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1.
Angew Chem Int Ed Engl ; 61(21): e202202264, 2022 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-35285128

RESUMO

The direct asymmetric reductive amination of heteroaryl ketones has been a long-standing synthetic challenge. Here we report the engineering of an amine dehydrogenase (AmDH) from Jeotgalicoccus aerolatus for the asymmetric synthesis of chiral α-(hetero)aryl primary amines in excellent conversions (up to 99 %) and enantioselectivities (up to 99 % ee). The best AmDH variant (Ja-AmDH-M33 ) exhibited high activity and specificity toward alkyl (hetero)aryl ketones, even for those bearing a bulky alkyl chain. An efficient directed evolution approach based on molecular docking was implemented to enlarge the active pocket with a more hydrophobic entrance, which is responsible for the high activity. The Ja-AmDH-M33 was also used for preparative-scale synthesis of pharmaceutically relevant amines and a key intermediate of chiral pincer ligands, which highlighted its practical application in synthetic chemistry.


Assuntos
Cetonas , Oxirredutases , Aminação , Aminas/química , Cetonas/química , Simulação de Acoplamento Molecular , Oxirredutases/metabolismo , Estereoisomerismo
2.
Enzyme Microb Technol ; 156: 110001, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35151127

RESUMO

In this study, a novel kind of Ni-NTA modified monodispersed SiO2 nanoflowers (Ni-NTA@SiO2 nanoflowers) were successfully synthesized. The obtained Ni-NTA@SiO2 nanoflowers were used to specifically adsorb and purify His-tagged old yellow enzyme (OYE1) and glucose dehydrogenase (GDH), which allows access to optically pure (3 S)- 3-methyl-cyclohexanone through asymmetric hydrogenation reaction, and forms a cofactor regeneration system. The protein loading amount on Ni-NTA@SiO2 nanoflowers was 40.17 mg/g support and the activity recoveries of OYE1 and GDH were 81.53% and 79.68%, respectively. The effects of pH and temperature on the activity of free and co-immobilized enzymes were investigated, and the stability as well as reusability were also measured. Compared to free enzymes, the co-immobilized enzymes showed higher thermal and storage stability. The co-immobilized enzymes were applied to asymmetric reduction of CC bonds for the synthesis of a chiral center with excellent enantioselectivity (ee > 99%), and the conversion was 46.02% after 7 cycles. This work introduced a one-pot multi-enzyme purification and co-immobilization strategy to construct efficient cofactor regeneration system with high activity and stability.


Assuntos
Enzimas Imobilizadas , Glucose 1-Desidrogenase , Enzimas Imobilizadas/metabolismo , Glucose 1-Desidrogenase/metabolismo , Hidrogenação , NADPH Desidrogenase/metabolismo , Dióxido de Silício/química
4.
Sci Total Environ ; 821: 153399, 2022 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-35092772

RESUMO

Thallium is a trace metal with severe toxicity. Contamination of thallium (Tl) generated by steel and non-ferrous metals industry is gaining growing concern worldwide. However, little is known on Tl contamination owing to industrial activities using carbonate minerals. This study revealed abundant geochemical mobile/bioavailable Tl (> 65.7%, in average; mostly in oxidizable fraction) in soils from a carbonate-hosted PbZn ore utilizing area in China for the first time. Unexpected Tl enrichment was observed in soil accompanying with 3655, 7820, 100.1, 27.3 and 29.9 mg/kg (in average) of Pb, Zn, As, Cd and Sb, respectively. Characterization using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis further confirmed that historical industrial activities impose anthropogenic catastrophic effects on the local agricultural soil system. The ecological and health risk assessment of heavy metal(loid)s in soils proclaimed serious potential non-carcinogenic risks of Pb and V to adults, and Pb, Tl and As to children. Sequential extraction analysis showed that Tl, as well as Pb, Zn, Mn, Co, and Cd, mainly existed in the mobile fractions (exchangeable/acid-extractable, reducible and oxidizable), indicating an ecological risk of biological accumulation of multiple metal(loid)s in this area. These findings provide a theoretical basis for taking appropriate remediation measures in order to ensure safety of soils in such industrial areas likewise.


Assuntos
Metais Pesados , Poluentes do Solo , Adulto , Carbonatos/análise , Criança , China , Monitoramento Ambiental , Humanos , Chumbo/análise , Metais Pesados/análise , Minerais/análise , Medição de Risco , Solo/química , Poluentes do Solo/análise , Tálio/análise , Zinco/análise , Compostos de Zinco
5.
ACS Appl Mater Interfaces ; 14(2): 2881-2892, 2022 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-34985854

RESUMO

Cascade catalysis that combines chemical catalysis and biocatalysis has received extensive attention in recent years, especially the integration of metal nanoparticles (MNPs) with enzymes. However, the compatibility between MNPs and enzymes, and the stability of the integrated nanocatalyst should be improved to promote the application. Therefore, in this study, we proposed a strategy to space-separately co-immobilize MNPs and enzymes to the pores and surface of a highly stable covalent organic framework (COF), respectively. Typically, Pd NPs that were prepared by in situ reduction with triazinyl as the nucleation site were distributed in COF (Tz-Da), and organophosphorus hydrolase (OPH) was immobilized on the surface of Tz-Da by a covalent method to improve its stability. The obtained integrated nanocatalyst Pd@Tz-Da@OPH showed high catalytic efficiency and reusability in the cascade degradation of organophosphate nerve agents. Furthermore, the versatility of the preparation strategy of COF-based integrated nanocatalyst has been preliminarily expanded: (1) Pd NPs and OPH were immobilized in the triazinyl COF (TTB-DHBD) with different pore sizes for cascade degradation of organophosphate nerve agent and the particle size of MNPs can be regulated. (2) Pt NPs and glucose oxidase were immobilized in COF (Tz-Da) to obtain an integrated nanocatalyst for efficient colorimetric detection of phenol.


Assuntos
Arildialquilfosfatase/metabolismo , Materiais Biocompatíveis/metabolismo , Nanopartículas Metálicas/química , Estruturas Metalorgânicas/metabolismo , Agentes Neurotóxicos/metabolismo , Organofosfatos/metabolismo , Arildialquilfosfatase/química , Biocatálise , Materiais Biocompatíveis/química , Teste de Materiais , Estruturas Metalorgânicas/química , Estrutura Molecular , Agentes Neurotóxicos/química , Organofosfatos/química , Paládio/química , Paládio/metabolismo
6.
Sci Total Environ ; 803: 150036, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34525718

RESUMO

Thallium (Tl) is a highly toxic trace metal. Lead (Pb)­zinc (Zn) smelting, which is a pillar industry in various countries, is regarded as one of the dominant anthropogenic sources of Tl contamination in the environment. In this study, thallium isotope data have been evaluated for raw material and a set of industrial wastes produced at different stages of Pb-Zn smelting in a representative large facility located by the North River, South China, in order to capture Tl isotope signatures of such typical anthropogenic origin for laying the foundation of tracking Tl pollution. Large variations in Tl isotopic compositions of raw Pb-Zn ores and solid smelting wastes produced along the process chain were observed. The ε205Tl values of raw Pb-Zn ores and return fines are -0.87 ± 0.26 and -1.0 ± 0.17, respectively, contrasted by increasingly more negative values for electrostatic precipitator dust (ε205Tl = -2.03 ± 0.14), lime neutralizing slag (ε205Tl = -2.36 ± 0.18), and acid sludge (ε205Tl = -4.62 ± 0.76). The heaviest ε205Tl (1.12 ± 0.51) was found in clinker. These results show that isotopic fractionation occurs during the smelting processes. Obviously, the lighter Tl isotope is enriched in the vapor phase (-3.75 ε205Tl units). Further XPS and STEM-EDS analyses show that Tl isotope fractionation conforms to the Rayleigh fractionation model, and adsorption of 205Tl onto hematite (Fe2O3) may play an important role in the enrichment of the heavier Tl isotope. The findings demonstrate that Tl isotope analysis is a robust tool to aid our understanding of Tl behavior in smelting processes and to provide a basis for source apportionment of Tl contaminations.


Assuntos
Tálio , Zinco , Monitoramento Ambiental , Resíduos Industriais , Isótopos/análise , Chumbo , Tálio/análise
7.
J Hazard Mater ; 423(Pt A): 126997, 2022 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-34474370

RESUMO

Thallium (Tl) is an extremely toxic metal, while its occurrence and fate in paddy soil environment remain understudied. Herein, the enrichment and migration mechanisms and potential health risks of Tl and metal(loid)s were evaluated in paddy soils surrounding an industrial park utilizing Tl-bearing minerals. The results showed that Tl contamination was evident (0.63-3.16 mg/kg) in the paddy soils and Tl was generally enriched in root of rice (Oryza sativa L.) with a mean content of 1.27 mg/kg. A remarkably high level of Tl(III) (30-50%) was observed in the paddy soils. Further analyses by STEM-EDS and XPS indicated that Tl(I) in the paddy soils was jointly controlled by adsorption, oxidation, and precipitation of Fe/Mn(hydr)oxide (e.g. hematite and birnessite), which might act as important stabilization mechanisms for inhibiting potential Tl uptake by rice grains. The health quotient (HQ) values indicated a potentially high Tl risk for inhabitants via consumption of the rice grains. Therefore, it is critical to establish effective measures for controlling the discharge of Tl-containing waste and wastewater from different industrial activities to ensure food safety in the rice paddy soils.


Assuntos
Oryza , Poluentes do Solo , China , Solo , Poluentes do Solo/análise , Tálio/análise
8.
Mol Biotechnol ; 63(6): 544-555, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33786739

RESUMO

Candida tropicalis can metabolize alkanes or fatty acids to produce long-chain dicarboxylic acids (DCAs). Fatty acid transporters located on the cell or peroxisome membrane may play an important role in this process. Using amino acid sequence homologous alignment, two putative proteins, CtFat1p and CtPxa1p, located on the cell and peroxisome membrane were found, respectively. Moreover, single- and double-knockout homologous recombination technology was used to study ctfat1p and ctpxa1p gene effects on DCA synthesis. In comparison to the wild-type strain, long-chain DCA yield decreased by 65.14%, 88.38% and 56.19% after single and double-copy knockout of ctfat1p genes and double-copy knockout of ctpxa1p genes, respectively, indicating that the knockout of ctfat1p and ctpxa1p genes had a significant effect on the conversion of oils and fats into long-chain DCAs by C. tropicalis. However, the yield of long-chain DCAs increased by 21.90% after single-knockout of the ctpxa1p gene, indicating that the single-knockout of the ctpxa1p gene may reduce fatty acid transport to peroxisome for further oxidation. Moreover, to improve the intracellular transport rate of fatty acids, ctfat1p copy number increased, increasing DCA yield by 30.10%. These results may provide useful information for enhancing the production of long-chain DCAs by C. tropicalis.


Assuntos
Alcanos/química , Candida tropicalis/química , Ácidos Graxos/química , Engenharia de Proteínas , Alcanos/metabolismo , Sequência de Aminoácidos/genética , Candida tropicalis/enzimologia , Candida tropicalis/metabolismo , Proteínas de Transporte de Ácido Graxo/metabolismo , Ácidos Graxos/metabolismo , Fermentação , Redes e Vias Metabólicas/genética , Oxirredução , Peroxissomos/enzimologia , Peroxissomos/genética , Engenharia de Proteínas/métodos , Alinhamento de Sequência
9.
J Colloid Interface Sci ; 590: 436-445, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33561593

RESUMO

Metal-organic frameworks (MOFs) have been emerged as a promising support for immobilizing enzymes owing to the tunable porosity, high surface area, and structural diversity. However, most of these possess nanometer size and small pores, which are difficult to recover them from the reaction medium and present low immobilization efficiency and protein loading capacity, and high substrate diffusion limitations. Herein, a novel magnetic amino-functionalized zeolitic imidazolate framework-8 (ZIF-8) with 3D highly ordered macroporous structure was synthesized using the assembled polystyrene (PS) nanosphere monoliths as a template. Subsequently, catalase (CAT) molecules were immobilized on the surface of macroporous magnetic ZIF-8 and inside the macropores by precipitation, covalent binding and cross-linking. The resultant immobilized CAT showed high immobilization efficiency (58%) and protein loading capacity (29%), leading to 500% higher activity than the immobilized CAT on ZIF-8 (CAT/ZIF-8). Meanwhile, the immobilized CAT could be easily recovered with a magnet without obvious activity loss. The traditional CAT/ZIF-8 lost its activity after 6 cycles, whereas, the immobilized CAT retained 90% activity of its initial activity after reusing for 8 cycles, indicating excellent reusability. In conclusion, this study provides a facile and efficient approach to immobilize enzymes on/in MOFs with enhanced activity and excellent recyclability.


Assuntos
Estruturas Metalorgânicas , Zeolitas , Catalase , Enzimas Imobilizadas , Fenômenos Magnéticos
10.
ACS Omega ; 6(4): 2777-2789, 2021 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-33553896

RESUMO

Due to its environmental friendliness and biodegradable ability, the enzymatic decolorization of azo dyes is the best option. However, the free enzyme suffers from various limitations, including poor stability, no repeatable use, and a high expense, which is the key drawback for its practical use. In this analysis, the laccase enzyme was immobilized in mesoporous silica coated magnetic multiwalled carbon nanotubes (Fe3O4-MWCNTs@SiO2) by a glutaraldehyde cross-linker to create an easily separable and stable enzyme. Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) were used to characterize the as-synthesized Fe3O4-MWCNTs@SiO2. Laccase immobilized in Fe3O4-MWCNTs@SiO2 showed a good improvement in temperature, pH, and storage stability. Moreover, the operational stability of the biocatalyst was improved, retaining 87% of its original activity even after 10 cycles of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) oxidation. The biocatalysts were applied for the decolorization of selected azo dyes without a mediator, and up to 99% of Eriochrome Black T (EBT), 98% of Acid Red 88 (AR 88), and 66% of Reactive Black 5 (RB5) were decolorized. Based on these properties, the biocatalysts can be potentially utilized in various environmental and industrial applications.

11.
J Hazard Mater ; 411: 125015, 2021 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-33445048

RESUMO

Cadmium (Cd) is a toxic heavy metal pollutant. Various industrial activities, especially metal smelting, are the main sources of Cd pollution. Cd isotopes have exhibited the ability to be excellent source tracers and can be used to assess the pollution contributions from different sources. Herein, in a typical lead-zinc smelter, Shaoguan, China, significant Cd isotopic fractionation was found during the high temperature smelting process and followed a Rayleigh distillation model. The heavier Cd isotopes were concentrated in the slag, while the lighter Cd isotopes were concentrated in the dust. In the downstream sediment profile of the smelter, sediments have extremely high Cd concentrations that far exceed the Chinese background sediment, indicating severe pollution levels. The ε114/110Cd of the sediment core, ranged from - 0.62 ± 0.5-1.73 ± 0.5, are found between slag (ε114/110Cd=10.42) and dust (ε114/110Cd=-5.68). The binary mixture model suggests that 88-93% of the Cd in sediment profile was derived from the slag, and 7-12% from the deposition of dust. The findings demonstrate the great potential to apply Cd isotopes as a new geochemical tool to distinguish anthropogenic sources and quantify the contribution from various sources in the environment.

12.
Environ Int ; 146: 106207, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33197789

RESUMO

Industrial activities tend to deteriorate adjacent agricultural lands due to accumulation of potentially toxic elements in soils and crops. However, better understanding of their distinctive source partitions and transfer process remains insufficient in steel-making area. The paper focuses on the pollution levels, health risks, and provenance identification of Tl, As, Pb, Cu, Ni, Co, Sb, Cd, Zn, Be, Cr, Fe, Mn, Mo, Sn, and V in common vegetables from different farmlands near a steel-making plant. The results showed that the Tl, As, Pb, Cd, Cr, Cu and Mn were of high-level contamination in soils and generally above the maximum permissible level (MPL). Calculation using hazard quotients (HQ) exhibited that consumption of the studied vegetables may entail significant health risks to residents, especially for children, resulting from the elevated contents of Tl, As and associated toxic elements. Calculation by binary mixing model using Pb isotopic compositions suggested that steel-making activities contributed to 35-80% of the contamination of Pb and As in vegetables. It is necessary to adopt appropriate remediation measures to mitigate the farmland contamination and ensure the food safety of the agricultural products.


Assuntos
Metais Pesados , Poluentes do Solo , Criança , China , Monitoramento Ambiental , Humanos , Metais Pesados/análise , Medição de Risco , Solo , Poluentes do Solo/análise , Aço , Verduras
13.
Langmuir ; 37(1): 417-427, 2021 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-33347295

RESUMO

Although loose nanofiltration membranes have been extensively studied for dye desalination, high-throughput membranes with antifouling and antibacterial properties are still highly needed. In this study, a zwitterion-modified molybdenum disulfide (MoS2) dual-layer loose nanofiltration membrane was prepared with the integration of antibacterial, antifouling, and high-flux properties. To be specific, MoS2 nanosheets were loaded on a polyacrylonitrile ultrafiltration membrane through pressure-assisted self-assembly. Then, poly (sulfobetaine methacrylate) (PSBMA) was coated on the surface of the MoS2 membrane via a simple polydopamine (PDA)-assisted one-step codeposition to prepare PSBMA/PDA/MoS2 nanofiltration membranes. Elemental and morphological analyses confirmed the formation of the MoS2 layer and PSBMA/PDA coating. In addition, the effect of the PSBMA amount and codeposition time on surface properties and membrane performances was investigated. Under optimum conditions, the as-prepared membrane showed excellent water permeance of 262 LMH/bar with good dye rejection (99.8% for methylene blue) and salt permeability, as well as excellent antifouling and antibacterial properties benefiting from the synergy of PSBMA/PDA coating layers and MoS2 layers.

14.
Chem Commun (Camb) ; 56(88): 13547-13550, 2020 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-33048068

RESUMO

Chemoenzymatic catalysts with hydrophobic nanopores were fabricated by co-immobilizing metal nanoparticles and enzymes into the dendritic organosilica nanoparticles. They demonstrated highly improved catalytic performance in chemoenzymatic asymmetric synthesis of chiral amines and alcohols. The hydrophobic microenvironment proved to be critical to enhanced stability, activity and cascade efficiency.

15.
Amino Acids ; 52(10): 1363-1374, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33021685

RESUMO

Corynebacterium glutamicum has a long and successful history in the biotechnological production of L-lysine. Besides the adjustment of metabolic pathways, intracellular and extracellular transport systems are critical for the cellular metabolism of L-lysine or its by-products. Here, three amino acid transmembrane transporters, namely, GluE, BrnE/BrnF, and LysP, which are widely present in C. glutamicum strains, were each investigated by gene knockout. In comparison with that in the wild-type strain, the yield of L-lysine increased by 9.0%, 12.3%, and 10.0% after the deletion of the gluE, brnE/brnF, and lysP genes, respectively, in C. glutamicum 23,604. Moreover, the amount of by-product amino acids decreased significantly when the gluE and brnE/brnF genes were deleted. It was also demonstrated that there was no effect on the growth of the strain when the gluE or lysP gene was deleted, whereas the biomass of C. glutamicum WL1702 (ΔbrnE/ΔbrnF) in the fermentation medium was significantly reduced in comparison with that of the wild type. These results also provide useful information for enhancing the production of L-lysine or other amino acids by C. glutamicum.


Assuntos
Sistemas de Transporte de Aminoácidos Básicos/genética , Corynebacterium glutamicum/metabolismo , Lisina/metabolismo , Sistemas de Transporte de Aminoácidos Básicos/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Corynebacterium glutamicum/genética , Corynebacterium glutamicum/crescimento & desenvolvimento , Fermentação , Deleção de Genes , Engenharia Metabólica , Redes e Vias Metabólicas , Metabolômica
16.
Sci Total Environ ; 742: 140321, 2020 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-32721712

RESUMO

Metal(loid) contamination caused by industrial activities in agricultural soils has become a universal environmental and food safety concern. This study revealed the contamination, pathway, and source contribution of metal(loid)s such as lead (Pb), zinc (Zn) and cadmium (Cd) in maize and soils in different residential areas impacted by long-term historical artisanal zinc smelting activities from Southwest China. Results revealed that the soils were contaminated heavily by metals like Pb, Zn and Cd, with contents of 40-14,280, 150-47,020 and 1.28-61.7 mg/kg, respectively. Hazard quotients of food uptake for Pb, Cd and Cr in maize grains were extremely high for residents, in particular for the children. To trace the sources of metal health risk, lead isotope fingerprinting and binary mixing modeling were applied. It indicated that the anthropogenic activities contributed over 80% to the Pb contamination in maize grains. The findings highlighted warning levels of health risks to the residents in consuming maize grains in the historical artisanal PbZn smelting area. Therefore, an effective strategy including pollution source control and remediation measures must be taken to improve the soil quality and guarantee food safety around the historical smelting areas likewise.


Assuntos
Metais Pesados/análise , Poluentes do Solo/análise , Criança , China , Monitoramento Ambiental , Humanos , Isótopos , Chumbo , Medição de Risco , Solo , Zea mays , Zinco/análise
17.
Environ Pollut ; 266(Pt 3): 115252, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32717591

RESUMO

Thallium (Tl) is a dispersed trace metal showing remarkable toxicity. Various anthropogenic activities may generate Tl contamination in river sediments, posing tremendous risks to aquatic life and human health. This paper aimed to provide insight into the vertical distribution, risk assessment and source tracing of Tl and other potentially toxic elements (PTEs) (lead, cadmium, zinc and copper) in three representative sediment cores from a riverine catchment impacted by multiple anthropogenic activities (such as steel-making and Pb-Zn smelting). The results showed high accumulations of Tl combined with associated PTEs in the depth profiles. Calculations according to three risk assessment methods by enrichment factor (EF), geoaccumulation index (Igeo) and the potential ecological risk index (PERI) all indicated a significant contamination by Tl in all the sediments. Furthermore, lead isotopes were analyzed to fingerprint the contamination sources and to calculate their quantitative contributions to the sediments using the IsoSource software. The results indicated that a steel-making plant was the most important contamination source (∼56%), followed by a Pb-Zn smelter (∼20%). The natural parental bedrock was found to contribute ∼24%. The findings highlight the importance of including multiple anthropogenic sources for quantitative fingerprinting of Tl and related metals by the lead isotopic approach in complicated environmental systems.


Assuntos
Metais Pesados/análise , Poluentes Químicos da Água/análise , China , Monitoramento Ambiental , Sedimentos Geológicos , Humanos , Metais/análise , Medição de Risco , Rios , Tálio/análise
18.
Int J Nanomedicine ; 15: 2685-2697, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32368049

RESUMO

BACKGROUND: Nanocarriers could deliver significantly higher amounts of antigen to antigen-presenting cells (APCs), which have great potential to stimulate humoral and cellular response in cancer immunotherapy. Thereafter, silica solid nanosphere (SiO2) was prepared, and a model antigen (ovalbumin, OVA) was covalently conjugated on the surface of SiO2 to form nanovaccine (OVA@SiO2). And the application of OVA@SiO2 for cancer immunotherapy was evaluated. MATERIALS AND METHODS: SiO2 solid nanosphere was prepared by the Stöber method, then successively aminated by aminopropyltriethoxysilane and activated with glutaraldehyde. OVA was covalently conjugated on the surface of activated SiO2 to obtain nanovaccine (OVA@SiO2). Dynamic light scattering, scanning electron microscope, and transmission electron microscope were conducted to identify the size distribution, zeta potential and morphology of OVA@SiO2. The OVA loading capacity was investigated by varying glutaraldehyde concentration. The biocompatibility of OVA@SiO2 to DC2.4 and RAW246.7 cells was evaluated by a Cell Counting Kit-8 assay. The uptake of OVA@SiO2 by DC2.4 and its internalization pathway were evaluated in the absence or presence of different inhibitors. The activation and maturation of bone marrow-derived DC cells by OVA@SiO2 were also investigated. Finally, the in vivo transport of OVA@SiO2 and its toxicity to organs were appraised. RESULTS: All results indicated the successful covalent conjugation of OVA on the surface of SiO2. The as-prepared OVA@SiO2 possessed high antigen loading capacity, which had good biocompatibility to APCs and major organs. Besides, OVA@SiO2 facilitated antigen uptake by DC2.4 cells and its cytosolic release. Noteworthily, OVA@SiO2 significantly promoted the maturation of dendritic cells and up-regulation of cytokine secretion by co-administration of adjuvant CpG-ODN. CONCLUSION: The as-prepared SiO2 shows promising potential for use as an antigen delivery carrier.


Assuntos
Antígenos/metabolismo , Vacinas Anticâncer/farmacologia , Imunoterapia/métodos , Nanosferas/química , Ovalbumina/química , Adjuvantes Imunológicos/administração & dosagem , Animais , Apresentação do Antígeno , Antígenos/administração & dosagem , Antígenos/química , Antígenos/imunologia , Vacinas Anticâncer/administração & dosagem , Vacinas Anticâncer/química , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/imunologia , Portadores de Fármacos/administração & dosagem , Portadores de Fármacos/química , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Nanosferas/administração & dosagem , Oligodesoxirribonucleotídeos/administração & dosagem , Ovalbumina/imunologia , Ovalbumina/farmacocinética , Células RAW 264.7 , Dióxido de Silício/química
19.
Nanomaterials (Basel) ; 10(5)2020 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-32365912

RESUMO

A nano-form composite of MXenes (Ti3C2Tx, Tx = -O, -OH, -F) was synthesized through depositing bismuth-nanoparticle (BiNPs) onto Ti3C2Tx sheets. Because of the preventive effect of the two-dimensional layered structure of Ti3C2Tx, the nanoparticles of Bi were uniform and well attached on the Ti3C2Tx. The obtained BiNPs/Ti3C2Tx nano-composite was applied for sensors construction of electrochemical detecting of Pb2+ and Cd2+ heavy metal ions. The produced BiNPs@Ti3C2Tx-based sensor showed high effective surface area and excellent conductivity. Also, the BiNPs were efficient for anodic-stripping voltammetric to detect heavy metal ions. After conditions optimization, the BiNPs@Ti3C2Tx nano-sensor could detect Pb2+ and Cd2+ simultaneously and the detection limits were 10.8 nM for Pb2+ and 12.4 nM for Cd2+. The BiNPs@Ti3C2Tx was promising for detecting heavy metal ions due to their high surface area, fast electron-transfer ability, environmental friendliness, and facial preparation.

20.
Ann Anat ; 231: 151529, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32437866

RESUMO

PURPOSE: To identify the body surface position and depth of the center of the intramuscular nerves dense region (CINDR) of the medial femoral muscles. METHODS: Utilizing twelve Chinese adult cadavers (six men and six women), with an age range from 35 to 75 (66.5±5.4) years, the body surface curves between the greater trochanter of the femur and the pubic tubercle and lateral femoral epicondyle were designated as horizontal (H) and longitudinal (L) reference lines, respectively. Sihler's staining was performed on one side of the medial femoral muscles to show the intramuscular nerve dense regions, and the contralateral CINDR was labeled with barium sulfate and scanned by computed tomography, and three-dimensional reconstruction was performed. The body surface projection point of CINDR was designated as P. Projection of P in the opposite direction was identified as P'. The intersection of the longitudinal line from P to line H, and that of the horizontal line from P to line L was designated as PH and PL, respectively. The percentage positions of PH and PL on the H and L lines and the depth of the CINDRs were determined under the Syngo system. RESULTS: The pectineus, gracilis, adductor longus, and adductor brevis muscles each possess one intramuscular nerve dense region; the adductor magnus muscle has two. The PH was located at 80.32%, 95.67%, 85.64%, 94.92%, 84.48%, and 88.83% of line H, respectively. PL was at 12.76%, 40.68%, 33.26%, 23.39%, 25.57%, and 35.29% of line L, respectively. The depth of CINDRs was at 17.58%, 27.89%, 23.05%, 30.45%, 34.09%, and 29.52% of PP' line, respectively. These percentage values are all means. No statistical difference was observed neither between the left and right sides nor between the male and female cadavers (P>0.05). CONCLUSION: These results may help improve the efficiency and efficacy of botulinum toxin A injection in the treatment of medial femoral muscle spasticity.


Assuntos
Espasticidade Muscular/prevenção & controle , Músculo Esquelético/inervação , Adulto , Idoso , Cadáver , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/diagnóstico por imagem , Coloração e Rotulagem/métodos , Coxa da Perna , Tomografia Computadorizada Espiral
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