Latest ArticlesOwing to their sophisticated information-processing capabilities, multi-input DNA circuits (DCs) show great potential in spatiotemporally precise in vivo imaging of diseases. Nevertheless, engineering simple yet versatile multi-input DCs remain a big challenge. Herein, tri-input DNA circuits (tiDCs) based on a DNAzyme-driven walker system were developed via a novel double-blocking strategy, enabling high spatiotemporal-precision fluorescence imaging in vivo. A hairpin structure containing photocleavable linker was designed as the first blocking unit to lock the miRNA-complementary strand, while the miRNA-complementary strand was introduced as the second blocking unit to inhibit the Zn2+-specific DNAzyme-contained walker strand. By leveraging upconversion nanoparticles for targeted delivery and light transduction, the tiDCs generated amplified fluorescence signals exclusively upon simultaneous inputs of near-infrared (NIR) light, miRNA, and Zn2+, achieving spatiotemporally controlled imaging of arthritis. This work establishes a programmable molecular platform for visualizing complex biological systems in vivo, offering new pathways to advance diagnostic precision and therapeutic outcomes.
The simultaneous discrimination of structurally similar biological thiols in living systems remains a significant challenge. To address this, we designed a novel self-calibrating SERS probe, 2-(3,5-dinitrophenoxy)-4-(2-(4-ethynylbenzoylamino)ethyl)phenyl-2-fluoro-5-nitrobenzoate (DEP), for the simultaneous detection of hydrogen sulfide (H2S), polysulfide (H2Sn), and cysteine (Cys). This single-molecule probe incorporates three distinct binding sites, each specific to a different biothiol, enabling multiplex detection through five characteristic Raman signals (178, 264, 454, 1186, and 1600 cm-1). The Raman band at 2056 cm-1, located in the silent region, serves as an internal reference to establish a ratiometric sensing strategy, thereby improving detection accuracy. The resulting spectral variations were processed statistically using principal component analysis (PCA), allowing for the simultaneous assay of the three thiols. The DEP probe was anchored onto biocompatible gold nanorods (AuNRs), optimized for 785 nm laser excitation, to form the final SERS biosensor. The developed platform successfully identified and differentiated H2S, H2Sn, and Cys in complex biological environments, including living neurons and brain microdialysates.
This study elucidates the pivotal role of hexameric capsule C in the Brønsted acid-catalyzed dimerization of styrenes to indanes. The confined environment significantly influences the reaction outcomes and requires the co-encapsulation of acid counter-anions for the effective stabilization of carbocation intermediates. These results indicate the potential to optimize the catalytic activity of hexameric capsule C through careful selection of suitable carbocation counter-anions.
Aqueous fluorescence quenching poses a significant challenge for organic fluorophores in biological applications. This study demonstrates an effective supramolecular strategy to overcome this limitation through host-guest complexation with methyl-β-cyclodextrin (M-β-CD). Three naphthalimide-based dyes (1a-1c) were obtained by incorporating an azabicycloheptane auxochrome and various targeting groups. Upon M-β-CD complexation, these dyes exhibited 2.3- to 3.4-fold enhancements in fluorescence quantum yields, with binding constants (Ka) of 1.32 × 104 (1a) and 7.09 × 103 L/mol (1b), confirming stable complex formation by 1H NMR spectra. Most remarkably, cellular imaging revealed an 18.7-fold fluorescence intensity increase for dye 1a (0.40 µmol/L) when complexed with M-β-CD. This work establishes a dual design strategy of using an azabicycloheptane as the auxochrome and supramolecular complexes to enhance the aqueous performance of naphthalimide fluorophores while maintaining their targeting capabilities, offering broad potential for biological imaging applications.
Axially chiral diaryl ethers are unique skeletons bearing dual-axial chirality, which have broad applications in biologically active molecules. However, the catalytic atroposelective construction of diaryl ethers is very limited. Atroposelective desymmetrization of prochiral diamines is a straightforward pathway to access C–O axially chiral diaryl ethers, but the direct use of industry feedstock chemicals as desymmetrization reagents is highly challenging. Herein, we report a chiral Brønsted acid-catalyzed desymmetrizing amidation of diamines with carboxylic acids by using ynamide as coupling reagent, enabling the efficient synthesis of C–O and C–C axially chiral anilines. The synthetic utility is demonstrated by one-pot amidation with carboxylic acids, scale-up reaction, synthesis of chiral ligand and catalyst, as well as the applications in asymmetric catalysis. Importantly, this reaction represents a rare atroposelective desymmetrization of diamines with carboxylic acids.
Substituted cyclopentadienyl (Cp) radicals, as well as other Cp and fluorenyl-based radicals, exhibit deviations from ideal fivefold D5h symmetric structures due to Jahn-Teller distortion. The unpaired electron is unequally distributed on the five carbons. Herein, we report the metalla-analogs of Cp radicals from one-electron reduction of antiaromatic osmacyclopentatriene complexes. The novel osmacyclopentatrienyl radicals are nonaromatic, with the single unpaired electron delocalized over the entire five-membered osmacycle. Furthermore, these osmacyclopentatrienyl radicals can be oxidized to regenerate osmacyclopentatrienes and reduced to form osmacyclopentadienes. This discovery provides new insights into radical chemistry and organometallic chemistry.
(-)-Veragranines A and B are two steroidal alkaloids that exhibit potent analgesic activity. Herein, we report a 5-step biomimetic synthesis of 5α,6-dihydroveragranine A form hecogenin acetate, which incorporates two well-designed cascade processes that significantly improve the synthetic efficiency. Based on synthesis, an alternative biosynthetic proposal of veragranines was proposed. Subsequently, we developed the first divergent approach enabling the synthesis of veragranines A and B in 10~12 steps from deoxycholic acid. The synthesis features a photoredox-catalyzed decarboxylative Minisci reaction that achieved good regioselective control and C20 stereochemistry inversion via a radical process. Besides, the strategic use of an A/B cis-fused starting material enabled late-stage introduction of the Δ5(6) double bond, simplifying its installation and providing a valuable strategy for the synthesis of related natural products. Notably, we evaluated a series of synthetic intermediates and derivatives of veragranines to assess their in vitro analgesic activity. We find that compound 16, which is easily accessible and features a saturated pyridine as the F-ring, emerges as a promising lead compound.
The reactivity of metal-catalyzed nitrene transfer reaction is typically governed by (2 + 1) cycloaddition reaction chemistry to forge aziridine heterocycles. Herein, we describe a strategy to overcome this classic reactivity using mixed-valency diruthenium(Ⅱ,Ⅲ) paddlewheel complexes or silver(I) catalysts. These metal complexes allow the efficient relay of the diradical nature of triplet nitrene reagents in catalytic fashion and enable (2 + 2 + 1) cycloaddition reactions of 1,6-dienes with nitrenes as an N1 unit. We have exemplified this concept in a broad substrate scope, including the functionalization of drug molecules and describe applications of the reaction products in the synthesis of drug analogues. This catalytic (2 + 2 + 1) cycloaddition now opens up new concepts and strategies in leveraging catalytic nitrene transfer reactions beyond classic aziridination chemistry.
Herein, a multiphase interfacial polymerization strategy has been developed to controllably fabricate A-to-B type Janus covalent organic framework (COF) membranes with asymmetric properties. This approach allows one-pot construction of heterostructured COF membranes with opposite wettability on the upper and lower surfaces via integrating simultaneous but independent interfacial polymerizations at two interfaces of a three-phase system. Being integrated two distinct two-dimensional COF layers with the same frame structure but differing in side chains, the Janus COF membranes exhibits hydrophilic feature on one side but displays hydrophobic characteristic on the other side. Additionally, the Janus COF membranes exhibit exceptional anti-pollution performance and exclusively permits unidirectional water transport. Notably, this unique property is non-designable in the homogeneous COF membranes fabricated from the same building blocks via the conventional two-phase interfacial polymerization method. The Janus membranes were further demonstrated to be a good candidate for membrane desalination with a high rejection for MgSO4. This novel multiphase interfacial polymerization strategy offers a general way to fabricate Janus membranes with designable, predictable, and controllable asymmetric properties from a wide range of materials, holding great potential for diverse applications.
Herein, we report a xanthium-like multicomponent supramolecular assembly with target and effective anticancer ability, which integrates photothermal therapy (PTT), chemodynamic therapy (CDT), and chemotherapy. The ferrocene-modified iron-based metal-organic frameworks (Fc-MIL-88B) act as the core-carrier to effectively doped photothermal reagent gold nanoparticles (Au) and encapsulate the model drug emodin, then further bind with the biotin-modified cyclodextrin (Bio-PE-CD) as the targeting "thorns" for cancer cells, ultimately forming the nanoreactor Fc-MIL-88B@Au@emodin@Bio-PE-CD. Notably, the supramolecular reactor not only exhibits tumor microenvironment-responsive disassembly performance to release anticancer drugs but also provides an abundant Fe source for intracellular Fenton reaction to produce hydroxyl radicals, then cooperating with the photothermal effect of gold nanoparticles to induce apoptosis of cancer cells. Finally, the trinity supramolecule exhibits excellent therapeutic efficacy and biosafety at the cellular and in vivo levels, providing a novel strategy for the development of synergistic antitumor nanoplatforms.
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