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1.
Nat Commun ; 12(1): 34, 2021 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-33397947

RESUMO

Colloidal gold nanoparticles (GNPs) serve as promising contrast agents in photoacoustic (PA) imaging, yet their utility is limited due to their absorption peak in the visible window overlapping with that of hemoglobin. To overcome such limitation, this report describes an ultrapure chain-like gold nanoparticle (CGNP) clusters with a redshift peak wavelength at 650 nm. The synthesized CGNP show an excellent biocompatibility and photostability. These nanoparticles are conjugated with arginine-glycine-aspartic acid (RGD) peptides (CGNP clusters-RGD) and validated in 12 living rabbits to perform multimodal photoacoustic microscopy (PAM) and optical coherence tomography (OCT) for visualization of newly developed blood vessels in the sub-retinal pigment epithelium (RPE) space of the retina, named choroidal neovascularization (CNV). The PAM system can achieve a 3D PAM image via a raster scan of 256 × 256 pixels within a time duration of 65 s. Intravenous injection of CGNP clusters-RGD bound to CNV and resulted in up to a 17-fold increase in PAM signal and 176% increase in OCT signal. Histology indicates that CGNP clusters could disassemble, which may facilitate its clearance from the body.


Assuntos
Ouro/química , Nanopartículas Metálicas/química , Microscopia , Imagem Molecular , Técnicas Fotoacústicas , Tomografia de Coerência Óptica , Animais , Neovascularização de Coroide/diagnóstico por imagem , Neovascularização de Coroide/patologia , Meios de Contraste/química , Feminino , Testes de Função Renal , Testes de Função Hepática , Masculino , Nanopartículas Metálicas/ultraestrutura , Camundongos , Oligopeptídeos/química , Coelhos , Distribuição Tecidual
2.
Environ Monit Assess ; 193(2): 60, 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-33442789

RESUMO

Acid mine drainage occurs due to the chemical and microbiological oxidation of sulfide minerals and can be a source of potentially toxic elements contamination of groundwater and surface water. The objective of this study was to identify microorganisms involved in sulfide oxidation in the tailings of a Bahia Gold Belt mine (Brazil). Samples of solids and water were collected at the mine tailings dam and characterized. The microorganisms were isolated after enrichment and subsequent purification. The major constituents of the tailings are Si, Fe, Al, S, and K. The sulfur content of the tailings is 0.98%. The major phases are quartz, muscovite, and clinochlore. Gravity concentrates of the tailings show several particles of pyrite, that is, the major sulfide phase. Molecular analysis identified the microorganisms isolated in the acid mine drainage process in this region. Five bacterium species were found: Acidithiobacillus spp., Acidithiobacillus ferrooxidans, Acidiphilium spp., Leptospirillum type II, and Sulfobacillus spp. No organisms of the archaea or eukaryote domains were found. The isolate was used in the bioleaching of copper sulfide ore, and the copper extraction was about 60% in 60 days for ground ore.


Assuntos
Monitoramento Ambiental , Ouro , Acidithiobacillus , Brasil , Mineração , Sulfetos
3.
Food Chem ; 340: 127835, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33002825

RESUMO

A simple, sensitive and rapid fluorometric system has been developed for the detection of aldicarb (ALD) based on inner filter effect (IFE) of gold nanoparticles (AuNPs) on fluorescence (FL) intensity of carbon quantum dots (CQDs). Addition of CQDs into AuNPs, gets them aggregated due to electrostatic interaction resulting in quenching the FL intensity of CQDs. With addition of ALD into AuNPs, an intercalated layer was formed between them through Au-N and Au-S bond which reduced IFE of AuNPs. Hence, CQDs FL intensity recovered along with ALD concentration varying between 3.8 and 76 µg L-1 with lower detection limit of 3.02 µg L-1. The spiked real samples study in fruits, vegetables and soft drinks revealed that this sensing platform was repeatable and effective for real samples. The validation of proposed method indicates that the ALD sensor is promising and adaptable for everyday on spot environment and food safety monitoring.


Assuntos
Aldicarb/análise , Análise de Alimentos/métodos , Substâncias Intercalantes/química , Nanopartículas Metálicas/química , Pontos Quânticos/química , Aldicarb/química , Carbono/química , Fluorescência , Análise de Alimentos/instrumentação , Contaminação de Alimentos/análise , Frutas/química , Ouro/química , Reprodutibilidade dos Testes , Espectrometria de Fluorescência/instrumentação , Espectrometria de Fluorescência/métodos , Verduras/química
4.
Food Chem ; 343: 128494, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33162257

RESUMO

A dual-mode fluorescence/colorimetric sensor based on carbon quantum dots (CQDs) and gold nanoparticles (GNPs) was developed for visual detection of malathion in cabbage. The CQDs-GNPs nanocomposite exhibited emission wavelength at 527 nm and absorption wavelength at 524 nm. The fluorescence intensity increased and absorption decreased with addition of malathion. Fluorescence and colorimetric calibration curves were established based on fluorescence intensity (R2 = 0.9914) and absorbance (R2 = 0.9608) in the range of 1 × 10-9-1 × 10-2 M, respectively. Furthermore, fluorescence and colorimetric standard arrays were prepared for visual detection of malathion according to the change of fluorescence brightness and color. Finally, the approximate concentrations of malathion in cabbage samples were estimated by the standard arrays and naked eyes. The calibration curves were used for accurate detection in cabbage samples with recoveries of 89.9%-103.4% (fluorescence) and 88.7%-107.6% (colorimetric). The established sensor for visual malathion detection in cabbage was accurate with strong application potential, especially for rapid screening.


Assuntos
Brassica/química , Carbono/química , Análise de Alimentos/métodos , Ouro/química , Malation/análise , Nanopartículas Metálicas/química , Pontos Quânticos/química , Calibragem , Colorimetria , Contaminação de Alimentos/análise , Limite de Detecção , Espectrometria de Fluorescência
5.
Oral Dis ; 27(2): 251-265, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32657515

RESUMO

OBJECTIVES: Gold nanoparticles (AuNPs) are used to deliver drugs and therapeutic small molecule inhibitors to cancer cells. Evidence shows that AuNPs coated with nuclear localization sequence can cross the nuclear membrane and induce cellular apoptosis. To determine the therapeutic role of AuNPs, we compared two nanoconstructs conjugated to doxorubicin (DOX) through pH-sensitive and pH-resistant linkers. MATERIALS AND METHODS: We tested DOX nanoconjugates' cytotoxicity, cellular and nuclear uptake in oral squamous cell carcinoma cell line. Furthermore, we evaluated the therapeutic effect of pH-sensitive and pH-resistant DOX bioconjugates in hamster buccal pouch carcinoma model. RESULTS: Our data indicate that pH-resistant and pH-sensitive DOX-nanoconjugates were equally localized in cancer cells, but the pH-resistant DOX nanoparticles were more localized in the nuclei inducing a 2-fold increase in the apoptotic effect compared with the pH-sensitive DOX nanoparticles. Our in vivo results show significantly higher tumor shrinkage and survival rates in animals treated with DOX pH-resistant AuNPs compared with pH-sensitive ones. CONCLUSION: Our findings suggest that AuNPs enhance the cytotoxic effect against cancer cells in addition to acting as drug carriers. DOX pH-resistant AuNPs enhanced accumulation of AuNPs in cancer cells' nuclei inducing a significant cellular apoptosis which was confirmed using in vitro and in vivo experiments without deleterious effects on blood cell count.


Assuntos
Carcinoma de Células Escamosas , Nanopartículas Metálicas , Neoplasias Bucais , Nanopartículas , Animais , Apoptose , Carcinoma de Células Escamosas/tratamento farmacológico , Linhagem Celular Tumoral , Doxorrubicina , Portadores de Fármacos , Sistemas de Liberação de Medicamentos , Ouro , Concentração de Íons de Hidrogênio , Neoplasias Bucais/tratamento farmacológico
6.
Biosens Bioelectron ; 171: 112731, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33075725

RESUMO

Rapid person-to-person transfer of viruses such as SARS-CoV-2 and their occasional mutations owing to the human activity and climate/ecological changes by the mankind led to creation of wrecking worldwide challenges. Such fast transferable pathogens requiring practical diagnostic setups to control their transfer chain and stop sever outbreaks in early stages of their appearance. Herein, we have addressed this urgent demand by designing a rapid electrochemical diagnostic kit composed of fixed/screen printed electrodes that can detect pathogenic viruses such as SARS-CoV-2 and/or animal viruses through the differentiable fingerprint of their viral glycoproteins at different voltage positions. The working electrode of developed sensor is activated upon coating a layer of coupled graphene oxide (GO) with sensitive chemical compounds along with gold nanostars (Au NS) that can detect the trace of viruses in any aquatic biological media (e.g., blood, saliva and oropharyngeal/nasopharyngeal swab) through interaction with active functional groups of their glycoproteins. The method do not require any extraction and/or biomarkers for detection of target viruses and can identify trace of different pathogenic viruses in about 1 min. The nanosensor also demonstrated superior limit of detection (LOD) and sensitivity of 1.68 × 10-22 µg mL-1 and 0.0048 µAµg.mL-1. cm-2, respectively, toward detection of SARS-CoV-2 in biological media, while blind clinical evaluations of 100 suspected samples furtherly confirmed the superior sensitivity/specificity of developed nanosystem toward rapid identification of ill people even at incubation and prodromal periods of illness.


Assuntos
Betacoronavirus/isolamento & purificação , Técnicas de Laboratório Clínico , Infecções por Coronavirus/diagnóstico , Técnicas Eletroquímicas/instrumentação , Pneumonia Viral/diagnóstico , Glicoproteína da Espícula de Coronavírus/análise , Animais , Técnicas Biossensoriais/instrumentação , Eletrodos , Desenho de Equipamento , Ouro/química , Grafite/química , Humanos , Limite de Detecção , Nanopartículas Metálicas/química , Pandemias
7.
Biosens Bioelectron ; 171: 112753, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33120235

RESUMO

A polyethyleneimine (PEI)-assisted copper in-situ growth (CISG) strategy was proposed as a controlled signal amplification strategy to enhance the sensitivity of gold nanoparticle-based lateral flow sensors (AuNP-LFS). The controlled signal amplification is achieved by introducing PEI as a structure-directing agent to regulate the thermodynamics of anisotropic Cu nanoshell growth on the AuNP surface, thus controlling shape and size of the resultant AuNP@Cu core-shell nanostructures and confining free reduction and self-nucleation of Cu2+ for improved reproducibility and decreased false positives. The PEI-CISG-enhanced AuNP-LFS showed ultrahigh sensitivities with the detection limits of 50 fg mL-1 for HIV-1 capsid p24 antigen and 6 CFU mL-1 for Escherichia coli O157:H7. We further demonstrated its clinical diagnostic efficacy by configuring PEI-CISG into a commercial AuNP-LFS detection kit for SARS-CoV-2 antibody detection. Altogether, this work provides a reliable signal amplification platform to dramatically enhance the sensitivity of AuNP-LFS for rapid and accurate diagnostics of various infectious diseases.


Assuntos
Técnicas Biossensoriais/métodos , Cobre/química , Infecções por Coronavirus/diagnóstico , Infecções por Escherichia coli/diagnóstico , Ouro/química , Infecções por HIV/diagnóstico , Pneumonia Viral/diagnóstico , Betacoronavirus/isolamento & purificação , Técnicas Biossensoriais/instrumentação , Técnicas de Laboratório Clínico , Desenho de Equipamento , Escherichia coli O157/isolamento & purificação , Proteína do Núcleo p24 do HIV/análise , HIV-1/isolamento & purificação , Humanos , Limite de Detecção , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Oxirredução , Pandemias , Polietilenoimina/química , Fitas Reagentes/análise
8.
Waste Manag ; 120: 530-537, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33162288

RESUMO

The application of laboratory-generated biochar and activated carbon adsorbents in gold iodized solution for the recycling of waste mobile phone printed circuit boards (WMPCBs) is investigated. This research aims to solve problems associated with the existing gold recovery technologies of WMPCBs. Currently, the disposal of WMPCBs is expensive, involves complex processes, and contributes to secondary pollution. In this study, laboratory-generated biochar is produced from corn straw, wheat straw, and wood chips by pyrolysis. The effects of factors on the adsorption efficiency are investigated, and the optimal operating conditions for biochar and activated carbon adsorption are determined. The following optimal parameters were found for activated carbon: temperature = 25 °C, particle size = 40-60 mesh, dosage = 0.05 g/10 mL, pH = 7, reaction time = 2 h, and oscillation frequency = 200 r/min. The adsorption efficiency reached 98.6%. For biochar, optimization involved: raw material from corn straw at a pyrolysis temperature = 700 °C, reaction time = 5 h, oscillation frequency = 200 r/min, pH = 3, dosage = 0.15 g/10 mL, and temperature = 50 °C. An adsorption efficiency of 98% was achieved. The two adsorbents were compared, and results demonstrated that the adsorption properties of the laboratory-generated biochar were slightly inferior to those of the activated carbon; however, they were similar. Biochar adsorption can reuse waste, which may not only solve the current problems related to WMPCB recycling, but can help to achieve a "win-win" situation of increased environmental protection and sustainable utilization of resources.


Assuntos
Telefone Celular , Carvão Vegetal , Adsorção , Ouro
9.
Waste Manag ; 120: 136-145, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33302016

RESUMO

The generation of wasted LEDs is expected to grow in the coming years, raising the challenge of recycling and recovering their valuable and critical materials. Due to the low concentration of these materials, the current recycling processes available for LEDs have a significant recovery limitation. This study proposes an innovative, clean and effective physical method to segregate the valuable and critical materials into different fractions while enhancing their concentration: particle size separation followed by electrostatic separation. After the determination of the best electrostatic separation conditions (varying tension and rotation) for each particle size, the final fractions were characterized by acid digestion and ICP-OES analysis. The analysis revealed that the economically valuable elements gold, silver, copper and tin became concentrated in the conductive fractions (80.18%, 94.22%, 96.55% and 93.29% of their total recovered mass, respectively), while the strategic critical elements, gallium, cerium and yttrium became concentrated in the non-conductive fractions (96.15%, 100% and 95.20% of their total recovered mass, respectively). Despite some limitations imposed by the mass losses, this novel route may be important to uncover new recycling alternatives, mainly for critical elements, and to improve the economic viability of the recycling routes.


Assuntos
Resíduo Eletrônico , Gálio , Cobre , Ouro , Reciclagem
10.
Food Chem ; 341(Pt 1): 128231, 2021 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-33011476

RESUMO

A sensitive photothermal immunochromatographic test strip (PITS) for the detection of deoxynivalenol (DON) was developed using flower-like gold nanoparticle-deposited manganese dioxide nanocarrier (FMD-G NC) labeled antibodies (Abs) as the photothermal-sensing probe. FMD was used as a template to deposit small gold nanoparticles (GNPs) to synthesize FMD-G NC with large specific surface area and significant photothermal conversion property. The FMD-G-Ab probe was competitively captured by DON target and antigen coated on test line (T-line), forming colorimetric signals under naked eyes and photothermal signals under an 808 nm laser. Under optimal conditions, the PITS exhibited sensitive and specific detection of DON from 0.19 ng mL-1 to 12 ng mL-1 with detection limits of 0.013 ng mL-1, which were over 15-fold and 58-fold more sensitive than visual FMD-G-ITS and traditional GNPs-ITS. In addition, the novel FMD-G-PITS possessed a universal applicability, which could be well applied in green bean, corn, and millet.


Assuntos
Cromatografia de Afinidade/instrumentação , Ouro/química , Limite de Detecção , Compostos de Manganês/química , Nanopartículas Metálicas/química , Conformação Molecular , Óxidos/química , Temperatura , Colorimetria
11.
Chemosphere ; 266: 129001, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33248726

RESUMO

The artisanal and small-scale gold mining (ASGM) sector uses the most mercury (Hg) worldwide. Despite health concerns associated with high Hg exposures in these communities, ASGM sites are often situated in resource limited and remote regions which challenge traditional human biomonitoring approaches. To help overcome such challenges, here we report on the development of a high-quality method to characterize chemical speciation of Hg in dried blood spots (DBS), and then apply this method to assess Hg exposures in people sampled from an ASGM community (Pueblito Mejia) and a nearby town (Barranco de Loba) in Colombia. We collected DBS and urine samples from 35 individuals in 2018, and used these to assess occupational (DBS inorganic Hg (InHg) and urine total Hg (THg) measures) and environmental (DBS methylmercury (MeHg) measures) exposure of participants to different forms of Hg. The accuracy and precision of the DBS-based measures generally met assay performance guideline. In study participants, the mean concentrations of DBS MeHg, InHg, and THg, and urine THg were 1.9, 4.1, 6.0, and 3.1 µg/L, respectively. For 37% of the participants, DBS THg values exceeded the 5 µg/L 'alert level' proposed by the German HBM Commission. About 60% of the blood Hg was in the InHg form thus exemplifying a need to speciate Hg in blood sampled from ASGM sites to better understand the contributions of environmental and occupational exposure sources. This study demonstrates the feasibility of using DBS for Hg speciation exposure assessments in remote and resource-limited areas such as ASGM communities.


Assuntos
Mercúrio , Colômbia , Exposição Ambiental/análise , Monitoramento Ambiental , Ouro , Humanos , Mercúrio/análise , Mineração
12.
Environ Sci Pollut Res Int ; 28(1): 262-269, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32812158

RESUMO

Act Force Gold®, Butaforce®, and Atraforce® are among the most commonly used pesticides in Nigeria. The lethal concentrations and the respective toxic units for the three pesticides were determined. The genotoxic effects of the three pesticides were investigated in the red blood cells of Clarias gariepinus using micronucleus (MN) assay. The 96 h LC50 was 4.75, 4.84, and 54.74 mg L-1 for Act Force Gold®, Butaforce®, and Atraforce®, respectively. The toxic units in ascending order of toxicity were 1.83, 20.66, and 21.05 for Act Force Gold®, Butaforce®, and Atraforce® respectively. The estimated safe levels based on NAS/NAE varied from 4.75 × 10-1-4.75 × 10-5 in Act Force Gold® through 4.64 × 10-1-4.85 × 10-5 in Butaforce® to 5.74-5.74 × 10-5 in Atraforce®. Fish specimens were exposed to the pesticides and sampling was done at regular intervals at days 1, 7, 14, and 21 and after another 7-day recovery period. The results obtained indicated concentration- and duration-dependent increase in % MN formation with maximum values of 3.40 ± 0.25 for Act Force Gold® on day 14 and 3.05 ± 0.36 and 2.35 ± 0.14 for Butaforce® and Atraforce® respectively on day 7 of exposure. The 7-day recovery period could not reverse the trend as the % MN values obtained were significantly different from the control. The results further support the use of MN assay in assessing the toxicity of aquatic pollutants and can be used in the monitoring of aquatic ecosystems.


Assuntos
Peixes-Gato , Poluentes Químicos da Água , Animais , Dano ao DNA , Ecossistema , Ouro , Nigéria , Poluentes Químicos da Água/toxicidade
13.
Water Res ; 189: 116589, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33166922

RESUMO

Electroactive biofilms (EABs) can be integrated with conductive nanomaterials to boost extracellular electron transfer (EET) for achieving efficient waste treatment and energy conversion in bioelectrochemical systems. However, the in situ nanomaterial-modified EABs of mixed-culture, and their response under environmental stress are rarely revealed. Here, two nanocatalyst-decorated EABs were established by self-assembled Au nanoparticles-reduced graphene oxide (Au-NPs/rGO) in mixed-biofilms with different maturities, then their multi-property were analyzed under long-term phenolic shock. Results showed that the power density of Au-NPs/rGO decorated EABs was significantly enhanced by 28.66-42.82% due to the intensified EET pathways inside biofilms. Meanwhile, the electrochemical and catalytic performance of EABs were controllably regulated by 0.3-3.0 g/L phenolic compounds, which, however, resulted in differential alterations in their architecture, composition, and viability. EABs originated with higher maturity displayed more compact structure, lower thickness (110 µm), higher biomass (8.67 mg/cm2) and viability (0.85-0.91), endowing it better antishock ability to phenolic compounds. Phenolic-shock also induced the heterogeneous distribution of extracellular polymeric substances in terms of both spatial and bonding degrees of the decorated EABs, which could be regarded as an active response to strike a balance between self-protection and EET under environmental pressure. Our findings provide a broader understanding of microbe-electrode interactions in the micro-ecology interface and improve their performance in the removal of complex contaminants for sustainable remediation and new-energy development.


Assuntos
Geobacter , Nanopartículas Metálicas , Biofilmes , Eletrodos , Ouro , Grafite
14.
Food Chem ; 343: 128548, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33221103

RESUMO

The development of substrate with high sensitivity and good reproducibility for surface-enhanced Raman scattering (SERS) detection of contaminants in foods has attracted more and more attention. Herein, a stable two-dimensional (2D) Au-Ag core-shell nanorods (Au@Ag NRs) nanoarray substrate with high-performance SERS activity was developed based on interface self-assembly strategy and successfully applied to the detection of thiram in apple sample. A broad linearity range of 0.01-10 mg/L and a low limit of detection of 0.018 mg/L were achieved for thiram solution. The substrate was stable and exhibited satisfactory sensitivity after preserving at ambient temperature for 4 weeks. Furthermore, this method presented the comparable result to that acquired from high-performance liquid chromatography (HPLC) with satisfactory recoveries of 93-116%. The study indicated that the prepared Au@Ag NRs nanoarray substrate was promising for SERS detection of contaminants such as pesticides in foods.


Assuntos
Ouro/química , Malus/química , Análise em Microsséries/métodos , Nanotubos/química , Prata/química , Tiram/análise , Armazenamento de Alimentos , Fungicidas Industriais/análise , Limite de Detecção , Malus/metabolismo , Reprodutibilidade dos Testes , Análise Espectral Raman , Temperatura , Fatores de Tempo
15.
Chemosphere ; 266: 129235, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33316472

RESUMO

The use of nanoparticles in consumer products is currently on the rise, so it is important to have reliable methods to predict any associated toxicity effects. Traditional in vitro assays fail to mimic true physiological responses of living organisms against nanoparticles whereas murine in vivo models are costly and ethically controversial. For these reasons, this study aimed to evaluate the efficacy of Galleria mellonella as an alternative, non-rodent in vivo model for examining nanoparticle toxicity. Silver, selenium, and functionalized gold nanoparticles were synthesized, and their toxicity was assessed in G. mellonella larvae. The degree of acute toxicity effects caused by each type of NP was efficiently detected by an array of indicators within the larvae: LD50 calculation, hemocyte proliferation, NP distribution, behavioral changes, and histological alterations. G. mellonella larvae are proposed as a nanotoxicological model that can be used as a bridge between in vitro and in vivo murine assays in order to obtain better predictions of NP toxicity.


Assuntos
Nanopartículas Metálicas , Mariposas , Animais , Ouro , Larva , Dose Letal Mediana , Nanopartículas Metálicas/toxicidade , Camundongos
16.
Food Chem ; 339: 127854, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-32829245

RESUMO

Gold nanoparticles (AuNPs)-based lateral flow assay (LFA) enables a rapid detection of tetracycline (TET) in food samples but suffers from low sensitivity. Herein, metal-polydopamine framework (MPF), as a label, was employed to load monoclonal antibodies (mAbs) directly as the probe in LFA for highly sensitive sensing of TET. Combining zeolitic imidazolate framework (ZIF-67) and polydopamine (PDA), a stable MPF with large size, well water-dispersible, excellent affinity and optical properties was prepared through a versatile layer-by-layer assembly (LLA) strategy. Under optimized conditions, the biosensor (MPF-LFA) exhibited a great linear relationship in the range of 0.09-6 ng/mL and a detection limit of 0.045 ng/mL for TET detection, which was over 66-fold more sensitive than traditional AuNPs based LFA. Furthermore, the MPF-LFA was successfully applied to the screening of TET in fish, chicken, milk and shrimp samples with satisfied recoveries from 91% to 114%.


Assuntos
Antibacterianos/análise , Análise de Alimentos/métodos , Ouro/química , Indóis/química , Estruturas Metalorgânicas/química , Polímeros/química , Tetraciclina/análise , Animais , Técnicas Biossensoriais/métodos , Limite de Detecção , Nanopartículas Metálicas/química , Leite/química , Alimentos Marinhos/análise , Zeolitas/química
17.
Food Chem ; 339: 127891, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-32861930

RESUMO

We propose a visual strategy for simultaneous detection of multiple adulterated components in beef by integration of multiple polymerase chain reaction (mPCR) with the lateral flow strip (LFS). The primer sets for adulterated components are uniquely designed with different nucleic acid tags (NAT), enabling the amplicons with specific wobbled sequences at two opposite ends. The wobbled sequences will precisely hybridize with the pre-immobilized capture probes on T lines (T1, T2 and T3) and C line, contributing to the coloration of LFS. Taking advantages of extraordinary amplification efficiency of PCR and simplicity of LFS, common adulterated components including chicken, duck and pork can be easily detected with LOD as low as 0.01% (wt%), which is comparable to that of quantitative real-time polymerase chain reaction (qPCR) but with more simplified operations and reduced costs. The method can be extended to identification of other components by replacing the functional primer set. This method can be a useful candidate for meat quality control at the resource-limited setups.


Assuntos
Galinhas/genética , Patos/genética , Carne/análise , Reação em Cadeia da Polimerase em Tempo Real/métodos , Animais , Bovinos , DNA/isolamento & purificação , DNA/metabolismo , Ouro/química , Limite de Detecção , Nanopartículas Metálicas/química , Reação em Cadeia da Polimerase em Tempo Real/instrumentação , Suínos
18.
Food Chem ; 339: 127881, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-32866703

RESUMO

A novel and rapid Electrochemical Immunosensing platform was developed for the direct sensing of antibody human immuno globulin gamma (IgG) interaction with virulence factor of S. aureus, staphylococcal protein A (SpA) in the presence of electroactive redox couple ferri/ferro cyanide (K3/K4[Fe(CN)6]). The receptor SpA was attached to BioPE-DOTAP binary lipid bilayer tethered on alkane thiol molecular cushions. Atomic force microscopy (AFM), High-resolution transmission electron microscope (TEM), Fourier-transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS) techniques were used to study the molecular interactions. The AFM images showed array like formation of BioPE-DOTAP on the monolayer surface. The IgG sensor showed a linear range from 10-21 M to 10-16 M.


Assuntos
Técnicas Eletroquímicas/métodos , Imunoglobulina G/metabolismo , Proteína Estafilocócica A/metabolismo , Eletrodos , Ferricianetos/química , Ferrocianetos/química , Ouro/química , Humanos , Imunoglobulina G/química , Microscopia de Força Atômica , Oxirredução , Ligação Proteica , Proteína Estafilocócica A/química
19.
Chemosphere ; 265: 129114, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33296754

RESUMO

TiO2-based nanomaterials are among the most promising photocatalysts for degrading organic dye pollutants. In this work, Au-TiO2 nanofibers were fabricated by the electrospinning technique, followed by calcination in air at 500 °C. Morphological and structural analyses revealed that the composite consists of TiO2 nanofibers with embedded Au nanoparticles that are extensively distributed throughout the porous fibrous structure of TiO2. The photocatalytic performance of these Au-embedded TiO2 nanofibers was evaluated in the photodegradation of Rhodamine B and methylene blue under solar simulator irradiation. Compared with pristine TiO2 nanofibers, the Au-embedded TiO2 nanofibers displayed far better photocatalytic degradation efficiency. The plasmon resonance absorption of Au nanoparticles in the visible spectral region and the effective charge separation at the heterojunction of the Au-TiO2 hybrid are the key factors that have led to the considerable enhancement of the photocatalytic activity. The results of this study clearly demonstrate the potential of Au-TiO2 electrospun nanofibers as solar-light-responsive photocatalysts for the effective removal of dye contaminants from aquatic environments.


Assuntos
Poluentes Ambientais , Nanopartículas Metálicas , Nanofibras , Catálise , Ouro , Titânio
20.
J Chromatogr A ; 1636: 461798, 2021 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-33341435

RESUMO

Liposomes, mainly formed by phospholipids and cholesterol that entrapped different compounds, were separated and characterized using asymmetric flow field-flow fractionation (AF4) coupled with a multi-angle light scattering detector (MALS). AF4 allows the separation of liposomes according to their hydrodynamic size, and the particle size can be estimated directly by their elution time. Besides, different synthesized liposome suspensions of liposomes with different species encapsulated in different places in liposomes were prepared with analytical purposes to be studied. These liposomes were: empty liposomes (e-Ls), magnetoliposomes (MLs) with Fe3O4@AuNPs-C12SH inside the lipid bilayer, and long-wavelength fluorophores encapsulated into the aqueous cavity of liposomes (Ls-LWF). The optimization process of the variables that affect the fractionation has been established. The separation effectiveness has been compared with the results achieved with a photon-correlation spectroscopy analyzer based on dynamic light scattering (DLS) and transmission electron microscopy (TEM), used in self-assembly structures characterization. In all cases, three different classes of liposomes have been obtained; two are commonly appaired in all studied samples, while only a third class is characteristic for each of the liposomes. This mean that the proposed methodology could be used for identifying liposomes according to the encapsulated material.


Assuntos
Difusão Dinâmica da Luz , Fracionamento por Campo e Fluxo/métodos , Lipossomos/química , Sistemas On-Line , Colesterol/química , Ouro/química , Hidrodinâmica , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Tamanho da Partícula , Reologia , Água
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