Latest ArticlesThe complexity of cancer therapy has led to the emergence of combination therapy as a promising approach to enhance treatment efficacy and safety. The integration of glutathione (GSH)-activatable two-photon photodynamic therapy (TP-PDT) and chemodynamic therapy (CDT) offers the possibility to advance precision and efficacy in anti-cancer treatments. In this study, a GSH-activatable photosensitizer (PS), namely copper-elsinochrome (CuEC), is synthesized and utilized for combination second near-infrared (NIR-Ⅱ) TP-PDT/CDT. The Cu2+ acts as a “lock”, suppressing the fluorescence and 1O2 generation ability of EC in a normal physiological environment (“OFF” state). However, the overexpressed GSH in the tumor microenvironment acts as the “key”, resulting in the release of EC (“ON” state) and Cu+ (reduced by GSH). The released EC can be utilized for fluorescence imaging and TP-PDT under NIR-Ⅱ (λ = 1000 nm) two-photon excitation, while Cu+ can generate highly toxic hydroxyl radicals (•OH) via Fenton-like reaction for CDT. Additionally, this process consumes GSH and diminishes the tumor’s antioxidant capacity, thereby augmenting the efficacy of combination therapy. The CuEC achieves significant tumor cell ablation in both 2D monolayer cells and 3D multicellular tumor spheres through the combination of NIR-Ⅱ TP-PDT and CDT.
Oxygen evolution reaction (OER) is one of the most important half-reactions related to metal-air batteries, fuel cells, and water-splitting. Due to the sluggish kinetic and multi-electron transfer, catalysts appear to be particularly important for the OER. Knowing the reaction mechanism is fundamental to developing new catalysts and improving OER efficiency. In this work, phase transition and atomic reconstruction on CoO (111) plane were revealed through ex-situ diffraction methods and X-ray absorption spectroscopy. At the same time, the electronic state evolution of Co(Ⅱ)/Co(Ⅲ) during the OER process has also been concluded by analyzing the magnetic properties. This work shows that during the OER process, Co(Ⅲ) experiences surface electron rearrangement from IS (intermediate-spin state) to LS (low-spin state) and then returns to IS/HS (high-spin state) under high voltage region. This work provides a new view to reveal the reaction mechanism through the magnetic property and it can be extended to more magnetic 3d transition metals for future catalyst design.
The first total synthesis of marine sesquiterpene (hydro)quinone meroterpenoids dysideanones A and E–G (1 and 4–6) has been accomplished in an enantioselective and divergent way. The sesquiterpene fragment and the aromatic moiety were efficiently connected via a site-selective and diastereoselective intermolecular alkylation of Wieland–Miescher ketone derivative 9 and benzyl bromide 10. The core 6/6/6/6-fused backbone of dysideanones was efficiently constructed through an intramolecular radical cyclization reaction. Dysideanone G (6) was easily prepared on a gram-scale and dysideanones A, E, and F (1, 4, and 5) were divergently transformed from dysideanone G (6) in one or two steps
Deprivation of glucose and lactate provides an effective pathway to terminate the nutrients supplement for tumor growth. In this work, biomimetic nanozymes called m@BGLC are constructed for catalytic tumor inhibition through nutrients deprivation and oxidative damage induction. Concretely, the catalytic enzymes of glucose oxidase (GOx), lactate oxidase (LOx) and chloroperoxidase (CPO) are precrosslinked with bovine serum albumin (BSA) to construct nanozymes, which are then biomimetic functionalized with cancer cell membrane to prepare m@BGLC. Benefiting from the biomimetic camouflage with homologous cell membrane, m@BGLC inherit homotypic binding and immune escape abilities, facilitating the tumor targeting accumulation and preferable cell internalization for improved drug delivery efficiency. Subsequently, under the cascade catalysis of nanozymes, m@BGLC consume glucose and lactate for tumor starvation therapy through nutrients deprivation, and meanwhile, the resulting hyprochloric acid (HClO) causes an oxidative damage of cells to synergistically inhibit tumor growth. In vitro and in vivo findings demonstrate a robust tumor eradication effect of m@BGLC without obvious adverse reactions via the targeted combination therapy. Such cascade catalytic nanomedicine may inspire the development of sophisticated strategies for tumor combination therapy under unfavorable tumor microenvironments.
Photodynamic therapy (PDT) not only directly eradicates tumor cells but also boosts immunogenicity, promoting antigen presentation and immune cell infiltration. However, the robust antioxidant defense mechanisms within tumor cells significantly weaken the efficacy of photodynamic immunotherapy. Herein, a supramolecular hybrid nanoassembly is constructed by exploring the synergistic effects of the photodynamic photosensitizer (pyropheophorbide a, PPa) and the ferroptosis inducer (erastin). The erastin-mediated inhibition of system Xc− significantly downregulates glutathione (GSH) expression, amplifying intracellular oxidative stress, leading to pronounced cell apoptosis, and promoting the release of damage-associated molecular patterns (DAMPs). Additionally, the precise cooperation of PPa and erastin enhances ferroptosis efficiency, exacerbating the accumulation of lipid peroxides (LPOs). Ultimately, LPOs serve as a "find me" signal, while DMAPs act as an "eat me" signal, collectively promoting dendritic cell maturation, enhancing infiltration of the cytotoxic T lymphocytes, and eliciting a robust immune response. This study opens new horizons for enhancing tumor immunotherapy through simultaneous ferroptosis-PDT.
Wastewater contains various high-risk trace organic pollutants, such as antibiotics and endocrine disruptors, which seriously restrict wastewater reuse. Cyclodextrin-based functional materials show great potential in the removal of trace pollutants because of their adsorption catalytic synergy. Clarifying the synergistic mechanism of cyclodextrin in oxidation is the key issue in confined catalytic oxidation process design. In this work, we fabricated a BiOIO3@BiOBr/β-CD heterojunction photocatalyst to study the synergistic mechanism of cyclodextrin in the photocatalytic oxidation process. The synergistic mechanism of cyclodextrin was investigated by combining radical chemistry, electrochemistry, spectroscopy, and time-dependent density functional theory. Results showed that the excited intermediate free radicals played an important role in promoting the photocatalytic degradation process. The heterojunction photocatalyst loaded with β-cyclodextrin (β-CD) at the electronic end (C[Cat.] = 0.2 mg/mL) removed about 97% of bisphenol A (BPA) within 30 min, and the first-order kinetic constant (kCDBIB = 0.112 min−1) was about twice that of the unloaded β-CD (kBIB = 0.057 min−1). Cyclodextrin loading improved the photocatalytic performance of the heterojunction and stimulated the intermediate to increase the free radical yield and regulate the reaction path.
In the field of Raman spectroscopy detection, the quest for a non–noble metal, recyclable, and highly sensitive detection substrate is of utmost importance. In this work, a new crystalline and noble metal–free substrate of [Bi(DMF)8][PMo12O40] (Bi–PMo12) is designed, which is composed of [PMo12O40]3− and solvated [Bi(DMF)8]3+ cations. Mechanistic studies have revealed that Raman scattering quenching phenomenon arises from two main factors. Firstly, it arises from the absorption of the scattered light due to the transition of a single electron in the reduced state of MoV between 4d orbitals. Secondly, after the interaction between the substrate and hydrazine, the surface undergoes varying degrees of roughening, leading to an impact on the scattered light intensity. These two effects collectively contribute to the detection of low concentrations of N2H4. As a result, Bi–PMo12 opens up a novel Raman scattering quenching mechanism to realize the detection of reduced N2H4 small molecules. A remarkably low detection limit of 4.5 × 10−9 ppm for N2H4 is achieved on the Bi–PMo12 substrate. This detection has a lower concentration than the currently known SERS detection of N2H4. Moreover, Bi–PMo12 can be recovered and reused through recrystallization, achieving a recovery rate of up to ca. 51%. This study reveals the underlying potential of crystalline polyoxometalate materials in the field of Raman detection, thus opening up new avenues for highly sensitive analysis using Raman techniques.
Glial fibrillary acidic protein (GFAP) is one of the discriminative biomarkers for diagnosing traumatic brain injury (TBI), and accurate determination of GFAP is clinically significant. In this study, a novel fluorescence immunoassay system was designed. We encapsulated carbon dots with a high fluorescence quantum yield (QY = 92.5%) inside silicon nanocapsules to serve as fluorescent markers. These markers were then integrated with the streptavidin (SA)-biotin biomagnification system and immunomagnetic separation technology for the sensitive detection of GFAP. Based on the signal cascade amplification effect of the silicon nanocapsules and SA-biotin, the fluorescence signal of the SA-biotin-modified immunofluorescence nanocapsules increased 3.6-fold compared to the carbon dot-based immunoprobe. The fluorescence immunoassay system was constructed for GFAP using SA-biotin-modified immunocapsules as the sensing probe and immunomagnetic nanoparticles as the immunorecognition probe. The fluorescence immunoassay system can specifically and ultra-sensitively quantify GFAP in blood samples, with a detection range of 10 pg/mL–10 ng/mL and detection limits of 3.2 pg/mL (serum) and 3.6 pg/mL (plasma). Moreover, the fluorescence immunoassay system exhibited prominent recoveries of 99.4%–100.4% (phosphate buffered saline), 96%–102.6% (serum), and 93.2%–110.2% (plasma), with favorable specificity and excellent stabilization. The novel fluorescence immunoassay system provides a new approach to the clinical analysis of GFAP and may serve as a potential tool for screening and diagnosing TBI.
Aryl ketones as photolabile protecting group (PPG) to modify purine imines is a novel nucleic acid protection strategy. Especially, photoprotection of N7-guanosine is the first reported photoprotected nucleoside that can affect the Hoogsteen recognition site of guanosine. However, the mechanism, which is pivotal to high efficiency of photorelease and applications of PPGs in biological and medical systems, is unclear. Here, a detailed deprotection mechanism of benzophenone protected guanosine (BP-Guo) at N7 position is reported. Upon irradiation, BP-Guo populates to singlet state, which generates 3[BP]-Guo via intersystem crossing process. Thereafter, triplet energy transfer competes with hydrogen atom transfer forming BP-3[Guo] and ketyl-Guo, respectively. Both species break CN bond to release guanosine. These results provide deeper insights into exploiting improved strategies for photo-protecting nucleic acids. In particular, the TTET pathway could trigger well-known cyclization reactions that brings about DNA mutagenic adducts. The latter should be avoided in developing improved strategies for photoprotecting nucleic acids.
The performance optimization of materials is an eternal theme and challenge in scientific research, which is reflected in ferroelectric filed to two hot topics of enhancing Curie temperature (TC) and functional versatility. The former one vitally determines ferroelectric operational temperature range while the latter would open up new application possibilities. Effective chemical modification or doping strategies on A-site and X-site components have been successfully developed in hybrid organic-inorganic perovskite (HOIP) ferroelectrics, however, the important role of adjusting B-site ions has long been overlooked. Here, we have implemented regulation on the ion radius of the B-site component to successfully obtain two new HOIP ferroelectrics (3-pyrrolinium)BBr3 (B = Mn and Ni). Compared to parent (3-pyrrolinium)CdBr3, the TC (ΔT = 99 K) was significantly optimized by replacing the Cd2+ with smaller Mn2+ or Ni2+ ions. More strikingly, the introduction of Mn2+ and Ni2+ ions with octahedral coordination bring out intriguing red emission and magnetism respectively, making the multifunctional integration in a single material for multiple uses. This work provides a feasible strategy for performance optimizing of HOIP ferroelectrics, and would shed light for constructing multifunctional ferroelectrics.
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