Neutral cholic acid–coumarin conjugate exhibit excellent anion binding properties by cooperative aryl CH and amide NH segments

<p>A neutral cholic acid–coumarin conjugate was developed for anion recognition. It is revealed by the experimental and theoretical results that the coumarin group can provide CH segments as hydrogen bond donors by cooperation with the adjoining amide NH segments. With excellent biocompatibility, this receptor with coumarin as fluorescence sensors also have the potential to be used as an efficient and non-destructive probe for anion detection in living cells. This work displays a new insight into the importance of coumarin group as anion recognition group, which is not well presented so far.</p

Nanotunnel Structures within Metal Oxides Induce Active Sites for the Strong Self-Reduction of Mn^IV to Mn^II

Zn2SiO4, Zn2GeO4, and CdAl2O4 possess high electron density in their six-membered-ring nanotunnels, manganese from MnO2 was successfully doped into them, and green or blue phosphors were produced in air. It is nanotunnel A with high electron density that induces active sites for the reduction of MnIV. MnIV is captured and reduced to MnII on active sites by seizing two electrons from native defect VO× (VO× + Mn4+ → VO·· + Mn2+). CdB4O7:0.02Mn2+ was also synthesized from MnO2 or MnCO3 to confirm the role of nanotunnels. Such inorganic crystals with unique nanotunnel structure may bring more amazing performances in the field of materials in the future

Dendritic Cu²⁺-Doped Ca₂SiO₄ Nanosphere for Cancer Therapy via Double Ion Interference

Ion interference therapy (IIT) is a promising cancer treatment strategy that can reverse ion distribution via bioactive nanomaterials so as to interfere with or hinder the physiological processes such as metabolism and proliferation of tumor cells. In this study, a dendritic Cu2+-doped calcium silicate nanosphere (Ca2SiO4) loaded with ruthenium red (RuR) and disulfiram (DSF) (RD-CCP) was constructed for self-enhanced chemodynamic therapy and IIT of tumors through the combination of Cu and Ca. Under the slightly acidic environment of the tumor, dendritic RD-CCP nanospheres (NPs) rapidly collapsed, and a toxic dithiocarbamate–Cu complex was generated in situ through the chelation reaction between DSF and the co-released Cu2+ ions. ROS accumulation was promoted by Fenton-like reaction between the Cu+ ions and the high level of H2O2 and glutathione. In addition, Ca2+-overload was promoted by the combination of the input of exogenous Ca2+ and the participation of RuR, which can inhibit the Ca2+ transport channel (MCU and SERCA), therefore promoting mitochondrial damage and enhancing oxidative stress in tumor cells. Furthermore, calcium transport channel imbalance caused by oxidative stress can promote tumor calcification and necrosis. In conclusion, dendritic RD-CCP NPs can simultaneously induce a Fenton-like response and a calcium-related signal imbalance at the tumor site through the double interference of Cu2+ and Ca2+, eventually leading to rapid tumor apoptosis, which has great application potential in the clinical application of tumor therapy

pH-Regulating Nanoplatform for the “Double Channel Chase ” of Tumor Cells by the Synergistic Cascade between Chlorine Treatment and Methionine-Depletion Starvation Therapy

During rapid proliferation and metabolism, tumor cells show a high dependence on methionine. The deficiency of methionine exhibits significant inhibition on tumor growth, which provides a potential therapeutic target in tumor therapy. Herein, ClO2-loaded nanoparticles (fluvastatin sodium&metformin&bupivacaine&ClO2@CaSiO3@MnO2-arginine-glycine-aspatic acid (RGD) (MFBC@CMR) NPs) were prepared for synergistic chlorine treatment and methionine-depletion starvation therapy. After outer layer MnO2 was degraded in the high glutathione (GSH) tumor microenvironment (TME), MFBC@CMR NPs released metformin (Me) to target the mitochondria, thus interfering with the tricarboxylic acid (TCA) cycle and promoting the production of lactate. In addition, released fluvastatin sodium (Flu) by the NPs acted on monocarboxylic acid transporter 4 (MCT4) in the cell membrane to inhibit lactate leakage and induce a decrease of intracellular pH, further prompting the NPs to release chlorine dioxide (ClO2), which then oxidized methionine, inhibited tumor growth, and produced large numbers of Cl– in the cytoplasm. Cl– could enter mitochondria through the voltage-dependent anion channel (VDAC) channel, which was opened by bupivacaine (Bup). The disruption of Cl– homeostasis promotes mitochondrial damage and membrane potential decline, leading to the release of cytochrome C (Cyt-C) and apoptosis inducing factor (AIF) and further inducing cell apoptosis. To sum up, the pH-regulating and ClO2-loaded MFBC@CMR nanoplatform can achieve cascade chlorine treatment and methionine-depletion starvation therapy toward tumor cells, which is of great significance for improving the clinical tumor treatment effect

Rapidly and highly efficient degradation of tetracycline hydrochloride in wastewater by 3D IO-TiO₂-CdS nanocomposite under visible light

Tetracycline hydrochloride as an environmental pollutant is biologically toxic and highly difficult to degrade. To solve this problem, an efficient catalyst IO-TiO2-CdS composite with honeycomb-like three-dimensional (3D) inverse opal TiO2 (IO-TiO2) and cadmium sulphide (CdS) was synthesized and applied in the degradation of tetracycline hydrochloride in this paper. More than 99% of the tetracycline hydrochloride (30 mg/L) can be degraded by IO-TiO2-CdS (30 mg) within 20 min under visible light irradiation. Surprisingly, the naphthol rings can be opened and degraded to alkane with a minimum molecular weight of 60, which is the smallest fragment among all publications. The three-dimensional ordered macroporous (3DOM) structure of IO-TiO2 improves the utilization of light via the slow photon effect. Meanwhile, the addition of CdS enhances the degradation efficiency of tetracycline by broadening the range of absorption spectrum and improving the separation of charge carrier on the catalyst. In addition to the degradation of tetracycline hydrochloride, IO-TiO2-CdS also shows a good degradation efficiency of Rhodamine B (RhB). This work provides a promising approach to construct visible light response photocatalysts with non-noble metal for efficient degradation of wastewater pollutants.</p

pH-Activated Scallop-Type Nanoenzymes for Oxidative Stress Amplification and Photothermal Enhancement of Antibacterial and Antibiofilm Effect

Ferric phosphate (FePOs) nanoenzymes can express peroxidase (POD) activity under the dual stimulation of an acidic environment and high H2O2 concentrations. In living organisms, this generates reactive oxygen species (ROS) in sites of lesion infection, and thus FePOs nanoenzymes can act as antimicrobial agents. Here, CeO2 and ZnO2 were immobilized in a scallop-type FePOs nanoenzyme material loaded with a photosensitizer, indocyanine green, to synthesize a multifunctional cascade nanoparticle system (FePOs–CeO2–ZnO2–ICG, FCZI NPs). H2O2 concentrations could be adjusted through the ZnO2 self-activation response to the slightly acidic environment in biofilms, further promoting the release of ROS from the POD-like reaction of FePOs, achieving amplification of oxidative stress, DNA and cell membrane damage, and exploiting the photodynamic/photothermal effects of indocyanine green to enhance the antibiofilm effects. CeO2 can remove redundant ROS by switching from Ce4+ to Ce3+ valence, enhancing its ability to fight chronic inflammation and oxidative stress and thus promoting the regeneration of tissues around infection. By maintaining the redox balance of normal cells, increasing ROS at the infection site, eliminating redundant ROS, and protecting normal tissues from damage, the synthesized system maximizes the elimination of biofilms and treatment at the infection site. Therefore, this work may pave the way for the application of biocompatible nanoenzymes