Latest ArticlesNanoplastics exhibit greater environmental biotoxicity than microplastics and can be ingested by humans through major routes such as tap water, bottled water and other drinking water. Nanoplastics present a challenge for air flotation due to their minute particle size, negative surface potential, and similar density to water. This study employed dodecyltrimethylammonium chloride (DTAC) as a modifier to improve conventional air flotation, which significantly enhanced the removal of polystyrene nanoplastics (PSNPs). Conventional air flotation removed only 3.09% of PSNPs, while air flotation modified by dodecyltrimethylammonium chloride (DTAC-modified air flotation) increased the removal of PSNPs to 98.05%. The analysis of the DTAC-modified air flotation mechanism was conducted using a combination of instruments, including a zeta potential analyzer, contact angle meter, laser particle size meter, high definition camera, scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and Fourier transform infrared spectrometer (FTIR). The results indicated that the incorporation of DTAC reversed the electrostatic repulsion between bubbles and PSNPs to electrostatic attraction, significantly enhancing the hydrophobic force in the system. This, in turn, improved the collision adhesion effect between bubbles and PSNPs. The experimental results indicated that even when the flotation time was reduced to 7 min, the DTAC-modified air flotation still achieved a high removal rate of 96.26%. Furthermore, changes in aeration, pH, and ionic strength did not significantly affect the performance of the modified air flotation for the removal of PSNPs. The removal rate of PSNPs in all three water bodies exceeded 95%. The DTAC-modified air flotation has excellent resistance to interference from complex conditions and shows great potential for practical application.
The radical difunctionalization of alkenes with sulfonyl bifunctional represents a powerful and straightforward approach to access functionalized alkane derivatives. However, both the mechanistic activation mode and the substrate scopes of this type of radical difunctionalizations are still limited. We demonstrate herein a modular photoredox strategy for the difunctionalization of alkenes, employing arylsulfonyl acetate as the bifunctional reagent. This approach involves a radical addition/Smiles rearrangement cascade process, offering a robust alternative for the synthesis of valuable γ,γ-diaryl and γ-aryl esters. A complementary oxidative bifunctional reagents activation mode is identified to govern the radical cascade reactions, facilitating the simultaneous incorporation of aryl and carboxylate-bearing alkyl groups into the alkenes with excellent diastereoselectivity. Noteworthy features of this method include mild reaction conditions, organophotocatalysis, high atom- and step-economy, excellent functional group compatibility and great structural diversity.
Chemodynamic therapy (CDT), using Fenton agents to generate highly cytotoxic •OH from H2O2 has been demonstrated as a powerful anticancer method. However, the insufficient endogenous H2O2 in tumor cells greatly limited its therapeutic effect. Herein, we prepared a pH-responsive β-lapachone-loaded iron-polyphenol nanocomplex (LIPN) through a one-pot method. β-Lapachone in LIPN selectively enhanced H2O2 concentration in tumor cells, and ferrous ions cascadely generated abundant cytotoxic •OH. Therefore, LIPN with cascade amplification of reactive oxygen species (ROS) showed high chemodynamic cytotoxicity in tumor cells, efficiently improving the expression of damage-associated molecular patterns (DAMPs), and exerting strong immunogenic cell death (ICD). As a result, LIPN exhibited efficient tumor inhibition ability in 4T1 subcutaneous tumor model in vivo with great biocompatibility. Additionally, the infiltration of cytotoxic CD8+ T lymphocytes and inhibition of regulatory CD4+ FoxP3+ T lymphocytes in tumors demonstrated the activation of immunosuppressive tumor microenvironment by LIPN-induced ICD. Therefore, this work provided a new approach to enhance ICD of chemodynamic therapy through selective cascade amplification of ROS in cancer cells.
The selective conversion of CO2 and NH3 into valuable nitriles presents significant potential for CO2 utilization. In this study, we exploited the synergistic interplay between silicon and fluoride to augment the nickel-catalyzed reductive cyanation of aryl pseudohalides containing silyl groups, utilizing CO2 and NH3 as the CN source. Our methodology exhibited exceptional compatibility with diverse functional groups, such as alcohols, ketones, ethers, esters, nitriles, olefins, pyridines, and quinolines, among others, as demonstrated by the successful synthesis of 58 different nitriles. Notably, we achieved high yields in the preparation of bifunctionalized molecules, including intermediates for perampanel, derived from o-silylaryl triflates, which are well-known as aryne precursors. Remarkably, no degradation of substrates or formation of aryne intermediates were observed. Mechanistic studies imply that the formation of penta-coordinated silyl isocyanate intermediates is crucial for the key C–C coupling step and the presence of vicinal silyl group in the substrate is beneficial to further make this step kinetically favorable.
Lipids serve as fundamental constituents of cell membranes and organelles. Recent studies have highlighted the significance of lipids as biomarkers in the diagnosis of breast cancer. Although liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) is widely employed for lipid analysis in complex samples, it suffers from limitations such as complexity and time-consuming procedures. In this study, we have developed dopamine-modified TiO2 nanoparticles (TiO2-DA) and applied the materials to assist the analysis of lipids by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The TiO2-DA can provide large specific surface area and acidic environment, well suited for lipid analysis. The method was initially validated using standard lipid molecules. Good sensitivity, reproducibility and quantification performance was observed. Then, the method was applied to the analysis of 90 serum samples from 30 patients with breast cancer, 30 patients with benign breast disease and 30 healthy controls. Five lipid molecules were identified as potential biomarkers for breast cancer. We constructed a classification model based on the MALDI-TOF MS signal of the 5 lipid molecules, and achieved high sensitivity, specificity and accuracy for the differentiation of breast cancer from benign breast disease and healthy control. We further collected another 60 serum samples from 20 healthy controls, 20 patients with benign breast disease and 20 patients with breast cancer for MALDI-TOF MS analysis to verify the accuracy of the classification model. This advancement holds great promise for the development of diagnostic models for other lipid metabolism-related diseases.
Photodynamic therapy (PDT) has received much attention in recent years. However, traditional photosensitizers (PSs) applied in PDT usually suffer from aggregation-caused quenching (ACQ) effect in H2O, single and inefficient photochemical mechanism of action (MoA), poor cancer targeting ability, etc. In this work, two novel Ru(Ⅱ)-based aggregation-induced emission (AIE) agents (Ru1 and Ru2) were developed. Both complexes exhibited long triplet excited lifetimes and nearly 100% singlet oxygen quantum yields in H2O. In addition, Ru1 and Ru2 displayed potent photo-catalytic reduced nicotinamide adenine dinucleotide (NADH) oxidation activity with turnover frequency (TOF) values of about 1779 and 2000 h−1, respectively. Therefore, both Ru1 and Ru2 showed efficient PDT activity towards a series of cancer cells. Moreover, Ru2 was further loaded in bovine serum albumin (BSA) to enhance the tumor targeting ability in vivo, and the obtained Ru2@BSA could selectively accumulate in tumor tissues and effectively inhibit tumor growth on a 4T1 tumor-bearing mouse model. So far as we know, this work represents the first report about Ru(Ⅱ) AIE agents that possess high singlet oxygen quantum yields and also potent photo-catalytic NADH oxidation activity, and may provide new ideas for rational design of novel PSs with efficient PDT activity.
Rational tuning of crystallographic surface and metal doping were effective to enhance the catalytic performance of metal organic frameworks, but limited work has been explored for achieving modulation of crystal facets and metal doping in a single system. MIL-68(In) was promising for photocatalytic applications due to its low toxicity and excellent photoresponsivity. However, its catalytic activity was constrained by severe carrier recombination and a lack of active sites. Herein, increased (001) facet ratio and active sites exposure were simultaneously realized by cobalt doping in MIL-68(In) through a one-pot solvothermal strategy. Optimized MIL-68(In/Co)-2.5 exhibited remarkable catalytic performance in comparison with pristine MIL-68(In) and other MIL-68(In/Co). The reaction kinetic constant and degradation efficiency of MIL-68(In/Co) were approximately twice and 17% higher than the pristine MIL-68(In) in 36 min reaction, respectively. Density functional theory calculations revealed that Co dopant could modulate the orientation of MIL-68(In) facets, facilitate the exchange of electrons and reduce the adsorption energy of peroxymonosulfate (PMS). This work provides a novel pathway for improvement of In-based MOFs in PMS/vis system, it also promotes the profound comprehension of the correlation between crystal facet regulation and catalytic activation in the PMS/vis system.
Tumor blockade therapy inhibits tumor progression by cutting off essential supplies of nutrients, oxygen, and biomolecules from the surrounding microenvironments. Inspired by natural processes, tumor biomineralization has evolved due to its biocompatibility, self-reinforcing capability, and penetration-independent mechanism. However, the selective induction of tumor biomineralization using synthetic tools presents a significant challenge. Herein, a metabolic glycoengineering-assistant tumor biomineralization strategy was developed. Specifically, the azido group (N3) was introduced onto the cytomembrane by incubating tumor cells with glycose analog Ac4ManNAz. In addition, a bisphosphonate-containing polymer, dibenzocyclooctyne-poly(ethylene glycol)-alendronate (DBCO-PEG-ALN, DBPA) was synthesized, which attached to the tumor cell surface via "click chemistry" reaction between DBCO and N3. Subsequently, the bisphosphonate group on the cell surface chelated with positively charged ions in the microenvironments, triggering a consecutive process of biomineralization. This physical barrier significantly reduced tumor cell viability and mobility in a calcium ion concentration-dependent manner, suggesting its potential as an effective anti-tumor strategy for in vivo applications.
The typical wastewater treatment is focused on the photocatalytic efficiency in the degradation of organic pollutants, with little attention to the involved selectivity which may correlate with toxicant residues. Herein, an electron localization strategy for specific O2 adsorption/activation enabled by photothermal/pyroelectric effect and in situ constructed active centers of single-atom Co and oxygen vacancy (Co-OV) on the Co/BiOCl-OV photocatalyst was developed for photocatalytic degradation of glyphosate (GLP) wastewater of high performance/selectivity. Under full-spectrum-light irradiation, a high GLP degradation rate of 99.8% with over 90% C‒P bond-breaking selectivity was achieved within 2 h, while effectively circumventing toxicant residues such as aminomethylphosphonic acid (AMPA). X-ray absorption spectroscopy and relevant characterizations expounded the tailored anchoring of Co single atoms onto the BiOCl-OV carrier and photothermal/pyroelectric effect. The oriented formation of more •O2− on Co/BiOCl-OV could be achieved with the Co-OV coupled center that had excellent O2 adsorption/activation capacity, as demonstrated by quantum calculations. The formed unique Co-OV active sites could largely decrease the C‒P bond-breaking energy barrier, thus greatly improving the selectivity toward the initial C‒P bond scission and the activity in subsequent conversion steps in the directional photocatalytic degradation of GLP. The electron localization strategy by in situ constructing the coupled active centers provides an efficient scheme and new insights for the low-toxic photodegradation of organic pollutants containing C‒X bonds.
Algal copper uptake (i.e., Cu bioavailability) in the euphotic zone plays a vital role in algal photosynthesis and respiration, affecting the primary productivity and the source and sink of atmospheric carbon. Algal Cu uptake is controlled by natural dissolved organic Cu (DOCu) speciation (i.e., complexed with the dissolved organic matter) that conventionally could be tested by model prediction or molecular-level characterizations in the lab, while DOCu uptake are hardly directly assessed. Thus, the new chemistry-biology insight into the mechanisms of the Cu uptake process in algae is urgent. The DOCu speciation transformation (organic DOCu to free Cu(Ⅱ) ions), enzymatic reduction-induced valence change (reduction of free Cu(Ⅱ) to Cu(Ⅰ) ions), and algal Cu uptake at the algae-water interface are imitated. Herein, an intelligent system with DOCu colorimetric sensor is developed for real-time monitoring of newly generated Cu(Ⅰ) ions. Deep learning with whole sample image-based characterization and powerful feature extraction capabilities facilitates colorimetric measurement. In this context, the Cu bioavailability with 7 kinds of organic ligands (e.g., amino acids, organic acids, carbohydrates) can be predicted by the mimetic intelligent biosensor within 15.0 min, i.e., the DOCu uptake and speciation is successfully predicted and streamlined by the biomimetic approach.
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