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1.
Mol Pharm ; 19(7): 2061-2076, 2022 07 04.
Artículo en Inglés | MEDLINE | ID: mdl-35731595

RESUMEN

5-Fluorouracil (5-FU) is a chemotherapeutic drug against many types of cancers, especially colorectal cancer. However, its short plasma half-life and serious adverse reactions limit its wide clinical applications. To overcome these shortcomings, a novel lipophilic 5-FU carbonate [XL-01, (5-fluoro-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl) methyl tetradecyl carbonate] was designed, synthesized, and encapsulated into liposome (LipoXL-01) by a thin-film dispersion method through formulation screening and optimization. LipoXL-01 was characterized by a particle size of around 100 nm, polydispersity index of 0.200, ζ-potential value of -41 mV, encapsulation efficiency of 93.9%, and drug-loading efficiency of 11.6%. The cellular uptake of LipoXL-01 was increased in a concentration-dependent manner on HCT15 cells. LipoXL-01 could enhance the induction of cell apoptosis and the inhibition of cell migration and arrest the ability of the cell cycle at the S-phase on HCT15 cells better than 5-FU. Additionally, LipoXL-01 exhibited a slow drug release profile with a cumulative release rate of 12% in 8 h. The results of pharmacokinetic and biodistribution studies revealed that LipoXL-01 had a long plasma half-life (7.21 h) and a high tumor accumulation (733 nmol/g at 8 h). The in vivo antitumor effect study also showed that LipoXL-01 had more potent efficacy than 5-FU (65 vs 48% of the tumor-inhibition rate). Simultaneously, negligible systemic toxicity was observed via analyzing the body weight as well as hematological and pathological parameters in the tested mice. The current study suggested that LipoXL-01 might be a promising nanocandidate for chemotherapy of colorectal cancer.


Asunto(s)
Antineoplásicos , Neoplasias Colorrectales , Animales , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Carbonatos , Línea Celular Tumoral , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/patología , Fluorouracilo/uso terapéutico , Liposomas/uso terapéutico , Ratones , Distribución Tisular
2.
Pharm Dev Technol ; 25(2): 260-265, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31709858

RESUMEN

Pectin-based hydrogel microcarriers have shown promise for drug delivery to the colonic region. Microcarriers must remain stable throughout the upper gastrointestinal tract for effective colonic delivery, an issue that traditional pectin-based microcarriers have faced. The positively-charged natural biopolymer oligochitosan and divalent cation Ca2+ were used to dually cross-link pectin-based hydrogel microcarriers to improve carrier stability through simulated gastric and intestinal environments. Microcarriers were characterized with Scanning Electron Microscope and Fourier-Transform Infrared analysis. An optical microscope was used to observe the change of microcarrier size and morphology over time in the simulated gastrointestinal environments. Fluorescently-labeled Dextran was used as a model drug for this system. Calcium-Oligochitosan-Pectin microcarriers exhibited relatively small drug release in the upper gastrointestinal regions and were responsive to the high pH and enzymatic activity of simulated colonic environment (over 94% release after 2 h), suggesting great potential for colonic drug delivery.


Asunto(s)
Calcio/química , Quitina/análogos & derivados , Colon/efectos de los fármacos , Portadores de Fármacos/química , Pectinas/química , Preparaciones Farmacéuticas/administración & dosificación , Preparaciones Farmacéuticas/química , Química Farmacéutica/métodos , Quitina/química , Quitosano , Sistemas de Liberación de Medicamentos/métodos , Concentración de Iones de Hidrógeno , Oligosacáridos , Solubilidad/efectos de los fármacos
3.
Environ Sci Technol ; 53(23): 13802-13811, 2019 Dec 03.
Artículo en Inglés | MEDLINE | ID: mdl-31697066

RESUMEN

Freezing is essential in the light-mediated transformation of organic pollutants. However, the effects of the freezing process on the reduction of Ag+ by natural organic matter (NOM) remains unclear, causing significant uncertainties in the natural formation of silver nanoparticles (AgNPs). This study investigated the sunlight-induced reduction of Ag+ by NOM under natural or controlled freezing processes. Natural (outdoor) freezing experiments demonstrated intense aggregation and precipitation of AgNPs in three aqueous media, including a NOM solution and two river water samples, under natural sunlight irradiation. Indoor experiments under simulated sunlight irradiation and controlled freezing processes showed that freezing at -20 °C and repeated freeze-thaw cycles (-20 to 4 °C) drastically accelerated the formation and growth of AgNPs compared to maintenance at 4 °C. Finally, under the natural freezing process, commercial AgNPs were found to influence the redox reduction of Ag+ probably through a reduction in dissolution rates and homoaggregation with AgNPs newly formed in the river water samples. Additionally, the enhancement effect of freezing on AgNP formation was confirmed in the presence of Ag+ and AgNPs both at environmentally relevant concentration levels, especially upon light irradiation. This work emphasizes the importance of freezing processes on the natural formation of AgNPs.


Asunto(s)
Nanopartículas del Metal , Plata , Congelación , Oxidación-Reducción , Luz Solar
4.
J Environ Sci (China) ; 78: 109-117, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30665629

RESUMEN

Biochar is extensively used as an effective soil amendment for environmental remediation. In addition to its strong contaminant sorption capability, biochar also plays an important role in chemical transformation of contaminant due to its inherent redox-active moieties. However, the transformation efficiency of inorganic contaminants is generally very limited when the direct adsorption of contaminants on biochar is inefficient. The present study demonstrates the role of Fe ion as an electron shuttle to enhance Cr(VI) reduction by biochars. Batch experiments were conducted to examine the effects of Fe(III) levels, pyrolysis temperature of biochar, initial solution pH, and biochar dosage on the efficiency of Cr(VI) removal. Results showed a significant enhancement in Cr(VI) reduction with an increase in Fe(III) concentration and a decrease of initial pH. Biochar produced at higher pyrolysis temperatures (e.g., 700°C) favored Cr(VI) removal, especially in the presence of Fe(III), while a higher biochar dosage proved unfavorable likely due to the agglomeration or precipitation of biochar. Speciation analysis of Fe and Cr elements on the surface of biochar and in the solution further confirmed the role of Fe ion as an electron shuttle between biochar and Cr(VI). The present findings provide a potential strategy for the advanced treatment of Cr(VI) at low concentrations as well as an insight into the environmental fate of Cr(VI) and other micro-pollutants in soil or aqueous compartments containing Fe and natural or engineered carbonaceous materials.


Asunto(s)
Carbón Orgánico/química , Cromo/química , Restauración y Remediación Ambiental/métodos , Contaminantes del Suelo/química , Electrones , Compuestos Férricos/química
5.
Environ Sci Technol ; 52(12): 6928-6935, 2018 06 19.
Artículo en Inglés | MEDLINE | ID: mdl-29791804

RESUMEN

Silver nanoparticles (AgNPs) are inevitably released into natural systems, particularly into aquatic environments, where they are oxidized and release Ag+, which is reduced back to AgNPs. Environmental freeze-thaw cycles or freezing may accelerate the dynamic transformation between AgNPs and Ag+. Herein, the significant morphological changes caused by freezing treatments were assessed by UV-vis spectroscopy and high-resolution transmission electron microscopy, which revealed that reductive regeneration, particle fusion, and coalescence of the AgNPs occurred. In addition, a stable Ag isotope was used to track the AgNP redox reaction, which was found to be accelerated under freezing and freeze-thaw cycles relative to the reaction of particles stored at a normal temperature (4 °C, 25 °C). Furthermore, natural organic matter was found to stabilize the particle morphology. Ca2+ and Cl- intensified the morphological changes and redox reaction through Ca2+-induced particle coalescence and Cl--enhanced reduction of Ag+ during the freeze-thaw treatment. These physicochemical changes also occurred for an environmentally relevant concentration of AgNPs (50 ng L-1) in simulated environmental conditions and natural water samples after freeze-thaw cycles. Since the morphological changes and redox acceleration induced by environmental freezing conditions could dramatically influence the mobility, bioavailability, toxicity, and environmental fate of AgNPs, the freeze-thaw-induced effects should be considered in the environmental risk assessment of AgNPs.


Asunto(s)
Nanopartículas del Metal , Plata , Congelación , Microscopía Electrónica de Transmisión , Oxidación-Reducción
6.
Environ Sci Technol ; 51(21): 12369-12376, 2017 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-29019663

RESUMEN

It is a great challenge to monitor the physical and chemical transformation of nanoparticles at environmentally relevant concentration levels, mainly because the commonly used techniques like dynamic light scattering and transmission electron microscopy are unable to characterize and quantify trace level nanoparticles in complex matrices. Herein, we demonstrate the on-line coupled system of hollow fiber flow field-flow fractionation (HF5), minicolumn concentration, and inductively coupled plasma mass spectrometry (ICPMS) detection as an efficient approach to study the aggregation and chemical transformation of silver nanoparticles (AgNPs) and ionic Ag species in the aqueous environment at ng/mL levels. Taking advantage of the in-line dialysis of HF5, the selective capture of Ag(I) species by the resin in minicolumn, and the high selectivity and sensitivity of ICPMS detection, we recorded the aggregation of 10 ng/mL AgNPs in complex matrices (e.g., NOM, Na+/Ca2+), revealing an interesting tiny AgNPs formation process of photoreduction of trace level Ag(I) that is different from larger AgNPs generated at high concentration of Ag(I) by accurate characterization and respectively identifying and quantifying new thiol-complexed Ag(I) and residual Ag(I) in the intertransformation of Ag(I) and AgNPs in domestic wastewater by simultaneously detecting the S and Ag signals via ICPMS.


Asunto(s)
Nanopartículas del Metal , Plata , Fraccionamiento de Campo-Flujo , Iones
7.
Phys Chem Chem Phys ; 19(7): 4956-4961, 2017 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-28155953

RESUMEN

The electron transport layer (ETL) plays a critical role in high efficiency perovskite solar cells. In this study, an anodic TiO2 nanotube film was transformed into a TiO2 nanotube network film, which maintained its advantage as an efficient ETL for perovskite solar cells. Compared with the mesoporous TiO2 nanoparticle ETL, the TiO2 nanotube network ETL can increase the efficiency of perovskite solar cells by 26.6%, which is attributed to its superior charge collection property and light trapping ability. The results confirm the importance of optimizing the electron collecting layer and suggest another way to design and fabricate novel perovskite solid state solar cells, potentially by using a TiO2 nanotube network film as an alternative high efficiency electrode.

8.
Anal Chem ; 87(16): 8441-7, 2015 Aug 18.
Artículo en Inglés | MEDLINE | ID: mdl-26222150

RESUMEN

The intertransformation of silver nanoparticles (AgNPs) and ionic silver (Ag(I)) in the environment determines their transport, uptake, and toxicity, demanding methods to simultaneously separate and quantify AgNPs and Ag(I). For the first time, hollow fiber flow field-flow fractionation (HF5) and minicolumn concentration were on-line coupled together with multiple detectors (including UV-vis spectrometry, dynamic light scattering, and inductively coupled plasma mass spectrometry) for full spectrum separation, characterization, and quantification of various Ag(I) species (i.e., free Ag(I), weak and strong Ag(I) complexes) and differently sized AgNPs. While HF5 was employed for filtration and fractionation of AgNPs (>2 nm), the minicolumn packed with Amberlite IR120 resin functioned to trap free Ag(I) or weak Ag(I) complexes coming from the radial flow of HF5 together with the strong Ag(I) complexes and tiny AgNPs (<2 nm), which were further discriminated in a second run of focusing by oxidizing >90% of tiny AgNPs to free Ag(I) and trapped in the minicolumn. The excellent performance was verified by the good agreement of the characterization results of AgNPs determined by this method with that by transmission electron microscopy, and the satisfactory recoveries (70.7-108%) for seven Ag species, including Ag(I), the adduct of Ag(I) and cysteine, and five AgNPs with nominal diameters of 1.4 nm, 10 nm, 20 nm, 40 nm, and 60 nm in surface water samples.


Asunto(s)
Fraccionamiento de Campo-Flujo/métodos , Espectrometría de Masas , Nanopartículas del Metal/análisis , Plata/análisis , Cromatografía Líquida de Alta Presión , Fraccionamiento de Campo-Flujo/instrumentación , Iones/química , Luz , Tamaño de la Partícula , Dispersión de Radiación , Plata/aislamiento & purificación , Espectrofotometría Ultravioleta , Agua/química
9.
Small ; 11(44): 5940-8, 2015 Nov 25.
Artículo en Inglés | MEDLINE | ID: mdl-26449376

RESUMEN

A novel 3D nanoarchitecture comprising in situ-formed N-doped CoNi alloy-encapsulated carbon nanotubes (CoNi-NCNTs) grown on N-doped porous carbon nanosheets (NPCNs) is designed and constructed for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). When evaluated as an electrocatalyst for ORR, the hybrid shows efficient catalytic activity, high selectivity, superior durability, and strong tolerance against methanol crossover compared with the commercial Pt/C catalyst. Such good oxygen reduction reaction performance is comparable to most of the previously reported results and the synergistic effect is found to boost the catalytic performance. Moreover, the constructed hybrid exhibits an excellent ORR activity with a current density of 10 mA cm(-2) at 1.59 V and an onset potential of 1.57 V, even beyond the state-of-the-art Ir/C catalyst in alkaline media. The enhancement in electrochemical performance can be attributed to the unique morphology and defect structures, high porosity, good conductive networks, and strongly interacting CoNi-NCNT and NPCN in the hybrid. These results suggest the possibility for the development of effective nanocarbon electrocatalysts to replace commercial noble metal catalysts for direct use in fuel cells and water splitting devices.

10.
Small ; 11(4): 414-9, 2015 Jan 27.
Artículo en Inglés | MEDLINE | ID: mdl-25208086

RESUMEN

By increasing the density of exposed active edges, the perpendicularly oriented structure of MoSe2 nanosheets facilitates ion/electrolyte transport at the electrode interface and minimizes the restacking of nanosheets, while the graphene improves the electrical contact between the catalyst and the electrode. This makes the MoSe2 /graphene hybrid perfect as a catalyst in the hydrogen evolution reaction (HER). It shows a greatly improved catalytic activity compared with bare MoSe2 nanosheets.

11.
Chin J Integr Med ; 2024 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-38676827

RESUMEN

OBJECTIVE: To investigate the therapeutic efficacy of cinnamaldehyde (CA) on systemic Candida albicans infection in mice and to provide supportive data for the development of novel antifungal drugs. METHODS: Ninety BALB/c mice were randomly divided into 3 groups according to a random number table: CA treatment group, fluconazole (positive control) group, and Tween saline (negative control) group, with 30 mice in each group. Initially, all groups of mice received consecutive intraperitoneal injections of cyclophosphamide at 200 mg/kg for 2 days, followed by intraperitoneal injection of 0.25 mL C. albicans fungal suspension (concentration of 1.0 × 107 CFU/mL) on the 4th day, to establish an immunosuppressed systemic Candida albicans infection animal model. Subsequently, the mice were orally administered CA, fluconazole and Tween saline, at 240, 240 mg/kg and 0.25 mL/kg respectively for 14 days. After a 48-h discontinuation of treatment, the liver, small intestine, and kidney tissues of mice were collected for fungal direct microscopic examination, culture, and histopathological examination. Additionally, renal tissues from each group of mice were collected for (1,3)- ß -D-glucan detection. The survival status of mice in all groups was monitored for 14 days of drug administration. RESULTS: The CA group exhibited a fungal clearance rate of C. albicans above 86.7% (26/30), significantly higher than the fluconazole group (60.0%, 18/30, P<0.01) and the Tween saline group (30.0%, 9/30, P<0.01). Furthermore, histopathological examination in the CA group revealed the disappearance of inflammatory cells and near-normal restoration of tissue structure. The (1,3)-ß-D-glucan detection value in the CA group (860.55 ± 126.73 pg/mL) was significantly lower than that in the fluconazole group (1985.13 ± 203.56 pg/mL, P<0.01) and the Tween saline group (5910.20 ± 320.56 pg/mL, P<0.01). The mouse survival rate reached 90.0% (27/30), higher than the fluconazole group (60.0%, 18/30) and the Tween saline group (30.0%, 9/30), with a significant difference between the two groups (both P<0.01). CONCLUSIONS: CA treatment exhibited significant therapeutic efficacy in mice with systemic C. albicans infection. Therefore, CA holds potential as a novel antifungal agent for targeted treatment of C. albicans infection.

12.
Colloids Surf B Biointerfaces ; 218: 112765, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-35981470

RESUMEN

Precise molecular engineering of AIEgens-based cationic delivery systems for high transfection efficiency (TE) and effective photodynamic therapy (PDT) holds a huge potential for cancer treatment. Herein, three amphiphiles (DT-C6/8/12-M) consisting of di(triazole-[12]aneN3) (M) and 1,1-dicyano-2-phenyl-2-(4-diphenylamino)phenyl-ethylene (DT) units have been developed to achieve luminescent tracking, efficient TE, and effective PDT in vitro and in vivo. These compounds exhibited strong aggregated induced emission (AIE) at 630 nm and mega Stokes shifts of up to 160 nm. They were able to bind DNA into nanoparticles with suitable sizes, positive surface potential, and good biocompatibility in the presence of DOPE. Among them, vector DT-C12-M/DOPE with n-dodecyl linker achieved a transfection efficiency as high as 42.3 folds that of Lipo2000 in PC-3 cell lines. DT-C12-M/DOPE exhibited the capability of successful endo/lysosomal escape and rapid nuclear delivery of pDNA, and the gene delivery process was clearly monitored via confocal laser scanning microscopy. Moreover, efficient reactive oxygen species (ROS) generation by DT-C12-M upon light irradiation led to effective PDT in vitro . We further show that combination of p53 gene therapy and PDT dramatically enhanced cancer therapeutic outcome in vivo. This "three birds, one stone" strategy offers a novel and promising approach for real-time tracking of gene delivery and better cancer treatment.


Asunto(s)
Nanopartículas , Neoplasias , Fotoquimioterapia , ADN/genética , Etilenos , Terapia Genética , Humanos , Neoplasias/tratamiento farmacológico , Neoplasias/genética , Especies Reactivas de Oxígeno , Triazoles , Proteína p53 Supresora de Tumor
13.
Eur J Pharm Sci ; 167: 106000, 2021 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-34517105

RESUMEN

Pancreatic cancer is an aggressive and highly lethal disease with a very poor prognosis. Our previous study found miriplatin can inhibit proliferation of various tumor cells, including pancreatic cancer cells. For the chemotherapy of pancreatic cancer, a novel recombinant human serum albumin (rHSA)-bound miriplatin nanoparticles (rHSA-miPt) were constructed by emulsion-diffusion evaporation method. The optimal formulation was composed of 150 mg of rHSA and 30 mg of miriplatin. The key parameters in rHSA-miPt production were 10 min of high-pressure homogenization in a solution with volume ratio of 10:2 of 5% glucose and chloroform. The rHSA-miPt was characterized with a particle size of 61 ± 10 nm, a zeta potential value of -18 ± 5 mV, encapsulation efficiency of 98.4%, drug loading of 16.4%, T1/2 of 13.3 h and Vd of 0.5 L in Sprague Dawley rats. The concentrations of platinum (Pt) in the tumors were 15 and 22-fold higher than those in the blood at 24 and 72 h in tumor-bearing mice, respectively. The internalization of rHSA-miPt through caveolae-dependent pathway. In vitro, the half-maximal inhibitory concentration (IC50) of rHSA-miPt was 12.7 µM vs more than 100 µM of gemcitabine (Gem). The inhibition rate of tumor growth was 76% of rHSA-miPt and 51% of Gem, respectively. Compared with Gem, rHSA-miPt was identified to be safer and less toxic based on body weight loss in mice (0% vs 20%), the survival rate of mice (100% vs 80%) and hematological and biochemical parameters of the mice including leukocytes, lymphocytes, neutrophils, monocytes, serum alanine aminotransferase and aspartate aminotransferase. The present study revealed that rHSA-miPt might be a promising candidate for pancreatic cancer therapy.


Asunto(s)
Nanopartículas , Neoplasias Pancreáticas , Animales , Ratones , Compuestos Organoplatinos , Neoplasias Pancreáticas/tratamiento farmacológico , Ratas , Ratas Sprague-Dawley , Albúmina Sérica Humana
14.
J Appl Biomater Funct Mater ; 17(1): 2280800018807108, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30803313

RESUMEN

PURPOSE:: Bioprinting is an alternative method for constructing tissues/organs for transplantation. This study investigated the cross-linker influence and post-printing modification using oligochitosan and chitosan for stability improvement. METHODS:: Oligochitosan was tested as a novel cross-linker to replace Ca2+ for pectin-based bio-ink. Oligochitosan (2 kD) and different molecular weight of chitosan were used to modify the bioprinted scaffold. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were used to characterize the scaffolds. RESULTS:: Oligochitosan failed to serve as a viable cross-linker. Successful post-printing modification was confirmed by FTIR and SEM analyses. CONCLUSION:: Regarding post-modification, chitosan-treated scaffolds showed enhanced stability compared to untreated scaffolds. In particular, scaffolds modified with 150 kD chitosan exhibited the highest stability.


Asunto(s)
Bioimpresión/métodos , Pectinas/química , Andamios del Tejido/química , Calcio/química , Quitina/análogos & derivados , Quitina/química , Quitosano , Tinta , Microscopía Electrónica de Rastreo , Oligosacáridos , Poloxámero/química , Espectroscopía Infrarroja por Transformada de Fourier
15.
Nanoscale Res Lett ; 12(1): 479, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28789483

RESUMEN

This work primarily studies the crystallization condition of molybdenum disulfide (MoS2) in MoS2/graphene hybrids by a temperature-varying hydrothermal method from 150 to 240 °C. Flower-like MoS2 nanoflakes were successfully grown on graphene nanosheets and characterized to understand the temperature-dependent crystallization process and the electrochemical performance. The highest electrocatalytic efficiency for both the dye-sensitized solar cell and the hydrogen evolution reaction was obtained by preparing the hybrid at 180 °C, which benefits from balanced high reactivity and high conductivity. This research leads to a better understanding of temperature dependence of MoS2 crystallization and offers guidelines for better catalytic material design. Graphical abstract Temperature-dependent Crystallization of MoS2 Nanoflakes on Graphene Nanosheets for Electrocatalysis.

16.
Technol Health Care ; 25(4): 651-655, 2017 Aug 09.
Artículo en Inglés | MEDLINE | ID: mdl-28436403

RESUMEN

One major challenge of bioprinting is to develop a viable bioink to act as an extracellular matrix. This study investigated a novel method for bioprinting using a pectin based bioink. Besides pectin, Pluronic® F-127 was incorporated into the bioink to obtain the desired shape during the initial bioprinting process at 37∘C. Once an object was printed it was treated with Ca2+ (pectin cross-linker) to create the final tissue/organ structure. The results indicated that pectin/Pluronic® F-127 is a potential bioink. Moreover, this methodology provides a novel and fast approach for bioprinting.


Asunto(s)
Bioimpresión/métodos , Matriz Extracelular , Pectinas/química , Andamios del Tejido , Calcio/química , Cationes Bivalentes , Humanos , Poloxámero/química
17.
Chem Commun (Camb) ; 53(5): 881-884, 2017 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-28004042

RESUMEN

This work reports on a highly porous N-doped graphene-based capacitive deionization device, which exhibits a high removal efficiency (90-100%), fast removal (<30 min), and good regeneration performance (10 cycles, 99% retention) for multiple heavy metals (Pb2+, Cd2+, Cu2+, Fe2+, etc.) in water with a wide range of concentrations (0.05-200 ppm).

18.
Environ Pollut ; 220(Pt B): 955-962, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-27836474

RESUMEN

AgCl and Ag2S prevalently exist in the environment as minerals and/or the chlorination and sulfidation products of ionic silver and elemental silver nanoparticles (AgNPs). In this work, we investigated the chemical transformation of AgCl and Ag2S under simulated sunlight (in water) and incineration (in sludge and simulated municipal solid waste, SMSW). In the presence of natural organic matter, AgCl in river water was observed to be transformed into AgNPs under simulated sunlight, while photo-reduction of Ag2S could not take place under the same experimental conditions. During the course of incineration, pure Ag2S was transformed into elemental silver while AgCl remained stable; however, both Ag2S in sludge and AgCl in SMSW can be transformed to elemental silver under incineration, evident by the results of X-ray absorption spectroscopy and scanning electron microscopy measurements. Incineration temperature played an important role in the transformation of Ag2S and AgCl into elemental silver. These results suggest that chemical transformations of Ag2S and AgCl into elemental silver could be a possible source of naturally occurring or unintentionally produced AgNPs, affecting the fate, transport, bioavailability and toxicity of silver. Therefore, it is necessary to include the contributions of this transformation process when assessing the risk of ionic silver/AgNPs and the utilization and management of incineration residues.


Asunto(s)
Contaminantes Ambientales/química , Compuestos de Plata/química , Contaminantes Ambientales/efectos de la radiación , Agua Dulce , Incineración , Nanopartículas del Metal/química , Microscopía Electrónica de Rastreo , Plata/química , Compuestos de Plata/efectos de la radiación , Residuos Sólidos , Luz Solar , Temperatura , Espectroscopía de Absorción de Rayos X
19.
Sci Rep ; 7(1): 10974, 2017 09 08.
Artículo en Inglés | MEDLINE | ID: mdl-28887479

RESUMEN

The Ebola virus transmits a highly contagious, frequently fatal human disease for which there is no specific antiviral treatment. Therefore, rapid, accurate, and early diagnosis of Ebola virus disease (EVD) is critical to public health containment efforts, particularly in developing countries where resources are few and EVD is endemic. We have developed a reduced graphene oxide-based field-effect transistor method for real-time detection of the Ebola virus antigen. This method uses the attractive semiconductor characteristics of graphene-based material, and instantaneously yields highly sensitive and specific detection of Ebola glycoprotein. The feasibility of this method for clinical application in point-of-care technology is evaluated using Ebola glycoprotein suspended in diluted PBS buffer, human serum, and plasma. These results demonstrate the successful fabrication of a promising field-effect transistor biosensor for EVD diagnosis.


Asunto(s)
Antígenos Virales , Técnicas Biosensibles , Ebolavirus , Fiebre Hemorrágica Ebola/diagnóstico , Transistores Electrónicos , Antígenos Virales/inmunología , Técnicas Biosensibles/instrumentación , Técnicas Biosensibles/métodos , Ebolavirus/inmunología , Diseño de Equipo , Fiebre Hemorrágica Ebola/inmunología , Humanos , Sistemas de Atención de Punto , Sensibilidad y Especificidad
20.
Int J Artif Organs ; 39(10): 518-523, 2016 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-27886350

RESUMEN

PURPOSE: To improve the stability of pectin-oligochitosan hydrogel microcapsules under physiological conditions. METHODS: Two different approaches were examined: change of the cross-linker length and treatment of the hydrogel microcapsules with 150 Mm CaCl2. Replacement of pectin with alginate was also studied. RESULTS AND CONCLUSIONS: It was observed that the molecular weight of the cross-linker oligochiotsan had no significant improvement on microcapsule stability. On the other hand, the treatment of pectin-oligochitosan microcapsules with Ca2+ increased the microcapsule stability significantly. Different types of alginate were used; however, no red-blood-cell-shaped microcapsules could be produced, which is likely due to the charge-density difference between deprotonated pectin and alginate polymers.

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