Regulation of Ru(bpy)32+ Electrochemiluminescence Based on Distance-Dependent Electron Transfer of Ferrocene for Dual-Signal Readout Detection of Aflatoxin B1 with High Sensitivity

2021 ◽  
Author(s):  
Yuye Li ◽  
Dong Liu ◽  
Shuyun Meng ◽  
Jiayi Zhang ◽  
Libo Li ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Aflatoxin B1 ◽  
High Sensitivity ◽  
Signal Readout

Computationally Assisted Design of High Signal-to-Noise Photoinduced Electron Transfer-Based Voltage-Sensitive Dyes

2020 ◽  
Author(s):  
Rishikesh Kulkarni ◽  
Anneliese Gest ◽  
Chun Kei Lam ◽  
Benjamin Raliski ◽  
Feroz James ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Dft Calculations ◽  
Photoinduced Electron Transfer ◽  
Density Functional ◽  
Embryonic Stem ◽  
High Sensitivity ◽  
Md Simulations ◽  
High Signal ◽  
Signal To Noise ◽  
Green Fluorescent

<p>High signal-to-noise optical voltage indicators will enable simultaneous interrogation of membrane potential in large ensembles of neurons. However, design principles for voltage sensors with high sensitivity and brightness remain elusive, limiting the applicability of voltage imaging. In this paper, we use molecular dynamics (MD) simulations and density functional theory (DFT) calculations to guide the design of a bright and sensitive green-fluorescent voltage-sensitive fluorophore, or VoltageFluor (VF dye), that uses photoinduced electron transfer (PeT) as a voltage-sensing mechanism. MD simulations predict an 11% increase in sensitivity due to membrane orientation, while DFT calculations predict an increase in fluorescence quantum yield, but a decrease in sensitivity due to a decrease in rate of PeT. We confirm these predictions by synthesizing a new VF dye and demonstrating that it displays the expected improvements by doubling the brightness and retaining similar sensitivity to prior VF dyes. Combining theoretical predictions and experimental validation has resulted in the synthesis of the highest signal-to-noise green VF dye to date. We use this new voltage indicator to monitor the electrophysiological maturation of human embryonic stem cell-derived medium spiny neurons. </p>

scholarly journals Comprehensive Metabolomic Analysis Reveals Dynamic Metabolic Reprogramming in Hep3B Cells with Aflatoxin B1 Exposure

Toxins ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 384
Author(s):  
Shufeng Wang ◽  
Xin Yang ◽  
Feng Liu ◽  
Xinzheng Wang ◽  
Xuemin Zhang ◽  
...  
Keyword(s):  
Aflatoxin B1 ◽  
Drug Targets ◽  
High Sensitivity ◽  
Tca Cycle ◽  
Acid Synthesis ◽  
Metabolic Reprogramming ◽  
Pyrimidine Metabolism ◽  
Rapid Separation ◽  
Hexosamine Pathway ◽  
Hep3b Cells

Hepatitis B virus (HBV) infection and aflatoxin B1 (AFB1) exposure have been recognized as independent risk factors for the occurrence and development of hepatocellular carcinoma (HCC), but their combined impacts and the potential metabolic mechanisms remain poorly characterized. Here, a comprehensive non-targeted metabolomic study was performed following AFB1 exposed to Hep3B cells at two different doses: 16 μM and 32 μM. The metabolites were identified and quantified by an ultra-performance liquid chromatography-mass spectrometry (UPLC-MS)-based strategy. A total of 2679 metabolites were identified, and 392 differential metabolites were quantified among three groups. Pathway analysis indicated that dynamic metabolic reprogramming was induced by AFB1 and various pathways changed significantly, including purine and pyrimidine metabolism, hexosamine pathway and sialylation, fatty acid synthesis and oxidation, glycerophospholipid metabolism, tricarboxylic acid (TCA) cycle, glycolysis, and amino acid metabolism. To the best of our knowledge, the alteration of purine and pyrimidine metabolism and decrease of hexosamine pathways and sialylation with AFB1 exposure have not been reported. The results indicated that our metabolomic strategy is powerful to investigate the metabolome change of any stimulates due to its high sensitivity, high resolution, rapid separation, and good metabolome coverage. Besides, these findings provide an overview of the metabolic mechanisms of the AFB1 combined with HBV and new insight into the toxicological mechanism of AFB1. Thus, targeting these metabolic pathways may be an approach to prevent carcinogen-induced cancer, and these findings may provide potential drug targets for therapeutic intervention.

scholarly journals Two-photon sensitive protecting groups operating via intramolecular electron transfer: uncaging of GABA and tryptophan

2015 ◽  
Vol 6 (4) ◽  
pp. 2419-2426 ◽  
Author(s):  
Karolina A. Korzycka ◽  
Philip M. Bennett ◽  
Eduardo Jose Cueto-Diaz ◽  
Geoffrey Wicks ◽  
Mikhail Drobizhev ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Photoinduced Electron Transfer ◽  
High Sensitivity ◽  
Protecting Groups ◽  
Intramolecular Electron Transfer ◽  
Modular Approach ◽  
Two Photon ◽  
Photon Excitation ◽  
Two Photon Excitation

We present a modular approach to photo-labile protecting groups based on photoinduced electron transfer, providing high sensitivity to two-photon excitation.

scholarly journals Simultaneous Rapid Detection of Aflatoxin B1 and Ochratoxin A in Spices Using Lateral Flow Immuno-Chromatographic Assay

Foods ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2738
Author(s):  
Xue Zhao ◽  
Xindi Jin ◽  
Zhang Lin ◽  
Qi Guo ◽  
Bin Liu ◽  
...  
Keyword(s):  
Ochratoxin A ◽  
Aflatoxin B1 ◽  
High Performance ◽  
Simultaneous Detection ◽  
High Sensitivity ◽  
Strong Stability ◽  
Test Strip ◽  
Chromatography Analysis ◽  
Relative Standard ◽  
Strip Test

Spices are susceptible to contamination by aflatoxin B1 (AFB1) and ochratoxin A (OTA), which are both mycotoxins with high toxicity and carcinogenicity. In this study, we aimed to develop an immuno-chromatographic strip test for the simultaneous quantification of AFB1 and OTA in spices by spraying the coupled antigens AFB1–ovalbumin (AFB1–OVA) and OTA–ovalbumin (OTA–OVA) on a nitrocellulose membrane. The test strip had high sensitivity, good specificity, and strong stability. The detection limits of these two mycotoxins in Chinese prickly ash, pepper, chili, cinnamon, and aniseed were 5 μg/kg. The false positivity rate was 2%, and the false negativity rate was 0%. The maximum coefficient of variation was 4.28% between batches and 5.72% within batches. The average recovery rates of AFB1 and OTA in spices were 81.2–113.7% and 82.2–118.6%, respectively, and the relative standard deviation (RSD) was <10%. The actual sample detection was consistent with high performance liquid chromatography analysis results. Therefore, the immuno-chromatographic test strips developed in this study can be used for the on-site simultaneous detection of AFB1 and OTA in spices. This method would allow the relevant regulatory agencies to strengthen supervision in an effort to reduce the possible human health hazards of such contaminated spices.

scholarly journals The Mechanism Underlying the Extreme Sensitivity of Duck to Aflatoxin B1

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Kuntan Wu ◽  
Minjie Liu ◽  
Huanbin Wang ◽  
Shahid Ali Rajput ◽  
Yajing Shan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Aflatoxin B1 ◽  
High Sensitivity ◽  
Metabolic Activation ◽  
Cytochrome P450s ◽  
Economic Losses ◽  
Metabolic Detoxification ◽  
Glutathione S Transferases ◽  
Extreme Sensitivity ◽  
Mutual Conversion

Most metabolites of aflatoxin B1 (AFB1), especially exo-AFB1-8,9-epoxide (AFBO), can induce the production of reactive oxygen species (ROS) to vary degrees, causing oxidative stress and liver damage, and ultimately induce liver cancer in humans and animals. Duck is one of the most sensitive animals to AFB1, and severe economic losses are caused by duck AFB1 poisoning every year, but the exact mechanism of this high sensitivity is still unclear. This review highlights significant advances in our understanding of the AFB1 metabolic activation, like cytochrome P450s (CYPs), and AFB1 metabolic detoxification, like glutathione S-transferases (GSTs) in poultry. In addition, AFB1 may have other metabolic pathways in poultry, such as the mutual conversion of AFB1 and aflatoxicol (AFL) and the process of AFBO to produce AFB1-8,9-dihydrodiol (AFB1-dhd) and further metabolize it into detoxification substances. This review also summarized some exogenous regulatory substances that can alleviate AFB1-induced oxidative stress.

Interaction of Mycotoxins with Copper-Folin Reagent

1978 ◽  
Vol 41 (5) ◽  
pp. 370-372
Author(s):  
MOHAMED Y. SIRAJ ◽  
TIMOTHY D. PHILLIPS ◽  
A. WALLACE HAYES
Keyword(s):  
Linear Relationship ◽  
Aflatoxin B1 ◽  
Analytical Method ◽  
Cytochalasin B ◽  
High Sensitivity ◽  
Blue Color ◽  
Penicillic Acid ◽  
Toxin Concentration ◽  
Color Development ◽  
Positive Materials

To study the interference by mycotoxins in protein measurements, solutions of various concentrations of aflatoxin B1, citrinin, cytochalasin B, ochratoxin A, patulin, penicillic acid, rubratoxins A and B, T-2 toxin and zearalenone were tested for a positive copper-Folin reaction. Except for T-2 toxin, all mycotoxins tested developed a blue color, characteristic of proteins, in the copper-Folin solution. The Lowry reaction for the mycotoxins was linear over the concentration range of 20–100 μg/ml for most of these toxins. Aflatoxin B1 and citrinin at 2 μg/ml and zearalenone at 0.5 mg/ml developed a blue color in the copper-Folin solution. The linear relationship between color development and toxin concentration plus high sensitivity makes the copper-Folin reaction a potential analytical method for these toxins but only in the absence of protein or other copper-Folin positive materials.

scholarly journals Powerful Electron-Transfer Screen-Printed Platforms as Biosensing Tools: The Case of Uric Acid Biosensor

Biosensors ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 2
Author(s):  
Rocco Cancelliere ◽  
Alessio Di Tinno ◽  
Antonino Cataldo ◽  
Stefano Bellucci ◽  
Laura Micheli
Keyword(s):  
Electron Transfer ◽  
Uric Acid ◽  
Carbon Nanomaterials ◽  
Point Of Care ◽  
High Sensitivity ◽  
Transfer Constant ◽  
Peak Separation ◽  
Depth Study ◽  
Good Repeatability ◽  
Screen Printed

The use of carbon nanomaterials (CNMs) in sensors and biosensor realization is one of the hottest topics today in analytical chemistry. In this work, a comparative in-depth study, exploiting different nanomaterial (MWNT-CO2H, -NH2, -OH and GNP) modified screen-printed electrodes (SPEs), is reported. In particular, the sensitivity, the heterogeneous electron transfer constant (k0), and the peak-to-peak separation (ΔE) have been calculated and analyzed. After which, an electrochemical amperometric sensor capable of determining uric acid (UA), based on the nano-modified platforms previously characterized, is presented. The disposable UA biosensor, fabricated modifying working electrode (WE) with Prussian Blue (PB), carbon nanotubes, and uricase enzyme, showed remarkable analytical performances toward UA with high sensitivity (CO2H 418 μA μM−1 cm−2 and bare SPE-based biosensor, 33 μA μM−1 cm−2), low detection limits (CO2H 0.5 nM and bare SPE-based biosensors, 280 nM), and good repeatability (CO2H and bare SPE-based biosensors, 5% and 10%, respectively). Moreover, the reproducibility (RSD%) of these platforms in tests conducted for UA determination in buffer and urine samples results are equal to 6% and 15%, respectively. These results demonstrate that the nanoengineered electrode exhibited good selectivity and sensitivity toward UA even in the presence of interfering species, thus paving the way for its application in other bio-fluids such as simple point-of-care (POC) devices.

scholarly journals Recent Advances in the Aptamer-Based Electrochemical Biosensors for Detecting Aflatoxin B1 and Its Pertinent Metabolite Aflatoxin M1

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3256 ◽  
Author(s):  
Hadi Beitollahi ◽  
Somayeh Tajik ◽  
Zahra Dourandish ◽  
Kaiqiang Zhang ◽  
Quyet Van Le ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Food Quality ◽  
Aflatoxin B1 ◽  
High Sensitivity ◽  
Present Review ◽  
Aflatoxin M1 ◽  
Electrochemical Biosensors ◽  
Human Being ◽  
Main Metabolite ◽  
Reliable Procedure

The notable toxicological impacts of aflatoxin B1 (AFB1) and its main metabolite, aflatoxin M1 (AFM1), on human being health make the evaluation of food quality highly significant. Due to the toxicity of those metabolites—even very low content in foodstuffs—it is crucial to design a sensitive and reliable procedure for their detection. Electrochemical aptamer-based biosensors are considered the most encouraging option, based on multi-placed analysis, rapid response, high sensitivity and specificity. The present review specifically emphasizes the potential utilization of the electrochemical aptasensors for determining the AFM1 and AFB1 with different electrodes.

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