Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 198
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Anal Chem ; 96(2): 810-820, 2024 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-38173421

RESUMO

Monitoring mitochondrial esterase activity is crucial not only for investigating mitochondrial metabolism but also for assessing the effectiveness of mitochondrial-targeting prodrugs. However, accurately detecting esterase activity within mitochondria poses challenges due to its ubiquitous presence in cells and the uncontrolled localization of fluorogenic probes. To overcome this hurdle and reveal variations among different mitochondria, we isolated mitochondria and preserved their activity and functionality in a buffered environment. Subsequently, we utilized a laboratory-built nano-flow cytometer in conjunction with an esterase-responsive calcein-AM fluorescent probe to measure the esterase activity of individual mitochondria. This approach enabled us to investigate the influence of temperature, pH, metal ions, and various compounds on the mitochondrial esterase activity without any interference from other cellular constituents. Interestingly, we observed a decline in the mitochondrial esterase activity following the administration of mitochondrial respiratory chain inhibitors. Furthermore, we found that mitochondrial esterase activity was notably higher in the presence of a high concentration of ATP compared to that of ADP and AMP. Additionally, we noticed a correlation between elevated levels of complex IV and increased mitochondrial esterase activity. These findings suggest a functional connection between the mitochondrial respiratory chain and mitochondrial esterase activity. Moreover, we detected an upsurge in mitochondrial esterase activity during the early stages of apoptosis, while cellular esterase activity decreased. This highlights the significance of analyzing enzyme activity within specific organelle subregions. In summary, the integration of a nano-flow cytometer and fluorescent dyes introduces a novel method for quantifying mitochondrial enzyme activity with the potential to uncover the alterations and unique functions of other mitochondrial enzymes.


Assuntos
Corantes Fluorescentes , Mitocôndrias , Mitocôndrias/metabolismo , Corantes Fluorescentes/química , Apoptose , Membranas Mitocondriais , Esterases/metabolismo
2.
Small ; : e2310712, 2024 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-38733222

RESUMO

Extracellular vesicles (EVs) are recognized as potential candidates for next-generation drug delivery systems. However, the inherent cancer-targeting efficiency is unsatisfactory, necessitating surface modification to attach cell-binding ligands. By utilizing phospholipase D from Streptomyces in combination with maleimide-containing primary alcohol, the authors successfully anchored ligands onto milk-derived EVs (mEVs), overcoming the issues of ligand leakage or functional alteration seen in traditional methods. Quantitative nano-flow cytometry demonstrated that over 90% of mEVs are effectively modified with hundreds to thousands of ligands. The resulting mEV formulations exhibited remarkable long-term stability in conjugation proportion, ligand number, size distribution, and particle concentration, even after months of storage. It is further shown that conjugating transferrin onto mEVs significantly enhanced cellular uptake and induced pronounced cytotoxic effects when loaded with paclitaxel. Overall, this study presents a highly efficient, stable, cost-effective, and scalable ligand conjugation approach, offering a promising strategy for targeted drug delivery of EVs.

3.
Clin Chem Lab Med ; 2024 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-38896030

RESUMO

Extracellular vesicles (EVs) represent a diverse class of nanoscale membrane vesicles actively released by cells. These EVs can be further subdivided into categories like exosomes and microvesicles, based on their origins, sizes, and physical attributes. Significantly, disease-derived EVs have been detected in virtually all types of body fluids, providing a comprehensive molecular profile of their cellular origins. As a result, EVs are emerging as a valuable addition to liquid biopsy techniques. In this collective statement, the authors share their current perspectives on EV-related research and product development, with a shared commitment to translating this newfound knowledge into clinical applications for cancer and other diseases, particularly as disease biomarkers. The consensus within this document revolves around the overarching recognition of the merits, unresolved questions, and existing challenges surrounding EVs. This consensus manuscript is a collaborative effort led by the Committee of Exosomes, Society of Tumor Markers, Chinese anti-Cancer Association, aimed at expediting the cultivation of robust scientific and clinically applicable breakthroughs and propelling the field forward with greater swiftness and efficacy.

4.
Mol Cell ; 61(6): 859-73, 2016 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-26990989

RESUMO

Dysregulation of MLL complex-mediated histone methylation plays a pivotal role in gene expression associated with diseases, but little is known about cellular factors modulating MLL complex activity. Here, we report that SON, previously known as an RNA splicing factor, controls MLL complex-mediated transcriptional initiation. SON binds to DNA near transcription start sites, interacts with menin, and inhibits MLL complex assembly, resulting in decreased H3K4me3 and transcriptional repression. Importantly, alternatively spliced short isoforms of SON are markedly upregulated in acute myeloid leukemia. The short isoforms compete with full-length SON for chromatin occupancy but lack the menin-binding ability, thereby antagonizing full-length SON function in transcriptional repression while not impairing full-length SON-mediated RNA splicing. Furthermore, overexpression of a short isoform of SON enhances replating potential of hematopoietic progenitors. Our findings define SON as a fine-tuner of the MLL-menin interaction and reveal short SON overexpression as a marker indicating aberrant transcriptional initiation in leukemia.


Assuntos
Proteínas de Ligação a DNA/genética , Histona-Lisina N-Metiltransferase/biossíntese , Leucemia Mieloide Aguda/genética , Proteína de Leucina Linfoide-Mieloide/biossíntese , Proteínas Proto-Oncogênicas/genética , Transcrição Gênica , Processamento Alternativo/genética , Linhagem Celular Tumoral , Cromatina/genética , Proteínas de Ligação a DNA/biossíntese , Regulação Leucêmica da Expressão Gênica , Histona-Lisina N-Metiltransferase/genética , Humanos , Leucemia Mieloide Aguda/patologia , Metilação , Antígenos de Histocompatibilidade Menor , Proteína de Leucina Linfoide-Mieloide/genética , Ligação Proteica , Isoformas de Proteínas/genética , Proteínas Proto-Oncogênicas/metabolismo
5.
Nanomedicine ; 56: 102720, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38007067

RESUMO

Flow cytometry allows to characterize nanoparticles (NPs) and extracellular vesicles (EVs) but results are often expressed in arbitrary units of fluorescence. We evaluated the precision and accuracy of molecules of equivalent soluble fluorophores (MESF) beads for calibration of NPs and EVs. Firstly, two FITC-MESF bead sets, 2 and 6 um in size, were measured on three flow cytometers. We showed that arbitrary units could not be compared between instruments but after calibration, comparable FITC MESF units were achieved. However, the two calibration bead sets displayed varying slopes that were consistent across platforms. Further investigation revealed that the intrinsic uncertainty related to the MESF beads impacts the robust assignment of values to NPs and EVs based on extrapolation into the dim fluorescence range. Similar variations were found with PE MESF calibration. Therefore, the same calibration materials and numbers of calibration points should be used for reliable comparison of submicron sized particles.


Assuntos
Vesículas Extracelulares , Nanopartículas , Calibragem , Fluoresceína-5-Isotiocianato , Citometria de Fluxo/métodos , Corantes Fluorescentes
6.
J Environ Manage ; 363: 121411, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38861887

RESUMO

Rural areas are the main source of ecosystem services in arid and semi-arid areas, and ecosystem services are the background conditions for rural revitalization. In this study, the spatial pattern of key ecosystem services in the countryside was assessed, and the trade-offs and synergistic relationships among ecosystem services were investigated, using the Tacheng-Emin Basin in China as the study area. Finally, the types of ecological function zoning and development strategies for the countryside are proposed. The results showed that: (1) the area of ecological land was large, and the average land use intensity was 2.48, which belonged to the medium intensity. (2) The mean values of the six ecosystem services are all in the middle and lower classes, and the spatial distribution of the five ecosystem services is similar, except for food production. (3) Except for grain production, the other five ecosystem services showed positive feedback to elevation. The other five ecosystem services are synergistic, and there are trade-offs between grain production and other ecosystem services. In the nonlinear interaction mechanism of ecosystem services, the fluctuation constraint occupies the largest proportion. (4) At smaller spatial scales, there are more types of ecosystem service clusters. Combining the results of the study, the villages in the study area can be categorized into five types. This study formulates five priority levels of rural ecological revitalization and proposes different development recommendations for the sustainable development of each type of village. This study is helpful for the fine management of land resources and the revitalization of rural ecology and provides a reference for the sustainable development of ecosystem services in arid and semi-arid areas.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , China , Ecologia
7.
Plant J ; 110(1): 243-261, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35043493

RESUMO

Flavan-3-ols are abundant in the tea plant (Camellia sinensis) and confer tea with flavor and health benefits. We recently found that alternative splicing of genes is likely involved in the regulation of flavan-3-ol biosynthesis; however, the underlying regulatory mechanisms remain unknown. Here, we integrated metabolomics and transcriptomics to construct metabolite-gene networks in tea leaves, collected over five different months and from five spatial positions, and found positive correlations between endogenous jasmonic acid (JA), flavan-3-ols, and numerous transcripts. Transcriptome mining further identified CsJAZ1, which is negatively associated with flavan-3-ols formation and has three CsJAZ1 transcripts, one full-length (CsJAZ1-1), and two splice variants (CsJAZ1-2 and -3) that lacked 3' coding sequences, with CsJAZ1-3 also lacking the coding region for the Jas domain. Confocal microscopy showed that CsJAZ1-1 was localized to the nucleus, while CsJAZ1-2 and CsJAZ1-3 were present in both the nucleus and the cytosol. In the absence of JA, CsJAZ1-1 was bound to CsMYC2, a positive regulator of flavan-3-ol biosynthesis; CsJAZ1-2 functioned as an alternative enhancer of CsJAZ1-1 and an antagonist of CsJAZ1-1 in binding to CsMYC2; and CsJAZ1-3 did not interact with CsMYC2. In the presence of JA, CsJAZ1-3 interacted with CsJAZ1-1 and CsJAZ1-2 to form heterodimers that stabilized the CsJAZ1-1-CsMYC2 and CsJAZ1-2-CsMYC2 complexes, thereby repressing the transcription of four genes that act late in the flavan-3-ol biosynthetic pathway. These data indicate that the alternative splicing variants of CsJAZ1 coordinately regulate flavan-3-ol biosynthesis in the tea plant and improve our understanding of JA-mediated flavan-3-ol biosynthesis.


Assuntos
Camellia sinensis , Processamento Alternativo/genética , Camellia sinensis/genética , Camellia sinensis/metabolismo , Flavonoides/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Chá/metabolismo
8.
Anal Chem ; 95(6): 3423-3433, 2023 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-36735936

RESUMO

Correlated analysis of multiple biochemical parameters at the single-particle level and in a high-throughput manner is essential for insights into the diversity and functions of biological nanoparticles (BNPs), such as bacteria and subcellular organelles. To meet this challenge, we developed a highly sensitive spectral nano-flow cytometer (S-nFCM) by integrating a spectral recording module to a laboratory-built nFCM that is 4-6 orders of magnitude more sensitive in side scattering detection and 1-2 orders of magnitude more sensitive in fluorescence detection than conventional flow cytometers. An electron-multiplying charge-coupled device (EMCCD) was used to acquire the full fluorescence spectra of single BNPs upon holographic grating dispersion. Up to 10,000 spectra can be collected in 1 min with 2.1 nm resolution. The precision, linearity, and sensitivity were examined. Complete discernment of single influenza viruses against the background signal, discrimination of different strains of marine cyanobacteria in a mixed sample based on their spectral properties of natural fluorescence, classification of bacterial categories exhibiting different patterns of antigen expression, and multiparameter analysis of single mitochondria for drug discovery were successfully demonstrated.


Assuntos
Nanopartículas , Mitocôndrias , Organelas
9.
Anal Bioanal Chem ; 415(7): 1287-1298, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35945289

RESUMO

Extracellular vesicles (EVs) have emerged as an attractive drug delivery system owing to their natural roles in intercellular communication. On account of the large intrinsic heterogeneity of EVs, it is highly desirable to evaluate not only the encapsulation efficiency but also the alteration of biological functionality after the drug-loading process at the single-particle level. However, the nanoscale size of EVs poses a great challenge. Taking advantage of nano-flow cytometry (nFCM) in the multiparameter analysis of single EVs as small as 40 nm, six commonly used drug-loading strategies (coincubation, electroporation, extrusion, freeze-thawing, sonication, and surfactant treatment) were exploited by employing doxorubicin (Dox) as the model drug. Encapsulation ratio, EV concentration, drug content, and membrane proteins of Dox-loaded EVs were measured at the single-particle level. Our data indicated that coincubation and electroporation outperformed other methods with an encapsulation ratio of approximately 45% and a higher Dox content in single EVs. Interestingly, the labeling ratios of membrane proteins indicated that varying degrees of damage to the surface proteins of EVs occurred upon extrusion, freeze-thawing, sonication, and surfactant treatment. Confocal fluorescence microscopy and flow cytometry analysis revealed that Dox-loaded EVs prepared by electroporation induced the strongest apoptosis followed by coincubation. These results correlated well with their cellular uptake rate and fundamentally with the Dox encapsulation efficiency of single EVs. nFCM provides a rapid and sensitive platform for single-particle assessment of drug-loading strategies for incorporating drugs into EVs.


Assuntos
Vesículas Extracelulares , Preparações Farmacêuticas/metabolismo , Vesículas Extracelulares/metabolismo , Doxorrubicina/farmacologia , Doxorrubicina/metabolismo , Eletroporação/métodos , Tensoativos
10.
J Allergy Clin Immunol ; 150(5): 1154-1167, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35792218

RESUMO

BACKGROUND: Hyperinflammation is a life-threatening condition associated with various clinical disorders characterized by excessive immune activation and tissue damage. Multiple cytokines promote the development of hyperinflammation; however, the contribution of IL-10 remains unclear despite emerging speculations for a pathological role. Clinical observations from hemophagocytic lymphohistiocytosis (HLH), a prototypical hyperinflammatory disease, suggest that IL-18 and IL-10 may collectively promote the onset of a hyperinflammatory state. OBJECTIVE: We aimed to investigate the collaborative roles of IL-10 and IL-18 in hyperinflammation. METHODS: A comprehensive plasma cytokine profile for 87 secondary HLH patients was first depicted and analyzed. We then investigated the systemic and cellular effects of coelevated IL-10 and IL-18 in a transgenic mouse model and cultured macrophages. Single-cell RNA sequencing was performed on the monocytes/macrophages isolated from secondary HLH patients to explore the clinical relevance of IL-10/IL-18-mediated cellular signatures. The therapeutic efficacy of IL-10 blockade was tested in HLH mouse models. RESULTS: Excessive circulating IL-10 and IL-18 triggered a lethal hyperinflammatory disease recapitulating HLH-like phenotypes in mice, driving peripheral lymphopenia and a striking shift toward enhanced myelopoiesis in the bone marrow. IL-10 and IL-18 polarized cultured macrophages to a distinct proinflammatory state with pronounced expression of myeloid cell-recruiting chemokines. Transcriptional characterization suggested the IL-10/IL-18-mediated cellular features were clinically relevant with HLH, showing enhanced granzyme expression and proteasome activation in macrophages. IL-10 blockade protected against the lethal disease in HLH mouse models. CONCLUSION: Coelevated IL-10 and IL-18 are sufficient to drive HLH-like hyperinflammatory syndrome, and blocking IL-10 is protective in HLH models.


Assuntos
Interleucina-10 , Interleucina-18 , Linfo-Histiocitose Hemofagocítica , Mielopoese , Animais , Camundongos , Modelos Animais de Doenças , Linfo-Histiocitose Hemofagocítica/patologia
11.
Angew Chem Int Ed Engl ; 62(44): e202309737, 2023 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-37665693

RESUMO

Every year vast quantities of silver are lost in various waste streams; this, combined with its limited, diminishing supply and rising demand, makes silver recovery of increasing importance. Thus, herein, we report a controllable, green process to produce a host of highly porous metal-organic framework (MOF)/oligomer composites using supercritical carbon dioxide (ScCO2 ) as a medium. One resulting composite, referred to as MIL-127/Poly-o-phenylenediamine (PoPD), has an excellent Ag+ adsorption capacity, removal efficiency (>99 %) and provides rapid Ag+ extraction in as little as 5 min from complex liquid matrices. Notably, the composite can also reduce sliver concentrations below the levels (<0.1 ppm) established by the United States Environmental Protection Agency. Using theoretical simulations, we find that there are spatially ordered polymeric units inside the MOF that promote the complexation of Ag+ over other common competing ions. Moreover, the oligomer is able to reduce silver to its metallic state, also providing antibacterial properties.

12.
J Am Chem Soc ; 144(24): 10736-10742, 2022 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-35671378

RESUMO

Herein, a nitrogen-embedded quintuple [7]helicene (N-Q7H) with an azapentabenzocorannulene core, which can be considered to be a helicene/azacorannulene hybrid π-system, was synthesized from azapentabenzocorannulene in a three-step process. N-Q7H is the first example of a multiple helicene with an azabuckybowl core. Single-crystal X-ray diffractometry unambiguously confirmed the structure of the propeller-shaped hybrid π-system. Owing to nitrogen-atom doping in the multiple helicenes and effective hybridization between the helicene and azacorannulene, N-Q7H exhibits considerably redshifted absorption and emission (yellow-to-green color change and green-to-near-infrared fluorescence change) relative to the azapentabenzocorannulene core. The broad absorption from the ultraviolet-visible to the NIR region is ascribable to the allowed transition between the highest occupied molecular orbital and the lowest unoccupied molecular orbital after symmetry breaking, as revealed by density functional theory calculations. Compared to previous propeller-shaped multiple helicenes with corannulene or hexabenzocoronene (etc.) as cores, N-Q7H demonstrates a significantly higher NIR fluorescence quantum efficiency of 28%. Additionally, the chiral-resolution and redox properties of N-Q7H were investigated. The excellent photophysical and inherent chiral properties of N-Q7H suggest that azapentabenzocorannulene can be used as an outstanding nitrogen-embedded core to construct novel multiple helicenes with wide application potential, including as NIR fluorescent bio-probes.

13.
Anal Chem ; 94(50): 17634-17644, 2022 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-36474427

RESUMO

Protein aggregation is one of the greatest challenges in biopharmaceuticals as it could decrease therapeutic efficacy, induce immunogenicity, and reduce shelf life of protein drugs. However, there lacks high-throughput methods than can count and size protein aggregates in the nanometer size range, especially for those smaller than 100 nm. Employing a laboratory-built nano-flow cytometer (nFCM) that enables light scattering detection of single silica nanoparticles as small as 24 nm with sizing resolution and accuracy comparable to those of electron microscopy, here, we report a new benchmark to analyze single protein aggregates as small as 40 nm. With an analysis rate of up to 10,000 particles/min, the size distribution and particle concentration of nanometer protein aggregates can be acquired in 2-3 min. Employing heat-induced aggregation of bovine serum albumin (BSA) at high concentrations as the model system, effects of different categories of excipients, including sugars, polyols, salts, and amino acids on the inhibition of protein aggregation were investigated. Strikingly enough, as high as 1010 to 1012 particles/mL of protein aggregates were observed in the size range of 40 to 200 nm for therapeutic proteins of human serum albumin injection, reconstituted recombinant human interieukin-2 solution, and human immunoglobulin injection. nFCM opens a new avenue to count and size nanometer protein aggregates, suggesting its future usability in the quality assessment and formulation promotion of therapeutic proteins.


Assuntos
Produtos Biológicos , Nanopartículas , Humanos , Agregados Proteicos , Soroalbumina Bovina/química , Albumina Sérica Humana , Tamanho da Partícula
14.
Anal Chem ; 94(27): 9740-9749, 2022 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-35770965

RESUMO

Nasopharyngeal carcinoma (NPC) is a malignant tumor commonly associated with Epstein-Barr virus (EBV) infection, and its early diagnosis as well as its differentiation from nasopharyngitis (NPG) remains challenging due to the insufficient sensitivity of routine screening methods in clinical practice. To date, circulating extracellular vesicles (EVs, 40-1000 nm) have shown appealing potential in liquid biopsy for cancer diagnosis and prognosis. Herein, nanoflow cytometry (nFCM) capable of single EV analysis was applied to examine the expression of surface proteins with very low copy numbers on individual EVs as small as 40 nm. The particle concentrations of five EV subsets exposing EBV-encoded latent membrane proteins (LMP1 and LMP2A) and tumor markers (PD-L1, EGFR, and EpCAM) in plasma were determined rapidly via single-particle enumeration. We identified a five-marker panel named EVSUM5 (an unweighted sum of the concentration of the five individual EV subsets) that significantly surpassed the traditional VCA-IgA assay in discriminating NPC patients from both healthy donors and NPG patients with accuracies of 96.3 and 83.1%, respectively. Moreover, EVSUM2 (an unweighted sum of virus-specific LMP1- and LMP2A-positive EVs) could achieve the diagnosis of NPG with an accuracy of 82.6%. Collectively, the work presented a rapid, reliable, and noninvasive method as well as two diagnostic markers to help more accurately differentiate NPC from NPG patients and healthy donors in clinical practice.


Assuntos
Infecções por Vírus Epstein-Barr , Vesículas Extracelulares , Neoplasias Nasofaríngeas , Biomarcadores Tumorais , Infecções por Vírus Epstein-Barr/metabolismo , Vesículas Extracelulares/metabolismo , Herpesvirus Humano 4 , Humanos , Carcinoma Nasofaríngeo/diagnóstico , Neoplasias Nasofaríngeas/diagnóstico
15.
Anal Chem ; 94(41): 14299-14307, 2022 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-36084271

RESUMO

The refractive index (RI) is a fundamental physical property of materials. Although measurement of the RI of biological nanoparticles (BNPs) in aqueous media is of great importance to basic research and biomedical applications, it is hampered by their tiny size, large intrinsic heterogeneity, and weak scattering. Here, we report the development of a label-free technique that can determine the RI of individual viruses and small extracellular vesicles (sEVs) with high precision and an analysis rate up to 10 000 particles per minute. This was achieved via the combination of high-sensitivity light-scattering detection by nanoflow cytometry (nFCM) and the Mie theory calculation. With the measured RIs for T7 virions, T7 capsids, and sEVs, the concentrations of nucleic acid in viral particles and protein in the lumen of sEVs were estimated. Furthermore, building upon a simplified core-shell model, the RIs of sEVs ranging from 40 to 200 nm were obtained. By using these RIs, a statistically robust size distribution of sEVs was acquired in minutes with accuracy and resolution matched closely with those of cryo-TEM measurements. Our approach could become an important tool in the RI determination of single BNPs.


Assuntos
Vesículas Extracelulares , Ácidos Nucleicos , Vírus , Citometria de Fluxo/métodos , Refratometria
16.
Inorg Chem ; 61(13): 5335-5342, 2022 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-35290043

RESUMO

Developing new photocatalysts for reduction of nitroarenes to anilines under mild conditions is very significant. Herein, a new polyoxometalate-based metal-organic framework (POMOF), {[Co(H2O)]2[Co2(H2O)6(TPT)][Co(TPT)PW11O39]}·3H2O·TPT (namely, CoW-TPT, TPT = 2,4,6-tri(4-pyridyl)-1,3,5-triazine), was prepared by incorporating Co(II)-substituted Keggin-type anions [PCoW11O39]5- and a photosensitizer (TPT) into a framework. In this structure, the direct coordination bond between [PCoW11O39]5- and TPT ligand and π···π interactions between TPT molecules are beneficial for the separation and migration of photogenerated carriers, thus improving the photocatalytic activity of CoW-TPT. The combination of both photosensitizer TPT and the electron-storable component [PCoW11O39]5- in a cooperative photocatalysis fashion is conducive to the photocatalytic multielectron reduction of nitroarenes. CoW-TPT provided a high conversion of 94.71% in the photocatalytic reduction of nitroarenes to anilines utilizing triethanolamine as the proton source and electron donor by sequential proton-coupled electron transfers.

17.
Inorg Chem ; 61(5): 2421-2427, 2022 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-35076213

RESUMO

A powerful and promising route for developing novel photocatalysts for light-driven toluene oxidation in water under mild conditions is presented. Herein, a novel polyoxometalate-based metal-organic framework (POMOF), {Co4W22-DPNDI}, is prepared by incorporating the unusual Co4-sandwiched POM anion [Co4(µ-OH)2(SiW11O39)2]10- ({Co4W22}) and the photoactive organic bridging link N,N'-bis(4-pyridylmethyl)naphthalene diimide (DPNDI) into a framework. {Co4W22} is a good candidate for photocatalytic water oxidation. DPNDI is easily excited to form the radical species DPNDI* in the presence of an electron donor, which is beneficial for activation of the inert O2. Anion···π interactions and covalent bonds between {Co4W22} and DPNDI facilitate electron-hole separation and electron transfer. {Co4W22-DPNDI} displays high catalytic activity for the activation of the C(sp3)-H bond of toluene using light as a driving force and inexpensive water as an oxygen source under mild conditions. In particular, the yield and selectivity are improved by replacing oxygen with water, which may be ascribed to the release of protons during the water oxidation process that facilitate the generation of •OH.

18.
Anal Chem ; 93(27): 9531-9540, 2021 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-34197088

RESUMO

Telomere length (TL) is a highly relevant biomarker for age-associated diseases and cancer, yet its clinical applications have been hindered by the inability of existing methods to rapidly measure the TL distribution and the percentage of chromosomes with critically short telomeres (CSTs, < 3 kb). Herein, we report the development of a high-throughput method to measure TL at the single-chromosome level. Metaphase chromosomes are isolated, hybridized with the Alexa Fluor 488-labeled telomeric peptide nucleic acid probe, and analyzed using a laboratory-built ultrasensitive nano-flow cytometer. The fluorescence intensity of individual chromosomes is converted to TL in kilobases upon external calibration. With an analysis rate of several thousand chromosomes per minute, a statistically robust TL distribution histogram is acquired in minutes, and the percentage of chromosomes with CSTs can be quickly assessed. By analyzing peripheral blood lymphocytes of 158 healthy donors, TL is found to shorten with age at a rate of 64 ± 3 bp/year and the percentage of chromosomes with CSTs increases with age at a rate of 0.32 ± 0.02%/year. Moreover, the data of 28 patients with chronic myeloid leukemia (CML) indicate that telomeres are significantly shorter at the time of diagnosis and the clinical phases of CML are closely associated with TL and the percentage of chromosomes with CSTs. This powerful tool could greatly deepen our understanding of telomere biology and improve the clinical utility of telomere biomarkers.


Assuntos
Leucemia Mielogênica Crônica BCR-ABL Positiva , Telômero , Citometria de Fluxo , Humanos , Hibridização in Situ Fluorescente , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Telômero/genética
19.
Inorg Chem ; 60(21): 16810-16816, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34672625

RESUMO

Developing new photocatalysts for sulfide oxidation utilizing in situ-generated 1O2 is very significant. Inspired by natural enzymatic processes, we synthesized a mimic sulfite oxidase (SO), {[Co(Mo4O13)(TPT)2]} (CoMo-TPT), by incorporating an isopolymolybdate anion [Mo4O13]2- into a 2,4,6-tri(4-pyridyl)-1,3,5-triazine (TPT)-based metal-organic framework under mild hydrothermal conditions. In this structure, {Mo4O13} units with intrinsic SO-like catalytic sites are beneficial for the selective oxidation of sulfite and thioether. The ultraviolet-visible spectra of CoMo-TPT exhibited strong absorption from 250 to 650 nm and potential application in the utilization of solar energy. Mott-Schottky measurements indicated that CoMo-TPT is an n-type semiconductor with a LUMO value of -0.70 V (vs NHE) and a HOMO value of 1.39 V. The transient photocurrent responses with strong current density cycles with visible light indicated CoMo-TPT has a high photochemical activity. The lower resistance indicated that CoMo-TPT has a higher efficiency of photoinduced electron and hole separation. CoMo-TPT displayed a high efficiency of 99% and a selectivity of 97.3% in photocatalytic oxidation of sulfides by utilizing in situ-generated 1O2 through a tandem process of formation of H2O2 from O2 followed by catalyzed disproportionation of H2O2.


Assuntos
Estruturas Metalorgânicas
20.
J Clin Lab Anal ; 35(12): e24087, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34724262

RESUMO

BACKGROUND: The measurement method for experimental resolution and related data to evaluate analytical performance is poorly explored in clinical research. We established a method to measure the experimental resolution of clinical tests, including biochemical tests, automatic hematology analyzer methods, immunoassays, chemical experiments, and qPCR, to evaluate their analytical performance. METHODS: Serially diluted samples in equal proportions were measured, and correlation analysis was performed between the relative concentration and the measured value. Results were accepted for p ≤ 0.01 of the correlation coefficient. The minimum concentration gradient (eg, 10%) was defined as the experimental resolution. For this method, the smaller the value, the higher the experimental resolution and the better the analytical performance. RESULTS: The experimental resolution of the most common biochemical indices reached 10%, with some even reaching 1%. The results of most counting experiments showed experimental resolution up to 10%, whereas the experimental resolution of the classical chemical assays reached 1%. Unexpectedly, the experimental resolution of more sensitive assays, such as immunoassays was only 25% when using the manual method and 10% for qPCR. CONCLUSION: This study established a method for measuring the experimental resolution of laboratory assays and provides a new index for evaluating the reliability of methods in clinical laboratories.


Assuntos
Análise Química do Sangue/métodos , Técnicas Imunológicas/métodos , Laboratórios Clínicos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Contagem de Células Sanguíneas , Análise Química do Sangue/normas , Ensaio de Imunoadsorção Enzimática/métodos , Humanos , Técnicas Imunológicas/normas , Laboratórios Clínicos/normas , Reação em Cadeia da Polimerase em Tempo Real/normas , Reprodutibilidade dos Testes , Espectrofotometria Atômica
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA