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Electron transfer is considered to be a typical parameter that affects the catalytic activity of nanozymes. However, there is still controversy regarding whether higher or lower electron transfer numbers are beneficial for improving the catalytic activity of nanozymes. To address this issue, we propose the introduction of Pd doping as an important electron regulation strategy to tune electron transfer between Pt and ZIF-8 carriers (PtxPd1@ZIF-8). We observe a volcano-shaped relationship between the electron transfer number and catalytic activity, reaching its peak at Pt4Pd1@ZIF-8. Mechanism studies indicate that as the electron transfer number from Pt to ZIF-8 carriers increases, the d-band center of the active site Pt increases, reducing the occupancy of antibonding states and enhancing the adsorption capacity of the key intermediate (*O). However, a further increase in the adsorption of *O energy makes it difficult to desorb and participate in the next reaction, thus exhibiting volcanic activity. The optimized Pt4Pd1@ZIF-8 nanozyme is applied to develop an immunoassay for the detection of zearalenone, achieving a detection limit of 0.01 µg/L, which is 6 times higher than that of the traditional enzyme-linked immunosorbent assay. This work not only reveals the potential regulatory mechanism of electron transfer on the catalytic activity of nanozymes but also improves the performance of nanozyme-based biosensors.
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Estructuras Metalorgánicas , Paladio , Platino (Metal) , Catálisis , Platino (Metal)/química , Paladio/química , Estructuras Metalorgánicas/química , Transporte de Electrón , Inmunoensayo/métodosRESUMEN
Rapid identification of chemical analogues in herbal medicines using liquid chromatography-mass spectrometry was an efficient tool for discoveries of potentially active ingredients. Multi-dimensional combination of various separation technologies could significantly enhance the capacities for detection of trace components and discrimination of multiple isomers. In this study, an integrated two-step filtering strategy on liquid chromatography-ion mobility tandem with quadrupole-time-of-flight mass spectrometry (LC-IM-QTOF MS) was developed for identification of analogues in complex matrixes. The extracted raw data were preliminarily filtered by a collision-cross section (CCS) interval generated from power regression with confidence level at 99% for prediction of analogues. Then, the remained ions were further screened using a mass defect filtering (MDF) window based on m/z and decimal m/z of potential skeletons and substituents. By applying this strategy, 86, 102, 73, and 57 isoquinoline alkaloids were identified in herbal materials of Coptis chinensis Franch (CC), C. deltoidea C.Y.Cheng et Hsiao (CD), C. teeta Wall (CT), and Corydalis yanhusuo W.T.Wang (CY). The integrated two-step filtering presented higher efficiencies on exclusion of the background interference and reducing the false-positive rates than previously reported approaches. This study facilitated the application of LC-IM-MS on small molecular analysis and promoted the discoveries of bioactive components of herbal medicines for further pharmacological researches and quality control.
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Medicamentos Herbarios Chinos , Cromatografía Líquida de Alta Presión , Cromatografía Liquida , Iones , Espectrometría de MasasRESUMEN
Shenfu Injection (SFI), derived from the classical traditional Chinese medicine formula "Shenfu Decoction", is a modern preparation used to treat heart failure and shock in clinic. In this study, an ultra-high performance liquid chromatography-triple quadruple tandem mass spectrometry (UHPLC-QQQ MS) method was established to simultaneously quantify twenty-eight main active components of SFI in rat plasma, including eighteen ginsenosides and ten aconite alkaloids. Multi-reaction monitoring in positive and negative ionization switching modes is used for mass spectrometry analysis, and the whole analysis process was within 14 min. The developed method was well validated and successfully applied to the pharmacokinetic study of multiple components of SFI in rat plasma. Eight PPD-type ginsenosides Ra2, Ra3, Rb1, Ra1, Rc, Rb2, Rb3 and Rd presented relative high systemic exposure levels among ginsenosides with AUC0-t larger than 10,000 µg h/L, while mesaconine and hypaconine possessed relative high plasma abundance among aconite alkaloids with AUC0-t at 142.50 ± 17.42 µg h/L and 40.65 ± 5.61 µg h/L, respectively. Several PPT-type ginsenosides had obviously higher AUC0-t levels (e.g. 639.70 ± 134.61 µg h/L for ginsenoside Re and 874.79 ± 188.87 µg h/L for ginsenoside Rg1) than alkaloids but similar t1/2 levels (0.14 ± 0.03 h for ginsenoside Re, 0.16 ± 0.03 h for ginsenoside Rg1, 0.04-0.33 h for aconite alkaloids), indicating their quick elimination. Collectively, the pharmacokinetic research of ginsenosides and aconite alkaloids in SFI would provide a scientific basis for its clinical use and drug-drug interactions.
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Medicamentos Herbarios Chinos , Ginsenósidos , Animales , Cromatografía Líquida de Alta Presión , Ratas , Reproducibilidad de los Resultados , Espectrometría de Masas en TándemRESUMEN
Currently, high-throughput approaches are lacking in the isolation of antibodies with functional readouts beyond simple binding. This situation has impeded the next generation of cancer immunotherapeutics, such as bispecific T cell engager (BiTE) antibodies or agonist antibodies against costimulatory receptors, from reaching their full potential. Here, we developed a highly efficient droplet-based microfluidic platform combining a lentivirus transduction system that enables functional screening of millions of antibodies to identify potential hits with desired functionalities. To showcase the capacity of this system, functional antibodies for CD40 agonism with low frequency (<0.02%) were identified with two rounds of screening. Furthermore, the versatility of the system was demonstrated by combining an anti-Her2 × anti-CD3 BiTE antibody library with functional screening, which enabled efficient identification of active anti-Her2 × anti-CD3 BiTE antibodies. The platform could revolutionize next-generation cancer immunotherapy drug development and advance medical research.
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COVID-19 pandemic caused by SARS-CoV-2 constitutes a global public health crisis with enormous economic consequences. Monoclonal antibodies against SARS-CoV-2 can provide an important treatment option to fight COVID-19, especially for the most vulnerable populations. In this work, potent antibodies binding to SARS-CoV-2 Spike protein were identified from COVID-19 convalescent patients. Among them, P4A1 interacts directly with and covers majority of the Receptor Binding Motif of the Spike Receptor-Binding Domain, shown by high-resolution complex structure analysis. We further demonstrate the binding and neutralizing activities of P4A1 against wild type and mutant Spike proteins or pseudoviruses. P4A1 was subsequently engineered to reduce the potential risk for Antibody-Dependent Enhancement of infection and to extend its half-life. The engineered antibody exhibits an optimized pharmacokinetic and safety profile, and it results in complete viral clearance in a rhesus monkey model of COVID-19 following a single injection. These data suggest its potential against SARS-CoV-2 related diseases.
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Anticuerpos Monoclonales/inmunología , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , COVID-19/inmunología , SARS-CoV-2/inmunología , Glicoproteína de la Espiga del Coronavirus/inmunología , Animales , Anticuerpos Monoclonales/metabolismo , Anticuerpos Monoclonales/uso terapéutico , Anticuerpos Neutralizantes/química , Anticuerpos Neutralizantes/metabolismo , Anticuerpos Antivirales/metabolismo , Especificidad de Anticuerpos/inmunología , COVID-19/epidemiología , Línea Celular Tumoral , Células Cultivadas , Chlorocebus aethiops , Femenino , Humanos , Macaca mulatta , Masculino , Mutación , Pandemias , Unión Proteica , Dominios Proteicos , SARS-CoV-2/efectos de los fármacos , SARS-CoV-2/metabolismo , Glicoproteína de la Espiga del Coronavirus/genética , Glicoproteína de la Espiga del Coronavirus/metabolismo , Resultado del Tratamiento , Células Vero , Tratamiento Farmacológico de COVID-19RESUMEN
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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Mining the antibody repertoire of plasma cells and plasmablasts could enable the discovery of useful antibodies for therapeutic or research purposes1. We present a method for high-throughput, single-cell screening of IgG-secreting primary cells to characterize antibody binding to soluble and membrane-bound antigens. CelliGO is a droplet microfluidics system that combines high-throughput screening for IgG activity, using fluorescence-based in-droplet single-cell bioassays2, with sequencing of paired antibody V genes, using in-droplet single-cell barcoded reverse transcription. We analyzed IgG repertoire diversity, clonal expansion and somatic hypermutation in cells from mice immunized with a vaccine target, a multifunctional enzyme or a membrane-bound cancer target. Immunization with these antigens yielded 100-1,000 IgG sequences per mouse. We generated 77 recombinant antibodies from the identified sequences and found that 93% recognized the soluble antigen and 14% the membrane antigen. The platform also allowed recovery of ~450-900 IgG sequences from ~2,200 IgG-secreting activated human memory B cells, activated ex vivo, demonstrating its versatility.
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Anticuerpos/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Técnicas Analíticas Microfluídicas/instrumentación , Análisis de la Célula Individual , Animales , Antígenos/inmunología , Linfocitos B/inmunología , Vacunas contra el Cáncer/inmunología , ADN/análisis , ADN/genética , Secuenciación de Nucleótidos de Alto Rendimiento/instrumentación , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Humanos , Inmunoglobulina G/genética , Ratones , Análisis de la Célula Individual/instrumentación , Análisis de la Célula Individual/métodosRESUMEN
BACKGROUNDS: Polymers, widely existing in food or dietary materials, have been attracting researchers, facing challenges, and needing effective strategies on targeted characterization in complex matrixes. METHODS: A modified data filtering strategy (including locating with drift time and m/z ranges, multiple mass defect filtering, validating MS information, and evaluating MS/MS spectra) was developed and applied for procyanidins in the grape seed extracts (GSE) using drift tube ion mobility-mass spectrometry. The procyanidin ions' trendlines were predicted by multi-model regression. Their collision cross-sections (CCSs) were calculated using single-field methods. RESULTS AND DISCUSSION: Totally, 769 CCSs belonging to 686 procyanidins with polymer degrees at 1-15 were characterized. The exponent regression was the most reasonable model (r2 ≥ 0.9379) to reveal the trendlines. The change tendency of CCSs with their polymer degrees, charge states, and linkage types were investigated. CONCLUSION: This study provided an innovative strategy for targeted characterization of polymers in complex matrixes.
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Biflavonoides/análisis , Biflavonoides/química , Catequina/análisis , Catequina/química , Extracto de Semillas de Uva/análisis , Espectrometría de Movilidad Iónica/métodos , Espectrometría de Movilidad Iónica/estadística & datos numéricos , Proantocianidinas/análisis , Proantocianidinas/química , Análisis de Regresión , Reproducibilidad de los Resultados , Espectrometría de Masas en Tándem/instrumentación , Espectrometría de Masas en Tándem/métodosRESUMEN
The creation of new colloidal materials involves the design of functional building blocks. Here, a microfluidic method for designing building blocks one by one, at high throughput, with a broad range of shapes is introduced. The method exploits a coupling between hydrodynamic interactions and depletion forces that controls the configurational dynamics of droplet clusters traveling in microfluidic channels. Droplet clusters can be solidified in situ with UV. By varying the flow parameters, clusters are prescribed a given size, geometry, chemical and/or magnetic heterogeneities enabling local bonding. Compact structures (chains, triangles, diamonds, tetrahedrons,...) and noncompact structures, such as crosses and T, difficult to obtain with current techniques are produced. Size dispersions are small (2%) and throughputs are high (30 000 h-1). The work opens a new pathway, based on microfluidics, for designing colloidal building blocks with a potential to enable the creation of new materials.
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Childhood emotional trauma contributes significantly to certain psychopathologies, such as post-traumatic stress disorder. In experimental animals, however, whether or not early-life stress results in behavioral abnormalities in adult animals still remains controversial. Here, we investigated both short-term and long-term changes of anxiety- and depression-like behaviors of Wistar rats after being exposed to chronic feral cat stress in juvenile ages. The 2-week predator stress decreased spontaneous activities immediately following stress but did not increase depression- or anxiety-like behaviors 4 weeks after the stimulation in adulthood. Instead, juvenile predator stress had some protective effects, though not very obvious, in adulthood. We also exposed genetic depression model rats, Wistar Kyoto (WKY) rats, to the same predator stress. In WKY rats, the same early-life predator stress did not enhance anxiety- or depression-like behaviors in both the short-term and long-term. However, the stressed WKY rats showed slightly reduced depression-like behaviors in adulthood. These results indicate that in both normal Wistar rats and WKY rats, early-life predator stress led to protective, rather than negative, effects in adulthood.