scholarly journals Glucose biosensor based on entrapment of glucose oxidase and myoglobin in silica gel by the sol-gel method

2005 ◽  
Vol 19 (2) ◽  
pp. 119-126 ◽  
Author(s):  
Mohammed A. Zaitoun
Keyword(s):  
Hydrogen Peroxide ◽  
Glucose Oxidase ◽  
Glucose Concentration ◽  
Decay Curve ◽  
Sol Gel ◽  
Porous Silica ◽  
Glucose Biosensor ◽  
Negative Peak ◽  
Before And After ◽  
Porous Silica Glass

A spectrophotometric method is presented to determine glucose employing the sol-gel technique. Myoglobin (Mb) and glucose oxidase are encapsulated in a transparent and porous silica glass. The produced gel (xerogel) is then immersed in water where increments of glucose are added to the solution with stirring; glucose diffuses into the sol-gel glass pores and a series of reactions take place. Glucose is first oxidized by glucose oxidase and oxygen to gluconate and hydrogen peroxide is generated. The liberated hydrogen peroxide oxidizes the Mb heme (Fe2+into Fe3+). The higher is the glucose concentration added, the more is the H2O2generated, and the more is the Mb oxidation (Fe2+to Fe3+) and as a result the higher is the absorbance at 400 nm (negative peak, lower absorbance value). All measurements are performed at this wavelength (400 nm), the negative peak obtained by subtracting the absorption spectra of Mb before and after oxidation. Measuring the slope of the absorbance decay versus time at 400 nm monitors increments of added glucose. Each glucose concentration has an accompanying unique decay curve with a unique slope. The higher is the glucose concentration; the steeper is the decay curve (higher slope value). The calibration curve was linear up to 40 mM.

Encapsulation and Reactivity of Proteins in Optically Transparent Porous Silicate Glasses Prepared by the Sol-Gel Method

1992 ◽  
Vol 277 ◽  
Author(s):  
Stacey A. Yamanaka ◽  
Lisa M. Ellerby ◽  
Ester H. Lan ◽  
Clinton R. Nishida ◽  
Fumito Nishida ◽  
...  
Keyword(s):  
Glucose Oxidase ◽  
Sol Gel ◽  
Porous Silica ◽  
Spectroscopic Properties ◽  
Visible Absorption ◽  
Copper Zinc Superoxide Dismutase ◽  
Optically Transparent ◽  
Copper Zinc ◽  
Porous Silica Glass ◽  
Glass Matrices

ABSTRACTCopper-zinc superoxide dismutase (CuZnSOD), myoglobin, hemoglobin and glucose oxidase are encapsulated in stable, optically transparent, porous, silica glass matrices synthesized under mild conditions using novel sol-gel synthetic techniques. The biomolecules retain their characteristic reactivities and spectroscopic properties. The porous glasses allow transport of small molecules into and out of the glasses at reasonable rates but retain the protein molecules within the pores. The chemical reactions of the immobilized proteins are monitored by means of changes in their visible absorption spectra. Four encapsulated proteins are studied: CuZnSOD reacts with CN−; metmyoglobin is reduced to its deoxy form and then reacts with O2 to make the oxy form and CO to make the carbonyl form; methemoglobin is reduced to its deoxy form and reacted with CO to make the carbonyl form; and glucose oxidase is reacted with glucose to make gluconic acid.

scholarly journals Development of a Ratiometric Fluorescent Glucose Sensor Using an Oxygen-Sensing Membrane Immobilized with Glucose Oxidase for the Detection of Glucose in Tears

Biosensors ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 86 ◽  
Author(s):  
Hong Dinh Duong ◽  
Ok-Jae Sohn ◽  
Jong Il Rhee
Keyword(s):  
Glucose Oxidase ◽  
Glucose Concentration ◽  
Glucose Sensor ◽  
Oxygen Sensing ◽  
Sol Gel ◽  
Glucose Sensing ◽  
Glucose Biosensor ◽  
Detection Range ◽  
Fluorescence Measurements ◽  
Sensing Membrane

Glucose concentration is an important parameter in biomedicine since glucose is involved in many metabolic pathways in organisms. Many methods for glucose detection have been developed for use in various applications, particularly in the field of healthcare in diabetics. In this study, ratiometric fluorescent glucose-sensing membranes were fabricated based on the oxygen levels consumed in the glucose oxidation reaction under the catalysis of glucose oxidase (GOD). The oxygen concentration was measured through the fluorescence quenching effect of an oxygen-sensitive fluorescent dye like platinum meso-tetra (pentafluorophenyl) porphyrin (PtP) by oxygen molecules. Coumarin 6 (C6) was used as a reference dye in the ratiometric fluorescence measurements. The glucose-sensing membrane consisted of two layers: The first layer was the oxygen-sensing membrane containing polystyrene particles (PS) doped with PtP and C6 (e.g., PS@C6^PtP) in a sol–gel matrix of aminopropyltrimethoxysilane and glycidoxypropyltrimethoxysilane (GA). The second layer was made by immobilizing GOD onto one of three supporting polymers over the first layer. These glucose-sensing membranes were characterized in terms of their response, reversibility, interferences, and stability. They showed a wide detection range to glucose concentration in the range of 0.1 to 10 mM, but high sensitivity with a linear detection range of 0.1 to 2 mM glucose. This stable and sensitive ratiometric fluorescent glucose biosensor provides a reliable way to determine low glucose concentrations in blood serum by measuring tear glucose.

Glucose concentration determination based on silica sol–gel encapsulated glucose oxidase optical biosensor arrays

Talanta ◽  
2010 ◽  
Vol 83 (1) ◽  
pp. 61-65 ◽  
Author(s):  
Gang Chang ◽  
Yoshiro Tatsu ◽  
Tatsushi Goto ◽  
Hiromasa Imaishi ◽  
Kenichi Morigaki
Keyword(s):  
Glucose Oxidase ◽  
Glucose Concentration ◽  
Sol Gel ◽  
Optical Biosensor ◽  
Silica Sol ◽  
Biosensor Arrays ◽  
Concentration Determination

scholarly journals Macrophage-like THP-1 cells show effective uptake of silica nanoparticles carrying inactivated diphtheria toxoid for vaccination

2020 ◽  
Vol 22 (1) ◽  
Author(s):  
Xinyue Huang ◽  
Danielle Paixão Cavalcante ◽  
Helen E Townley
Keyword(s):  
Mesoporous Silica ◽  
Silica Nanoparticles ◽  
Mesoporous Silica Nanoparticles ◽  
Sol Gel ◽  
Porous Silica ◽  
Diphtheria Toxoid ◽  
Similar Distribution ◽  
Antigen Delivery ◽  
Before And After ◽  
Post Synthesis

AbstractNanoparticles may be used in vaccinology as an antigen delivery and/or an immunostimulant to enhance immunity. Porous silica has been identified as an effective adjuvant for more than a decade, and we have therefore investigated the take up rate by an immortalized macrophage-like cell line of a number of mesoporous silica nanoparticles (MSNPs) with differing diameter and pore size. The MSNPs were synthesized using a sol-gel reaction and post-synthesis removal of the template. The MSNPs showed a clear distribution in take up rate peaking at 217 nm, whereas a comparison with solid spherical nanoparticles showed a similar distribution peaking at 377 nm. The MSNPs were investigated before and after loading with antigen. Diphtheria toxoid was used as a proof-of-concept antigen and showed a peak macrophage internalization of 53.42% for loaded LP3 particles which had a diameter of 217.75 ± 5.44 nm and large 16.5 nm pores. Optimal MSNP sizes appeared to be in the 200–400 nm range, and larger pores showed better antigen loading. The mesoporous silica particles were shown to be generally biocompatible, and cell viability was not altered by the loading of particles with or without antigen.

Glucose Biosensor Based on Pt Nanoparticles/Graphene Chitosan Bionanocomposites

2013 ◽  
Vol 328 ◽  
pp. 695-699 ◽  
Author(s):  
Hui Ping Liu ◽  
Gong Yong Zhan ◽  
Qi Zhi Dong ◽  
Yan An Lv ◽  
Jian Fang Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Peroxide ◽  
Glucose Oxidase ◽  
Hybrid Film ◽  
Pt Nanoparticles ◽  
Glucose Sensing ◽  
Glucose Biosensor ◽  
Redox Behavior ◽  
Amperometric Response ◽  
Scanning Electron

In this paper, we fabricated a bionanocomposite film of glucose oxidase/Pt nanoparticles/graphene-chitosan (GOD/PtNPs/GR-Chit) for glucose sensing. The hybrid bionanocomposites modified GCE were characterized by scanning electron microscopy (SEM), cyclic voltammetry, and amperometric i-t curve. It was found that the PtNPs were uniformly deposited on the surface of GR-Chit hybrid film. The resultant PtNPs/GR-Chit/GCE exhibited a high electrochemical catalytic ability to hydrogen peroxide (H2O2), due to the electrocatalytic synergy of GR and PtNPs. The redox behavior of the GOD/PtNPs/GR-Chit/GCE is a surface-controlled process. Finally, we obtained the amperometric response of the GOD/PtNPs/GR-Chit/GCE toward different concentration of glucose, and also achieved a sensitive glucose oxidase biosensor with a detection limit of 4.6μM glucose.

Decomposition of Glucose-Sensitive Layer-by-Layer Films Using Hemin, DNA, and Glucose Oxidase

2019 ◽  
Author(s):  
Kentaro Yoshida ◽  
Yu Kashimura ◽  
Toshio Kamijo ◽  
Tetsuya Ono ◽  
Takenori Dairaku ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Glucose Oxidase ◽  
Glucose Concentration ◽  
Dna Cleavage ◽  
Electrostatic Interactions ◽  
Glucose Solution ◽  
Layer By Layer ◽  
Sensitive Layer ◽  
Physiological Conditions ◽  
Lbl Films

Glucose-sensitive films were prepared by the layer-by-layer (LbL) deposition of poly(ethyleneimine) (H-PEI) solution and DNA solution (containing glucose oxidase (GOx)). H-PEI/DNA+GOx multilayer films were constructed using electrostatic interactions. The (H-PEI/DNA+GOx)5 film was then partially decomposed by hydrogen peroxide (H2O2). The mechanism for the decomposition of the LbL film was considered to involve a more reactive oxygen species (ROS) that was formed by the reaction of hemin and H2O2, which then caused nonspecific DNA cleavage. GOx present in the LbL films reacts with glucose to generate hydrogen peroxide. Therefore, decomposition of the H-PEI/DNA+GOx)5 film was observed when the thin film was immersed in a glucose solution. A (H-PEI/DNA+GOx)5 film exposed to a glucose solution for periods of 24, 48 72, and 96 h indicated decomposition of the film increased with the time. The rate of LbL film decomposition increased with the glucose concentration. At pH and ionic strength close to physiological conditions, it was possible to slowly decompose the LbL film at a sub-millimolar glucose concentration.

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