced the solubility of four different therapeutic scFvs with an average solubility of 83.8 ± 4.6% in the BL21(DE3) strain, despite its reducing cytoplasmic environment. Compared to other tags, CSQ-tag showed superior solubility, with 1.8-fold higher solubility than MBP-tag across four scFvs. The solubility enhancement of the CSQ-tag is attributed to two main characteristics: highly acidic sequences with a low isoelectric point of 3.95, and intrinsically disordered protein properties. Furthermore, CSQ-tag can cost-effectively purify therapeutic scFvs with high purity over 95% using the calcium-dependent phase transition properties. Importantly, the anti-VEGF-scFv produced with the CSQ-tag showed a binding affinity of 25.8 pM, similar to that of the existing therapeutic brolucizumab. Therefore, CSQ-tag can significantly improve productivity and simultaneously maintain scFvs’ functional integrity, thereby serving as a promising tool for universal expression and purification of therapeutic scFvs.

The COVID‐19 pandemic has underscored the urgent need for deployable vaccine platforms capable of rapidly responding to emerging and re‐emerging variants of human coronaviruses. BP26, an outer membrane protein of the zoonotic bacterium Brucella , self‐assembles into a highly ordered, barrel‐like nanoparticle that can serve as a vaccine platform, demonstrating immunogenicity against the influenza virus and cancer when combined with specific antigens. Here, we expanded its versatility by incorporating the SpyTag/SpyCatcher pair, enabling modular and site‐specific antigen conjugation via simple mixing. SpyCatcher was genetically fused to BP26, and SpyTag to the receptor binding domain (RBD) of the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) spike protein, generating RBD‐displaying BP26 nanoparticles (BP26‐RBD). Immunization of mice with BP26‐RBD elicited strong RBD‐specific and neutralizing antibody responses and conferred protection against lethal SARS‐CoV‐2 challenge. This plug‐and‐play nanoparticle design supports antigen production in diverse expression systems, retains antigenic structure, and allows multivalent display, providing a cost‐effective and rapidly adaptable strategy for next‐generation vaccines targeting evolving viral threats.

Rapid and effective bleeding control remains a clinical priority, particularly for deep or irregular wounds where conventional dressings are inadequate. Here, an ionically responsive, powder‐based hemostatic system (AGCL) composed of alginate, gellan gum, chitosan, and a glutaraldehyde crosslinker is presented. Upon contact with calcium ions in blood, AGCL rapidly forms an adhesive hydrogel network within ≈1 s, enabling ultrafast gelation and a high blood uptake ratio (≈725%). The powder exhibits strong bioadhesion (>40 kPa), excellent sealing under mixed‐mode loading, and robust storage stability for up to 24 months under ambient conditions. In vitro assays confirm minimal hemolysis (<3%), high cytocompatibility, and greater than 99% antibacterial efficacy. In various bleeding models, AGCL significantly reduced blood loss and time to hemostasis compared to TachoSil, a clinical benchmark. Furthermore, AGCL accelerated re‐epithelialization, angiogenesis, and collagen deposition in murine skin and liver wound models, supporting high‐quality tissue regeneration without systemic toxicity. These results demonstrate that AGCL integrates rapid coagulation, strong adhesion, long‐term biostability, and regenerative capacity in a single platform. Its powder format offers distinct advantages in versatility, ease of application, and storability, making it a promising candidate for next‐generation topical hemostats in trauma care, surgery, and emergency medicine.

Inflammatory bowel disease (IBD) is a chronic disorder characterized by intestinal barrier dysfunction, excessive immune activation, and oxidative stress. Current treatment options, such as 5‐aminosalicylic acid (5‐ASA), exhibit limited therapeutic efficacy due to poor bioavailability and inability to restore intestinal homeostasis. Herein, a novel nanomedicine that can be orally administered, low‐molecular‐weight chitosan‐conjugated rosmarinic acid nanoparticles (LMWC‐RANPs), designed to enhance IBD treatment through its mucoadhesive, antioxidant, and immunomodulatory properties, are introduced. LMWC‐RANPs exhibit strong mucoadhesion, leading to prolonged retention in the inflamed gastrointestinal tract and efficient ROS scavenging. In a DSS‐induced mouse model of colitis, LMWC‐RANPs significantly alleviate disease symptoms by reducing body weight loss, preserving colon length, and restoring intestinal barrier integrity. Additionally, LMWC‐RANPs effectively modulate the mucosal immune response by promoting macrophage polarization from pro‐inflammatory (M1) to anti‐inflammatory (M2) phenotypes and reducing Th17 cell populations while enhancing regulatory T cell (Treg) frequencies. Furthermore, oral administration of LMWC‐RANPs exhibits no observable systemic toxicity in healthy mice, as confirmed by hematological and histopathological analyses. Collectively, these findings demonstrate the potential of LMWC‐RANPs as a safe and effective therapeutic for inflammatory bowel disease, with broader implications for other gut‐associated inflammatory diseases.

Atopic dermatitis (AD) is a common chronic inflammatory skin disease with a growing prevalence worldwide. Topical corticosteroids and non‐steroidal calcineurin inhibitors (CNIs) are used as first‐line therapies for AD, but various side effects limit their long‐term use. Here, the first synthetic bilirubin(IIIα)‐derived nanoparticle is reported, designated BRNP(IIIα), and shows that it exhibits robust antioxidative and immunomodulatory effects and effectively reduces the clinical symptoms of AD upon topical treatment. BRNP(IIIα) in 1% high molecular weight hyaluronic acid (BRNP(IIIα)/HA) readily infiltrates into the dermis layer, notably downregulates disease‐associated reactive oxygen species (ROS) and inflammatory chemokines and cytokines, and suppresses the recruitment of leukocytes and mast cells to AD‐induced lesions. BRNP(IIIα)/HA also significantly reduces the tissue‐resident memory T cell population, suggesting that it may inhibit recurrence. Furthermore, BRNP(IIIα)/HA does not induce any adverse effect related to skin irritation/sensitization or eye irritation in human tissue. Collectively, the findings suggest that BRNP(IIIα)/HA may be useful as an alternative to corticosteroids or CNIs for the safe, effective, and long‐term topical treatment of AD.