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1.
Carbohydr Polym ; 300: 120240, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36372505

RESUMO

Kinetic models and mechanism of isomaltooligosaccharides (IMOs) by hydroxyl (OH) radicals-driven degradation in ultraviolet/hydrogen peroxide system were investigated. Electron paramagnetic resonance spectra indicated that UV radiation played an important role in the steady generation of OH radicals. The OH radicals could effectively decrease the molecular weight of IMOs and significantly oxidize hydroxy group into carbonyl and carboxy groups. Main components of IMOs were separated and identified by HPAEC-PAD and UHPLC-MS/MS methods. Degradation behaviors of IMOs were well fitted to pseudo first-order kinetics. The hydrogen abstraction by OH radicals from different CH sites at pyranose ring began a cascade reaction leading to cleavage of α-glycosidic linkage or CC bonds with formation of stable uronic/aldonic acids. Degradation rate was closely influenced by the degree of polymerization (DP) of IMOs, the initial concentrations of IMOs and H2O2. The results would pave the way for free radicals-driven degradation of polysaccharides.


Assuntos
Radical Hidroxila , Poluentes Químicos da Água , Radical Hidroxila/química , Peróxido de Hidrogênio/química , Raios Ultravioleta , Espectrometria de Massas em Tandem , Poluentes Químicos da Água/química , Cinética , Oxirredução
2.
J Environ Sci (China) ; 125: 26-36, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36375912

RESUMO

Herein, a one-step co-pyrolysis protocol was adopted for the first time to prepare a novel pyrogenic carbon-Cu0/Fe3O4 heteroatoms (FCBC) in CO2 ambiance to discern the roles of each component in PDS activation. During co-pyrolysis, CO2 catalyzed formation of reducing gases by biomass which facilitated reductive transformation of Fe3+ and Cu2+ to Cu0 and Fe3O4, respectively. According to the analysis, the resulting metal (oxide) catalyzed graphitization of biocharand decomposition of volatile substances resulting in an unprecedented surface area (1240 m2/g). The resulting FCBC showed greater structural defects and less electrical impedance. Batch experiments indicated that Rhodamine B (RhB) degradation by FCBC (100%) was superior to Fe3O4 (50%) and Cu0/Fe3O4 (76.4%) in persulfate (PDS) system, which maintained reasonable efficiency (75.6%-63.6%) within three cycles. The reactive oxygen species (ROS) associated with RhB degradation was identified by an electron paramagnetic resonance and confirmed by scavenging experiments. RhB degradation invoked both (sulfate and dominantly hydroxyl) radical and non-radical (singlet oxygen, 1O2) pathways. Regarding FCBC, Cu0 can continuously react with Fe3+ in Fe3O4 to generate larger quantities of Fe2+, and both Cu0 and Fe2+ activated PDS to yield sulfate radicals which was quickly converted to hydroxyl radical. Besides, Cu0/Cu2+ could complex with PDS to form a metastable complex, which particularly contributed to 1O2 generation. These cascade reactions by FCBC were reinforced by carbonyl group of biochar and favorable electron transfer ability. This work highlighted a new approach to prepare a magnetic and environment-benign heterogonous catalyst to remove organic pollutants in water.


Assuntos
Grafite , Pirólise , Dióxido de Carbono , Carvão Vegetal/química , Sulfatos/química , Radical Hidroxila
3.
J Environ Sci (China) ; 124: 557-569, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36182163

RESUMO

Atmospheric oxidizing capacity (AOC) is the fundamental driving factors of chemistry process (e.g., the formation of ozone (O3) and secondary organic aerosols (SOA)) in the troposphere. However, accurate quantification of AOC still remains uncertainty. In this study, a comprehensive field campaign was conducted during autumn 2019 in downtown of Beijing, where O3 and PM2.5 episodes had been experienced successively. The observation-based model (OBM) is used to quantify the AOC at O3 and PM2.5 episodes. The strong intensity of AOC is found at O3 and PM2.5 episodes, and hydroxyl radical (OH) is the dominating daytime oxidant for both episodes. The photolysis of O3 is main source of OH at O3 episode; the photolysis of nitrous acid (HONO) and formaldehyde (HCHO) plays important role in OH formation at PM2.5 episode. The radicals loss routines vary according to precursor pollutants, resulting in different types of air pollution. O3 budgets and sensitivity analysis indicates that O3 production is transition regime (both VOC and NOx-limited) at O3 episode. The heterogeneous reaction of hydroperoxy radicals (HO2) on aerosol surfaces has significant influence on OH and O3 production rates. The HO2 uptake coefficient (γHO2) is the determining factor and required accurate measurement in real atmospheric environment. Our findings could provide the important bases for coordinated control of PM2.5 and O3 pollution.


Assuntos
Poluentes Atmosféricos , Ozônio , Compostos Orgânicos Voláteis , Aerossóis/análise , Poluentes Atmosféricos/análise , Pequim , China , Monitoramento Ambiental , Formaldeído , Radical Hidroxila/análise , Ácido Nitroso , Oxidantes , Oxirredução , Ozônio/análise , Material Particulado/análise , Compostos Orgânicos Voláteis/análise
4.
J Hazard Mater ; 442: 130088, 2023 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-36206712

RESUMO

Understanding the photocatalytic reductive dehalogenation mechanism of halogenated aromatic pollutants is of great research value. However, the proton source in the photocatalytic dehalogenation process of representative halogenated aromatic pollutants by TiO2 is not clear. In this study, the TiO2 surface was modified by hydrochloric acid, sodium hydroxide, and sodium fluoride to obtain TiO2 samples with different hydroxyl groups. It was found that the hydroxyl groups on the surface of TiO2 affects the sequence of proton and electron transfer in dehalogenation. The abundance of hydroxyl groups on the surface of TiO2 can accelerate the reductive dehalogenation process of representative halogenated aromatic pollutants. The kinetic solvent isotope effect was used to study the proton-coupled electron transfer process in the reaction. It shows that the enriching of protons on TiO2 bridging oxygen (bridging hydroxyl groups) is conducive to the rapid step of protonation of the reactant, and subsequent proton and electron transfer. On the contrary, the bridging hydroxyl groups can be removed by reacting with strongly basic sodium hydroxide and sodium ions can occupy the bridging oxygen. The substitution of bridging oxygen by fluorine ions can also lead to the destruction of bridge hydroxyl groups. Significantly, the absence of bridging hydroxyl groups on titanium dioxide will lead to the dehalogenation of representative halogenated aromatic pollutants initiated by electron transfer. This study is helpful to understand dehalogenation reaction paths catalyzed by TiO2.


Assuntos
Poluentes Ambientais , Prótons , Flúor , Hidróxido de Sódio , Ácido Clorídrico , Fluoreto de Sódio , Titânio , Radical Hidroxila , Oxigênio , Solventes , Sódio
5.
J Hazard Mater ; 442: 130014, 2023 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-36152542

RESUMO

Percarbonate (SPC) has drawn considerable attention due to its merits in the safety of handling and transport, stability, and price as well as environmental friendliness, which has been extensively applied in advanced oxidation processes (AOPs) for water decontamination. Nevertheless, comprehensive information on the application of SPC-AOPs for the treatment of organic compounds in aquatic media is scarce. Hence, the focus of this review is to shed light on the mechanisms of reactive oxygen species (ROS) evolution in typical SPC-AOPs (i.e., Fenton-like oxidation, photo-assisted oxidation, and discharge plasma-involved oxidation processes). These SPC-AOPs enable the formation of multiple reactive species like hydroxyl radical (•OH), superoxide radical (O2•-), singlet oxygen (1O2), carbonate radicals (CO3•-), and peroxymonocarbonate (HCO4-), which together or solely contribute to the degradation of target pollutants. Simultaneously, the potential challenges in practical applications of SPC-AOPs are systematically discussed, which include the influence of water quality parameters, cost-effectiveness, available active sites, feasible activation approaches, and ecotoxicity. Subsequently, enhancing strategies to improve the feasibility of SPC-AOPs in the practical implementation are tentatively proposed, which can be achieved by introducing reducing and chelating agents, developing novel activation approaches, designing multiple integrated oxidation processes, as well as alleviating the toxicity after SPC-AOPs treatment. Accordingly, future perspectives and research gaps in SPC-AOPs are elucidated. This review will hopefully offer valuable viewpoints and promote the future development of SPC-AOPs for actual water purification.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Radical Hidroxila/química , Espécies Reativas de Oxigênio , Superóxidos , Oxigênio Singlete , Poluentes Químicos da Água/química , Carbonatos/química , Oxirredução , Peróxido de Hidrogênio/química , Quelantes
6.
J Hazard Mater ; 442: 129913, 2023 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-36152544

RESUMO

Hexavalent chromium (Cr(VI)) was activated by ultraviolet-A light-emitting diode (UVA-LED), resulting in efficient removal of various pollutants, including dye, pharmaceuticals, and pesticides, with pseudo-first-order rate constants of 0.0610-0.159 min-1. Comparatively, UVA-LED or Cr(VI) alone barely degraded selected pollutants. Both HO• and Cr(V) were produced in the UVA-LED/Cr(VI) system based on scavenging and probing experiments, UV-visible and electron spin resonance spectra analysis. HO• was demonstrated to be the dominant reactive species via stepwise regeneration of Cr(V) to Cr(VI). The quantum yield of HO• was determined to be 7.79 × 10-4 mol Es-1 at a Cr(VI) dosage of 0.5 mM and pH of 6.0. Additionally, the degradation efficiency of sulfamethoxazole (SMX) as a model compound decreased linearly as UVA-LED wavelengths increased from 365 to 405 nm, while SMX was barely degraded at visible light irradiation wavelength ranges (449-505 nm). SMX degradation efficiency increased from 71.0 % to 97.5 % as Cr(VI) dosage increased from 0.05 to 0.7 mM. pH displayed a negative impact on SMX degradation with its removal efficiency decreasing from 99.4 % to 13.3 % as pH increased from 3.0 to 9.0. This study first reported that HO• was generated via activation of Cr(VI) by UVA-LED, which is instructive for the removal of pollutants co-existed in chromium-containing wastewater.


Assuntos
Poluentes Ambientais , Praguicidas , Poluentes Químicos da Água , Radical Hidroxila , Águas Residuárias/química , Descontaminação , Oxirredução , Cromo/química , Sulfametoxazol/química , Preparações Farmacêuticas , Poluentes Químicos da Água/química
7.
Spectrochim Acta A Mol Biomol Spectrosc ; 285: 121837, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36137499

RESUMO

Quantifying the mid-range infrared hydroxyl stretch absorbance region has traditionally been a challenge due to the wavenumber dependence of the attenuation coefficient. Interpretation often assigns a single attenuation coefficient to each type of hydrogen-bonded aggregate. This work leverages a recently developed technique of scaling hydroxyl stretching absorbances in the mid-infrared region with a continuous attenuation coefficient function that produces integrated areas which directly correlate to hydroxyl concentrations. After scaling, the hydroxyl absorbance is fitted with five curves, of which four are dominant. These four curves represent unique hydroxyl configurations and translate to specific aggregate structures. The technique is applied to ethanol and 1-butanol. The resulting population distributions of hydrogen-bonded hydroxyl configurations are compared with the resummed thermodynamic perturbation theory (RTPT) model for linear chains as a function of concentration and temperature. The model is demonstrated to capture the critical features of the distributions.


Assuntos
1-Butanol , Etanol , Etanol/química , Ligação de Hidrogênio , Hidrogênio , Radical Hidroxila , Cicloexanos
8.
Sci Total Environ ; 855: 158644, 2023 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-36096216

RESUMO

Traditional NOx treatment methods require external reducing reagents and harsh reaction conditions, which is not conducive to effectively eliminate NOx at low concentration, especially at ppb levels. Fortunately, low concentration NOx can be removed by photocatalytic oxidation under mild reaction conditions. Bismuth (Bi)-based photocatalysts with the layered structure have obtained considerable concerns of photocatalytic NOx oxidation. This review focused on typical layered Bi-based photocatalysts (Bi2WO6, Bi2O2CO3, BiOY (YCl, Br, and I), BiOIO3, and BiOCOOH) with the structure of [Bi2O2]2+ layer for photocatalytic NOx oxidation. The strategies (morphological control, defect engineering, heterostructure construction, etc.) to improve photocatalytic oxidation activity were summarized. Furthermore, the mechanism involving various free radicals (hydroxyl radical, superoxide radical, etc.) of photocatalytic oxidation of NOx was proposed. In addition, the non-NO2 selectivity was also illuminated. Lastly, the current drawbacks and further research directions for photocatalytic NOx oxidation were elaborated. The development of photocatalysts with high photocatalytic activity, wide light absorption range, and non-NO2 selectivity is the focus of future research. This review aims to provide a pandect and theoretical guidance for the practical application of photocatalytic oxidation of NOx.


Assuntos
Bismuto , Óxidos de Nitrogênio , Bismuto/química , Oxirredução , Radical Hidroxila/química , Catálise
9.
Sci Total Environ ; 855: 158750, 2023 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-36108839

RESUMO

Tylosin (TYL) is a ubiquitous macrolide antibiotic which has been frequently detected in natural aqueous environment. Montmorillonite (MMT), a major component of natural suspended particles, plays essential roles in the transportation and transformation processes of various organic contaminants. This study systematically investigated the photodegradation behavior and mechanism of TYL in MMT suspensions under simulated sunlight irradiation. In the existence of 0.1 g L-1 Na-MMT, >80.8 % TYL was degraded after 8 h irradiation, which was significantly higher than that in the absence of MMT (42.5 %). Further mechanistic studies suggested that the synergistic effects including the formation of surface complex and the generation of surface hydroxyl radicals play essential roles in the accelerated TYL phototransformation. Meanwhile, other factors like exchangeable cations of MMTs, pH and ionic strength could also strongly influence the TYL photodegradation. The probable degradation pathways of TYL in MMT suspension was further proposed based on the detected intermediates and DFT calculations. Photobacterium phospherium T3 bioluminescent assay revealed that the photodegradation products of TYL have a lower acute toxicity than bulk TYL, especially in the presence of MMT. This study provides new insights for the photodegradation pathways of organic contaminants in aqueous environments, which is of great importance for assessing the fate and risk of emerging pollutants in natural surface water bodies.


Assuntos
Tilosina , Poluentes Químicos da Água , Adsorção , Fotólise , Bentonita , Radical Hidroxila , Água
10.
Med Gas Res ; 13(2): 89-91, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36204788

RESUMO

Most of the drugs used in modern medical treatments are symptomatic treatments and are far from being a cure for the diseases. The adverse effects are unavoidable in the drugs in modern medical treatments. Molecular hydrogen (H2) has a remarkable therapeutic effect on various diseases, and many clinical studies have reported that H2 has no adverse effects. Therefore, H2 is a novel medical gas that is outside the concept of modern medical treatment. H2, unlike drugs, works on the root of many diseases by scavenging the two kinds of strong reactive oxygen species, hydroxyl radical (·OH) and peroxynitrite (ONOO-). Since the H2 alleviates the root of diseases and can treat many diseases at the same time, the medical application of H2 may be called "machine gun therapy." In this review, we demonstrated that the root of many diseases is based on ·OH-induced oxidative stress in the mitochondria, and at the same time, the root of chronic inflammation is also attributed to ·OH.


Assuntos
Hidrogênio , Ácido Peroxinitroso , Hidrogênio/farmacologia , Hidrogênio/uso terapêutico , Radical Hidroxila , Estresse Oxidativo , Ácido Peroxinitroso/farmacologia , Espécies Reativas de Oxigênio
11.
J Colloid Interface Sci ; 630(Pt B): 704-713, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36347097

RESUMO

The degradation and mineralization of volatile organic compounds (VOCs) in gas-solid phase photocatalytic systems suffer great challenges due to the low electron transfer efficiency and slow benzene ring-opening kinetics. Hence, a heterojunction photocatalyst of Bi2SiO5/TiO2 has been synthesized by a facile method. Bi2SiO5/TiO2 shows the ability of mineralizing toluene to CO2 with a degradation rate of 85.5%, while TiO2 is 49.0% and presents a continuous deactivation. Experimental characterizations and theoretical calculations indicate that a unique electron transfer channel of Bi/Si-O-Ti can be established in the heterojunction sample due to the coupling of the interface. The channel facilitates electron transfer to the catalyst surface, generating •OH radicals with strong oxidation and ring-opening ability. Moreover, in-situ DRIFTS reveal that the selective generation of benzoic acid on Bi2SiO5/TiO2 heterojunction plays a critical role in the ring-opening of toluene. This work discloses a novel paradigm to obtain the deep and durable photocatalytic mineralization of toluene.


Assuntos
Radical Hidroxila , Tolueno , Elétrons , Titânio
12.
J Environ Sci (China) ; 124: 300-309, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36182139

RESUMO

Cyanide (CN-) is extensively used in the process of plating devices and for surface treatment in the electroplating industry and is extremely hazardous to humans and the environment. Peroxymonosulfate (PMS)-based advanced oxidation processes (AOPs) hold considerable promise for CN- removal. However, the activity of sulfate radical and hydroxyl radical generated in the PMS activation process is low in the base condition, leading to a drop in its efficiency in CN- removal. Thus, a photo-electrocatalytic system (PEC), developed using a TiO2 photoanode and a carbon aerogel cathode, was used to activate PMS for the removal of CN- from wastewater through the generation of radicals and non-radicals. The PEC/PMS system could effectively remove CN-, with the removal efficiency reaching 98.5% within 2 min, when PMS concentration was at the 0.25 mmol/L level, and the applied bias voltage was -0.5 V. The main active species in the PEC/PMS system were superoxide radicals and singlet oxygen, which was proved through electron paramagnetic resonance detection and quenching experiments. Results obtained through in-situ Raman measurements, photocurrent tests, and electrochemical impedance spectroscopy measurements indicated that the TiO2 could activate PMS to generate active species. Following many cycles of experimentation, it was discovered that the system displayed high catalytic performance and possessed satisfactory stability to remove CN- economically and efficiently.


Assuntos
Nanotubos , Oxigênio Singlete , Carbono/química , Cianetos , Humanos , Radical Hidroxila/química , Peróxidos/química , Oxigênio Singlete/química , Superóxidos , Titânio , Águas Residuárias
13.
Anal Chim Acta ; 1235: 340537, 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-36368825

RESUMO

As the most aggressive reactive oxygen species (ROS), hydroxyl radical (•OH) can directly modulate the biological ion channel and interfere with the progression of diseases. Inspired by biological •OH-activated ion channel, we reported a novel •OH-regulated glass nanopore functionalized with protoporphyrin Ⅸ (PP) film. This system showed outstanding •OH selective response owing to the ultra-fast reaction between •OH and thiol derivatives. In this case, the PP film is responsible for the changing not only of wettability but also of the inner surface charge. The synergetic effect of the dual transitions can regulate the ion transportation within the nanochannels and enabled tremendous enhancement of responsive efficiency. The detection limit could be achieved down to 1.58 nM. Taking advantage of the excellent analytical performance and mechanical qualities of this glass nanopore, the changes of •OH in single living cells were in situ monitored. Together, this study is beneficial for exploring the role of •OH in pathological events and shows promising potential for biomedical research.


Assuntos
Radical Hidroxila , Nanoporos , Espécies Reativas de Oxigênio , Vidro
14.
RNA Biol ; 19(1): 1179-1189, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36369947

RESUMO

Given the challenges for the experimental determination of RNA tertiary structures, probing solvent accessibility has become increasingly important to gain functional insights. Among various chemical probes developed, backbone-cleaving hydroxyl radical is the only one that can provide unbiased detection of all accessible nucleotides. However, the readouts have been based on reverse transcription (RT) stop at the cleaving sites, which are prone to false positives due to PCR amplification bias, early drop-off of reverse transcriptase, and the use of random primers in RT reaction. Here, we introduced a fixed-primer method called RL-Seq by performing RtcB Ligation (RL) between a fixed 5'-OH-end linker and unique 3'-P-end fragments from hydroxyl radical cleavage prior to high-throughput sequencing. The application of this method to E. coli ribosomes confirmed its ability to accurately probe solvent accessibility with high sensitivity (low required sequencing depth) and accuracy (strong correlation to structure-derived values) at the single-nucleotide resolution. Moreover, a near-perfect correlation was found between the experiments with and without using unique molecular identifiers, indicating negligible PCR biases in RL-Seq. Further improvement of RL-Seq and its potential transcriptome-wide applications are discussed.


Assuntos
Aminoacil-tRNA Sintetases , Proteínas de Escherichia coli , RNA/genética , RNA/química , Radical Hidroxila/química , Conformação de Ácido Nucleico , Nucleotídeos , Solventes/química , Escherichia coli/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Aminoacil-tRNA Sintetases/genética , Proteínas de Escherichia coli/genética
15.
Biosensors (Basel) ; 12(10)2022 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-36290967

RESUMO

Copper peroxide/zeolitic imidazolate framework/polydopamine nanoparticles (CP/ZIF-8/PDA)-based fluorescence-linked immunosorbent assay (FLISA) was designed for the sensitive and high-throughput determination of carcinoembryonic antigen (CEA) by self-supplied H2O2 generation. Specifically, the CEA aptamer was modified on the surface of CP/ZIF-8/PDA to form an immunoprobe. The structures of CP and ZIF-8 could be broken under acidic conditions, and produced the Cu2+ and H2O2 due to the dissociation the CP. A subsequent Fenton-type reaction of Cu2+ and H2O2 generated hydroxyl radical (·OH). o-phenylenediamine (OPD) was oxidized by the ·OH to form 2, 3-diaminophenazine (DPA) with a significant fluorescence signal. CP/ZIF-8/PDA could be used as an efficient Fenton-type reactant to generate a large amount of ·OH to promote OPD oxidation. The sensitive detection of CEA could be realized. Under optimal conditions, the FLISA platform displayed a linear detection range from 0.01 to 20 ng mL-1 with a detection limit of 7.6 pg mL-1 for CEA. This strategy has great application potential for sensitive and high-throughput determination for other biomarkers in the field of biomedicine.


Assuntos
Técnicas Biossensoriais , Nanopartículas , Antígeno Carcinoembrionário , Cobre/química , Imunoadsorventes , Peróxido de Hidrogênio , Limite de Detecção , Radical Hidroxila , Peróxidos , Nanopartículas/química
16.
Molecules ; 27(20)2022 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-36296418

RESUMO

Repurposing of waste beer yeast (WBY) that a main by-product of brewing industry has attracted considerable attention in recent years. In this study, the protein and polypeptide were extracted by ultrasonic-assisted extraction and enzymatic hydrolysis with process optimization, which resulted in a maximum yield of 73.94% and 61.24%, respectively. Both protein and polypeptide of WBY were composed of 17 Amino acids (AA) that included seven essential amino acids (EAA), and typically rich in glutamic acid (Glu) (6.46% and 6.13%) and glycine (Gly) (5.26% and 6.02%). AA score (AAS) revealed that the threonine (Thr) and SAA (methionine + cysteine) were the limiting AA of WBY protein and polypeptide. Furthermore, the antioxidant activities of WBY polypeptide that lower than 10 kDa against hydroxyl radical, DPPH radical, and ABTS radical were 95.10%, 98.37%, and 69.41%, respectively, which was significantly higher than that of WBY protein (25-50 kDa). Therefore, the protein and polypeptide extracted from WBY can be a source of high-quality AA applying in food and feed industry. Due to small molecular weight, abundant AA, and great antioxidant activity, WBY polypeptide can be promisingly used as functional additives in the pharmaceutical and healthcare industry.


Assuntos
Aminoácidos , Antioxidantes , Antioxidantes/farmacologia , Antioxidantes/química , Aminoácidos/metabolismo , Cerveja , Saccharomyces cerevisiae/metabolismo , Radical Hidroxila , Cisteína , Peptídeos/química , Treonina , Glicina , Metionina , Preparações Farmacêuticas , Glutamatos
17.
J Mater Chem B ; 10(43): 8981-8987, 2022 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-36300361

RESUMO

Chemodynamic therapy (CDT) can efficiently combat tumor cells through a robust catalyst in the presence of H2O2. However, the insufficient intracellular H2O2 level and inefficiency of catalysts in tumor cells limit the production of enough toxic hydroxyl radicals (˙OH) to achieve satisfactory efficacy for CDT. Herein, a supramolecular organometallic drug complex (SOMDC) with H2O2 self-provision was proposed to intensify the intracellular autocatalysis for enhancing the CDT effect. The obtained SOMDC could self-assemble into supramolecular organometallic drug micelles (SOMDMs), which could be effectively dissociated because the endogenous H2O2 in tumor cells can rapidly destroy the host-guest interactions. The released DOX prodrug effectively upregulated the endogenous H2O2 level and amplified the Fenton-like intracellular autocatalysis to guarantee a remarkable ˙OH production for improving CDT efficiency. In vitro and in vivo evaluations showed that SOMDC exhibited excellent anticancer activity with reduced toxicity to normal tissues. Therefore, this novel strategy with H2O2 self-provision to intensify intracellular autocatalysis for enhancing the CDT effect may provide new insights for cancer therapy.


Assuntos
Nanopartículas , Pró-Fármacos , Peróxido de Hidrogênio , Nanopartículas/uso terapêutico , Radical Hidroxila , Pró-Fármacos/farmacologia
18.
Oxid Med Cell Longev ; 2022: 5089857, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36246405

RESUMO

Single-atom nanozymes (SAZs) with reaction specificity and optimized catalytic properties have great application prospects in tumor therapy. But the complex tumor microenvironment (low content of H2O2) limits its therapeutic effect. In this study, we developed a bionic mesoporous Fe SAZs/DDP nanosystem (CSD) for enhanced nanocatalytic therapy (NCT)/chemotherapy by simultaneously encapsulating the chemotherapeutic drugs cisplatin (DDP) and Fe SAZs with high peroxidase (POD) activity into the cancer cell membrane. CSD could evade immune recognition and actively targets tumor sites, and DDP upregulates endogenous H2O2 levels by activating nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, thereby enhancing SAZs-mediated hydroxyl radical (·OH) production, which subsequently leads to mitochondrial damage and intolerance to chemotherapy drug. We used the HGC27/DDP cell line for in vitro and in vivo experiments. The results showed that CSD achieved good therapeutic benefits, without any side effects such as inflammatory reaction. This system can induce multiple antitumor effect with H2O2 self-supply, mitochondrial damage, and ATP downregulation and eventually lead to chemosensitization.


Assuntos
Cisplatino , Neoplasias , Trifosfato de Adenosina , Biomimética , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Cisplatino/farmacologia , Cisplatino/uso terapêutico , Resistencia a Medicamentos Antineoplásicos , Humanos , Peróxido de Hidrogênio , Radical Hidroxila , NADP , NADPH Oxidases/metabolismo , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Peroxidases , Espécies Reativas de Oxigênio/metabolismo , Microambiente Tumoral
19.
Molecules ; 27(19)2022 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-36234964

RESUMO

Data on alkaloid interactions with the physiologically important transition metals, iron and copper, are mostly lacking in the literature. However, these interactions can have important consequences in the treatment of both Alzheimer's disease and cancer. As isoquinoline alkaloids include galanthamine, an approved drug for Alzheimer's disease, as well as some potentially useful compounds with cytostatic potential, 28 members from this category of alkaloids were selected for a complex screening of interactions with iron and copper at four pathophysiologically relevant pH and in non-buffered conditions (dimethyl sulfoxide) by spectrophotometric methods in vitro. With the exception of the salts, all the alkaloids were able to chelate ferrous and ferric ions in non-buffered conditions, but only five of them (galanthine, glaucine, corydine, corydaline and tetrahydropalmatine) evoked some significant chelation at pH 7.5 and only the first two were also active at pH 6.8. By contrast, none of the tested alkaloids chelated cuprous or cupric ions. All the alkaloids, with the exception of the protopines, significantly reduced the ferric and cupric ions, with stronger effects on the latter. These effects were mostly dependent on the number of free aromatic hydroxyls, but not other hydroxyl groups. The most potent reductant was boldine. As most of the alkaloids chelated and reduced the ferric ions, additional experimental studies are needed to elucidate the biological relevance of these results, as chelation is expected to block reactive oxygen species formation, while reduction could have the opposite effect.


Assuntos
Doença de Alzheimer , Citostáticos , Quelantes/química , Cobre/química , Dimetil Sulfóxido , Galantamina , Humanos , Radical Hidroxila , Ferro/química , Isoquinolinas/farmacologia , Espécies Reativas de Oxigênio , Substâncias Redutoras , Sais
20.
Anal Chim Acta ; 1232: 340478, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-36257748

RESUMO

In view of the optimal catalytic efficiency (∼100%), single-atom site catalysts are being widely exploited in a range of areas including organic synthesis, energy conversion, environmental remediation, biotherapy, etc. However, low loading ratio of the unitary active sites on single-atom site catalysts dramatically hinders the remarkable improvement of their catalytic activity. Hereby, a facile low-temperature reduction protocol was adopted for synthesizing CoN4-supported Co2N metal clusters on graphitic carbon nitride, which show the remarkably superior chemiluminescent (CL) catalytic capacity than some reported pure single-atom site catalysts. Nitrogen-encapsulated Co2N clusters coupled with isolated Co-N4 moieties (Co2N@Co-N4) endowed the synergetic catalysts with high Co content of 53.2 wt%. Through X-ray absorption spectroscopy, the synergetic active sites (Co2N@Co-N4) afforded the CoN4-supported Co2N clusters with the remarkable catalytic activity for accelerating the decomposition of H2O2 to produce extensive superoxide radical anion rather than singlet oxygen or hydroxyl radical. Therefore, the CoN4-supported Co2N clusters possessed the superb enhancement effect on luminol-H2O2 CL reaction by ∼22829 times. The CoN4-supported Co2N clusters were utilized as signal probes to establish a CL immunochromatographic assay (ICA) platform for quantitating mycotoxins. Herein, aflatoxin B1 was employed as a mode analyte and the limit of detection was as low as 0.33 pg mL-1 (3σ). As a proof-of-principle work, the developed ICA protocol was successfully employed on the detection of aflatoxin B1 spiked in Angelica dahurica and Ganoderma lucidum with acceptable recoveries of 84.0-107.0%. The ideal practicability of the work elucidates that CoN4-supported Co2N clusters showed a new perspective for developing the sensitive CL biosensing.


Assuntos
Radical Hidroxila , Luminol , Luminol/química , Superóxidos , Oxigênio Singlete/química , Peróxido de Hidrogênio/química , Limite de Detecção , Aflatoxina B1 , Metais , Nitrogênio , Imunoensaio
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