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1.
Ecotoxicol Environ Saf ; 274: 116207, 2024 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-38492484

RESUMEN

Plastic pollution is a common concern of global environmental pollution. Polystyrene (PS) and polyethylene (PE) account for almost one-third of global plastic production. However, so far, there have been few reports on microbial strains capable of simultaneously degrading PS and PE. In this study, Microbacterium esteraromaticum SW3, a non-pathogenic microorganism that can use PS or PE as the only carbon source in the mineral salt medium (MM), was isolated from plastics-contaminated soil and identified. The optimal growth conditions for SW3 in MM were 2% (w/v) PS or 2% (w/v) PE, 35°C and pH 6.3. A large number of bacteria and obvious damaged areas were observed on the surface of PS and PE products after inoculated with SW3 for 21 d. The degradation rates of PS and PE by SW3 (21d) were 13.17% and 5.39%, respectively. Manganese peroxidase and lipase were involved in PS and PE degradation by SW3. Through Fourier infrared spectroscopy detection, different functional groups such as carbonyl, hydroxyl and amidogen groups were produced during the degradation of PS and PE by SW3. Moreover, PS and PE were degraded into alkanes, ketones, carboxylic acids, esters and so on detected by GC-MS. Collectively, we have isolated and identified SW3, which can use PS or PE as the only carbon source in MM as well as degrade PS and PE products. This study not only provides a competitive candidate strain with broad biodegradability for the biodegradation of PS and/or PE pollution, but also provides new insights for the study of plastic biodegradation pathways.


Asunto(s)
Actinomycetales , Poliestirenos , Poliestirenos/metabolismo , Polietileno/metabolismo , Suelo , Actinomycetales/metabolismo , Biodegradación Ambiental , Carbono , Plásticos/metabolismo , Microbacterium
2.
J Nanobiotechnology ; 21(1): 282, 2023 Aug 19.
Artículo en Inglés | MEDLINE | ID: mdl-37598148

RESUMEN

Ophthalmic inflammatory diseases, including conjunctivitis, keratitis, uveitis, scleritis, and related conditions, pose considerable challenges to effective management and treatment. This review article investigates the potential of advanced nanomaterials in revolutionizing ocular anti-inflammatory drug interventions. By conducting an exhaustive analysis of recent advancements and assessing the potential benefits and limitations, this review aims to identify promising avenues for future research and clinical applications. The review commences with a detailed exploration of various nanomaterial categories, such as liposomes, dendrimers, nanoparticles (NPs), and hydrogels, emphasizing their unique properties and capabilities for accurate drug delivery. Subsequently, we explore the etiology and pathophysiology of ophthalmic inflammatory disorders, highlighting the urgent necessity for innovative therapeutic strategies and examining recent preclinical and clinical investigations employing nanomaterial-based drug delivery systems. We discuss the advantages of these cutting-edge systems, such as biocompatibility, bioavailability, controlled release, and targeted delivery, alongside potential challenges, which encompass immunogenicity, toxicity, and regulatory hurdles. Furthermore, we emphasize the significance of interdisciplinary collaborations among material scientists, pharmacologists, and clinicians in expediting the translation of these breakthroughs from laboratory environments to clinical practice. In summary, this review accentuates the remarkable potential of advanced nanomaterials in redefining ocular anti-inflammatory drug therapy. We fervently support continued research and development in this rapidly evolving field to overcome existing barriers and improve patient outcomes for ophthalmic inflammatory disorders.


Asunto(s)
Sistemas de Liberación de Medicamentos , Ojo , Humanos , Disponibilidad Biológica , Hidrogeles , Liposomas
3.
J Am Chem Soc ; 139(5): 1706-1713, 2017 02 08.
Artículo en Inglés | MEDLINE | ID: mdl-28085258

RESUMEN

Ordered mesoporous materials (OMMs) have received increasing interest due to their uniform pore size, high surface area, various compositions and wide applications in energy conversion and storage, biomedicine and environmental remediation, etc. The soft templating synthesis using surfactants or amphiphilic block copolymers is the most efficient method to produce OMMs with tailorable pore structure and surface property. However, due to the limited choice of commercially available soft templates, the common OMMs usually show small pore size and amorphous (or semicrystalline) frameworks. Tailor-made amphiphilic block copolymers with controllable molecular weights and compositions have recently emerged as alternative soft templates for synthesis of new OMMs with many unique features including adjustable mesostructures and framework compositions, ultralarge pores, thick pore walls, high thermal stability and crystalline frameworks. In this Perspective, recent progresses and some new insights into the coassembly process about the synthesis of OMMs based on these tailor-made copolymers as templates are summarized, and typical newly developed synthesis methods and strategies are discussed in depth, including solvent evaporation induced aggregation, ligand-assisted coassembly, solvent evaporation induced micelle fusion-aggregation assembly, homopolymer assisted pore expanding and carbon-supported crystallization strategy. Then, the applications of the obtained large-pore OMMs in catalysis, sensor, energy conversion and storage, and biomedicine by loading large-size guest molecules (e.g., protein and RNA), precious metal nanoparticles and quantum dots, are discussed. At last, the outlook on the prospects and challenges of future research about the synthesis of large-pore OMMs by using tailor-made amphiphilic block copolymers are included.


Asunto(s)
Polímeros/síntesis química , Tensoactivos/síntesis química , Interacciones Hidrofóbicas e Hidrofílicas , Micelas , Tamaño de la Partícula , Polímeros/química , Porosidad , Propiedades de Superficie , Tensoactivos/química
4.
J Trop Pediatr ; 63(3): 182-188, 2017 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-27765889

RESUMEN

This study aimed to analyze the epidemiological characteristics of hand, foot and mouth disease (HFMD) during 2008-14 in Wenzhou, China. The epidemiological data of HFMD retrieved from the Wenzhou Center for Disease Control and Prevention were retrospectively analyzed. HFMD infections with enterovirus 71 (EV71), Cox A16 or other pathogens were further verified by polymerase chain reaction (PCR) and real-time PCR. A total of 213 617 cases of HFMD were reported between 2008 and 2014 in Wenzhou. The average incidence was 384.31 of 100 000, and the fatality rate was 0.14‰. The incidence of HFMD peaked between April and July, and it occurred more frequently in males than in females. Approximately 92.68% of the HFMD patients were children aged <5 years. Nearly 80% of the cases were diagnosed within 2 days after onset. The major HFMD pathogen was EV71. This study suggested that appropriate comprehensive prevention and control measures should be taken to avoid the spread of HFMD.


Asunto(s)
Infecciones por Coxsackievirus/diagnóstico , Enterovirus Humano A/aislamiento & purificación , Enfermedad de Boca, Mano y Pie/epidemiología , Enfermedad de Boca, Mano y Pie/virología , Adolescente , Adulto , Niño , Preescolar , China/epidemiología , Infecciones por Coxsackievirus/epidemiología , Enterovirus Humano A/genética , Enfermedad de Boca, Mano y Pie/diagnóstico , Humanos , Incidencia , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa , Densidad de Población , ARN Viral/genética , Estudios Retrospectivos
5.
Environ Sci Technol ; 50(2): 906-14, 2016 Jan 19.
Artículo en Inglés | MEDLINE | ID: mdl-26704724

RESUMEN

Herein, we report for the first time on the fabrication of a robust, thermoresponsive polymer membrane produced by the combination of an elastic polyurethane (TPU) microfiber web and poly(N-isopropylacrylamide) (PNIPAM). PNIPAM hydrogel is evenly coated on the surface of TPU microfibers, and thus, the wettability of TPU-PNIPAM membrane is amplified by taking advantage of the hierarchical structure and increased surface roughness. The TPU-PNIPAM membrane possesses switchable superhydrophilicity and superhydrophobicity as the temperature of membrane changes from 25 to 45 °C. The composite membrane is shown successfully able to separate a 1 wt % oil-in-water emulsion and 1 wt % water-in-oil emulsion at 25 and 45 °C, respectively, with a high separation efficiency of ≥99.26%. Furthermore, the composite membranes show excellent mechanical properties, and they are highly flexible and mechanically tough. The smart composite membranes reported here have shown great potential for further development for practical high-efficiency oil-water separations.


Asunto(s)
Membranas Artificiales , Aceites/química , Polímeros/química , Agua/química , Humectabilidad , Acrilamidas , Resinas Acrílicas , Hidrogel de Polietilenoglicol-Dimetacrilato , Poliuretanos , Temperatura
6.
Soft Matter ; 11(28): 5610-3, 2015 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-26096216

RESUMEN

DNA was covalently grafted onto poly(propargyl methacrylate) (PPMA) via "click" chemistry to synthesize the amphiphilic polymer brush. The PPMA-g-DNA brush could assemble into a primary structure of a nanofiber, which can be compactly spun into a multiple-strand helix in micron-length. The brush could also self-assemble with DNA labelled gold nanoparticles.


Asunto(s)
ADN/química , Metacrilatos/química , Nanopartículas/química , Polímeros/química , Química Clic , Oro/química , Propiedades de Superficie
7.
Chem Soc Rev ; 42(9): 4054-70, 2013 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-23258081

RESUMEN

The self-assembly of small surfactants and Pluronic® amphiphilic copolymers has enabled the synthesis of a range of ordered mesoporous materials with high surface area, diverse compositions, variable pore structures and tunable pore sizes. It has recently been realized that non-Pluronic block copolymers can be used as robust templates for the synthesis of novel and high-performance mesoporous materials with crystalline frameworks, ultra-large pores, and abundant pore symmetries, which are not accessible using the Pluronic counterparts. In this review, we introduce the principle of self-assembly of block copolymers and their phase separations, and summarize recently developed synthetic methods and strategies for ordered mesoporous silicas, metal oxides, carbons and metals which have shown superior performances for applications in various fields, including solar cells, batteries, fuel cells, and sensors.


Asunto(s)
Polímeros/química , Tensoactivos/química , Tamaño de la Partícula , Porosidad , Propiedades de Superficie
8.
Bioelectrochemistry ; 158: 108723, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38733720

RESUMEN

Bidirectional electron transfer is about that exoelectrogens produce bioelectricity via extracellular electron transfer at anode and drive cytoplasmic biochemical reactions via extracellular electron uptake at cathode. The key factor to determine above bioelectrochemical performances is the electron transfer efficiency under biocompatible abiotic/biotic interface. Here, a graphene/polyaniline (GO/PANI) nanocomposite electrode specially interfacing exoelectrogens (Shewanella loihica) and augmenting bidirectional electron transfer was conducted by in-situ electrochemical modification on carbon paper (CP). Impressively, the GO/PANI@CP electrode tremendously improved the performance of exoelectrogens at anode for wastewater treatment and bioelectricity generation (about 54 folds increase of power density compared to blank CP electrode). The bacteria on electrode surface not only showed fast electron release but also exhibited high electricity density of extracellular electron uptake through the proposed direct electron transfer pathway. Thus, the cathode applications of microbial electrosynthesis and bio-denitrification were developed via GO/PANI@CP electrode, which assisted the close contact between microbial outer-membrane cytochromes and nanocomposite electrode for efficient nitrate removal (0.333 mM/h). Overall, nanocomposite modified electrode with biocompatible interfaces has great potential to enhance bioelectrochemical reactions with exoelectrogens.


Asunto(s)
Fuentes de Energía Bioeléctrica , Electrodos , Grafito , Grafito/química , Transporte de Electrón , Fuentes de Energía Bioeléctrica/microbiología , Compuestos de Anilina/química , Compuestos de Anilina/metabolismo , Materiales Biocompatibles/química , Materiales Biocompatibles/metabolismo , Shewanella/metabolismo , Nanocompuestos/química , Técnicas Electroquímicas/métodos
9.
Anticancer Drugs ; 24(6): 641-7, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23571496

RESUMEN

The purpose of this study was to compare the efficacy and safety of a single subcutaneous injection of pegylated filgrastim with daily filgrastim as a prophylaxis for neutropenia induced by commonly used chemotherapy regimens. Fifteen centers enrolled 337 chemotherapy-naive cancer patients with normal bone marrow function. All patients randomized into AOB and BOA arms received two cycles of chemotherapy. Patients received a single dose of pegylated filgrastim 100 µg/kg in cycle 1 (AOB) or cycle 2 (BOA) and daily doses of filgrastim 5 µg/kg/day in cycle 1 (BOA) or cycle 2 (AOB). Efficacy and safety parameters were recorded. The primary end point was the rate of protection against grade 4 neutropenia after chemotherapy [defined as the rate at which the absolute neutrophil count (ANC) remained >0.5×10(9)/l throughout the entire cycle]. Ninety-four percent of patients receiving pegylated filgrastim or filgrastim did not develop grade 4 neutropenia. The incidence of ANC<1.0×10(9)/l was 16.0% (50/313) after support with either pegylated filgrastim or filgrastim. The incidences of febrile neutropenia and antibiotic administration were similar in both groups. Notably, faster ANC recovery was observed with pegylated filgrastim support. The ANC nadir was also earlier with pegylated filgrastim (day 7) support than with filgrastim support (day 9), although the depth of nadir was not significantly different. A single subcutaneous injection of pegylated filgrastim 100 µg/kg provided adequate and safe neutrophil support comparable with daily subcutaneous injections of unmodified filgrastim 5 µg/kg/day in patients receiving commonly used standard-dose mild-to-moderate myelosuppressive chemotherapy regimens.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Factor Estimulante de Colonias de Granulocitos/administración & dosificación , Neutropenia/inducido químicamente , Neutropenia/prevención & control , Polietilenglicoles/administración & dosificación , Adulto , Anciano , Estudios Cruzados , Femenino , Filgrastim , Factor Estimulante de Colonias de Granulocitos/efectos adversos , Humanos , Inyecciones Subcutáneas , Masculino , Persona de Mediana Edad , Polietilenglicoles/efectos adversos , Proteínas Recombinantes/administración & dosificación , Proteínas Recombinantes/efectos adversos
10.
Zhonghua Gan Zang Bing Za Zhi ; 21(2): 101-4, 2013 Feb.
Artículo en Zh | MEDLINE | ID: mdl-23663880

RESUMEN

OBJECTIVE: To investigate the relation of thyroid function with hashimoto thyroiditis (HT, an autoimmune disease of unknown etiology also known as chronic lymphocytic thyroiditis) in patients with chronic hepatitis C (CHC) receiving treatment with pegylated-interferon-alpha (Peg-IFNa) based on the observation that HT is common among individuals undergoing IFN-based therapy. METHODS: One-hundred-and-seven patients with chronic hepatitis C were enrolled for study between January 2008 and December 2010. Thyroid function was assessed by electrochemiluminescence assays to detect serum levels of anti-thyroid peroxidase (A-TPO) antibodies, thyroid stimulating hormone (TSH), and free thyroxine (FT4) prior to initiation of the IFN-based therapy. The treatment strategies (drugs, doses, schedules) were designed according to HT status (CHC with HT, or CHC without HT). Patients were monitored during the 24 weeks of treatment (including measuring serum alanine aminotransferase (ALT), TSH, and FT4 every two to four weeks, and HCV RNA every four weeks) so that the IFNa dose could be adjusted and thyroid medications (levothyroxine sodium or methimazole) added as necessary. The response rate at end of treatment (week 24) was assessed. RESULTS: Twenty-one of the CHC patients were diagnosed with HT, and the incidence of thyroid dysfunction among the CHC patients with HT was 71.4% (15/21); among the CHC patients with no HT, the incidence of thyroid dysfunction was significantly lower (30.2% (26/86), X2 = 12.1995, P less than 0.01). In the CHC patients with HT, 90.5% (19/21) had serum levels of A-TPO antibodies that were more than or equal to 2-times higher than the normal value at the end of treatment. Of the 15 CHC patients with HT and thyroid dysfunction, 73.3% (11/15) continued to show thyroid dysfunction at the end of treatment. Hypothyroidism was the most common form of thyroid dysfunction observed (4/11), and all of those patients responded to levothyroxine sodium treatment. The virological response rates of the two groups (CHC with HT and CHC without HT) were not significantly different at any time point examined (treatment week 4, 12, and 24, P more than 0.05). CONCLUSION: The incidence of thyroid dysfunction is significantly higher among CHC patients with HT than among CHC patients without HT. If suspected, these patients should be carefully monitored because the clinical symptoms of thyroid dysfunction are not obvious and the drug therapy should be carefully adjusted to minimize the thyroid dysfunction while maximizing the antiviral effect.


Asunto(s)
Antivirales/uso terapéutico , Enfermedad de Hashimoto/tratamiento farmacológico , Hepatitis C Crónica/tratamiento farmacológico , Interferón-alfa/uso terapéutico , Polietilenglicoles/uso terapéutico , Ribavirina/uso terapéutico , Adolescente , Adulto , Anciano , Quimioterapia Combinada , Femenino , Enfermedad de Hashimoto/complicaciones , Hepatitis C Crónica/complicaciones , Humanos , Masculino , Persona de Mediana Edad , Proteínas Recombinantes/uso terapéutico , Adulto Joven
11.
Angew Chem Int Ed Engl ; 52(40): 10505-10, 2013 Sep 27.
Artículo en Inglés | MEDLINE | ID: mdl-23943495

RESUMEN

Templated pores: A resol-assisted solvent-evaporation-induced self-assembly (RA-EISA) gives unique ordered mesoporous niobia spheres by using the amphiphilic diblock copolymer PEO-b-PS as a template. The mesoporous Nb2O5 spheres have ordered hexagonal structures, large pore size and high surface area, and a nanocrystalline framework. They show excellent electrochemical sensing of hydrogen peroxide.


Asunto(s)
Técnicas Biosensibles/métodos , Formaldehído/química , Niobio/química , Óxidos/química , Fenoles/química , Polietilenglicoles/química , Polímeros/química , Técnicas Biosensibles/instrumentación , Técnicas Electroquímicas/instrumentación , Técnicas Electroquímicas/métodos , Microscopía Electrónica de Rastreo , Porosidad , Dispersión del Ángulo Pequeño , Propiedades de Superficie , Difracción de Rayos X
12.
Environ Sci Technol ; 46(18): 9995-10003, 2012 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-22897436

RESUMEN

Osmotically driven membrane processes (including forward osmosis (FO) and pressure retarded osmosis (PRO)) have received increasing attention in recent decades. The performance of an FO/PRO membrane is significantly limited by internal concentration polarization, which is a strong function of the membrane support layer pore structure. The objective of the current study was to develop microscopic characterization methods for quantitative/semiquantitative analysis of membrane pore structure (both pore diameter and porosity distribution across membrane thickness). The use of confocal laser scanning microscopy (CLSM) for noninvasive characterization of the internal pore structure of FO/PRO membranes is reported for the first time. By performing optical sectioning, information on pore diameter, porosity depth profile and pore connectivity can be obtained. The CLSM porosity results are further compared to those obtained using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and reasonably good agreement was observed. A comparison of these characterization methods reveals their complementary nature, and a combination of these techniques may allow a more comprehensive understanding of membrane structure. The current study also provided a comprehensive insight into the pore structure of commercially available FO/PRO membranes.


Asunto(s)
Membranas Artificiales , Ósmosis , Microscopía Confocal , Microscopía Electrónica de Rastreo , Microscopía Electrónica de Transmisión , Presión Osmótica , Porosidad
13.
J Colloid Interface Sci ; 625: 435-445, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-35724466

RESUMEN

Mesoporous vanadium oxide nanospheres are a very promising nanozyme for antibacterial and chemical sensing. However, controllable synthesis of mesoporous vanadium oxide nanospheres with uniform structure and small diameter (<200 nm) remains challenging. Herein, mesoporous vanadium oxide nanospheres (MVONs) with a small, uniform and adjustable particle size (52-105 nm), large mesopore size (5.1-5.8 nm), and high specific surface area (up to 63.7 m2 g-1) are constructed via a self-template strategy using tannic acid, formaldehyde and vanadium compounds as a polymerizable ligand, cross-linking agent and metal source, respectively. The relationships between synthesis conditions and material nanostructure are systematically investigated. The particle size and peroxidase-like activity of MVONs can be easily changed by adding different amounts of Pluronic block copolymer F127. Owing to the mesoporous structure, high specific surface area and small particle size, MVONs can effectively convert H2O2 into extremely toxic reactive oxygen species, and further kill Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). This research establishes a universal, reliable method for synthesizing mesoporous vanadium oxide nanospheres, which might be used in catalysis, biosensors, and antibacterial treatment.


Asunto(s)
Nanosferas , Antibacterianos/química , Antibacterianos/farmacología , Escherichia coli , Peróxido de Hidrógeno/química , Nanosferas/química , Óxidos/farmacología , Peroxidasas , Poloxámero , Porosidad , Staphylococcus aureus , Vanadio
14.
Anal Chim Acta ; 1230: 340273, 2022 Oct 16.
Artículo en Inglés | MEDLINE | ID: mdl-36192073

RESUMEN

Electrochemical techniques have been demonstrated as powerful tools for various applications in analytical science. However, due to limited electrochemically active surface areas and poor anti-inference performance, their sensitivity and stability are weakened in real samples. By integrating electrochemical techniques with ratio-signal output modes and molecular imprinting polymers (MIPs), the newly constructed ratiometric molecularly imprinted electrochemical sensors (RMIECs) can outcompete conventional electrochemical techniques with higher sensitivity and stability, easier pretreatment, better selectivity and reproducibility, and are more adapted to complex environments. Fascinated by the superior performances of RMIECs, researchers from all research fields have been devoted to the design and development of RMIECs in different applications. For the first time, we summarize distinct ratiometric signal output modes and highlight four different types of RMIECs as well as their design, working principle and applications in analytical fields. In addition, the current challenges and prospects are carefully discussed to provide innovative idea tactics for developing new electrochemical methods.


Asunto(s)
Técnicas Biosensibles , Impresión Molecular , Técnicas Biosensibles/métodos , Técnicas Electroquímicas/métodos , Impresión Molecular/métodos , Polímeros/química , Reproducibilidad de los Resultados
15.
Biosensors (Basel) ; 12(10)2022 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-36290940

RESUMEN

Listeria monocytogenes is a hazardous foodborne pathogen that is able to cause acute meningitis, encephalitis, and sepsis to humans. The efficient detection of 3-hydroxy-2-butanone, which has been verified as a biomarker for the exhalation of Listeria monocytogenes, can feasibly evaluate whether the bacteria are contained in food. Herein, we developed an outstanding 3-hydroxy-2-butanone gas sensor based on the microelectromechanical systems using Au/ZnO NS as a sensing material. In this work, ZnO nanosheets were synthesized by a hydrothermal reaction, and Au nanoparticles (~5.5 nm) were prepared via an oleylamine reduction method. Then, an ultrasonic treatment was carried out to modified Au nanoparticles onto ZnO nanosheets. The XRD, BET, TEM, and XPS were used to characterize their morphology, microstructure, catalytic structure, specific surface area, and chemical composition. The response of the 1.0% Au/ZnO NS sensors vs. 25 ppm 3-hydroxy-2-butanone was up to 174.04 at 230 °C. Moreover, these sensors presented fast response/recovery time (6 s/7 s), great selectivity, and an outstanding limit of detection (lower than 0.5 ppm). This work is full of promise for developing a nondestructive, rapid and practical sensor, which would improve Listeria monocytogenes evaluation in foods.


Asunto(s)
Nanopartículas del Metal , Materiales Inteligentes , Óxido de Zinc , Humanos , Óxido de Zinc/química , Oro , Acetoína , Biomarcadores
16.
Aging (Albany NY) ; 14(1): 443-461, 2022 01 12.
Artículo en Inglés | MEDLINE | ID: mdl-35020600

RESUMEN

Human glutathione peroxidase1 (hGPx1) is a good antioxidant and potential drug, but the limited availability and poor stability of hGPx1 have affected its development and application. To solve this problem, we prepared a hGPx1 mutant (GPx1M) with high activity in an Escherichia coli BL21(DE3)cys auxotrophic strain using a single protein production (SPP) system. In this study, the GPx1M was conjugated with methoxypolyethylene glycol-succinimidyl succinate (SS-mPEG, Mw = 5 kDa) chains to enhance its stability. SS-mPEG-GPx1M and GPx1M exhibited similar enzymatic activity and stability toward pH and temperature change, and in a few cases, SS-mPEG-GPx1M was discovered to widen the range of pH stability and increase the temperature stability. Lys 38 was confirmed as PEGylated site by liquid-mass spectrometry. H9c2 cardiomyoblast cells and Sprague-Dawley (SD) rats were used to evaluate the effects of GPx1M and SS-mPEG-GPx1M on preventing or alleviating adriamycin (ADR)-mediated cardiotoxicity, respectively. The results indicated that GPx1M and SS-mPEG-GPx1M had good antioxidant effects in vitro and in vivo, and the effect of SS-mPEG-GPx1M is more prominent than GPx1M in vivo. Thus, PEGylation might be a promising method for the application of GPx1M as an important antioxidant and potential drug.


Asunto(s)
Antioxidantes/farmacología , Glutatión Peroxidasa/metabolismo , Animales , Antioxidantes/química , Antioxidantes/metabolismo , Línea Celular , Diseño de Fármacos , Escherichia coli , Glutatión Peroxidasa/química , Humanos , Concentración de Iones de Hidrógeno , Modelos Moleculares , Mutación , Miocitos Cardíacos , Polietilenglicoles/química , Conformación Proteica , Estabilidad Proteica , Ratas , Ratas Sprague-Dawley , Succinimidas/química , Temperatura , Glutatión Peroxidasa GPX1
17.
J Am Chem Soc ; 133(50): 20369-77, 2011 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-22047467

RESUMEN

A solvent evaporation induced aggregating assembly (EIAA) method has been demonstrated for synthesis of highly ordered mesoporous silicas (OMS) in the acidic tetrahydrofuran (THF)/H(2)O mixture by using poly(ethylene oxide)-b-poly(methyl methacrylate) (PEO-b-PMMA) as the template and tetraethylorthosilicate (TEOS) as the silica precursor. During the continuous evaporation of THF (a good solvent for PEO-b-PMMA) from the reaction solution, the template molecules, together with silicate oligomers, were driven to form composite micelles in the homogeneous solution and further assemble into large particles with ordered mesostructure. The obtained ordered mesoporous silicas possess a unique crystal-like morphology with a face centered cubic (fcc) mesostructure, large pore size up to 37.0 nm, large window size (8.7 nm), high BET surface area (508 m(2)/g), and large pore volume (1.46 cm(3)/g). Because of the large accessible mesopores, uniform gold nanoparticles (ca. 4.0 nm) can be introduced into mesopores of the OMS materials using the in situ reduction method. The obtained Au/OMS materials were successfully applied to fast catalytic reduction of 4-nitrophenol in the presence of NaHB(4) as the reductant. The supported catalysts can be reused for catalytic reactions without significant decrease in catalysis performance even after 10 cycles.


Asunto(s)
Polímeros/química , Dióxido de Silicio/química , Solventes/química , Catálisis , Microscopía Electrónica de Rastreo , Microscopía Electrónica de Transmisión , Dispersión de Radiación
18.
Sci Total Environ ; 751: 141491, 2021 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-32861946

RESUMEN

Dissolved black carbon (DBC) is becoming increasingly concerned by researchers due to its unique environmental behavior. However, understanding of the influence mechanism of biopolymer compositions of cellulose (CEL), hemicellulose (HEM) and lignin (LIG) on the formation and physiochemical characteristics of DBC from lignocellulose-based biochar is limited. This study therefore examined the formation of DBCs derived from the biopolymer compositions, corn straw (CS), corncob (CC), bamboo sawdust (BS) and pinewood sawdust (PS) under the heat treatment temperatures (HTTs) of 300-500 °C. Zeta potential and hydrodynamic diameters (Dh) of DBCs produced under 300 °C were further investigated. DBC formation may be closely associated with the HTT-dependent heterogeneities of biopolymer compositions, in which significant effects of CEL and HEM charring on physiochemical properties of DBCs were identified under the HTT of 300 and 400 °C, while the formation of DBCs was closely related to LIG and its proportions in biomass under high HTT (>500 °C). On the rise of the HTT, the carbonaceous structures of biopolymer compositions were reorganized and converted to graphitic structures in biochar accompanied by the large decomposition or carbonization of CEL and HEM, leading to the reduced carbon content, surface functional groups, aromaticity and molecular weight of DBCs, as well as the decrease of protein-like and relative increase of fulvic-like fluorescent substances in most DBCs. LIG in biomass may facilitate the migration of DBCs due to abundant surface negative charges and the formation of low Dh. This study offered new insights into our understanding of influencing mechanisms of biopolymer compositions on the characteristic of DBCs under different HTTs.


Asunto(s)
Carbón Orgánico , Lignina , Carbono
19.
ACS Appl Mater Interfaces ; 13(18): 21087-21096, 2021 May 12.
Artículo en Inglés | MEDLINE | ID: mdl-33908764

RESUMEN

The bottom-up construction of enzyme-based artificial cells is generating increasing interest, but achieving artificial cells for "all artificial modules" remains challenging in synthetic biology. Here, we introduce a fully synthetic cell system by integration of biomimetic nanozymes into giant unilamellar vesicles (GUVs). To mimic native peroxidase for free radical generation by taking advantage of Fenton catalysis reactions, we designed and prepared a de novo artificial nanozyme composed of ferritin heavy-chain scaffold protein and catalytic Fe3O4 nanoparticles as the active center. As two examples in bioapplications, we showed this nanozyme-powered GUV system not only mimics intracellular oxidative stress pathways but also induces tumor cell death by sensing and responding to external chemical signals. Specifically, we recreated intracellular biochemical events, including DNA damage and lipid peroxidation, in the compartmentalized GUVs by taking advantage of nanozyme induction of defined catalytic reactions. Additionally, the GUV system also actively induced DNA double-strand breakage and lipid damage of tumor cells, in response to the high expression of H2O2 within the tumor microenvironment. This concept-of-proof study offers a promising option for defining catalysis in biological systems and gives new insights into the de novo creation of artificial cells in a fully synthetic manner.


Asunto(s)
Nanopartículas de Magnetita/química , Imitación Molecular , Estrés Oxidativo , Liposomas Unilamelares/química , Catálisis , Línea Celular Tumoral , Roturas del ADN de Doble Cadena , Humanos , Peroxidación de Lípido , Microscopía Electrónica de Transmisión , Prueba de Estudio Conceptual
20.
Bioresour Technol ; 341: 125807, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34474237

RESUMEN

In recent years, visualization and characterization of lignocellulose at different scales elucidate the modifications of its ultrastructural and chemical features during hydrothermal pretreatment which include degradation and dissolving of hemicelluloses, swelling and partial hydrolysis of cellulose, melting and redepositing a part of lignin in the surface. As a result, cell walls are swollen, deformed and de-laminated from the adjacent layer, lead to a range of revealed droplets that appear on and within cell walls. Moreover, the certain extent morphological changes significantly promote the downstream processing steps, especially for enzymatic hydrolysis and anaerobic fermentation to bioethanol by increasing the contact area with enzymes. However, the formation of pseudo-lignin hinders the accessibility of cellulase to cellulose, which decreases the efficiency of enzymatic hydrolysis. This review is intended to bridge the gap between the microstructure studies and value-added applications of lignocellulose while inspiring more research prospects to enhance the hydrothermal pretreatment process.


Asunto(s)
Celulosa , Lignina , Biomasa , Hidrólisis
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