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1.
Int J Mol Sci ; 22(6)2021 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-33804129

RESUMEN

SARS-CoV-2 currently lacks effective first-line drug treatment. We present promising data from in silico docking studies of new Methisazone compounds (modified with calcium, Ca; iron, Fe; magnesium, Mg; manganese, Mn; or zinc, Zn) designed to bind more strongly to key proteins involved in replication of SARS-CoV-2. In this in silico molecular docking study, we investigated the inhibiting role of Methisazone and the modified drugs against SARS-CoV-2 proteins: ribonucleic acid (RNA)-dependent RNA polymerase (RdRp), spike protein, papain-like protease (PlPr), and main protease (MPro). We found that the highest binding interactions were found with the spike protein (6VYB), with the highest overall binding being observed with Mn-bound Methisazone at -8.3 kcal/mol, followed by Zn and Ca at -8.0 kcal/mol, and Fe and Mg at -7.9 kcal/mol. We also found that the metal-modified Methisazone had higher affinity for PlPr and MPro. In addition, we identified multiple binding pockets that could be singly or multiply occupied on all proteins tested. The best binding energy was with Mn-Methisazone versus spike protein, and the largest cumulative increases in binding energies were found with PlPr. We suggest that further studies are warranted to identify whether these compounds may be effective for treatment and/or prophylaxis.


Asunto(s)
Antivirales/química , Metales/química , Metisazona/química , Simulación del Acoplamiento Molecular , /química , Antivirales/metabolismo , Calcio/química , Calcio/metabolismo , /metabolismo , /metabolismo , /metabolismo , Diseño de Fármacos , Humanos , Hierro/química , Hierro/metabolismo , Magnesio/química , Magnesio/metabolismo , Manganeso/química , Manganeso/metabolismo , Metales/metabolismo , Metisazona/metabolismo , Modelos Moleculares , Simulación de Dinámica Molecular , Unión Proteica , Glicoproteína de la Espiga del Coronavirus/química , Glicoproteína de la Espiga del Coronavirus/metabolismo , Zinc/química , Zinc/metabolismo
2.
Int J Mol Sci ; 22(6)2021 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-33809032

RESUMEN

Iron is essential for multiple bacterial processes and is thus required for host colonization and infection. The antimicrobial activity of multiple iron chelators and gallium-based therapies against different bacterial species has been characterized in preclinical studies. In this review, we provide a synthesis of studies characterizing the antimicrobial activity of the major classes of iron chelators (hydroxamates, aminocarboxylates and hydroxypyridinones) and gallium compounds. Special emphasis is placed on recent in-vitro and in-vivo studies with the novel iron chelator DIBI. Limitations associated with iron chelation and gallium-based therapies are presented, with emphasis on limitations of preclinical models, lack of understanding regarding mechanisms of action, and potential host toxicity. Collectively, these studies demonstrate potential for iron chelators and gallium to be used as antimicrobial agents, particularly in combination with existing antibiotics. Additional studies are needed in order to characterize the activity of these compounds under physiologic conditions and address potential limitations associated with their clinical use as antimicrobial agents.


Asunto(s)
Infecciones Bacterianas/tratamiento farmacológico , Galio/uso terapéutico , Quelantes del Hierro/uso terapéutico , Hierro/metabolismo , Antibacterianos/efectos adversos , Antibacterianos/uso terapéutico , Bacterias/efectos de los fármacos , Bacterias/patogenicidad , Infecciones Bacterianas/microbiología , Farmacorresistencia Bacteriana , Humanos , Ácidos Hidroxámicos/química , Ácidos Hidroxámicos/uso terapéutico , Hierro/química , Quelantes del Hierro/química , Pruebas de Sensibilidad Microbiana
3.
Int J Mol Sci ; 22(6)2021 Mar 19.
Artículo en Inglés | MEDLINE | ID: mdl-33808898

RESUMEN

Ferroptosis is gaining followers as mechanism of selective killing cancer cells in a non-apoptotic manner, and novel nanosystems capable of inducing this iron-dependent death are being increasingly developed. Among them, polydopamine nanoparticles (PDA NPs) are arousing interest, since they have great capability of chelating iron. In this work, PDA NPs were loaded with Fe3+ at different pH values to assess the importance that the pH may have in determining their therapeutic activity and selectivity. In addition, doxorubicin was also loaded to the nanoparticles to achieve a synergist effect. The in vitro assays that were performed with the BT474 and HS5 cell lines showed that, when Fe3+ was adsorbed in PDA NPs at pH values close to which Fe(OH)3 begins to be formed, these nanoparticles had greater antitumor activity and selectivity despite having chelated a smaller amount of Fe3+. Otherwise, it was demonstrated that Fe3+ could be released in the late endo/lysosomes thanks to their acidic pH and their Ca2+ content, and that when Fe3+ was co-transported with doxorubicin, the therapeutic activity of PDA NPs was enhanced. Thus, reported PDA NPs loaded with both Fe3+ and doxorubicin may constitute a good approach to target breast tumors.


Asunto(s)
Antineoplásicos/farmacología , Ferroptosis/efectos de los fármacos , Indoles/química , Indoles/farmacología , Nanopartículas/química , Polímeros/química , Polímeros/farmacología , Animales , Neoplasias de la Mama , Calcio/metabolismo , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Sinergismo Farmacológico , Femenino , Humanos , Hierro/química , Hierro/metabolismo , Ratones , Especies Reactivas de Oxígeno/metabolismo
4.
Nat Commun ; 12(1): 1558, 2021 03 10.
Artículo en Inglés | MEDLINE | ID: mdl-33692352

RESUMEN

Iron (Fe) is an essential nutrient, but is poorly bioavailable because of its low solubility in alkaline soils; this leads to reduced agricultural productivity. To overcome this problem, we first showed that the soil application of synthetic 2'-deoxymugineic acid, a natural phytosiderophore from the Poaceae, can recover Fe deficiency in rice grown in calcareous soil. However, the high cost and poor stability of synthetic 2'-deoxymugineic acid preclude its agricultural use. In this work, we develop a more stable and less expensive analog, proline-2'-deoxymugineic acid, and demonstrate its practical synthesis and transport of its Fe-chelated form across the plasma membrane by Fe(III)•2'-deoxymugineic acid transporters. Possibility of its use as an iron fertilizer on alkaline soils is supported by promotion of rice growth in a calcareous soil by soil application of metal free proline-2'-deoxymugineic acid.


Asunto(s)
Ácido Azetidinocarboxílico/análogos & derivados , Fertilizantes , Hierro/química , Ácido Azetidinocarboxílico/química , Sideróforos/química , Suelo/química
5.
Molecules ; 26(4)2021 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-33669560

RESUMEN

The production of cyclic carbonates from CO2 cycloaddition to epoxides, using the C-scorpionate iron(II) complex [FeCl2{κ3-HC(pz)3}] (pz = 1H-pyrazol-1-yl) as a catalyst, is achieved in excellent yields (up to 98%) in a tailor-made ionic liquid (IL) medium under mild conditions (80 °C; 1-8 bar). A favorable synergistic catalytic effect was found in the [FeCl2{κ3-HC(pz)3}]/IL system. Notably, in addition to exhibiting remarkable activity, the catalyst is stable during ten consecutive cycles, the first decrease (11%) on the cyclic carbonate yield being observed during the 11th cycle. The use of C-scorpionate complexes in ionic liquids to afford cyclic carbonates is presented herein for the first time.


Asunto(s)
Dióxido de Carbono/química , Carbonatos/química , Reacción de Cicloadición , Hierro/química , Catálisis , Compuestos Epoxi/química , Líquidos Iónicos/química , Cinética , Espectrofotometría Infrarroja , Temperatura
6.
Molecules ; 26(4)2021 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-33671156

RESUMEN

The objective of this paper is to compare conventional, ultrasound, microwave, and French press methods for the extraction of antioxidant compounds from Decatropis bicolor in an aqueous medium. This plant is widely used in Mexican traditional medicine for breast cancer treatment. Despite that, there are few studies on D. bicolor. Two response surface designs were applied to establish the best conditions of the liberation of antioxidants from D. bicolor, which were determined by DPPH• and Ferric Reducing Antioxidant Power (FRAP) techniques. The total phenolic content was evaluated by the Folin-Ciocalteu method. The results showed that D. bicolor is a source of antioxidants (669-2128 mg ET/100 g and 553-1920 mg EFe2+/100 g, respectively) and phenolic compounds (2232-9929 mg EGA/100 g). Among the physical factors that were analyzed, the temperature was the determinant factor to liberate the compounds of interest by using low concentrations of the sample and short times of extraction. The French press was the most efficient method, obtaining values of antioxidant activity and phenolic compounds even higher than those reported by using extraction methods with solvents such as methanol.


Asunto(s)
Antioxidantes/aislamiento & purificación , Bioquímica/métodos , Rutaceae/química , Agua/química , Antioxidantes/análisis , Compuestos de Bifenilo/química , Hierro/química , Microondas , Fenoles/análisis , Picratos/química , Ultrasonido
7.
Molecules ; 26(4)2021 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-33670050

RESUMEN

Desulfurized gypsum (DG) as a soil modifier imparts it with bulk solid sulfite. The Fe(III)-sulfite process in the liquid phase has shown great potential for the rapid removal of As(III), but the performance and mechanism of this process using DG as a sulfite source in aqueous solution remains unclear. In this work, employing solid CaSO3 as a source of SO32-, we have studied the effects of different conditions (e.g., pH, Fe dosage, sulfite dosage) on As(III) oxidation in the Fe(III)-CaSO3 system. The results show that 72.1% of As(III) was removed from solution by centrifugal treatment for 60 min at near-neutral pH. Quenching experiments have indicated that oxidation efficiencies of As(III) are due at 67.5% to HO•, 17.5% to SO5•- and 15% to SO4•-. This finding may have promising implications in developing a new cost-effective technology for the treatment of arsenic-containing water using DG.


Asunto(s)
Arsénico/química , Calcio/química , Hierro/química , Sulfitos/química , Contaminantes Químicos del Agua/química , Agua/química , Arsénico/aislamiento & purificación , Oxidación-Reducción , Contaminantes Químicos del Agua/aislamiento & purificación , Purificación del Agua
8.
Food Chem ; 345: 128812, 2021 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-33601655

RESUMEN

Due to complex matrixes and specific reagent deficiency, the rapid detection of histamine is still a challenge to date. Based on the high peroxidase-like activity of iron-cobalt co-doped carbon dots, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) was established for histamine detection using the mimic enzyme labeled with histamine antibody (His-Ab). Through the competitive binding of the labeled His-Ab to solid-phase and sample antigens, histamine content was detected with a linear range of 2.5-150 µg mL-1. The detection limit based on 3σ/K was 0.50 mg kg-1, which was much lower than those of commercial His-kit and HPLC methods. The ic-ELISA method was applied to histamine detection in fish samples with the recovery of (103.4 ± 0.5)%, which was in accord with those of commercial His-kit and HPLC methods. The results indicated that the established ic-ELISA method was suitable for rapid detection of histamine in fish samples with high accuracy, sensitivity and stability.


Asunto(s)
Peces/metabolismo , Histamina/análisis , Puntos Cuánticos/química , Animales , Anticuerpos/química , Anticuerpos/inmunología , Carbono/química , Cobalto/química , Ensayo de Inmunoadsorción Enzimática , Histamina/inmunología , Hierro/química , Límite de Detección , Reproducibilidad de los Resultados , Alimentos Marinos/análisis
9.
Int J Nanomedicine ; 16: 1037-1050, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33603367

RESUMEN

Purpose: Hepatocellular carcinoma (HCC) is one of the most common fatal cancers, with no curative therapy available. The concept of ferroptosis is attracting increasing attention in cancer research. Herein, we describe the use of a nanodevice as an effective strategy for inducing ferroptosis to manage HCC. Methods: To improve ferroptosis-induced treatment of HCC, we constructed sorafenib (sor)-loaded MIL-101(Fe) nanoparticles (NPs) [MIL-101(Fe)@sor] and evaluated the efficacy of ferroptosis-based HCC therapy after co-administration with the iRGD peptide both in vitro and in vivo. Results: The prepared MIL-101(Fe) NPs have several promising characteristics including drug-loading, controllable release, peroxidase activity, biocompatibility, and T2 magnetic resonance imaging ability. MIL-101(Fe)@sor NPs significantly induced ferroptosis in HepG2 cells, increased the levels of lipid peroxidation and malondialdehyde, and reduced those of glutathione and glutathione peroxidase 4 (GPX-4). The in vivo results showed that the MIL-101(Fe)@sor NPs significantly inhibited tumor progression and decreased GPX-4 expression levels, with negligible long-term toxicity. Meanwhile, co-administration of MIL-101(Fe)@sor NPs with iRGD significantly accelerated ferroptosis. Conclusion: Our findings suggest that MIL-101(Fe)@sor NPs co-administered with iRGD are a promising strategy for inducing HCC ferroptosis.


Asunto(s)
Ferroptosis , Hierro/química , Neoplasias Hepáticas/tratamiento farmacológico , Estructuras Metalorgánicas/química , Oligopéptidos/administración & dosificación , Oligopéptidos/uso terapéutico , Sorafenib/administración & dosificación , Sorafenib/uso terapéutico , Animales , Antineoplásicos/administración & dosificación , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Carcinoma Hepatocelular/tratamiento farmacológico , Carcinoma Hepatocelular/patología , Endocitosis/efectos de los fármacos , Ferroptosis/efectos de los fármacos , Células Hep G2 , Humanos , Peroxidación de Lípido/efectos de los fármacos , Neoplasias Hepáticas/patología , Estructuras Metalorgánicas/ultraestructura , Ratones , Nanopartículas/química , Nanopartículas/toxicidad , Nanopartículas/ultraestructura , Peroxidasa/metabolismo , Conejos , Sorafenib/farmacología , Pruebas de Toxicidad
10.
Nat Commun ; 12(1): 1086, 2021 02 17.
Artículo en Inglés | MEDLINE | ID: mdl-33597529

RESUMEN

The dynamics of photodissociation and recombination in heme proteins represent an archetypical photochemical reaction widely used to understand the interplay between chemical dynamics and reaction environment. We report a study of the photodissociation mechanism for the Fe(II)-S bond between the heme iron and methionine sulfur of ferrous cytochrome c. This bond dissociation is an essential step in the conversion of cytochrome c from an electron transfer protein to a peroxidase enzyme. We use ultrafast X-ray solution scattering to follow the dynamics of Fe(II)-S bond dissociation and 1s3p (Kß) X-ray emission spectroscopy to follow the dynamics of the iron charge and spin multiplicity during bond dissociation. From these measurements, we conclude that the formation of a triplet metal-centered excited state with anti-bonding Fe(II)-S interactions triggers the bond dissociation and precedes the formation of the metastable Fe high-spin quintet state.


Asunto(s)
Citocromos c/metabolismo , Compuestos Ferrosos/metabolismo , Hierro/metabolismo , Metales/metabolismo , Metionina/metabolismo , Citocromos c/química , Transporte de Electrón/efectos de la radiación , Compuestos Ferrosos/química , Hemo/química , Hemo/metabolismo , Hierro/química , Metales/química , Metionina/química , Simulación de Dinámica Molecular , Fotólisis , Espectrometría por Rayos X
11.
Int J Mol Sci ; 22(2)2021 Jan 14.
Artículo en Inglés | MEDLINE | ID: mdl-33466760

RESUMEN

Synthetic organic dyes are widely used in various industrial sectors but are also among the most harmful water pollutants. In the last decade, significant efforts have been made to develop improved materials for the removal of dyes from water, in particular, on nanostructured adsorbent materials. Metal organic frameworks (MOFs) are an attractive class of hybrid nanostructured materials with an extremely wide range of applications including adsorption. In the present work, an iron-based Fe-BTC MOF, prepared according to a rapid, aqueous-based procedure, was used as an adsorbent for the removal of alizarin red S (ARS) and malachite green (MG) dyes from water. The synthesized material was characterized in detail, while the adsorption of the dyes was monitored by UV-Vis spectroscopy. An optimal adsorption pH of 4, likely due to the establishment of favorable interactions between dyes and Fe-BTC, was found. At this pH and at a temperature of 298 K, adsorption equilibrium was reached in less than 30 min following a pseudo-second order kinetics, with k″ of 4.29 × 10-3 and 3.98 × 10-2 g∙mg-1 min-1 for ARS and MG, respectively. The adsorption isotherm followed the Langmuir model with maximal adsorption capacities of 80 mg∙g-1 (ARS) and 177 mg∙g-1 (MG), and KL of 9.30·103 L∙mg-1 (ARS) and 51.56·103 L∙mg-1 (MG).


Asunto(s)
Antraquinonas/química , Colorantes/química , Estructuras Metalorgánicas/química , Colorantes de Rosanilina/química , Adsorción , Algoritmos , Calor , Concentración de Iones de Hidrógeno , Hierro/química , Modelos Químicos , Estructura Molecular , Termodinámica , Agua/química , Contaminantes Químicos del Agua/química
12.
Int J Mol Sci ; 22(2)2021 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-33440733

RESUMEN

Flavonoids are common plant natural products able to suppress ROS-related damage and alleviate oxidative stress. One of key mechanisms, involved in this phenomenon is chelation of transition metal ions. From a physiological perspective, iron is the most significant transition metal, because of its abundance in living organisms and ubiquitous involvement in redox processes. The chemical, pharmaceutical, and biological properties of flavonoids can be significantly affected by their interaction with transition metal ions, mainly iron. In this review, we explain the interaction of various flavonoid structures with Fe(II) and Fe(III) ions and critically discuss the influence of chelated ions on the flavonoid biochemical properties. In addition, specific biological effects of their iron metallocomplexes, such as the inhibition of iron-containing enzymes, have been included in this review.


Asunto(s)
Antioxidantes/química , Antioxidantes/farmacología , Complejos de Coordinación/química , Flavonoides/química , Hierro/química , Animales , Quelantes/química , Quelantes/farmacología , Hemo/química , Humanos , Iones/química , Iones/metabolismo , Estructura Molecular , Unión Proteica , Relación Estructura-Actividad
13.
Int J Biol Macromol ; 171: 17-27, 2021 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-33412196

RESUMEN

Herein, an effective adsorbent, 3D porous tubular network-structured citric acid-chitosan/Fe/polyethyleneimine beads (CCFPB) with multifunctional active groups and strong selectivity, was prepared for the selective removal of Cu2+ from simulated wastewater. Compared with pure chitosan beads (CB), the adsorption capacity of CCFPB for Cu2+ was increased by 127 mg g-1 (238%), and the adsorption equilibrium time was shortened by 480 min. The CCFPB showed porous surface and a novel 3D porous tubular network structure in interior, which were benefit to the diffusion of Cu2+ from surface to interior of the CCFPB and the shortening of adsorption equilibrium time. The common coexisting ions in the simulated wastewater had almost no effect on the adsorption of Cu2+ by CCFPB, and the adsorption was fast and reached equilibrium within 10 h. The adsorption process followed pseudo-second-order kinetics and the Langmuir isotherm model (qm = 240.9 mg g-1 for Cu2+). The adsorption mechanism of CCFPB for Cu2+ was mainly the synergistic interaction with amino, carboxyl, and hydroxyl groups. This strategy shows great potential for developing a variety of novel, highly active, and reusable immobilized functional beads materials for effective separation of Cu2+ from multi-ion wastewater.


Asunto(s)
Quitosano/química , Ácido Cítrico/química , Cobre/aislamiento & purificación , Contaminantes Químicos del Agua/aislamiento & purificación , Purificación del Agua/métodos , Adsorción , Cationes Bivalentes , Humanos , Concentración de Iones de Hidrógeno , Hierro/química , Cinética , Polietileneimina/química , Porosidad , Termodinámica , Aguas Residuales/química
14.
J Environ Sci Health B ; 56(3): 222-234, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33417510

RESUMEN

Surface-enhanced Raman scattering (SERS) is a promising technique for rapid detection of pesticide residues. However, conventional SERS substrates require extraction processes which are time consuming and they also lack selectivity, stability and reproducibility. Herein, we present a multifunctional stable zero-valent iron based core-shell substrate. It combines magnetic separation, selective adsorption by molecular imprinting technique and sensitive detection of carbaryl by SERS. The core-shell substrate was successfully prepared by immobilizing silver on the surface of zero-valent iron microspheres. Subsequent molecular imprinting on the bimetallic magnetic silver microspheres ensured selective removal and detection. The substrate exhibited magnetization saturation of 8.89 emu/g providing efficient analyte separation. It showed high sensitivity and selectivity toward carbaryl detection to nanomolar concentration level. Linear regression models for peaks at Raman shift 1599 cm-1 and 2233 cm-1 demonstrated a good linear fit with R2=0.9738 and R2=0.8952 respectively. The composite was successfully applied on spiked water samples resulting in average recovery rate of 89%. The findings of this study demonstrate great substrate potential for application in separation and detection of trace quantities of chemical contaminants for environment safety and protection.


Asunto(s)
Carbaril/análisis , Nanopartículas del Metal/química , Residuos de Plaguicidas/análisis , Espectrometría Raman/métodos , Contaminantes Químicos del Agua/análisis , Adsorción , Hierro/química , Fenómenos Magnéticos , Microesferas , Impresión Molecular/métodos , Oxidación-Reducción , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Plata/química
15.
Ecotoxicol Environ Saf ; 208: 111552, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33396093

RESUMEN

A novel material that nano zero valent iron (nZVI) loaded on biochar with stable starch stabilization (nZVI/SS/BC) was synthesized and used for the removal of hexavalent chromium [Cr(VI)] in simulated wastewater. It was indicated that as the pyrolysis temperature of rice straw increased, the removal rate of Cr(VI) by nZVI/SS/BC first increased and then decreased. nZVI/SS/BC made from biochar pyrolyzed at 600 °C (nZVI/SS/BC600) had the highest removal efficiency and was suitable for a wide pH range (pH 2.1-10.0). The results showed that 99.67% of Cr(VI) was removed by nZVI/SS/BC600, an increase of 45.93% compared to the control group, which did not add soluble starch during synthesis. The pseudo-second-order model and the Langmuir model were more in line with reaction. The maximum adsorption capacity for Cr(VI) by nZVI/SS/BC600 was 122.86 mg·g-1. The properties of the material were analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) mapping, Brunauer-Emmett-Teller (BET), Fourier-transform infrared (FTIR), and X-ray diffraction (XRD). The results showed that the nZVI particles were uniformly supported on the biochar, and the BET surface areas of nZVI/SS/BC was 40.4837 m2·g-1, an increase of 8.79 times compared with the control group. Mechanism studies showed that soluble starch reduced the formation of metal oxides, thereby improving the reducibility of the material, and co-precipitates were formed during the reaction. All results indicated that nZVI/SS/BC was a potential repair material that can effectively overcome the limitations of nZVI and achieve efficient and rapid repair of Cr(VI).


Asunto(s)
Carbón Orgánico/química , Cromo/química , Contaminantes Químicos del Agua/química , Adsorción , Hierro/química , Pirólisis , Almidón , Temperatura , Contaminantes Químicos del Agua/análisis , Purificación del Agua , Difracción de Rayos X
16.
Ecotoxicol Environ Saf ; 208: 111735, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33396064

RESUMEN

The transformation between hexavalent chromium (Cr6+) and trivalent chromium (Cr3+) has a significant impact on ecosystems, as Cr6+ has higher levels of toxicity than Cr3+. In this regard, a variety of Cr6+ reduction processes occurring in natural environments have been studied extensively. In this work, we investigate the reductive transformation of Cr6+ by ferrous ions (Fe2+) in ice at -20 °C, and compare the same process in water at 25 °C. The Fe2+-mediated reduction of Cr6+ occurred much faster in ice than it did in water. The accelerated reduction of Cr6+ in ice is primarily ascribed to the accumulation of Cr6+, Fe2+, and protons in the grain boundaries formed during freezing, which constitutes favorable conditions for redox reactions between Cr6+ and Fe2+. This freeze concentration phenomenon was verified using UV-visible spectroscopy with o-cresolsulfonephthalein (as a pH indicator) and confocal Raman spectroscopy. The reductive transformation of Cr6+ (20 µM) by Fe2+ in ice proceeded rapidly under various Fe2+ concentrations (20-140 µM), pH values (2.0-5.0), and freezing temperatures (-10 to -30 °C) with a constant molar ratio of oxidized Fe2+ to reduced Cr6+ (3:1). This result implies that the proposed mechanism (i.e., the redox reaction between Cr6+ and Fe2+ in ice) can significantly contribute to the natural conversion of Cr6+ in cold regions. The Fe2+-mediated Cr6+ reduction kinetics in frozen Cr6+-contaminated wastewater was similar to that in frozen Cr6+ solution. This indicates that the variety of substrates typically present in electroplating wastewater have a negligible effect on the redox reaction between Cr6+ and Fe2+ in ice; it also proposes that the Fe2+/freezing process can be used for the treatment of Cr6+-contaminated wastewater.


Asunto(s)
Cromo/química , Congelación , Eliminación de Residuos Líquidos/métodos , Contaminantes Químicos del Agua/química , Cromo/análisis , Ecosistema , Galvanoplastia , Hierro/química , Cinética , Oxidación-Reducción , Aguas Residuales/química , Agua/química , Contaminantes Químicos del Agua/análisis
17.
Arch Environ Contam Toxicol ; 80(1): 248-258, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33398394

RESUMEN

Arsenic contamination in drinking water is a great concern in different regions of the world as well as in India. Several technologies have been investigated to remove arsenic from water, such as coagulation and co-precipitation, ion exchange, adsorption, and reverse osmosis. In the present research, electrocoagulation with iron electrodes has been assessed as a treatment technology for arsenic removal from groundwater to reach concentrations below 0.01 mg/L (WHO limit) and which is technically effective, affordable for the local area, and easy to operate and maintain. Electrochemically generated iron is converted to hydrated ferric oxide within the contaminated water, which takes up the arsenic from water. A downstream filtration unit (sand or activated alumina) is applied to remove ferric hydroxide flocs produced during the process. The laboratory experiments were conducted in a batch reactor using iron plates as electrodes with monopolar configuration to study the effects of initial pH and electro-charge loading (ECL) on arsenic removal. The optimum operating condition was observed for an electro-charge loading of 25-30 Coulombs/L at pH 7.0 and an initial arsenic concentration of 0.2 mg/L. Two field trials were implemented in West Bengal after suitably designing the electrocoagulation system. Arsenic removal was significant (75-80%) delivering safe water with arsenic below 0.01 mg/L (acceptable limit). Passivation of the electrodes occurred during the operation and calcium-based (including iron) deposition was observed on the cathodes. Passivation is avoidable after running regular polarity reversal of the electrodes.


Asunto(s)
Arsénico/análisis , Técnicas Electroquímicas/métodos , Agua Subterránea/química , Contaminantes Químicos del Agua/análisis , Purificación del Agua/métodos , Adsorción , Electrodos , Compuestos Férricos/química , India , Hierro/química , Minerales/química
18.
Nat Commun ; 12(1): 667, 2021 01 28.
Artículo en Inglés | MEDLINE | ID: mdl-33510173

RESUMEN

Biological organic-inorganic materials remain a popular source of inspiration for bioinspired materials design and engineering. Inspired by the self-assembling metal-reinforced mussel holdfast threads, we tested if metal-coordinate polymer networks can be utilized as simple composite scaffolds for direct in situ crosslink mineralization. Starting with aqueous solutions of polymers end-functionalized with metal-coordinating ligands of catechol or histidine, here we show that inter-molecular metal-ion coordination complexes can serve as mineral nucleation sites, whereby significant mechanical reinforcement is achieved upon nanoscale particle growth directly at the metal-coordinate network crosslink sites.


Asunto(s)
Bivalvos/química , Reactivos de Enlaces Cruzados/química , Hidrogeles/química , Metales/química , Minerales/química , Polímeros/química , Animales , Catecoles/química , Hierro/química , Microscopía Electrónica de Transmisión , Nanocompuestos/química , Nanocompuestos/ultraestructura , Dispersión del Ángulo Pequeño , Espectrometría Raman , Difracción de Rayos X
19.
Biomed Pharmacother ; 136: 111228, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33454595

RESUMEN

Iron overload is increasingly implicated as a contributor to the pathogenesis of COVID-19. Indeed, several of the manifestations of COVID-19, such as inflammation, hypercoagulation, hyperferritinemia, and immune dysfunction are also reminiscent of iron overload. Although iron is essential for all living cells, free unbound iron, resulting from iron dysregulation and overload, is very reactive and potentially toxic due to its role in the generation of reactive oxygen species (ROS). ROS react with and damage cellular lipids, nucleic acids, and proteins, with consequent activation of either acute or chronic inflammatory processes implicated in multiple clinical conditions. Moreover, iron-catalyzed lipid damage exerts a direct causative effect on the newly discovered nonapoptotic cell death known as ferroptosis. Unlike apoptosis, ferroptosis is immunogenic and not only leads to amplified cell death but also promotes a series of reactions associated with inflammation. Iron chelators are generally safe and are proven to protect patients in clinical conditions characterized by iron overload. There is also an abundance of evidence that iron chelators possess antiviral activities. Furthermore, the naturally occurring iron chelator lactoferrin (Lf) exerts immunomodulatory as well as anti-inflammatory effects and can bind to several receptors used by coronaviruses thereby blocking their entry into host cells. Iron chelators may consequently be of high therapeutic value during the present COVID-19 pandemic.


Asunto(s)
/metabolismo , Quelantes del Hierro/uso terapéutico , Sobrecarga de Hierro/tratamiento farmacológico , Hierro/metabolismo , Lactoferrina/uso terapéutico , Humanos , Hierro/sangre , Hierro/química , Lactoferrina/farmacología
20.
J Environ Sci Health B ; 56(3): 259-271, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33459173

RESUMEN

The binding of rhodamine B (RB) to human serum albumin (HSA) in the absence and presence of Cu2+ or Fe3+ under simulated physiological conditions was studied by using various biophysical methods for the first time. The results showed that the interaction between HSA and RB could spontaneously result in the formation of HSA-RB complex (namely, static quenching mechanism) through hydrophobic interactions and hydrogen bonds irrespective of the absence or presence of metal ions. The presence of metal ions led to the reduction of binding affinity of RB to HSA compared with no metal ions, which might result from the conformational change of HSA caused by the binding of metal ions. Furthermore, the analysis of UV-vis absorption, circular dichroism, synchronous fluorescence and three-dimensional fluorescence experiments demonstrated that the addition of RB induced conformational and microenvironmental changes of HSA without and with metal ions. In short, this work will be helpful to in-depth understand the transport mechanism and biological effect of RB and the effect of metal ions on the interaction of HSA-RB in vivo.


Asunto(s)
Cobre/química , Hierro/química , Rodaminas/metabolismo , Albúmina Sérica Humana/química , Albúmina Sérica Humana/metabolismo , Sitios de Unión , Dicroismo Circular , Cobre/metabolismo , Humanos , Enlace de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Hierro/metabolismo , Conformación Proteica , Rodaminas/química , Espectrometría de Fluorescencia , Espectrofotometría Ultravioleta , Termodinámica
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