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1.
J Nanobiotechnology ; 18(1): 130, 2020 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-32912236

RESUMO

Fast point-of-care (POC) diagnostics represent an unmet medical need and include applications such as lateral flow assays (LFAs) for the diagnosis of sepsis and consequences of cytokine storms and for the treatment of COVID-19 and other systemic, inflammatory events not caused by infection. Because of the complex pathophysiology of sepsis, multiple biomarkers must be analyzed to compensate for the low sensitivity and specificity of single biomarker targets. Conventional LFAs, such as gold nanoparticle dyed assays, are limited to approximately five targets-the maximum number of test lines on an assay. To increase the information obtainable from each test line, we combined green and red emitting quantum dots (QDs) as labels for C-reactive protein (CRP) and interleukin-6 (IL-6) antibodies in an optical duplex immunoassay. CdSe-QDs with sharp and tunable emission bands were used to simultaneously quantify CRP and IL-6 in a single test line, by using a single UV-light source and two suitable emission filters for readout through a widely available BioImager device. For image and data processing, a customized software tool, the MultiFlow-Shiny app was used to accelerate and simplify the readout process. The app software provides advanced tools for image processing, including assisted extraction of line intensities, advanced background correction and an easy workflow for creation and handling of experimental data in quantitative LFAs. The results generated with our MultiFlow-Shiny app were superior to those generated with the popular software ImageJ and resulted in lower detection limits. Our assay is applicable for detecting clinically relevant ranges of both target proteins and therefore may serve as a powerful tool for POC diagnosis of inflammation and infectious events.


Assuntos
Biomarcadores/análise , Proteína C-Reativa/análise , Imunoensaio/métodos , Interleucina-6/análise , Pontos Quânticos/química , Sepse/diagnóstico , Anticorpos/imunologia , Betacoronavirus/isolamento & purificação , Proteína C-Reativa/imunologia , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/virologia , Humanos , Interleucina-6/imunologia , Limite de Detecção , Pandemias , Pneumonia Viral/diagnóstico , Pneumonia Viral/virologia , Sistemas Automatizados de Assistência Junto ao Leito , Sepse/metabolismo , Software , Raios Ultravioleta
2.
ACS Nano ; 14(9): 12234-12247, 2020 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-32845122

RESUMO

The first step of SARS-CoV-2 infection is binding of the spike protein's receptor binding domain to the host cell's ACE2 receptor on the plasma membrane. Here, we have generated a versatile imaging probe using recombinant Spike receptor binding domain conjugated to fluorescent quantum dots (QDs). This probe is capable of engaging in energy transfer quenching with ACE2-conjugated gold nanoparticles to enable monitoring of the binding event in solution. Neutralizing antibodies and recombinant human ACE2 blocked quenching, demonstrating a specific binding interaction. In cells transfected with ACE2-GFP, we observed immediate binding of the probe on the cell surface followed by endocytosis. Neutralizing antibodies and ACE2-Fc fully prevented binding and endocytosis with low nanomolar potency. Importantly, we will be able to use this QD nanoparticle probe to identify and validate inhibitors of the SARS-CoV-2 Spike and ACE2 receptor binding in human cells. This work enables facile, rapid, and high-throughput cell-based screening of inhibitors for coronavirus Spike-mediated cell recognition and entry.


Assuntos
Endocitose , Nanopartículas Metálicas/química , Peptidil Dipeptidase A/metabolismo , Pontos Quânticos/química , Glicoproteína da Espícula de Coronavírus/metabolismo , Betacoronavirus/metabolismo , Infecções por Coronavirus/metabolismo , Ouro , Humanos , Pandemias , Peptidil Dipeptidase A/fisiologia , Pneumonia Viral/metabolismo , Ligação Proteica , Glicoproteína da Espícula de Coronavírus/química , Vírion
3.
Int J Nanomedicine ; 15: 5473-5489, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32801701

RESUMO

Introduction: Biofilms protect bacteria from antibiotics and this can produce drug-resistant strains, especially the main pathogen of periodontitis, Porphyromonas gingivalis. Carbon quantum dots with various biomedical properties are considered to have great application potential in antibacterial and anti-biofilm treatment. Methods: Tinidazole carbon quantum dots (TCDs) and metronidazole carbon quantum dots (MCDs) were prepared by a hydrothermal method with the clinical antibacterial drugs tinidazole and metronidazole, respectively. Then, TCDs and MCDs were characterized by transmission electron microscopy, UV-visible spectroscopy, infrared spectroscopy and energy-dispersive spectrometry. The antibacterial effects were also investigated under different conditions. Results: The TCDs and MCDs had uniform sizes. The results of UV-visible and energy-dispersive spectrometry confirmed their important carbon polymerization structures and the activity of the nitro group, which had an evident inhibitory effect on P. gingivalis, but almost no effect on other bacteria, including Escherichia coli, Staphylococcus aureus and Prevotella nigrescens. Importantly, the TCDs could penetrate the biofilms to further effectively inhibit the growth of P. gingivalis under the biofilms. Furthermore, it was found that the antibacterial effect of TCDs lies in its ability to impair toxicity by inhibiting the major virulence factors and related genes involved in the biofilm formation of P. gingivalis, thus affecting the self-assembly of biofilm-related proteins. Conclusion: The findings demonstrate a promising new method for improving the efficiency of periodontitis treatment by penetrating the P. gingivalis biofilm with preparations of nano-level antibacterial drugs.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Porphyromonas gingivalis/efeitos dos fármacos , Pontos Quânticos/química , Animais , Antibacterianos/efeitos adversos , Aderência Bacteriana/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Carbono/química , Carbono/farmacologia , Escherichia coli/efeitos dos fármacos , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Humanos , Metronidazol/química , Metronidazol/farmacologia , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Transmissão , Periodontite/microbiologia , Porphyromonas gingivalis/genética , Porphyromonas gingivalis/fisiologia , Coelhos , Espectrofotometria Ultravioleta , Staphylococcus aureus/efeitos dos fármacos , Tinidazol/química , Tinidazol/farmacologia , Fatores de Virulência/antagonistas & inibidores
4.
Biosens Bioelectron ; 166: 112436, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32750677

RESUMO

Our recent experience of the COVID-19 pandemic has highlighted the importance of easy-to-use, quick, cheap, sensitive and selective detection of virus pathogens for the efficient monitoring and treatment of virus diseases. Early detection of viruses provides essential information about possible efficient and targeted treatments, prolongs the therapeutic window and hence reduces morbidity. Graphene is a lightweight, chemically stable and conductive material that can be successfully utilized for the detection of various virus strains. The sensitivity and selectivity of graphene can be enhanced by its functionalization or combination with other materials. Introducing suitable functional groups and/or counterparts in the hybrid structure enables tuning of the optical and electrical properties, which is particularly attractive for rapid and easy-to-use virus detection. In this review, we cover all the different types of graphene-based sensors available for virus detection, including, e.g., photoluminescence and colorimetric sensors, and surface plasmon resonance biosensors. Various strategies of electrochemical detection of viruses based on, e.g., DNA hybridization or antigen-antibody interactions, are also discussed. We summarize the current state-of-the-art applications of graphene-based systems for sensing a variety of viruses, e.g., SARS-CoV-2, influenza, dengue fever, hepatitis C virus, HIV, rotavirus and Zika virus. General principles, mechanisms of action, advantages and drawbacks are presented to provide useful information for the further development and construction of advanced virus biosensors. We highlight that the unique and tunable physicochemical properties of graphene-based nanomaterials make them ideal candidates for engineering and miniaturization of biosensors.


Assuntos
Betacoronavirus/isolamento & purificação , Técnicas Biossensoriais , Técnicas de Laboratório Clínico , Infecções por Coronavirus/diagnóstico , Grafite , Pneumonia Viral/diagnóstico , Vírus/isolamento & purificação , Reações Antígeno-Anticorpo , Betacoronavirus/genética , Betacoronavirus/patogenicidade , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Técnicas Biossensoriais/tendências , Técnicas de Laboratório Clínico/instrumentação , Técnicas de Laboratório Clínico/métodos , Técnicas de Laboratório Clínico/estatística & dados numéricos , Colorimetria , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/virologia , DNA Viral/análise , DNA Viral/genética , Técnicas Eletroquímicas , Desenho de Equipamento , Grafite/química , Humanos , Luminescência , Nanoestruturas/química , Hibridização de Ácido Nucleico , Pandemias , Pneumonia Viral/epidemiologia , Pneumonia Viral/virologia , Pontos Quânticos/química , Análise Espectral Raman , Ressonância de Plasmônio de Superfície , Virologia/métodos , Vírus/genética , Vírus/patogenicidade
5.
Int J Nanomedicine ; 15: 4691-4703, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32636625

RESUMO

Purpose: Gd-encapsulated carbonaceous dots (Gd@C-dots) have excellent stability and magnetic properties without free Gd leakage, therefore they can be considered as a safe alternative T1 contrast agent to commonly used Gd complexes. To improve their potential for cancer diagnosis and treatment, affibody-modified Gd@C-dots targeting non-small-cell lung cancer (NSCLC) EGFR-positive tumors with enhanced renal clearance were developed and synthesized. Materials and Methods: Gd@C-dots were developed and modified with Ac-Cys-ZEGFR:1907 through EDC/NHS. The size, morphology, and optical properties of the Gd@C-dots and Gd@C-dots-Cys-ZEGFR:1907 were characterized. Targeting ability was evaluated by in vitro and in vivo experiments, respectively. Residual gadolinium concentration in major organs was detected with confocal imaging and inductively coupled plasma mass spectrometry (ICP-MS) ex vivo. H&E staining was used to assess the morphology of these organs. Results: Gd@C-dots with nearly 20 nm in diameter were developed and modified with Ac-Cys-ZEGFR:1907. EGFR expression in HCC827 cells was higher than NCI-H520. In cell uptake assays, EGFR-expressing HCC827 cells exhibited significant MR T1WI signal enhancement when compared to NCI-H520 cells. Cellular uptake of Gd@C-dots-Cys-ZEGFR:1907 was reduced, when Ac-Cys-ZEGFR:1907 was added. In vivo targeting experiments showed that the probe signal was significantly higher in HCC827 than NCI-H520 xenografts at 1 h after injection. In contrast to Gd@C-dots, Gd@C-dots-Cys-ZEGFR:1907 nanoparticles can be efficiently excreted through renal clearance. No morphological changes were observed by H&E staining in the major organs after injection of Gd@C-dots-Cys-ZEGFR:1907. Conclusion: Gd@C-dots-Cys-ZEGFR:1907 is a high-affinity EGFR-targeting probe with efficient renal clearance and is therefore a promising contrast agent for clinical applications such as diagnosis and treatment of NSCLC EGFR-positive malignant tumors.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/diagnóstico por imagem , Meios de Contraste/farmacocinética , Neoplasias Pulmonares/diagnóstico por imagem , Imagem por Ressonância Magnética/métodos , Pontos Quânticos/química , Animais , Carcinoma Pulmonar de Células não Pequenas/patologia , Linhagem Celular Tumoral , Meios de Contraste/química , Receptores ErbB/metabolismo , Feminino , Gadolínio/química , Gadolínio/farmacocinética , Humanos , Rim/efeitos dos fármacos , Rim/metabolismo , Neoplasias Pulmonares/patologia , Camundongos Nus , Nanopartículas/química , Distribuição Tecidual , Ensaios Antitumorais Modelo de Xenoenxerto
6.
Ecotoxicol Environ Saf ; 201: 110813, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32544745

RESUMO

The bioaccumulation potential and toxic effects of engineered nanomaterials (ENMs) to earthworms are poorly understood. Two studies were conducted following OECD TG 222 on Eisenia fetida to assess the effects of CdTe QDs with different coatings and soil ageing respectively. Earthworms were exposed to carboxylate (COOH), ammonium (NH4+), or polyethylene glycol (PEG) coated CdTe QDs, or a micron scale (bulk) CdTe material, at nominal concentrations of 50, 500 and 2000 mg CdTe QD kg-1 dry weight (dw) for 28 days in Lufa 2.2 soil. In the fresh soil study, earthworms accumulated similar amounts of Cd and Te in the CdTe-bulk exposures, while the accumulation of Cd was higher than Te during the exposures to CdTe QDs. However, neither the total Cd, nor Te concentrations in the earthworms, were easily explained by the extractable metal fractions in the soil or particle dissolution. There were no effects on survival, but some retardation of growth was observed at the higher doses. Inhibition of Na+/K+-ATPase activity with disturbances to tissue electrolytes, as well as tissue Cu and Mn were observed, but without depletion of total glutathione in the fresh soil experiment. Additionally, juvenile production was the most sensitive endpoint, with estimated nominal EC50 of values >2000, 108, 65, 96 mg CdTe kg-1 for bulk, PEG-, COOH- and NH4+-coated CdTe QDs, respectively. In the aged soil study, the accumulation of Cd and Te was higher than in the fresh soil study in all CdTe QD exposures. Survival of the adult worms was reduced in the top CdTe-COOH and -NH4+ QD exposures by 55 ±â€¯5 and 60 ±â€¯25%, respectively; and with decreases in growth. The nominal EC50 values for juvenile production in the aged soil were 165, 88, 78 and 63 mg CdTe kg-1 for bulk, PEG-, COOH- and NH4+-coated CdTe QDs, respectively. In conclusion, exposure to nanoscale CdTe QDs, regardless of coating, caused more severe toxic effects that the CdTe bulk material and the toxicity increased after soil ageing. There were some coating-mediated effects, likely due to differences in the metal content and behaviour of the materials.


Assuntos
Compostos de Cádmio/toxicidade , Oligoquetos/efeitos dos fármacos , Pontos Quânticos/toxicidade , Poluentes do Solo/toxicidade , Solo/química , Telúrio/toxicidade , Animais , Bioacumulação , Compostos de Cádmio/química , Compostos de Cádmio/metabolismo , Modelos Teóricos , Oligoquetos/metabolismo , Tamanho da Partícula , Pontos Quânticos/química , Pontos Quânticos/metabolismo , Reprodução/efeitos dos fármacos , Poluentes do Solo/química , Poluentes do Solo/metabolismo , Propriedades de Superfície , Telúrio/química , Telúrio/metabolismo , Fatores de Tempo
7.
Food Chem ; 328: 127091, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32474237

RESUMO

Methanol is highly toxic for human, so methanol detection is valuable especially in water and ethanol medium without complicated and time consuming procedure. In this work, we present a new fluorescence probe for direct detection of methanol in aqueous and ethanol medium based on the ZnS:Mn2+ quantum dot (QDs) and soluble N-methylpolypyrrole (NMPPy) hybrid. Moreover, the number of spectroscopic techniques were used to study the chemical composition and optical properties of the resultant QDs as well as investigation on the sensing mechanism toward methanol. Also, methanol can be determined by using ZnS:Mn2+ QDs/NMPPy hybrid based switchable fluorescence sensing system, with high sensitivity, high selectivity and a very good detection limit of 1 mM with linearity in the concentration range of 25-230 mM (~0.1-0.9% v/v) in aqueous solution. Finally, the ZnS:Mn2+ QDs/NMPPy hybrid as optical sensor was successfully utilized to determine the amount of methanol in real alcoholic beverage samples.


Assuntos
Etanol/química , Metanol/análise , Polímeros/química , Pirróis/química , Pontos Quânticos/química , Espectrometria de Fluorescência/instrumentação , Sulfetos/química , Água/química , Compostos de Zinco/química , Corantes Fluorescentes/química , Humanos , Limite de Detecção , Magnésio/química , Metanol/química
8.
Food Chem ; 328: 127063, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32485582

RESUMO

A magnetic fluorescence probe was fabricated by coating carbon quantum dots-doped molecularly imprinted polymers (MIPs) layers on the surface of Fe3O4 particles (MFMP) for detection of N-acyl homoserine lactones (AHLs) signaling molecules. N-Z-L-homoserine lactone molecular was used as the template to prepare AHLs MIP layers, employing MAA and HEMA as functional monomers. The developed MFMP owned superparamagnetism, fluorescence, fast response and class-selectivity. If AHLs (C4-HSL, C6-HSL, C8-HSL, C10-HSL, C12-HSL and C14-HSL) were captured by the MFMP, they quenched the fluorescence of the probe. Fluorescence dropped linearly in the concentration ranges of 3.65 × 10-3 µmol/L-0.96 × 10-1 µmol/L for AHLs. The MFMP was applied to the analysis of fish juice and milk samples, and recoveries ranged from 83.10% to 90.74% with relative standard deviation less than 5.1%. This study offered a novel strategy to fabricated AHLs fluorescence probe with great potential for wide-ranging application in agri-food products.


Assuntos
Acil-Butirolactonas/análise , Carbono/química , Peixes , Corantes Fluorescentes/química , Leite/química , Impressão Molecular , Pontos Quânticos/química , Animais , Imãs/química , Polímeros/síntese química
9.
Proc Natl Acad Sci U S A ; 117(26): 14636-14641, 2020 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-32541064

RESUMO

Understanding the coordination of cell-division timing is one of the outstanding questions in the field of developmental biology. One active control parameter of the cell-cycle duration is temperature, as it can accelerate or decelerate the rate of biochemical reactions. However, controlled experiments at the cellular scale are challenging, due to the limited availability of biocompatible temperature sensors, as well as the lack of practical methods to systematically control local temperatures and cellular dynamics. Here, we demonstrate a method to probe and control the cell-division timing in Caenorhabditis elegans embryos using a combination of local laser heating and nanoscale thermometry. Local infrared laser illumination produces a temperature gradient across the embryo, which is precisely measured by in vivo nanoscale thermometry using quantum defects in nanodiamonds. These techniques enable selective, controlled acceleration of the cell divisions, even enabling an inversion of division order at the two-cell stage. Our data suggest that the cell-cycle timing asynchrony of the early embryonic development in C. elegans is determined independently by individual cells rather than via cell-to-cell communication. Our method can be used to control the development of multicellular organisms and to provide insights into the regulation of cell-division timings as a consequence of local perturbations.


Assuntos
Temperatura Corporal/fisiologia , Divisão Celular/fisiologia , Desenvolvimento Embrionário/fisiologia , Pontos Quânticos/química , Termometria , Animais , Caenorhabditis elegans/embriologia , Nanodiamantes/química , Termometria/instrumentação , Termometria/métodos
10.
Food Chem ; 326: 126935, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32447160

RESUMO

Carbon dots (CDs) have been a new class of fascinating carbon-based fluorescent nanomaterials. In the present work, new N-doped CDs with highly crystalline graphite structures are prepared from renewable precursors, chitosan and tartaric acid, and are well characterized. The prepared CDs are applied as a biocompatible fluorescent sensor for the sequential detection of Fe3+ and AA. Among various transition metal ions, Fe3+ can selectively quench the fluorescence of CDs. Upon the further addition of AA, the quenched fluorescence of CDs is then restored as Fe3+ is reduced to Fe2+ by AA, which can be utilized for the fluorescent determination of AA. A good linear relationship in the range of 0-150 µM of AA concentration is established with a low detection limit of 0.02 µM. Moreover, the practical applications of this fluorescent sensing method in measurement of AA in food samples are successfully realized with satisfactory results.


Assuntos
Ácido Ascórbico/análise , Carbono/química , Compostos Férricos/análise , Nanoestruturas/análise , Espectrometria de Fluorescência/métodos , Fluorescência , Limite de Detecção , Nitrogênio/química , Pontos Quânticos/química , Espectrometria de Fluorescência/instrumentação
11.
Int J Nanomedicine ; 15: 2765-2776, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32425520

RESUMO

Purpose: Over the past decades, quantum dots (QDs) have shown the broad application in diverse fields, especially in intracellular probing and drug delivery, due to their high fluorescence intensity, long fluorescence lifetime, strong light-resistant bleaching ability, and strong light stability. Therefore, we explore a kind of therapeutic potential against cancer with fluorescent imaging. Methods: In the current study, a new type of QDs (QDs@L-Cys-TAEA-5-FUA) capped with L-cysteine (L-Cys) and tris(2-aminoethyl)amine (TAEA) ligands, and conjugated with 5-fluorouracil-1-acetic acid (5-FUA) has been synthesized. Ligands were characterized by electrospray ionization mass spectrometry and H-nuclear magnetic resonance (1H NMR) spectroscopy. The modified QDs were characterized by transmission electron microscopy, ultraviolet and visible spectrophotometry (UV-Vis), and fluorescence microscopy. And the biological activity of modified QDs was explored by using MTT assay with HeLa, SMMC-7721 HepG2, and QSG-7701 cells. The fluorescence imaging of modified QDs was obtained by fluorescence microscope. Results: The modified QDs are of controllable sizes in the range of 4-5 nm and they possess strong optical emission properties. UV-Vis and fluorescence spectra demonstrated that the L-Cys-TAEA-5-FUA was successfully incorporated into QD nanoparticles. The MTT results demonstrated that L-Cys-TAEA-5-FUA modified QDs could efficiently inhibit the proliferation of cancer cells as compared to the normal cells, illustrating their antitumor efficacy. The mechanistic studies revealed that the effective internalization of modified QDs inside cancer cells could inhibit their proliferation, through excessive production of intracellular reactive oxygen species, leading to apoptosis process. Conclusion: The present study suggests that modified QDs can enter cells efficiently and could be employed as therapeutic agents for the treatment of various types of cancers with fluorescent imaging.


Assuntos
Antimetabólitos Antineoplásicos/farmacologia , Fluoruracila/farmacologia , Pontos Quânticos/química , Antimetabólitos Antineoplásicos/administração & dosagem , Antimetabólitos Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Cisteína/química , Portadores de Fármacos/administração & dosagem , Portadores de Fármacos/química , Etilenodiaminas/química , Fluoruracila/administração & dosagem , Fluoruracila/química , Células HeLa , Células Hep G2 , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Microscopia Eletrônica de Transmissão , Microscopia de Fluorescência , Pontos Quânticos/uso terapêutico , Espécies Reativas de Oxigênio/metabolismo , Espectrofotometria Ultravioleta
12.
Int J Nanomedicine ; 15: 3217-3233, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32440120

RESUMO

Introduction: Since CdTe quantum dots (QDs) are still widely considered as advanced fluorescent probes because of their far superior optical performance and fluorescence efficiency over non-cadmium QDs, it is important to find ways to control their toxicity. Methods: In this study, the adverse effects of two cadmium-containing QDs, ie, CdTe QDs and CdTe@ZnS QDs, on the nervous system of nematode C. elegans, the hippocampus of mice, and cultured microglia were measured in order to evaluate the neuroinflammation caused by cadmium-containing QDs and the potential mechanisms. Results: Firstly, we observed that cadmium-containing QD exposure-induced immune responses and neurobehavioral deficit in nematode C. elegans. In the mice treated with QDs, neuroinflammatory responses to QDs in the hippocampus, including microglial activation and IL-1ß release, occurred as well. When investigating the mechanisms of cadmium-containing QDs causing IL-1ß-mediated inflammation, the findings suggested that cadmium-containing QDs activated the NLRP3 inflammasome by causing excessive ROS generation, and resulted in IL-1ß release. Discussion: Even though the milder immune responses and neurotoxicity of CdTe@ZnS QDs compared with CdTe QDs indicated the protective role of ZnS coating, the inhibitions of NLRP3 expression and ROS production completely reduced the IL-1ß-mediated inflammation. This provided valuable information that inhibiting target molecules is an effective and efficient way to alleviate  the toxicity of cadmium-containing QDs, so it is important to evaluate QDs through a mechanism-based risk assessment.


Assuntos
Encéfalo/patologia , Compostos de Cádmio/farmacologia , Inflamação/patologia , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Pontos Quânticos/química , Sulfetos/farmacologia , Telúrio/farmacologia , Compostos de Zinco/farmacologia , Animais , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/imunologia , Linhagem Celular , Inflamassomos/metabolismo , Interleucina-1beta/metabolismo , Masculino , Camundongos Endogâmicos ICR , Microglia/efeitos dos fármacos , Microglia/patologia , Espécies Reativas de Oxigênio/metabolismo
13.
Chemosphere ; 251: 126381, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32443232

RESUMO

In this study, carbon quantum dots (CQDs) were used to decorate a TiO2/g-C3N4 (TCN) film electrode. The morphological, optical, and electrochemical properties of the TiO2/g-C3N4/CQDs nanorod arrays (TCNC NRAs) film were investigated using transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL), and electrochemical impedance spectroscopy (EIS). The improved optical properties, photoelectrochemical properties and photoelectrocatalytic (PEC) performance of photoanode can be observed by doping CQDs onto the TCN NRAs film. Compared with TiO2 NRAs and TCN NRAs, the narrower band gap of 2.47 eV and longer lifetime of photoinduced electron-hole pairs were observed in the TCNC NRAs. Under visible light irradiation and a bias voltage of 1.2 V, the photocurrent density and 1,4-dioxane (1,4-D) removal rate of PEC process with TCNC NRAs electrode reached 0.16 mA/cm2 and 77.9%, respectively, which was 2.5 times and 1.5 times of that with TCN NRAs electrode. TCNC NRAs electrode could keep >75% of the 1,4-D removal rate during five cycles tests. High PEC performance with TCNC NRAs electrode could be attributed to the enhanced charge separation and the change of electron transfer mechanism from typical heterojunction to Z-scheme, which may increase the active species production and change the dominant reactive species from O2·- to ·OH. Our experimental results should be useful for studying the degradation of 1,4-D and developing efficient PEC materials.


Assuntos
Dioxanos/química , Pontos Quânticos/química , Carbono , Eletrodos , Luz , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Nanotubos/química , Titânio
14.
Int J Nanomedicine ; 15: 1951-1965, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32256071

RESUMO

Introduction: Indium phosphide (InP) quantum dots (QDs) have shown a broad application prospect in the fields of biophotonics and nanomedicine. However, the potential toxicity of InP QDs has not been systematically evaluated. In particular, the effects of different surface modifications on the biodistribution and toxicity of InP QDs are still unknown, which hinders their further developments. The present study aims to investigate the biodistribution and in vivo toxicity of InP/ZnS QDs. Methods: Three kinds of InP/ZnS QDs with different surface modifications, hQDs (QDs-OH), aQDs (QDs-NH2), and cQDs (QDs-COOH) were intravenously injected into BALB/c mice at the dosage of 2.5 mg/kg BW or 25 mg/kg BW, respectively. Biodistribution of three QDs was determined through cryosection fluorescence microscopy and ICP-MS analysis. The subsequent effects of InP/ZnS QDs on histopathology, hematology and blood biochemistry were evaluated at 1, 3, 7, 14 and 28 days post-injection. Results: These types of InP/ZnS QDs were rapidly distributed in the major organs of mice, mainly in the liver and spleen, and lasted for 28 days. No abnormal behavior, weight change or organ index were observed during the whole observation period, except that 2 mice died on Day 1 after 25 mg/kg BW hQDs treatment. The results of H&E staining showed that no obvious histopathological abnormalities were observed in the main organs (including heart, liver, spleen, lung, kidney, and brain) of all mice injected with different surface-functionalized QDs. Low concentration exposure of three QDs hardly caused obvious toxicity, while high concentration exposure of the three QDs could cause some changes in hematological parameters or biochemical parameters related to liver function or cardiac function. More attention needs to be paid on cQDs as high-dose exposure of cQDs induced death, acute inflammatory reaction and slight changes in liver function in mice. Conclusion: The surface modification and exposure dose can influence the biological behavior and in vivo toxicity of QDs. The surface chemistry should be fully considered in the design of InP-based QDs for their biomedical applications.


Assuntos
Pontos Quânticos/toxicidade , Animais , Análise Química do Sangue , Feminino , Índio/química , Camundongos Endogâmicos BALB C , Microscopia de Fluorescência , Fosfinas/química , Pontos Quânticos/química , Sulfetos/química , Propriedades de Superfície , Distribuição Tecidual , Compostos de Zinco/química
15.
Ecotoxicol Environ Saf ; 196: 110569, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32278141

RESUMO

Cadmium-quantum dots (Cd-QDs) possess unique properties as optoelectronic devices for sensitive detection in food and biomedicine fields. However, the toxic effects of Cd-QDs to single cells is still controversial, due to the release mechanism of QDs to Cd2+in situ and the cytotoxic effects of QDs and Cd2+ respectively are still unclear. In this paper, the release rule of Cd2+ from CdTe QDs within single cells was investigated in situ by using flow cytometry method and the dose-response relationships were explored. Besides, an all-inclusive microscopy system was optimized for live cell imaging to observe the real-time entry process of CdTe QDs into cells. We found that intracellular CdTe QDs and Cd2+ contents were increased based on the dosage and exposing time. A dissociated saturation of Cd2+ from CdTe QDs was exist within cells. CdTe QDs induced more serious cytotoxicity on kidney cells than hepatocytes. The toxicity of oxidative stress, cell apoptosis effects induced by CdTe QDs and Cd2+ are also in consistent with this result. This research develops analytical method to quantify the uptake and release of Cd-QDs to primary cells in situ and can provide technical support in studying the cytotoxicity portion contributed by nanoparticles (NPs) and metal ions.


Assuntos
Compostos de Cádmio/toxicidade , Hepatócitos/efeitos dos fármacos , Rim/efeitos dos fármacos , Pontos Quânticos/toxicidade , Telúrio/toxicidade , Animais , Apoptose/efeitos dos fármacos , Compostos de Cádmio/química , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Rim/citologia , Masculino , Camundongos Endogâmicos C57BL , Estresse Oxidativo/efeitos dos fármacos , Pontos Quânticos/química , Telúrio/química
16.
Food Chem ; 322: 126719, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32283377

RESUMO

In this study, a sensitive immunoassay using immunomagnetic nanobeads (MNBs), manganese dioxide nanoflowers (MnO2 NFs) and quantum dots (QDs) was developed for simultaneous detection of E. coli O157: H7 and Salmonella typhimurium. MnO2 NFs were synthesized, functionalized and incubated with QDs to obtain QDs@MnO2 nanocomposites, followed by modification with antibodies (pAbs) to obtain pAb-QDs@MnO2 nanocomposites (QM NCs). Target bacteria were first conjugated with MNBs and QM NCs to form MNB-bacteria-QM complexes. Then, QDs were quickly released from the complexes using glutathione to reduce MnO2 to Mn2+. Finally, fluorescent intensity at characteristic wavelength was measured by optical detector to determine target bacteria. This immunoassay could simultaneously and quantitatively detect E. coli from 1.5 × 101 to 1.5 × 106 CFU/mL with detection limit of 15 CFU/mL and Salmonella from 4.0 × 101 to 4.0 × 106 CFU/mL with detection limit of 40 CFU/mL in 2 h. The mean recovery for both bacteria in spiked chicken samples was ∼96%.


Assuntos
Escherichia coli O157/isolamento & purificação , Imunoensaio/métodos , Compostos de Manganês/química , Óxidos/química , Pontos Quânticos/química , Salmonella typhimurium/isolamento & purificação , Escherichia coli O157/crescimento & desenvolvimento , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Imunoensaio/instrumentação , Limite de Detecção , Salmonella typhimurium/crescimento & desenvolvimento
17.
Anal Chim Acta ; 1113: 43-51, 2020 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-32340668

RESUMO

This study fabricated a dual-emission probe consisting of monolayer MoS2 quantum dots (M - MoS2 QDs) and L-cystine-linked boron-dipyrromethene (L-Cys-BODIPY) molecules for ratiometric sensing of biothiols, thiol product-related enzyme reactions, and ratiometric imaging of glutathione (GSH)-related reactions in HeLa cells. The formation of L-Cys-BODIPY-adsorbed M - MoS2 QDs (named as BODIPY-M-MoS2 QDs) was demonstrated by comparing them with M - MoS2 QDs using transmission electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. The BODIPY-M-MoS2 QDs exhibited dual-emission bands, excellent biocompatibility, and good resistance to photobleaching. It was found that the adsorbed L-Cys-BODIPY molecules rarely quenched the fluorescence of M - MoS2 QDs, and meanwhile, they were self-quenched by π-π stacking between each BODIPY backbones. The presence of biothiols induced the reduction of weakly fluorescent L-Cys-BODIPY to strongly fluorescent of L-cysteine-conjugated BODIPY. Since having a much higher molar absorption coefficient than L-Cys-BODIPY, the liberated L-cysteine-conjugated BODIPY behaved as an effective inner filter to absorb the excitation light and subsequently quenched the fluorescence of M - MoS2 QDs. The appearance of L-cysteine-conjugated BODIPY could barely affected to the fluorescence lifetime of M - MoS2 QDs, confirming the inner filter effect of L-cysteine-conjugated BODIPY onto the fluorescence of M - MoS2 QDs. The present probe not only provided a linear ratiometric response to 1-10 mM GSH, 1-10 µM cysteine, and 1-10 µM of homocysteine but also remarkably showed the ratiometric detection of thiol products from the reactions of 1-900 units L-1 S-adenosylhomocysteine (SAH) hydrolase and SAH as well as 1-850 units L-1 GSH reductase and disulfide GSH. Additionally, the present probe was well-suited for ratiometric imaging of intracellular GSH levels in non-treated and drug-treated HeLa cells.


Assuntos
Cisteína/análise , Corantes Fluorescentes/química , Glutationa/análise , Homocisteína/análise , Pontos Quânticos/química , Compostos de Boro/química , Cistina/química , Dissulfetos/química , Células HeLa , Humanos , Limite de Detecção , Molibdênio/química , Espectrometria de Fluorescência/métodos
18.
Int J Nanomedicine ; 15: 2045-2058, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32273701

RESUMO

Bone regeneration remains a great clinical challenge. Two-dimensional materials, especially graphene and its derivative graphene oxide, have been widely used for bone regeneration. Since its discovery in 2014, black phosphorus (BP) nanomaterials including BP nanosheets and BP quantum dots have attracted considerable scientific attention and are considered as prospective graphene substitutes. BP nanomaterials exhibit numerous advantages such as excellent optical and mechanical properties, electrical conductivity, excellent biocompatibility, and good biodegradation, all of which make them particularly attractive in biomedicine. In this review, we comprehensively summarize recent advances of BP-based nanomaterials in bone regeneration. The advantages are reviewed, the different synthesis methods of BP are summarized, and the applications to promote bone regeneration are highlighted. Finally, the existing challenges and perspectives of BP in bone regeneration are briefly discussed.


Assuntos
Regeneração Óssea/fisiologia , Nanoestruturas/química , Nanoestruturas/uso terapêutico , Fósforo/química , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/uso terapêutico , Regeneração Óssea/efeitos dos fármacos , Grafite/química , Humanos , Pontos Quânticos/química
19.
Food Chem ; 320: 126611, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32199201

RESUMO

Histamine, one of the most important biogenic amines (BAs) is considered as food hazard and therefore various agencies have fixed threshold in different food and beverages. In this manuscript, two novel fluorescent turn-on probes were developed for the instantaneous detection of histamine. The ß-cyclodextrin (ß-CD) capped ZnO quantum dots (QDs) were decorated with the vitamin B6 cofactors like pyridoxal 5'-phosphate (PLP) and pyridoxal (Py) by forming host-guest inclusion complexation between the capped ß-CD and PLP/Py. The cofactors decorated QDs (ZnO@PLP and ZnO@Py) were applied for the sensing of BAs. Addition of histamine to the ZnO@PLP and ZnO@Py solution resulted selective fluorescence enhancement at 473 nm and 460 nm, respectively. Without any interference from the other tested BAs, the fluorescence response of the probes ZnO@PLP and ZnO@Py showed good linearity to histidine concentration from 2.49 to 24.4 µM and 7.44 to 47.6 µM with the detection limit down to 0.59 µM and 0.97 µM, respectively.


Assuntos
Técnicas Biossensoriais/métodos , Corantes Fluorescentes , Histamina/análise , Pontos Quânticos/química , Vitamina B 6 , Óxido de Zinco , Limite de Detecção , beta-Ciclodextrinas
20.
Top Curr Chem (Cham) ; 378(2): 35, 2020 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-32219574

RESUMO

Quantum dots (QDs) are a special type of engineered nanomaterials with outstanding optoelectronic properties that make them as a very promising alternative to conventional luminescent dyes in biomedical applications, including biomolecule (BM) targeting, luminescence imaging and drug delivery. A key parameter to ensure successful biomedical applications of QDs is the appropriate surface modification, i.e. the surface of the nanomaterials should be modified with the appropriate functional groups to ensure stability in aqueous solutions and it should be conjugated with recognition elements capable of ensuring an efficient tagging of the BMs of interest. In this review we summarize the most relevant strategies used for surface modification of QDs and for their conjugation to BMs in preparation of their application in nanoplatforms for luminescent BM sensing and imaging-guided targeting. The applications of conjugations of photoluminescent QDs with different BMs in both in vitro and in vivo chemical sensing, immunoassays or luminescence imaging are reviewed. Recent progress in the application of functionalized QDs in ultrasensitive detection in bioanalysis, diagnostics and imaging strategies are reported. Finally, some key future research goals in the progress of bioconjugation of QDs for diagnosis are identified, including novel synthetic approaches, the need for exhaustive characterization of bioconjugates and the design of signal amplification schemes.


Assuntos
Técnicas Biossensoriais/métodos , Pontos Quânticos/química , Humanos
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