scholarly journals Rubpy Dye-Doped Silica Nanoparticles as Signal Reporter in a Dot Fluorescence Immunoassay Strip

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Nualrahong Thepwiwatjit ◽  
Aree Thattiyaphong ◽  
Pichet Limsuwan ◽  
Kooranee Tuitemwong ◽  
Pravate Tuitemwong
Keyword(s):  
Silica Nanoparticles ◽  
Uv Light ◽  
Spherical Shape ◽  
High Sensitivity ◽  
Average Diameter ◽  
Test Strip ◽  
Test Sample ◽  
Positive Sample ◽  
Rapid Screening ◽  
Fluorescence Immunoassay

This paper describes an application of Rubpy dye-doped silica nanoparticles (RSNPs) as signal reporter in a dot fluorescence immunoassay strip for rapid screening ofVibrio choleraO1 (VCO1). These nanoparticles have a spherical shape with an average diameter of 45 nm. They appear luminescent orange when excited with a 312 nm UV lamp. Based on the sandwich immunoassay principle, a test strip was made of a nitrocellulose membrane dotted with monoclonal antibodies against VCO1 as analyte capture molecules. After introducing a test sample, followed by polyclonal rabbit anti-VCO1 antibody conjugated RSNPs as detection reporters and one washing step, the presence or absence of the target bacteria could be identified under UV light by naked eyes. A positive sample would signal a bright orange dot on the strip. The proposed assay had a detection limit of4.3×103 cfu/mL and was successfully applied as a rapid screening test for VCO1 in food samples with high sensitivity, specificity, and accuracy.

Synthesis and Photocatalytic Properties of Three-Dimensional Mesoporous Titanium Dioxide

NANO ◽  
2021 ◽  
Vol 16 (09) ◽  
Author(s):  
Xiao Ye ◽  
Lei Xu ◽  
Zi-Yan Li ◽  
Rui-Qi Gang ◽  
Yi Xia ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Flue Gas ◽  
Photocatalytic Oxidation ◽  
Ph Value ◽  
Uv Light ◽  
Three Dimensional ◽  
Spherical Shape ◽  
Average Diameter ◽  
Strong Light ◽  
Mesoporous Titanium Dioxide

The three-dimensional (3D) mesoporous titanium dioxide (TiO2) was synthesized by microwave-assisted hydrothermal method, using titanium sulfate as titanium source and urea to adjust pH value. Its structure and photocatalytic oxidation properties were studied. The results show that the TiO2 particles have a 3D mesoporous structure, uniform distribution and spherical shape, the average diameter is about 0.67[Formula: see text][Formula: see text]m. These properties provide strong light adsorption, high specific surface area, which increases the active site of the photocatalyst, porosity can also enhance the ability of the material to adsorb pollutants, thus has better stability. It was applied to photocatalytic degradation of 10[Formula: see text]mg/L rhodamine B (RhB) solution. After 80[Formula: see text]min of irradiation under 420[Formula: see text]nm ultraviolet (UV) light, the degradation rate of RhB reached more than 90%. In addition, it also provided an excellent photocatalytic efficiency of removing Hg0 in simulated flue gas. The removal efficiency could still reach over 86% after 40 h, which could be used in the treatment of heavy metal pollutants such as metallurgical flue gas.

DETERMINATION OF A SUITABLE CONDITION OF GRAFT COPOLYMERIZATION OF VINYLTRIETHOXYSILANE ONTO NR TO FORM NANOMATRIX STRUCTURE

2018 ◽  
Vol 91 (4) ◽  
pp. 767-775 ◽  
Author(s):  
Yuanbing Zhou ◽  
Yoshimasa Yamamoto ◽  
Seiichi Kawahara
Keyword(s):  
Silica Nanoparticles ◽  
Graft Copolymerization ◽  
Monomer Concentration ◽  
Minor Component ◽  
Suitable Condition ◽  
Average Diameter ◽  
Silica Matrix ◽  
Rubber Particles ◽  
Hydrolysis And Condensation ◽  
Nanomatrix Structure

ABSTRACT Graft copolymerization of vinyltriethoxysilane (VTES) onto NR particles in the latex stage is a unique reaction, since it occurs together with hydrolysis and condensation of the triethoxysilane group of VTES to form a colloidal silica linking to the rubber particles. These reactions may contribute to the formation of a silica nanomatrix structure that consists of a dispersoid of rubber particles as the major component and a silica matrix as the minor component. Here, the graft copolymerization of VTES followed by hydrolysis and condensation is investigated to determine a suitable condition to prepare NR with a silica nanomatrix structure. The mechanical properties of the resulting graft copolymer are discussed in relation to the morphology, silica content, and gel content of the rubber. Based on morphological observations, NR particles with an average diameter of approximately 1 μm are well dispersed in a nanomatrix consisting of silica nanoparticles. The thickness of the silica nanomatrix increases as the monomer concentration increases, and a long incubation time generates large silica nanoparticles. The tensile strength and viscoelastic properties are significantly improved by forming the silica nanomatrix structure, with its continuous structure that prevents the NR particles from merging.

scholarly journals Persistent luminescence nanoparticles for cancer theranostics application

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Nian Liu ◽  
Xiao Chen ◽  
Xia Sun ◽  
Xiaolian Sun ◽  
Junpeng Shi
Keyword(s):  
Uv Light ◽  
Combined Therapy ◽  
Tumor Therapy ◽  
High Sensitivity ◽  
Persistent Luminescence ◽  
Therapeutic Drugs ◽  
High Penetration ◽  
Recent Developments ◽  
Cancer Theranostics

AbstractPersistent luminescence nanoparticles (PLNPs) are unique optical materials that emit afterglow luminescence after ceasing excitation. They exhibit unexpected advantages for in vivo optical imaging of tumors, such as autofluorescence-free, high sensitivity, high penetration depth, and multiple excitation sources (UV light, LED, NIR laser, X-ray, and radiopharmaceuticals). Besides, by incorporating other functional molecules, such as photosensitizers, photothermal agents, or therapeutic drugs, PLNPs are also widely used in persistent luminescence (PersL) imaging-guided tumor therapy. In this review, we first summarize the recent developments in the synthesis and surface functionalization of PLNPs, as well as their toxicity studies. We then discuss the in vivo PersL imaging and multimodal imaging from different excitation sources. Furthermore, we highlight PLNPs-based cancer theranostics applications, such as fluorescence-guided surgery, photothermal therapy, photodynamic therapy, drug/gene delivery and combined therapy. Finally, future prospects and challenges of PLNPs in the research of translational medicine are also discussed.

scholarly journals Linking a rapid throughput plate-assay with high-sensitivity stable-isotope label LCMS quantification permits the identification and characterisation of low β-L-ODAP grass pea lines

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Peter M. F. Emmrich ◽  
Martin Rejzek ◽  
Lionel Hill ◽  
Paul Brett ◽  
Anne Edwards ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Internal Standard ◽  
High Sensitivity ◽  
Spectrophotometric Assay ◽  
Rapid Screening ◽  
Grass Pea ◽  
Stable Isotope Label ◽  
Tissue Samples ◽  
Plate Assay ◽  
Accurate Quantification

Abstract Background Grass pea (Lathyrus sativus) is an underutilised crop with high tolerance to drought and flooding stress and potential for maintaining food and nutritional security in the face of climate change. The presence of the neurotoxin β-L-oxalyl-2,3-diaminopropionic acid (β-L-ODAP) in tissues of the plant has limited its adoption as a staple crop. To assist in the detection of material with very low neurotoxin toxin levels, we have developed two novel methods to assay ODAP. The first, a version of a widely used spectrophotometric assay, modified for increased throughput, permits rapid screening of large populations of germplasm for low toxin lines and the second is a novel, mass spectrometric procedure to detect very small quantities of ODAP for research purposes and characterisation of new varieties. Results A plate assay, based on an established spectrophotometric method enabling high-throughput ODAP measurements, is described. In addition, we describe a novel liquid chromatography mass spectrometry (LCMS)-based method for β-L-ODAP-quantification. This method utilises an internal standard (di-13C-labelled β-L-ODAP) allowing accurate quantification of β-L-ODAP in grass pea tissue samples. The synthesis of this standard is also described. The two methods are compared; the spectrophotometric assay lacked sensitivity and detected ODAP-like absorbance in chickpea and pea whereas the LCMS method did not detect any β-L-ODAP in these species. The LCMS method was also used to quantify β-L-ODAP accurately in different tissues of grass pea. Conclusions The plate-based spectrophotometric assay allows quantification of total ODAP in large numbers of samples, but its low sensitivity and inability to differentiate α- and β-L-ODAP limit its usefulness for accurate quantification in low-ODAP samples. Coupled to the use of a stable isotope internal standard with LCMS that allows accurate quantification of β-L-ODAP in grass pea samples with high sensitivity, these methods permit the identification and characterisation of grass pea lines with a very low ODAP content. The LCMS method is offered as a new ‘gold standard’ for β-L-ODAP quantification, especially for the validation of existing and novel low- and/or zero-β-L-ODAP genotypes.

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 Inverse problem for tripotential measures in the study of buried cavities

1996 ◽  
Vol 39 (1) ◽  
Author(s):  
P. Cosentino ◽  
D. Luzio ◽  
R. Martorana
Keyword(s):  
Apparent Resistivity ◽  
Random Noise ◽  
Source Parameters ◽  
Spherical Shape ◽  
Average Diameter ◽  
Unknown Parameters ◽  
Fundamental Parameters ◽  
Spherical Models ◽  
Source Models ◽  
Biased Estimates

This paper presents a solution to the inverse electrical problem for the interpretation of apparent resistivity anomalies due to empty buried cavities of quasi-spherical shape when tripotential measures are carried out. The anomalies of the apparent resistivities ra,rb andrg,and the composed resistivitiesrmand rt were previously calculated for a sufficient class of spherical models of resistivity anomalies. Then, for the whole class of models, some functionals of spatial distribution of the apparent and composed resistivity were identified and analyzed. They represent the average characteristics of the anomalies and, depending in a simple way on the fundamental parameters of the sources of the anomalies (average diameter and depth), they allow reliable estimates to be determined. Among the studied functionals, those allowing the most stable and less biased estimates of the anomaly source parameters are identified by numerical simulations with random noise perturbed data. Finally the trend of standard deviation and bias of the estimates of the unknown parameters were analyzed by varying the source models and the set of functionals used for the inversion.

scholarly journals Facile Hydrothermal Synthesis of SnO2 Nanospheres as Photocatalysts

2017 ◽  
Vol 2017 ◽  
pp. 1-6
Author(s):  
Wenquan Hu ◽  
Xiaoguang Yuan
Keyword(s):  
Methylene Blue ◽  
Methyl Orange ◽  
Organic Dyes ◽  
Uv Light ◽  
Average Diameter ◽  
Potential Candidate ◽  
Wastewater Purification ◽  
Uv Light Irradiation ◽  
Degradation Rates ◽  
Photocatalytic Activities

Large amounts of SnO2 nanospheres are successfully synthesized through a simple and effective hydrothermal method. The as-synthesized products consist of numerous small SnO2 nanocrystals with an average diameter of 40 nm. The as-prepared SnO2 nanospheres are further used as the photocatalysts for photodegrading several organic dyes (methylene blue, methyl orange, Congo red, and rhodamine B) under UV light irradiation. The photocatalytic results show that the as-synthesized SnO2 nanospheres possess high photocatalytic activities. Compared with the degradation rates of other dyes, that of methylene blue reaches 98.5% by 30 min irradiation. It reveals that the as-prepared product might be potential candidate in wastewater purification.

scholarly journals Preparation Method of Spherical and Monocrystalline Aluminum Powder

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 375 ◽  
Author(s):  
Mateusz Skalon ◽  
Marek Hebda ◽  
Ricardo Buzolin ◽  
Gernot Pottlacher ◽  
Stefan Mitsche ◽  
...  
Keyword(s):  
Silica Nanoparticles ◽  
Aluminum Powder ◽  
Electron Backscatter Diffraction ◽  
High Surface ◽  
Spherical Shape ◽  
Production Method ◽  
Processing Temperature ◽  
Powder Preparation ◽  
New Production ◽  
Aluminum Particles

This paper presents a new production method for a spherical and monocrystalline aluminum powder. Aluminum powder of irregular particle shapes was mixed with silica nanoparticles and heated to a temperature above the melting point of aluminum. Due to its molten state, high surface tension, and poor wettability, the aluminum particles were transformed into liquid and spherical droplets separated by silica nanoparticles. The spherical shape was then retained when the aluminum particles solidified. The influence of the processing temperature on the particle shape, phase composition, and microstructure was investigated. Moreover, calorimetric, X-ray diffraction, grain size, and scanning electron microscopy with electron backscatter diffraction (SEM-EBSD) measurements of the particles’ microstructure are presented. It is proven that, by this means, a spherical and monocrystalline aluminum powder can be efficiently created directly from an air-atomized irregular powder. The observed phenomenon of particles becoming round is of great importance, especially when considering powder preparation for powder-based additive manufacturing processes.

scholarly journals High Sensitivity of NO Gas Sensors Based on Novel Ag-Doped ZnO Nanoflowers Enhanced with a UV Light-Emitting Diode

ACS Omega ◽  
2018 ◽  
Vol 3 (10) ◽  
pp. 13798-13807 ◽  
Author(s):  
You-Ting Tsai ◽  
Shoou-Jinn Chang ◽  
Liang-Wen Ji ◽  
Yu-Jen Hsiao ◽  
I-Tseng Tang ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Uv Light ◽  
Light Emitting Diode ◽  
High Sensitivity ◽  
Light Emitting ◽  
Doped Zno

scholarly journals Co-doped MnFe2O4 nanoparticles: magnetic anisotropy and interparticle interactions

2019 ◽  
Vol 10 ◽  
pp. 856-865 ◽  
Author(s):  
Bagher Aslibeiki ◽  
Parviz Kameli ◽  
Hadi Salamati ◽  
Giorgio Concas ◽  
Maria Salvador Fernandez ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Anisotropy ◽  
Structural Changes ◽  
Spherical Shape ◽  
Average Diameter ◽  
Cobalt Doping ◽  
Interparticle Interactions ◽  
Co Doping ◽  
Particle Anisotropy ◽  
Interaction Regime

The effect of cobalt doping on the magnetic properties of Mn1− x Co x Fe2O4 nanoparticles was investigated. All samples consist of ensembles of nanoparticles with a spherical shape and average diameter of about 10 nm, showing small structural changes due to the substitution. Besides having the same morpho-structural properties, the effect of the chemical composition, i.e., the amount of Co doping, produces marked differences on the magnetic properties, especially on the magnetic anisotropy, with evident large changes in the coercive field. Moreover, Co substitution has a profound effect on the interparticle interactions, too. A dipolar-based interaction regime is detected for all samples; in addition, the intensity of the interactions shows a possible relation with the single particle anisotropy. Finally, the sample with the strongest interaction regime shows a superspin glass state confirmed by memory effect dynamics.

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