An amperometric bienzymatic cholesterol biosensor based on functionalized graphene modified electrode and its electrocatalytic activity towards total cholesterol determination

Talanta ◽  
2012 ◽  
Vol 99 ◽  
pp. 302-309 ◽  
Author(s):  
Revanasiddappa Manjunatha ◽  
Gurukar Shivappa Suresh ◽  
Jose Savio Melo ◽  
Stanislaus F. D'Souza ◽  
Thimmappa Venkatarangaiah Venkatesha
Keyword(s):  
Total Cholesterol ◽  
Modified Electrode ◽  
Electrocatalytic Activity ◽  
Functionalized Graphene ◽  
Cholesterol Biosensor ◽  
Cholesterol Determination

scholarly journals An Electrochemical Cholesterol Biosensor Based on A CdTe/CdSe/ZnSe Quantum Dots—Poly (Propylene Imine) Dendrimer Nanocomposite Immobilisation Layer

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3368 ◽  
Author(s):  
Kefilwe Mokwebo ◽  
Oluwatobi Oluwafemi ◽  
Omotayo Arotiba
Keyword(s):  
Quantum Dots ◽  
Modified Electrode ◽  
Cholesterol Oxidase ◽  
Shell Growth ◽  
Modified Electrodes ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Poly Propylene ◽  
Cholesterol Biosensor

We report the preparation of poly (propylene imine) dendrimer (PPI) and CdTe/CdSe/ZnSe quantum dots (QDs) as a suitable platform for the development of an enzyme-based electrochemical cholesterol biosensor with enhanced analytical performance. The mercaptopropionic acid (MPA)-capped CdTe/CdSe/ZnSe QDs was synthesized in an aqueous phase and characterized using photoluminescence (PL) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, transmission electron microscopy (TEM), X-ray power diffraction (XRD), energy dispersive X-ray (EDX) spectroscopy. The absorption and emission maxima of the QDs red shifted as the reaction time and shell growth increased, indicating the formation of CdTe/CdSe/ZnSe QDs. PPI was electrodeposited on a glassy carbon electrode followed by the deposition (by deep coating) attachment of the QDs onto the PPI dendrimer modified electrode using 1-Ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC), and N-hydroxysuccinimide (NHS) as a coupling agent. The biosensor was prepared by incubating the PPI/QDs modified electrode into a solution of cholesterol oxidase (ChOx) for 6 h. The modified electrodes were characterized by voltammetry and impedance spectroscopy. Since efficient electron transfer process between the enzyme cholesterol oxidase (ChOx) and the PPI/QDs-modified electrode was achieved, the cholesterol biosensor (GCE/PPI/QDs/ChOx) was able to detect cholesterol in the range 0.1–10 mM with a detection limit (LOD) of 0.075 mM and sensitivity of 111.16 μA mM−1 cm−2. The biosensor was stable for over a month and had greater selectivity towards the cholesterol molecule.

scholarly journals Synthesis of well-dispersive 2.0 nm Pd–Pt bimetallic nanoclusters supported on β-cyclodextrin functionalized graphene with excellent electrocatalytic activity

RSC Advances ◽  
2017 ◽  
Vol 7 (4) ◽  
pp. 1947-1955 ◽  
Author(s):  
Xin Ran ◽  
Long Yang ◽  
Qing Qu ◽  
Shunling Li ◽  
Ying Chen ◽  
...  
Keyword(s):  
Electrocatalytic Activity ◽  
Reduction Method ◽  
Functionalized Graphene ◽  
Bimetallic Nanoclusters

Illustration for the preparation of the Pd–Pt@β-CD-RGO nanohybrid using an in situ reduction method.

Facile synthesized SnO 2 decorated functionalized graphene modified electrode for sensitive determination of daidzein

Talanta ◽  
2017 ◽  
Vol 168 ◽  
pp. 1-9 ◽  
Author(s):  
Yamin Fu ◽  
Lu Wang ◽  
Yinghao Duan ◽  
Lina Zou ◽  
Baoxian Ye
Keyword(s):  
Modified Electrode ◽  
Functionalized Graphene ◽  
Sensitive Determination

An Electrochemically Reduced Copper/Reduced Graphene Oxide Film Modified Electrode for Sensitive Non-Enzymatic Glucose Detection in Human Serum

2021 ◽  
Author(s):  
Sopit Phetsang ◽  
Pinit Kidkhunthod ◽  
Narong Chanlek ◽  
Jaroon Jakmunee ◽  
Pitchaya Mungkornasawakul ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Human Serum ◽  
Reduced Graphene Oxide ◽  
Modified Electrode ◽  
Electrocatalytic Activity ◽  
Glucose Sensor ◽  
Electrochemical Sensors ◽  
High Sensitivity ◽  
Detection Range ◽  
Reduced Graphene

Abstract Numerous studies suggest that modification with functional nanomaterials can enhance the electrode electrocatalytic activity, sensitivity, and selectivity of the electrochemical sensors. Here, a highly sensitive and cost-effective disposable non-enzymatic glucose sensor based on copper(II)/reduced graphene oxide modified screen-printed carbon electrode is demonstrated. Facile fabrication of the developed sensing electrodes is carried out by the adsorption of copper(II) onto graphene oxide modified electrode, then following the electrochemical reduction. The proposed sensor illustrates good electrocatalytic activity toward glucose oxidation with a wide linear detection range from 0.10 mM to 12.5 mM, low detection limit of 65 µM, and high sensitivity of 172 µA mM− 1 cm− 2 along with satisfactory anti-interference ability, reproducibility, stability, and the acceptable recoveries for the detection of glucose in a human serum sample (95.6–106.4%). The copper(II)/reduced graphene oxide based sensor with the superior performances is a great potential for the quantitation of glucose in real samples.

scholarly journals Highly Sensitive Detection of Dopamine at Ionic Liquid Functionalized RGO/ZIF-8 Nanocomposite-Modified Electrode

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Lei Cheng ◽  
Youjun Fan ◽  
Xingcan Shen ◽  
Hong Liang
Keyword(s):  
Ionic Liquid ◽  
Modified Electrode ◽  
Electrocatalytic Activity ◽  
Electrochemical Impedance ◽  
Modified Electrodes ◽  
Differential Pulse ◽  
Zeolitic Imidazolate Framework ◽  
Response Range ◽  
Highly Sensitive ◽  
Highly Sensitive Detection

A hybrid and hierarchical nanocomposite was successfully prepared by the growth of zeolitic imidazolate framework-8 (ZIF-8) on the template of ionic liquid (IL, [Bmim][BF4]) functionalized reduced graphene oxide (IL-RGO). The structure and morphology of the IL-RGO/ZIF-8 nanocomposite were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FTIR), and Raman spectroscopy. The results showed that RGO sheets were refrained from restacking by IL, and ZIF-8 nanoparticles grew well on the surface of IL-RGO. Owing to the synergistic effect from large surface area and excellent electrocatalytic activity of ZIF-8 and great electrical conductivity of IL-RGO, a highly sensitive sensor for dopamine (DA) can be obtained. IL-RGO/ZIF-8-modified electrode exhibits good electrocatalytic activity and electroconductive properties towards DA which were investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). Compared with bare or IL-RGO-modified electrodes, the IL-RGO/ZIF-8-modified electrode effectively depressed the oxidation overpotential of DA. The linear response range of DA was from 1.0×10−7 to 1.0×10−4 mol/L with a low detection of limit 3.5×10−8 mol/L. In addition, the sensor was shown to provide satisfactory stability for the determination of DA.

Method for Fully Automated Determination of Total Cholesterol in Blood Serum, Including Saponification and Extraction

1968 ◽  
Vol 14 (10) ◽  
pp. 960-966 ◽  
Author(s):  
J van der Honing ◽  
C C Saarloos ◽  
J Stip
Keyword(s):  
Carbon Tetrachloride ◽  
Blood Serum ◽  
Total Cholesterol ◽  
Standard Error ◽  
New Method ◽  
Automated Method ◽  
The Relationship ◽  
Cholesterol Determination ◽  
Automated Determination

Abstract A fully automated method has been developed for the determination of total cholesterol in blood serum, using the AutoAnalyzer system. According to the new method, based on the cholesterol determination of Abell et al. (1), the serum sample is saponified and subsequently extracted with carbon tetrachloride. After treatment with Liebermann-Burchard reagent, the amount of cholesterol is determined at 630 nm. The method can be used for free and esterified cholesterol because saponification is carried out. The relationship between the new method and that of Abell et al. is linear. The correlation coefficient is 0.98 and the standard error 1.5%. According to the new method, 30 samples can be analyzed per hour.

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