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1.
J Proteome Res ; 2020 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-32538096

RESUMO

Patients with non-obstructive coronary artery disease (NOCAD) have high risk associated with acute myocardial infarction (AMI), and fragmented QRS (fQRS) has predictive value of AMI after percutaneous coronary intervention (PCI). A cohort of 254 participants were recruited including 136 NOCAD and 118 AMI patients from Xi'an No.1 Hospital. Comprehensive metabolomics was performed by UPLC-Q/TOF-MS with multivariate statistical analyses. The hazard ratios were performed to discriminate the prognostic in AMI after PCI between differential metabolites and fQRS. OPLS-DA separated metabolites from NOCAD and AMI in serum. A total of 23 differential metabolites were identified between NOCAD and AMI. In addition, 4 differential metabolites namely acetylglycine, threoninyl-glycine, glutarylglycine and nonanoylcarnitine were identified between fQRS and non-fQRS in AMI. The hazard ratios demonstrate the metabolites were associated with the risk of cardiac death, recurrent angina, re-admissions and major adverse cardiovascular events, which may clarify the mechanism of fQRS as a predictor in the prognostic of AMI after PCI. This study identified novel differential metabolites to distinguish the difference from NOCAD to AMI and clarify the mechanism of fQRS in prognostic of AMI after PCI, which may provide novel insights into potential risks and prognostic of AMI.

2.
Eur J Neurosci ; 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32293081

RESUMO

Recent experimental results have shown that the detection of cues in behavioral attention tasks relies on transient increases of acetylcholine (ACh) release in frontal cortex and cholinergically driven oscillatory activity in the gamma frequency band (Howe et al. Journal of Neuroscience, 2017, 37, 3215). The cue-induced gamma rhythmic activity requires stimulation of M1 muscarinic receptors. Using biophysical computational modeling, we show that a network of excitatory (E) and inhibitory (I) neurons that initially displays asynchronous firing can generate transient gamma oscillatory activity in response to simulated brief pulses of ACh. ACh effects are simulated as transient modulation of the conductance of an M-type K+ current which is blocked by activation of muscarinic receptors and has significant effects on neuronal excitability. The ACh-induced effects on the M current conductance, gKs , change network dynamics to promote the emergence of network gamma rhythmicity through a Pyramidal-Interneuronal Network Gamma mechanism. Depending on connectivity strengths between and among E and I cells, gamma activity decays with the simulated gKs transient modulation or is sustained in the network after the gKs transient has completely dissipated. We investigated the sensitivity of the emergent gamma activity to synaptic strengths, external noise and simulated levels of gKs modulation. To address recent experimental findings that cholinergic signaling is likely spatially focused and dynamic, we show that localized gKs modulation can induce transient changes of cellular excitability in local subnetworks, subsequently causing population-specific gamma oscillations. These results highlight dynamical mechanisms underlying localization of ACh-driven responses and suggest that spatially localized, cholinergically induced gamma may contribute to selectivity in the processing of competing external stimuli, as occurs in attentional tasks.

3.
Environ Pollut ; 261: 114085, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32066063

RESUMO

To simultaneously achieve biological denitrification and bio-energy recovery from sludge, the effects of nitrite on the two-phase anaerobic digestion (AD) of waste activated sludge were explored. Herein, effects of nitrite on the acidogenic phase are optimized, and the corresponding influence mechanisms are investigated. The experimental results show that the optimal nitrite treatment conditions for improving the acidogenic phase are an initial pH of 8.0, a nitrite addition concentration of 500 mg NO2--N·L-1, and a fermentation time of six days. By comparing the effects of nitrite and nitrate on the acidogenic phase, it was found that it was the nitrite, not the nitrate, that significantly enhanced the sludge organic solubilization, hydrolysis, and acidification, which are primarily attributed to the redox property of nitrite. Based on an analysis of different forms of soluble nitrogen concentrations, there was no obvious accumulation of nitrite or nitrate during the acidogenic phase. An analysis of the methane production and the volatile solid (VS) degradation during the two-phase AD revealed that the nitrite improved the methane production from the methanogenic phase and enhanced the VS degradation of sludge during the entire two-phase AD process. These findings could provide references for simultaneously treating nitrite-rich wastewater and improving anaerobic sludge digestion via two-phase system.

4.
Lab Chip ; 20(3): 655-664, 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-31934716

RESUMO

Time-resolved luminescence detection using long-lived probes with lifetimes in the microsecond region have shown great potential in ultrasensitive and multiplexed bioanalysis. In flow cytometry, however, the long lifetime poses a significant challenge to measure wherein the detection window is often too short to determine the decay characteristics. Here we report a time-resolved microfluidic flow cytometer (tr-mFCM) incorporating an acoustic-focusing chip, which allows slowing down of the flow while providing the same detection conditions for every target, achieving accurate lifetime measurement free of autofluorescence interference. Through configuration of the flow velocity and detection aperture with respect to the time-gating sequence, a multi-cycle luminescence decay profile is captured for every event under maximum excitation and detection efficiency. A custom fitting algorithm is then developed to resolve europium-stained polymer microspheres as well as leukemia cells against abundant fluorescent particles, achieving counting efficiency approaching 100% and lifetime CVs (coefficient of variation) around 2-6%. We further demonstrate lifetime-multiplexed detection of prostate and bladder cancer cells stained with different europium probes. Our acoustic-focusing tr-mFCM offers a practical technique for rapid screening of biofluidic samples containing multiple cell types, especially in resource-limited environments such as regional and/or underdeveloped areas as well as for point-of-care applications.

5.
Chemosphere ; 243: 125421, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31995876

RESUMO

A sludge structure perspective of the effects of humic matter (HM) on the anaerobic digestion (AD) of sewage sludge was proposed and investigated in this study. It was observed that the net cumulative methane production of sludge was significantly lower in the presence of HM. The fractal dimension values of sludge samples were increased by the addition of HM, whilst their total surface energy values were decreased, indicating that HM reinforced the stability of the sludge structure. Analyses of the physicochemical properties of different sludge samples revealed that HM enhanced the structural stability of sludge organic substances and restricted its organic solubility by interacting with the biopolymers to form a dense granular aggregate, thereby reducing the random-coil degree of extracellular organic substances and its active sites for enzymes, which suggested that HM could inhibit AD by changing the sludge structure. It was further confirmed by the biochemical methane potential (BMP) assay process. The BMP tests and corresponding kinetic analyses revealed that HM can restrict the potentials of sludge organic solubilisation, hydrolysis and acidification processes, but not necessarily the rates of these processes by enhancing the structural stability of high molecular weight readily biodegradable organic matter (RBOM) and restricting the mobility of low molecular weight RBOM (i.e., hydrolysis products). These findings can enrich understanding of the AD of sludge and may thus aid in the development of more effective methods to improve sludge treatment.


Assuntos
Substâncias Húmicas/análise , Metano/química , Esgotos/química , Purificação da Água/métodos , Anaerobiose , Biopolímeros , Reatores Biológicos , Hidrólise , Solubilidade
6.
J Hazard Mater ; 389: 121847, 2020 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-31843416

RESUMO

Anaerobic digestion (AD) of waste activated sludge (WAS) is an important bio-energy strategy that has been hindered by low conversion efficiency. This paper presents a comprehensive review of research on the sludge's property and enhancing AD of WAS, and proposes two perspectives of material structure and microbial activity on improving AD efficiency. In the first part of this review, the key principle problems for hindering AD efficiency are identified based on the concept of AD. Then, the possibility that the complex microstructure and composition of WAS are responsible for poor biodegradability is considered and main methods for enhancing AD are summarized. In the third part, according to the published works, the main knowledge gaps in research are recognized as the identification and specific activity adjustment of functional microbes, the understanding of key constituents of WAS and their interactions, the deciphering of complex structure of sludge organic substance, and the revealing of relationships between complex nature of WAS and biodegradability. Further discussions reveal that to enhance AD more studies should be centered on the sludge's structure and properties in future. However, this review is expected to provide the clear and accurate research directions for enhancing AD efficiency of WAS.

7.
Nanoscale ; 11(42): 20274-20283, 2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31626264

RESUMO

We report a facile chemical technique for synthesizing nanotube-based hybrid materials for near-infrared-driven photocatalytic hydrogen (H2) production. Upconversion nanoparticles (UCNPs), NaYF4:Yb,Tm,Gd (NYFG) and NaYF4:Yb,Tm (NYF), were engineered on C3N4 nanotubes (C3N4 NTs) separately to construct heterojunction structures. With a UCNP loading content of 15 wt%, the NYFG/C3N4 NT heterojunction exhibits the highest H2 generation rate of 311.6 µmol g-1 with an apparent quantum efficiency of 0.80 ‰, about 1.4 times higher than that of the NYF/C3N4 NT nanocomposite under 980 nm laser irradiation. Comprehensive characterization reveals that the enhanced photocatalytic performance of the Gd doped nanostructure is attributed to the synergistic effect, stronger interaction, higher emission intensities, and faster charge transfer between the UCNPs and C3N4 NTs. Moreover, the steady-state and dynamic fluorescence spectra indicate that the energy from NYFG NPs was transferred to C3N4 NTs via a fluorescence-resonance energy-transfer process. Our work demonstrates the potential of developing near-infrared-responsive photocatalysts for energy and environmental applications.

8.
Nat Commun ; 10(1): 3695, 2019 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-31420541

RESUMO

Sub-diffraction microscopy enables bio-imaging with unprecedented clarity. However, most super-resolution methods require complex, costly purpose-built systems, involve image post-processing and struggle with sub-diffraction imaging in 3D. Here, we realize a conceptually different super-resolution approach which circumvents these limitations and enables 3D sub-diffraction imaging on conventional confocal microscopes. We refer to it as super-linear excitation-emission (SEE) microscopy, as it relies on markers with super-linear dependence of the emission on the excitation power. Super-linear markers proposed here are upconversion nanoparticles of NaYF4, doped with 20% Yb and unconventionally high 8% Tm, which are conveniently excited in the near-infrared biological window. We develop a computational framework calculating the 3D resolution for any viable scanning beam shape and excitation-emission probe profile. Imaging of colominic acid-coated upconversion nanoparticles endocytosed by neuronal cells, at resolutions twice better than the diffraction limit both in lateral and axial directions, illustrates the applicability of SEE microscopy for sub-cellular biology.


Assuntos
Imageamento Tridimensional/métodos , Microscopia Confocal/métodos , Microscopia de Fluorescência por Excitação Multifotônica/métodos , Nanopartículas/ultraestrutura , Neurônios/ultraestrutura , Animais , Endocitose , Células PC12 , Ratos
9.
Biomacromolecules ; 20(5): 2148-2158, 2019 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-30995832

RESUMO

Poly(amidoamine) dendrimer (PAMAM) is well-known for its high efficiency as a drug delivery vehicle. However, the intrinsic cytotoxicity and lack of a detectable signal to facilitate tracking have impeded its practical applications. Herein, we have developed a novel label-free fluorescent and biocompatible PAMAM derivative by simple surface modification of PAMAM using acetaldehyde. The modified PAMAM possessed a strong green fluorescence, which was generated by the C=N bonds of the resulting Schiff Bases via n-π* transition, while the intrinsic cytotoxicity of PAMAM was simultaneously ameliorated. Through further PEGylation, the fluorescent PAMAM demonstrated excellent intracellular tracking in human melanoma SKMEL28 cells. In addition, our PEGylated fluorescent PAMAM derivative achieved enhanced loading and delivery efficiency of the anticancer drug doxorubicin (DOX) compared to the original PAMAM. Importantly, the accelerated kinetics of DOX-encapsulated fluorescent PAMAM nanocomposites in an acidic environment facilitated intracellular drug release, which demonstrated comparable cytotoxicity to that of the free-form doxorubicin hydrochloride (DOX·HCl) against melanoma cells. Overall, our label free fluorescent PAMAM derivative offers a new opportunity of traceable and controlled delivery for DOX and other drugs of potential clinical importance.

10.
Sci Total Environ ; 654: 1064-1071, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30841381

RESUMO

Nitrite, a product of the nitritation of sewage or digestion liquid, has been used to pretreat waste activated sludge (WAS) before anaerobic digestion. In this study, the effects of free nitrous acid (FNA) and nitrite on two-phase anaerobic sludge bioconversion were investigated. The experimental results indicated that both nitrite and FNA promoted sludge organic solubilization. Notably, nitrite promoted volatile fatty acids (VFAs) accumulation while FNA inhibited VFA accumulation in the first phase (acidogenic phase). In the second phase (methanogenic phase), neither nitrite nor FNA improved the net cumulative methane production from WAS. Although net cumulative methane production was not enhanced by the addition of nitrite or FNA, the volatile solids (VS) degradation rate was improved with nitrite addition in the two-phase anaerobic digestion process, indicating that nitrite is more favorable than FNA for the two-phase anaerobic digestion of WAS. It is expected that these findings can offer useful insights into future design of anaerobic digestion system with the treatment by the nitrite from digestion liquid.


Assuntos
Anaerobiose/efeitos dos fármacos , Nitritos/análise , Ácido Nitroso/análise , Eliminação de Resíduos Líquidos/métodos , Reatores Biológicos , Ácidos Graxos Voláteis , Esgotos/microbiologia
11.
Rejuvenation Res ; 22(4): 313-324, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30411995

RESUMO

Salviae miltiorrliza-borneol Jun-Shi coupled-herbs have been widely used for treatment of ischemia stroke. Salvianolic acid B was the most abundant and bioactive compound of Salviae miltiorrliza and used for prevention and treatment of cerebrovascular diseases. However, the scientific intension and compatible mechanism of Salvianolic acid B - borneol combination were still unknown. A metabolomics study approach based on ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS) combined with a pathological study has been applied to study the metabolic disturbances of cerebral ischemia and evaluate the efficacies of Sal B and Sal B/borneol against cerebral ischemia in middle cerebral artery occlusion (MCAO) rats. The neuroprotection of Sal B and Sal B/borneol was reversed through the evaluation of neurological deficits, infarct volume, and neuronal apoptosis in MCAO model. The metabonomic analysis revealed that the MCAO-induced cerebral ischemia could be ameliorated by Sal B through improving the energy metabolism, lipids metabolism, inflammatory responses, and oxidant stress. Borneol could enhance the neuroprotective effects, was associated with the increased concentration of Sal B, and attenuate the function of sphingolipid metabolism pathway in cerebral ischemia rats. These findings perhaps clarify the mechanism of neuroprotective effects of treating ischemia stroke by Sal B or Sal B/borneol preliminarily through metabolomics and push the quality promotion and the composition of borneol/Sal B in secondary development of prescription.


Assuntos
Benzofuranos/uso terapêutico , Isquemia Encefálica/tratamento farmacológico , Canfanos/uso terapêutico , Espectrometria de Massas , Metabolômica , Animais , Benzofuranos/farmacologia , Isquemia Encefálica/patologia , Canfanos/farmacologia , Cromatografia Líquida de Alta Pressão , Masculino , Malondialdeído/metabolismo , Redes e Vias Metabólicas/efeitos dos fármacos , Metaboloma/efeitos dos fármacos , Análise Multivariada , Neuroproteção/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Análise de Componente Principal , Ratos Sprague-Dawley
12.
Adv Mater ; 30(51): e1803717, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30328157

RESUMO

Glioblastoma multiforme (GBM) is a fatal central nervous system tumor without effective treatment. Chemotherapeutic agents are mainstays in the treatment of glioblastoma. However, the effectiveness of these is seriously hindered by poor blood-brain-barrier (BBB) penetrance and tumor targeting, together with short biological half-life. Improved chemotherapy is thus urgently needed for GBM. Multifunctional nanoparticle delivery systems offer much promise in overcoming current limitations. Accordingly, a multifunctional biomimetic nanomedicine is developed by functionalizing the surface of red blood cell membranes (RBCms) with angiopep-2 and loading pH-sensitive nanoparticles (polymer, doxorubicin (Dox), and lexiscan (Lex)) using the functionalized cell membrane to generate the novel nanomedicine, Ang-RBCm@NM-(Dox/Lex). The studies toward orthotopic U87MG human glioblastoma tumor-bearing nude mice show that the Ang-RBCm@NM-(Dox/Lex) nanomedicine has much improved blood circulation time, superb BBB penetration, superior tumor accumulation and retention. Moreover, effective suppression of tumor growth and significantly improved medium survival time are also observed after Ang-RBCm@NM-(Dox/Lex) treatment. The results show that this biomimetic nanoplatform can serve as a flexible and powerful system for GBM treatment which can be readily adapted for the treatment of other central nervous system (CNS) disorders.


Assuntos
Materiais Biomiméticos/química , Transformação Celular Neoplásica , Glioblastoma/patologia , Nanomedicina/métodos , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Doxorrubicina/química , Doxorrubicina/farmacologia , Doxorrubicina/uso terapêutico , Eritrócitos/citologia , Humanos , Camundongos , Peptídeos/metabolismo
13.
Nat Nanotechnol ; 13(10): 941-946, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30082923

RESUMO

Deep tissue imaging in the second near-infrared (NIR-II) window holds great promise for physiological studies and biomedical applications1-6. However, inhomogeneous signal attenuation in biological matter7,8 hampers the application of multiple-wavelength NIR-II probes to multiplexed imaging. Here, we present lanthanide-doped NIR-II nanoparticles with engineered luminescence lifetimes for in vivo quantitative imaging using time-domain multiplexing. To achieve this, we have devised a systematic approach based on controlled energy relay that creates a tunable lifetime range spanning three orders of magnitude with a single emission band. We consistently resolve selected lifetimes from the NIR-II nanoparticle probes at depths of up to 8 mm in biological tissues, where the signal-to-noise ratio derived from intensity measurements drops below 1.5. We demonstrate that robust lifetime coding is independent of tissue penetration depth, and we apply in vivo multiplexing to identify tumour subtypes in living mice. Our results correlate well with standard ex vivo immunohistochemistry assays, suggesting that luminescence lifetime imaging could be used as a minimally invasive approach for disease diagnosis.


Assuntos
Imunoconjugados/química , Elementos da Série dos Lantanídeos/química , Substâncias Luminescentes/química , Nanopartículas/química , Neoplasias/diagnóstico por imagem , Imagem Óptica/métodos , Animais , Linhagem Celular Tumoral , Feminino , Humanos , Luminescência , Medições Luminescentes/métodos , Camundongos Endogâmicos BALB C , Camundongos Nus , Espectroscopia de Luz Próxima ao Infravermelho
14.
Huan Jing Ke Xue ; 39(1): 284-291, 2018 Jan 08.
Artigo em Chinês | MEDLINE | ID: mdl-29965694

RESUMO

To improve anaerobic digestion biogas yield, the removal of organic-bonding metals by EDTA pretreatment was investigated to strengthen the anaerobic biogas effect. The results showed that after EDTA pretreatment (experimental group), the organic-bonding metals were reduced from (5.09±0.57)% to (1.37±0.20)% (calculated with TS) and dissolved organic matter increased significantly (SCOD improved 627%), suggesting that this method could remove a large amount of organic-bonding metals and enhance the dissolution of organic sludge. According to the results for the apparent activation energy (AAE) of sludge organic matter dissolution, the AAE of the experiment group was 36% lower than the control group, showing that pretreatment could effectively reduce the reaction energy barrier for organic matter dissolution. In a test of anaerobic acid production lasting 16 days, the VFAs of the experiment group were higher than the control group, with the largest upgrade of 42%. In the anaerobic methane production test (BMP) that lasted for 22 days, compared with control group, the accumulated biogas production of the experiment group increased by 48%. Through further research on the dynamics of methane production, the rate-limiting step in the experiment group was methanogenesis, while that of the control group was hydrolysis, indicating that removal of organic-bonding metals by EDTA pretreatment could effectively accelerate the hydrolysis rate.


Assuntos
Reatores Biológicos , Metais/isolamento & purificação , Metano/biossíntese , Esgotos/química , Anaerobiose
16.
Chem Commun (Camb) ; 54(29): 3609-3612, 2018 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-29570195

RESUMO

A superior biocompatible spherical nucleic acid (SNA) conjugate was fabricated by grafting siRNA onto the surface of a core composed of a spherical DNA nanostructure that we have termed a DNA nanoclew (DC). After uptake by cultured cancer cells, SNA nanoparticles release engrafted siRNAs by cleavage of the intracellular Dicer enzyme. Moreover, in vitro experiments reveal that such SNAs demonstrate potent gene knockdown at both mRNA and protein levels, while with negligible cytotoxicity.


Assuntos
DNA/química , Sistemas de Liberação de Medicamentos/métodos , Técnicas de Silenciamento de Genes/métodos , Nanopartículas/química , RNA Interferente Pequeno/administração & dosagem , Inativação Gênica , Células HeLa , Humanos , Nanopartículas/toxicidade , Hibridização de Ácido Nucleico , Tamanho da Partícula , RNA Interferente Pequeno/química , RNA Interferente Pequeno/metabolismo , RNA Interferente Pequeno/toxicidade , Ribonuclease III/química
17.
Neuron ; 97(6): 1253-1260.e7, 2018 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-29503190

RESUMO

Neuroligins (NLs) are critical for synapse formation and function. NL3 R451C is an autism-associated mutation. NL3 R451C knockin (KI) mice exhibit autistic behavioral abnormalities, including social novelty deficits. However, neither the brain regions involved in social novelty nor the underlying mechanisms are clearly understood. Here, we found decreased excitability of fast-spiking interneurons and dysfunction of gamma oscillation in the medial prefrontal cortex (mPFC), which contributed to the social novelty deficit in the KI mice. Neuronal firing rates and phase-coding abnormalities were also detected in the KI mice during social interactions. Interestingly, optogenetic stimulation of parvalbumin interneurons in the mPFC at 40 Hz nested at 8 Hz positively modulated the social behaviors of mice and rescued the social novelty deficit in the KI mice. Our findings suggest that gamma oscillation dysfunction in the mPFC leads to social deficits in autism, and manipulating mPFC PV interneurons may reverse the deficits in adulthood.


Assuntos
Moléculas de Adesão Celular Neuronais/genética , Moléculas de Adesão Celular Neuronais/metabolismo , Ritmo Gama/fisiologia , Aprendizagem em Labirinto/fisiologia , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Córtex Pré-Frontal/metabolismo , Comportamento Social , Animais , Transtorno Autístico/genética , Transtorno Autístico/fisiopatologia , Técnicas de Introdução de Genes/métodos , Células HEK293 , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Optogenética/métodos , Córtex Pré-Frontal/fisiopatologia , Distribuição Aleatória
19.
J Mater Chem B ; 6(47): 7862-7870, 2018 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-32255031

RESUMO

Nanohybrids fabricated with upconversion nanoparticles (UCNPs) and gold nanoparticles (NPs) hold great promise for near-infrared photothermal therapy (NIR-PTT) and upconversion fluorescence imaging. However, the obstacles of poor solubility in water and finite hydrophilic modification method for UCNPs limit their application in biological fields. Herein, we report a novel UCNP@Al(OH)3/Au nanohybrid mediated by a highly hydrophilic and biocompatible Al(OH)3 layer to realize a synergistic targeted PTT and fluorescence imaging capability to U87MG tumor-bearing mice under NIR light irradiation. The modification with Al(OH)3 layers can improve the water solubility of UCNPs. And cytotoxicity assays and hemolysis assay showed that the modification with Al(OH)3 layers makes UCNPs have low cytotoxicity and good biocompatibility. In addition, the Al(OH)3 layers are thin enough to allow fluorescence resonance energy transfer (FRET) between UCNPs and gold NPs to occur, giving the NPs a good PTT effect for tumor-bearing mice. Meanwhile, as the pH-sensitive Al(OH)3 layers decompose in acidic tumor microenvironments with Au NPs detached from their surface, the FRET effect no longer occurred, subsequently leading to the fluorescence intensity of naked UCNPs being recovered for good imaging effects. The study suggests that Al(OH)3 mediation layer as a promising hydrophilic nanoplatform can potentially be used for the preparation of superior hydrophilic NPs and pH-stimulated drug release carriers for theranostic application in vivo.

20.
Nat Methods ; 14(12): 1191-1197, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29039415

RESUMO

Pooled CRISPR screens are a powerful tool for assessments of gene function. However, conventional analysis is based exclusively on the relative abundance of integrated single guide RNAs (sgRNAs) between populations, which does not discern distinct phenotypes and editing outcomes generated by identical sgRNAs. Here we present CRISPR-UMI, a single-cell lineage-tracing methodology for pooled screening to account for cell heterogeneity. We generated complex sgRNA libraries with unique molecular identifiers (UMIs) that allowed for screening of clonally expanded, individually tagged cells. A proof-of-principle CRISPR-UMI negative-selection screen provided increased sensitivity and robustness compared with conventional analysis by accounting for underlying cellular and editing-outcome heterogeneity and detection of outlier clones. Furthermore, a CRISPR-UMI positive-selection screen uncovered new roadblocks in reprogramming mouse embryonic fibroblasts as pluripotent stem cells, distinguishing reprogramming frequency and speed (i.e., effect size and probability). CRISPR-UMI boosts the predictive power, sensitivity, and information content of pooled CRISPR screens.


Assuntos
Sistemas CRISPR-Cas/genética , Linhagem da Célula/genética , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Edição de Genes , RNA Guia , Análise de Célula Única/métodos , Animais , Células Cultivadas , Fibroblastos/citologia , Técnicas de Inativação de Genes , Vetores Genéticos , Camundongos , Células-Tronco Pluripotentes/citologia , Retroviridae/genética , Razão Sinal-Ruído
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