Latest ArticlesMicroneedles (MNs) represent a rapidly evolving transdermal drug delivery method, with ongoing development efforts focused on overcoming challenges such as limited drug loading and pore occlusion. Herein, we report dissolvable MNs vaccine with excellent drug loading as well as other positive features that make it an ideal delivery carrier in tumor immunotherapy. This study employs a biodegradable polydopamine-based nano-delivery system to co-encapsulate both Toll-like receptor 7/8 agonist resiquimod (R848) and ovalbumin (OVA) antigens, which are subsequently incorporated into MN patches to achieve synergistic photothermal-immunotherapeutic effects. The MN vaccine targets tumor sites via transdermal administration, exhibiting significant therapeutic efficacy by enabling deep tissue drug release and maintaining prolonged therapeutic levels for at least 3 days. The MN tips are rapidly degraded under photothermal action to release R848 and OVA, can effectively polarizes the tumor-associated macrophages to M1-type macrophages and activate dendritic cells to enhance immune response in vivo, thereby, the MN vaccines have shown excellent efficacy and good safety, resulting in a sufficient and persistent anti-tumor cellular immune response with potent tumor immunotherapeutic efficacy. In brief, this study demonstrates that MN administration successfully delivers polydopamine-based nanotherapeutics to tumor sites and validates their anti-tumor efficacy.
Natural material-based hydrogels have emerged as ideal candidates for serving as infected wound dressings relying on the extracellular matrix-like microstructure, biocompatibility and the supplying of the wet healing microenvironment. Nevertheless, these hydrogels suffer from limitations including the weak mechanical property, poor water retention ability and inadequate antibacterial property. Herein, we develop a stratum corneum-inspired all-natural-based biogel dressing by directly incorporating natural moisturizing factor (NMF) into gelatin/chitosan quaternary ammonium salt (QCS) hydrogels without necessitating any chemical modification. The sodium pyrrolidone carboxylic acid (PCA-Na, an NMF compound) equipping carboxyl groups forms the ionic crosslink with gelatin containing protonated amino groups and QCS involving quaternary ammonium groups by electrostatic interaction, leading to a significant melioration in the mechanical strength of the biogel. The highly hydrophilic PCA-Na contributes to form additional hydrogen bonds and heighten resistance to dehydration of the biogel, mimicking the role of NMF in the stratum corneum. The excellent broad-spectrum antibacterial property, temperature-controlled reversible fluid-gel transition property and complete degradability are also gathered. A Staphylococcus aureus-infected full-thickness wound repair experiment manifests that our biogel effectively promotes infected wound healing by inhibiting inflammatory factors, facilitating formation of the granulation tissue and angiogenesis. This work paves a valuable way for designing multifunctional natural material-based hydrogel dressings.
Nanozymes have demonstrated significant potential as robust enzyme-mimicking catalysts due to their high stability, low cost and easy preparation. However, achieving precise enantioselective control of nanozymes remains a significant challenge. In this study, the supramolecular chiral nanozymes were engineered by integrating supramolecular chiral polyaniline (P/M-PANI) scaffolds with platinum-nickel nanoparticles (Pt-Nix NPs). The resulting P/M-PANI@Pt-Nix nanozymes exhibited high catalytic activity toward the oxidation of 3,4-dihydroxy-S/R-phenylalanine (S/R-DOPA). Moreover, systematic modulation of the Pt/Ni atomic ratio in Pt-Nix NPs enabled precise regulation of interfacial interactions and chiral transfer effects, thereby optimizing enantioselectivity. Density functional theory (DFT) calculations further revealed that the distinct adsorption energies of DOPA and its oxidation products on Pt-Nix surfaces directly correlated with the observed catalytic efficiency trends. This work demonstrated that compositional tuning of catalytic centers is an effective strategy for manipulating both catalytic efficiency and enantioselectivity, providing valuable insights for the rational design of smart supramolecular chiral nanozymes.
The construction of lanthanide nanoclusters that are stable in aqueous solution is challenging, which has led to a sluggish application in the field of bioimaging. Herein, a chelating ligand protection strategy was used to construct nonanuclear lanthanide clusters (Ln9, Ln = Eu, Dy, and Gd) that is stable in aqueous solution. The first fluorescence imaging performance of lanthanide clusters targeting mitochondrial organelles was achieved, with colocalization coefficients of up to 0.96 (MCF-7) and 0.93 (MDA-MB-231) with commercial mitochondrial dyes, respectively. Eu9 can be rapidly taken up by zebrafish and shows excellent fluorescence imaging results, demonstrating its excellent in vivo imaging performance. In addition, the longitudinal and transverse relaxation rates r1 and r2 of Gd9 with highly aggregated Gd(Ⅲ) ions are 39.42 and 50.58 mmol L−1 s−1, respectively, showing great application potential as a new and efficient T1-weighted nanocluster-based magnetic resonance imaging contrast agents.
The meta-selective trifluoromethylation of pyridines has remained a significant challenge due to the inherent electronic constraints of the aromatic system. This study developed a novel dearomatization-rearomatization strategy based on 1,4-dihydropyridinephosphonate intermediates, which underwent copper-catalyzed regioselective C–CF3 bond formation with Togni Ⅱ reagent followed by DABCO-promoted rearomatization, achieving highly regioselective meta-C-H trifluoromethylation of pyridine derivatives. This approach accommodated mostly meta-substituted pyridine substrates and enabled late-stage meta-C-H trifluoromethylation of pharmaceutical molecules containing pyridine motifs.
Inherently chiral calix[4]arenes (ICCs) represent a unique class of chiral macrocyclic arenes, which hold significant potentials in chiral recognition, sensing, and asymmetric catalysis. However, accessing these distinct chiral molecules poses notable challenges, with their catalytic enantioselective synthesis being largely underdeveloped. Herein, we report an efficient enantioselective synthesis of ICCs using an asymmetric C-H brominative desymmetrization strategy. Utilizing the chiral phosphoric acid-catalyzed asymmetric electrophilic aromatic ortho-bromination reaction of phenol, we successfully broke the symmetry of prochiral calix[4]arenes, which resulted in the formation of various 1,3-bis-phenyl rings-substituted ICCs with good yields and high enantioselectivities. Moreover, the asymmetric di-bromination of bis-phenol-containing prochiral calix[4]arenes was demonstrated, yielding ICCs featuring three or even four rings displaying various modifications with high enantioselectivity. Leveraging the versatility of the introduced bromide handle and the phenolic hydroxyl group in the ICC products, a range of derivatizations were performed to produce diverse ICC derivatives, one of which exhibited notable chiroptical properties, highlighting the significance of this method.
The variable oxidation states of nickel catalysts play an essential yet elusive role in reductive coupling reactions, wherein the rapid conversion of nickel species with different oxidation states into NiⅠ has been recognized as a crucial factor in controlling the catalytic turnover and inhibiting side reactions. Beyond the popular strategies for reductive (re)generation of NiⅠ species, spontaneous comproportionation of Ni0 and NiⅡ species can form NiⅠ during catalysis, which is an approach holding great promises yet still relatively underexplored in catalysis. Herein, we transform the intermolecular comproportionation into an entropically more favorable intramolecular pathway by taking advantage of a tetradentate nitrogen ligand (dppn), which effectively brings two catalytic Ni centers in close proximity. This strategy enables ready generation of catalytically active NiⅠ species for reductive diarylation of dienes with aryl iodides using Mn as the terminal reductant. Mechanistic studies reveal that the dppn ligand facilitates the assembly of a dinickel complex, where one nickel acts as the catalytic site for oxidative addition and coupling while the other nickel functions as an electron reservoir. The intramolecular comproportionation pathway establishes a robust strategy for accessing the often fleeting and elusive NiⅠ intermediates critical in forging C–C bonds in the reductive coupling reactions.
A three-step cascade artificial light-harvesting system was constructed by the supramolecular assembly of cation-pillar[5]arene (CP5), tetraphenylethene-sulfonate (TPESF), 4,7-di(2-thienyl)-2,1,3-benzothiadiazole (DBT), sulforhodamine 101 (SR101) and chlorin e6 (Ce6). Inspired by the aggregate state in nanoparticles, CP5-TPESF nanoparticles emitted significant blue fluorescence as FRET donors because of TPESF's AIE effect. Due to the donor emission overlapping the acceptors' absorption, a three-step sequential energy transfer process was successfully constructed in CP5-TPESF-DBT-SR101-Ce6 nanoparticles, which achieved the significant energy transfer efficiency of 87% and antenna effect of 30.8. Benefitting to three-step cascade light-harvesting process and energy transfer to Ce6, Ce6* was excited to release 1O2 in CP5-TPESF-DBT-SR101-Ce6 nanoparticles, which was used as efficient photooxidation catalyst to realize the photooxidation reaction of 4-(methylthio)toluene to 4-(methylsulfinyl)toluene. Notably, the photooxidation yield of CP5-TPESF-DBT-SR101-Ce6 LHS was significantly improved to 89%, suggesting potential in converting solar energy to chemical energy storage.
Selective targeting to the subcellular organelle of cancer cells could provide a novel method to realize precise in situ self-assembly for enhanced therapeutic efficiency. Herein, a series of cationic compounds have been synthesized to investigate their subcellular targeting abilities, we found the amino group functionalized planar cationic molecules could selectively locate in the mitochondria of cancer cells (Pearson's coefficient > 0.9), while in the lysosomes of normal cells (Pearson's coefficient > 0.9). Moreover, due to the intermolecular hydrogen bond, the TPE derivative (TPE-NH2) was selected to investigate the in situ self-assembly behavior with negatively charged molecules in the mitochondria of MB49 cancer cells, which could impair the mitochondrial membrane, leading to the elevated reactive oxygen species (ROS), downregulating glutathione peroxidase 4 (GPX4) protein, and finally resulting in LPO for ferroptosis. Moreover, the aggregation-enhanced ROS generation ability of TPE-NH2 made it an ideal candidate for PDT. Under the white light irradiation, the synergetic ferroptosis could be realized to suppress the cancer cell proliferation. Finally, this in situ self-assembly for synergetic therapy would also be realized in vivo to suppress the tumor growth.
Cycloparaphenylenes (CPPs) and related carbon nanohoops have garnered significant research interest owing to their unique optoelectronic properties, charge transport characteristics, and host-guest chemistry. Nevertheless, the development of heteroatom-doped carbon nanorings, particularly nitrogen-doped (N-doped) systems, remains limited, and systematic investigations of their host-guest interactions are still scarce. In this work, we present the synthesis of a series of size-controlled aza[10]CPP derivatives designed as optimal hosts for fullerene C60 encapsulation. The acid-responsive optical properties of these N-doped nanorings were thoroughly examined through absorption and fluorescence spectroscopy. Furthermore, we experimentally evaluated and theoretically analyzed the variations in their binding affinities toward C60, elucidating key structural factors that govern supramolecular complexation, including π-π stacking interactions, geometric adaptability, and charge distribution. These findings would provide new insights for advancing strained nanohoop systems in supramolecular chemistry and organic electronic applications.
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