Self-Polymerized Dopamine-Decorated Au NPs and Coordinated with Fe-MOF as a Dual Binding Sites and Dual Signal-Amplifying Electrochemical Aptasensor for the Detection of CEA

2020 ◽  
Vol 12 (5) ◽  
pp. 5500-5510 ◽  
Author(s):  
Jifan Li ◽  
Lei Liu ◽  
Yongjian Ai ◽  
Yang Liu ◽  
Hongbin Sun ◽  
...  
Keyword(s):  
Binding Sites ◽  
Electrochemical Aptasensor ◽  
Au Nps

Detection of Cytochrome C Using a Selective and Sensitive Methylene Blue-Based Electrochemical Aptasensor

2020 ◽  
pp. 1-8
Author(s):  
Mohadeseh Safaei ◽  
Hadi Beitollahi ◽  
Masoud Reza Shishehbore
Keyword(s):  
Methylene Blue ◽  
Detection Limit ◽  
Cytochrome C ◽  
Au Nanoparticles ◽  
Sandwich Immunoassay ◽  
Electrochemical Aptasensor ◽  
Au Nps ◽  
Peak Current ◽  
Aptamer Probe

The present research aimed to detect the cytochrome C using methylene blue (MB)-anchored ultrasensitive electrochemical aptamer conjugated with Au nanoparticles (NPs), as a new electrochemical sandwich immunoassay. Aptamer-Au NPs could act as sandwich amplification element and MB accumulation reagent. According to the results, the interaction of MB and guanine occurred strongly on aptamer probe. After switching the aptamer structure by the cytochrome C, the MB- labeled aptamer probe was forced to detach from the sensing interface. Moreover, the cytochrome C concentrations (0.05-10.0 µM) with 5.0 nM detection limit reduced linearly the peak current of MB. In conclusion, an acceptable selectivity was observed for the constructed aptasensor in detecting the cytochrome C.

Development of Ochratoxin A Aptasensor Based on Au Nanoparticles@g-C3N4

2020 ◽  
Vol 16 (8) ◽  
pp. 1296-1303
Author(s):  
Xiaojuan Xia ◽  
Mei Li ◽  
Min Wang ◽  
Meng-Qiao Gu ◽  
Kuan-Neng Chi ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Ochratoxin A ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Carbon Nitride ◽  
Au Nanoparticles ◽  
Quantitative Detection ◽  
Carbon Electrode ◽  
Electrochemical Aptasensor ◽  
Au Nps

Ochratoxin is teratogenic, carcinogenic and immunotoxic to humans. It contains ochratoxin in many foods, so the detection of ochratoxin in food is particularly important. In this paper, gold nanoparticles (Au NPs)@g-C3N4 composite was synthesized by loading Au NPs on carbon nitride material, and it was immobilized on the surface of glassy carbon electrode by chitosan (Chit) as the substrate of electrochemical aptasensors. An ochratomycin A electrochemical aptasensor was constructed by hybridizing DNA1 and ochratoxin A (OTA) aptamers. The resulting hybrid strands were immobilized on the substrate of glassy carbon electrode. Electrochemical alternating current impedance (EIS) was used to detect the impedance value of the aptasensor when incubating different concentrations of OTA. The impedance value is inversely ratio to the concentration of OTA, achieving quantitative detection of OTA. The aptasensor can detect OTA with a linear range of 0.5–100 ng/mL, the linear correlation coefficient is 0.9506, and the detection limit is 0.167 ng/mL. This aptasensor provides a novel and efficient method for detecting OTA.

Facile preparation of an electrochemical aptasensor based on Au NPs/graphene sponge for detection of homocysteine

2021 ◽  
pp. 149735
Author(s):  
Xiao-Hong Wen ◽  
Xue-Feng Zhao ◽  
Bo-Fang Peng ◽  
Kai-Ping Yuan ◽  
Xiao-Xi Li ◽  
...  
Keyword(s):  
Electrochemical Aptasensor ◽  
Au Nps ◽  
Graphene Sponge ◽  
Facile Preparation

Monolayer protected gold nanoparticles with metal-ion binding sites: functional systems for chemosensing applications

2015 ◽  
Vol 51 (49) ◽  
pp. 9922-9931 ◽  
Author(s):  
C. Pezzato ◽  
S. Maiti ◽  
J. L.-Y. Chen ◽  
A. Cazzolaro ◽  
C. Gobbo ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Metal Ions ◽  
Binding Sites ◽  
Metal Ion ◽  
Ion Binding ◽  
Metal Ion Binding ◽  
Au Nps ◽  
Functional Systems ◽  
Ion Binding Sites ◽  
Metal Ion Binding Sites

Au NPs containing binding sites for metal ions in the monolayer are attractive components of sensing assays.

Conformation of Ribosomes from Escherichia Coli

1974 ◽  
Vol 32 ◽  
pp. 210-211
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Binding Sites ◽  
Ribosomal Proteins ◽  
Fluorescent Dyes ◽  
Protein Biosynthesis ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Dimensional Structure ◽  
Complete Understanding ◽  
And Function

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.

Electron Probe Analysis of Muscle

1982 ◽  
Vol 40 ◽  
pp. 398-401
Author(s):  
A. V. Somlyo ◽  
H. Shuman ◽  
A. P. Somlyo
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Resting State ◽  
Binding Sites ◽  
Electron Probe ◽  
Frog Skeletal Muscle ◽  
Electron Probe Analysis ◽  
Probe Analysis

Electron probe analysis of frozen dried cryosections of frog skeletal muscle, rabbit vascular smooth muscle and of isolated, hyperpermeab1 e rabbit cardiac myocytes has been used to determine the composition of the cytoplasm and organelles in the resting state as well as during contraction. The concentration of elements within the organelles reflects the permeabilities of the organelle membranes to the cytoplasmic ions as well as binding sites. The measurements of [Ca] in the sarcoplasmic reticulum (SR) and mitochondria at rest and during contraction, have direct bearing on their role as release and/or storage sites for Ca in situ.

Sites of Insulin Action Using Ferritin Labeling

1971 ◽  
Vol 29 ◽  
pp. 540-541
Author(s):  
Burton B. Silver ◽  
Ronald S. Nelson
Keyword(s):  
Electron Microscopy ◽  
Binding Sites ◽  
Anterior Pituitary ◽  
Insulin Action ◽  
Diabetic Rats ◽  
Insulin Antibody ◽  
Fat Pad ◽  
Target Organs ◽  
Uranium Salts ◽  
Sugar Levels

Some investigators feel that insulin does not enter cells but exerts its influence in some manner on the cell surface. Ferritin labeling of insulin and insulin antibody was used to determine if binding sites of insulin to specific target organs could be seen with electron microscopy.Alloxanized rats were considered diabetic if blood sugar levels were in excess of 300 mg %. Test reagents included ferritin, ferritin labeled insulin, and ferritin labeled insulin antibody. Target organs examined were were diaphragm, kidney, gastrocnemius, fat pad, liver and anterior pituitary. Reagents were administered through the left common carotid. Survival time was at least one hour in test animals. Tissue incubation studies were also done in normal as well as diabetic rats. Specimens were fixed in gluteraldehyde and osmium followed by staining with lead and uranium salts. Some tissues were not stained.

Fluorescence ratio imaging of dynamic intracellular ionic signals

1988 ◽  
Vol 46 ◽  
pp. 42-43
Author(s):  
R. Y. Tsien ◽  
A. Minta ◽  
M. Poenie ◽  
J.P.Y. Kao ◽  
A. Harootunian
Keyword(s):  
Binding Sites ◽  
Living Cells ◽  
Molecular Engineering ◽  
Ph Indicators ◽  
Highly Sensitive ◽  
Fluorescence Ratio Imaging ◽  
Ratio Imaging ◽  
Technical Advances ◽  
Indicator Dyes ◽  
Fluorescein Dyes

Recent technical advances now enable the continuous imaging of important ionic signals inside individual living cells with micron spatial resolution and subsecond time resolution. This methodology relies on the molecular engineering of indicator dyes whose fluorescence is strong and highly sensitive to ions such as Ca2+, H+, or Na+, or Mg2+. The Ca2+ indicators, exemplified by fura-2 and indo-1, derive their high affinity (Kd near 200 nM) and selectivity for Ca2+ to a versatile tetracarboxylate binding site3 modeled on and isosteric with the well known chelator EGTA. The most commonly used pH indicators are fluorescein dyes (such as BCECF) modified to adjust their pKa's and improve their retention inside cells. Na+ indicators are crown ethers with cavity sizes chosen to select Na+ over K+: Mg2+ indicators use tricarboxylate binding sites truncated from those of the Ca2+ chelators, resulting in a more compact arrangement of carboxylates to suit the smaller ion.

Lectin Binding Studies on RNA Tumor Virus-Infected Cells

1975 ◽  
Vol 33 ◽  
pp. 326-327
Author(s):  
D. C. Hixson
Keyword(s):  
Binding Sites ◽  
Lectin Binding ◽  
Culture Conditions ◽  
3T3 Cells ◽  
Binding Studies ◽  
Con A ◽  
Microscopic Studies ◽  
Tumor Virus ◽  
Infected Cells ◽  
Cell Culture Conditions

The abilities of plant lectins to preferentially agglutinate malignant cells and to bind to specific monosaccharide or oligosaccharide sequences of glycoproteins and glycolipids make them a new and important biochemical probe for investigating alterations in plasma membrane structure which may result from malignant transformation. Electron and light microscopic studies have demonstrated clustered binding sites on surfaces of SV40-infected or tryp- sinized 3T3 cells when labeled with concanavalin A (con A). No clustering of con A binding sites was observed in normal 3T3 cells. It has been proposed that topological rearrangement of lectin binding sites into clusters enables con A to agglutinate SV40-infected or trypsinized 3T3 cells (1). However, observations by other investigators have not been consistent with this proposal (2) perhaps due to differences in reagents used, cell culture conditions, or labeling techniques. The present work was undertaken to study the lectin binding properties of normal and RNA tumor virus-infected cells and their associated viruses using lectins and ferritin-conjugated lectins of five different specificities.

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