Latest ArticlesThe reactive oxygen species (ROS) generation efficiency is always limited by the extreme tumor microenvironment (TME), leading to unsatisfactory antitumor effects in photodynamic therapy (PDT). As a promising gas therapy molecule, nitric oxide (NO) is independent of oxygen and could even synergize ROS to enhance the therapeutic effect. However, the short half-life, instability, and uncontrollable release of exogenous NO limited the application of tumor synergistic therapy. Herein, we reported a novel kind of red-emissive carbon dots (CDs) that was capable of lysosome-targeted and light-controlled NO delivery. The CDs were synthesized by using metformin and methylene blue (MB) via a hydrothermal method. The obtained metformin-MB CDs (MMCDs) exhibited a higher 1O2 quantum yield and NO generation efficiency under light emitting diode (LED) light irradiation. Noteworthily, the 1O2 could further in situ oxidize NO into peroxynitrite anions (ONOO−), which own the higher cytotoxicity against cancer cells. Cell experiments indicate that MMCDs could destruct lysosome membrane integrity and kill almost 80% of HepG2 cells under light irradiation while very low cytotoxicity in the dark. Moreover, MMCDs significantly decreased tumor volume and weight after phototherapy in hepatoma HepG2-bearing mice. Our study provides a new strategy for light-controlled NO generation as well as precise lysosome-targeting for enhancement of PDT efficiency.
Application of transition metal boride (TMB) catalysts towards hydrolysis of NaBH4 holds great significance to help relieve the energy crisis. Herein, we present a facile and versatile metal-organic framework (MOF) assisted strategy to prepare Co2B-CoPOx with massive boron vacancies by introducing phytic acid (PA) cross-linked Co complexes that are acquired from reaction of PA and ZIF-67 into cobalt boride. The PA etching effectively breaks down the structure of ZIF-67 to create more vacancies, favoring the maximal exposure of active sites and elevation of catalytic activity. Experimental results demonstrate a drastic electronic interaction between Co and the dopant phosphorous (P), thereby the robustly electronegative P induces electron redistribution around the metal species, which facilitates the dissociation of B-H bond and the adsorption of H2O molecules. The vacancy-rich Co2B-CoPOx catalyst exhibits scalable performance, characterized by a high hydrogen generation rate (HGR) of 7716.7 mL min−1 g−1 and a low activation energy (Ea) of 44.9 kJ/mol, rivaling state-of-the-art catalysts. This work provides valuable insights for the development of advanced catalysts through P doping and boron vacancy engineering and the design of efficient and sustainable energy conversion systems.
Cancer cell spheroids (CCS) are a valuable three-dimensional cell model in cancer studies because they could replicate numerous characteristics of solid tumors. Increasing researches have used matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) to investigate the spatial distribution of endogenous compounds (e.g., lipids) in CCS. However, only limited lipid species can be detected owing to a low ion yield by using MALDI. Besides, it is still challenging to fully characterize the structural diversity of lipids due to the existence of isomeric/isobaric species. Here, we carried out the initial application of MALDI coupled with laser-postionization (MALDI-2) and trapped ion mobility spectrometry (TIMS) imaging in HCT116 colon CCS to address these challenges. We demonstrated that MALDI-2 is capable of detecting more number and classes of lipids in HCT116 colon CCS with higher signal intensities than MALDI. TIMS could successfully separate numerous isobaric/isomeric species of lipids in CCS. Interestingly, we found that some isomeric/isobaric species have totally different spatial distributions in colon CCS. Further MS/MS imaging analysis was employed to determine the compositions of fatty acid chains for isomeric species by examining disparities in signal intensities and spatial distributions of product ions. This work stresses the robust ability of TIMS and MALDI-2 imaging in analyzing endogenous lipids in CCS, which could potentially become powerful tools for future cancer studies.
Cultural relics have their unique artistic, cultural and historical value, and the protection of important cultural relics is conducive to the inheritance of historical culture. As a kind of cementing agent and binder commonly seen in cultural relics protection, epoxy resin is widely used in the bonding and consolidation of various materials in cultural relics, which has important practical application value. In this review, a systematic classification of commonly used epoxy resins, including their molecular structures, synthesis reactions and properties are provided, the problems and solutions of epoxy resin in cultural relics protection are summarized. The solutions are classified into three aspects: functional epoxy resin, blending modification, and other modification. Representative application examples of epoxy resin are listed in the field of cultural relics protection, and the development direction of epoxy resin in cultural relics protection in the future is proposed, which provides useful guidance for the modification of epoxy resin and its application in cultural relics protection in the future.
A novel N, O modified Mn3O4@porous carbon catalyst (NOC-Mn3O4) was prepared by direct carbonization using the manganese-metal organic framework (Mn-MOF) and covalent organic framework (COF) as precursors to activate peroxymonosulfate (PMS) for the degradation of bisphenol A (BPA) and rhodamine B (RhB). Benefiting from the N and O co-doping of COF, larger specific surface area, faster electron transfer and Mn cycling, the optimum 1NOC-Mn3O4 could significantly improve the degradation performance of BPA and RhB (92.1% and 96.9% within 30 min) as compared to C-Mn3O4 without COF doping. In addition, 1NOC-Mn3O4 showed good reusability and strong anti-interference ability. Radical quenching experiments, X-ray photoelectron spectroscopy (XPS), Electron paramagnetic resonance spectrometer (EPR) and electrochemical tests showed that the 1NOC-Mn3O4/PMS system degraded BPA and RhB by both radical and non-radical pathways. Moreover, the possible degradation pathways of BPA and RhB were proposed by liquid chromatography-mass spectrometry (LC-MS). Except for that, the toxicity of BPA, RhB and their intermediates were evaluated. This study opens up a new prospect for the design of COF-doped PMS catalysts.
The surface tension of troposphere aerosols can significantly influence their atmospheric processes and key properties, particularly on the morphology, the phase transition, the activation as cloud condensation nuclei, and the gas-particle partitioning. However, directly measuring the surface tension of single ambient aerosol is quite challenging, due to the limitations of their picolitre volumes and thermal motion. Here, we developed a dual laser tweezers Raman spectroscopy (DLT-RS) system to directly sense the surface tension of single airborne microdroplets (PM10 particles). A pair of aerosol droplets were trapped and driven to coalesce by the laser tweezers. Meanwhile, the backscattering light intensity and bright-field images during the coalescence process were recorded to characterize the aerosol surface tension. A remarkable advantage of directly sensing aerosol surface tension is that the solutes in aerosols are often supersaturated, which is common in atmospheric aerosols but almost unavailable in bulk solutions. We experimentally measured the surface tension of aerosols composed of nitrates or oxalic acid/nitrate mixture. Besides, the variation of surface tension during aerosol aging process was also explored, which brings possible implications on the surface evolution of actual ambient aerosol during their atmospheric lifetime.
The research on gas-liquid multiphase reactions using micro reactors is becoming increasingly widespread, given their excellent mass transfer performance. Establishing an accurate and reliable method to measure the gas-liquid mass transfer performance of micro reactors is crucial for evaluating and optimizing the design of micro reactor structure. In this paper, the physical absorption method of aqueous solution-CO2 and the chemical absorption method of sodium carbonate solution-CO2 were proposed. By analyzing the chemical reaction equilibrium during the absorption process, the relationship between the mass transfer of CO2 and the solubility of hydroxide ions in the solution was established, and the total gas-liquid mass transfer coefficient was immediately obtained by measuring the pH value. The corresponding testing platform and process have been established based on the characteristics of the proposed method to ensure fast and accurate measurement. In addition, the chemical absorption method takes into account temperature factors that were not previously considered. The volumetric mass transfer coefficient measured by these two methods is in the same range as those measured by other methods using the same microchannel structure in previous literature. The methods have the advantages of low equipment cost, faster measurement speed, and simpler procedures, which can facilitate its wide application to the evaluation of the mass transfer performance and hence can guide the structure optimization of microchannel reactors.
Achieving a high carrier migration efficiency by constructing built-in electric field is one of the promising approaches for promoting photocatalytic activity. Herein, we have designed a donor-acceptor (D-A) crystalline carbon nitride (APMCN) with 4-amino-2,6-dihydroxypyrimidine (AP) as electron donor, in which the pyrimidine ring was well embedded in the heptazine ring via hydrogen-bonding effect during hydrothermal process. The APMCN shows superior charge-transfer due to giant built-in electric field (5.94 times higher than pristine carbon nitride), thereby exhibiting excellent photocatalytic H2 evolution rate (1350 µmol/h) with a high AQY (62.8%) at 400 nm. Mechanistic analysis based on detailed experimental investigation together with theoretical analysis reveals that the excellent photocatalytic activity is attributed to the promoted charge separation by the giant internal electric field originated from the D–A structure.
Photocatalytic conversion of CO2 into small-molecule chemical feedstocks can meet the growing demand for energy and alleviate the global warming. Herein, a p-n ZnO@CDs@Co3O4 heterojunction with sandwich structure was constructed by calcination method of self-assembled ZIF-8@CDs@ZIF-67. The ZnO@CDs@Co3O4 with well-defined interfacial structure exhibited the significantly enhanced photocatalytic CO2 reduction activity, and the optimal catalyst indicated the (CO + CH4) evolution rate of 214.53 µmol g−1 h−1 under simulated solar light, which was superior to ZnO, Co3O4 and binary ZnO@Co3O4. The internal cavity, exposed active sites, multiple interfaces and constructed p-n heterojunction can facilitate the light harvesting and photoexcited electron transfer. Besides, after introduction of CDs placed in the middle layer between ZnO and Co3O4, CDs with excellent photoelectric property further promoted charge separation and migration. This work represents an appealing strategy to construct well-defined photocatalysts for boosting CO2 photoreduction.
Aging is a natural physiological process with various challenges, related to the loss of homeostasis within the organism, which is not a disease, but a significantly strong risk factor for multiple diseases, including myocardial infarction, stroke, some age-related cancers, macular degeneration, osteoarthritis, neurodegeneration, and many others. In the body, the main manifestation of aging is cellular aging, which exists within tissues and has a local or global impact on tissue function. However, the lack of effective aging detection tools has always been an issue that cannot be ignored in the field of aging research. Therefore, it is necessary to construct a non-invasive tool for in vivo detection of aging. Here, we show that the photoacoustic probe (LGAL), which has peak excitation and emission wavelengths in the near-infrared optical window, binds in vivo and at high contrast to the hallmark of aging, and allows for the microscopic imaging of aging through the intact mice. Firstly, this tool LGAL has been successfully applied to detect senescence in cells, displaying stronger photoacoustic signals than normal cells. Then, by using the photoacoustic probe, the blood vessels and tissues inside the mice can be visualized. Young and elderly mice exhibit varying intensities of photoacoustic signals, marking the first time a probe has been used to explore the aging of blood vessels and tissues inside the mice. Finally, we monitored the changes in the degree of aging during tumor treatment under photoacoustic (PA) imaging for the first time. As the treatment time increased, the degree of aging of the tumor gradually deepened. We expect the powerful tool could be a noninvasive and powerful tool for the study of aging biology.
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