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In this paper, we are reporting aqueous synthesis of internally Copper (Cu) doped ZnSe/ZnS core-shell quantum dots (QDs). The colloidal nanocrystals synthesised were characterized by XRD, SEM, TEM, and EDX analysis. The optical studies were done using UV-Visible Spectroscopy and photoluminescence (PL) spectroscopy. From the TEM analysis it was found that the synthesised quantum dots were of 5-10nm in size. The XRD pattern shows the crystalline nature and the core-shell structure of the synthesised QDs. The EDX analysis confirms the presence of elemental composition of the QD system. The synthesised QDs were further conjugated with glucose oxidase (GOD) enzyme and the modified QD-GOD system was used as glucose sensor. The FTIR and PL studies confirm the adsorption of glucose on the synthesised nanocomposites. [ABSTRACT FROM AUTHOR]

Objective: The primary objective of the research undertaken was to appraise the impact of bosentan on the pharmacokinetic activity of anti-diabetic medicines in diabetic rats as well as normal rats. Methods: The animals under study both normal and diabetic were studied after receiving oral dosages of sitagliptin, bosentan along with combination of both, proper washout was maintained amid periods. At regular interval blood samples in series were taken through tail vain of rats, it was further subjected in analysis of glucose. To analyze glucose oxidase/peroxidase technique was used. Results: Level of blood glucose was found to be reduced with Sitagliptine in both diabetic and non-diabetic rats; Peak effect observed to last around 8 hours. Bosentan had a modest hypoglycemia effect on its own, but when combined with sitagliptin, it significantly reduced hypoglycemic activity in rats. According to the literature, Bosentan is a recognised inducer of Cytochrome P450 2C9 and 3A4 isozymes. As a result, Bosentan appears to influence the isozymes involved in sitagliptin metabolism (Cytochrome P450 3A4 and, to a lesser extent, CYP2C8), resulting in a reduced hypoglycemic activity. Conclusions: Although there was an interaction between the two medications, it did not appear to be of the pharmacodynamic kind and appeared to be of the pharmacokinetic type. When these medicines are taken together, however, blood glucose levels should be closely monitored. [ABSTRACT FROM AUTHOR]

Diabetes is a disease that can trigger other diseases. Diabetes can affect anyone from children to adults. Measurement of glucose levels in the blood can be done in two ways, namely invasively, which means testing the blood directly and secondly, non-invasively, namely measuring blood sugar levels without having to test the blood directly. For non-invasive testing of blood glucose levels, it can be done by making a glucose sensor based on GOX immobilized material on optical fiber and infrared optical biosensor. Measurement of blood glucose levels can be done through urine or by placing it on a layer of human skin. The output of these measurements can be in the form ofa voltage that is read by the sensor system or can be a number of measurement results that can be read directly. [ABSTRACT FROM AUTHOR]

Mesoporous TiO2 (m-TiO2) was successfully synthesized without using any template. The presence of organic ligands such as acetic acid contributes well in the formation of the mesoporous framework in TiO2. Based on nitrogen (N2) adsorption/desorption measurement, the pore size and pore volume of TiO2 were 3.25 nm and 0.287 cm3.g-1, respectively with surface area of 82.32 m2.g-1. The fabricated m-TiO2 exhibits the anatase phase with a tetragonal crystal structure. Through morphological observations using SEM, it can be obviously seen that grain growth of m-TiO2 is spherical with the grain structure formed comes from particle packings. In this study, the acquired m-TiO2 was immobilized with the glucose oxidase (GOx) enzyme and its specific capacitance (Cp) characteristics was compared to the m-TiO2. Electrochemical measurements show that m-TiO2 and m-TiO2/GOx electrodes possess Cp value of 3.46 and 2.70 F.g-1, respectively measured by employing scan rate of 50 mV.s−1 under condition of 0.1 M PBS containing 0.5 mM of glucose. [ABSTRACT FROM AUTHOR]

In this work, we have accounted a silver nano-cluster for colorimetric glucose biosensors. The characterization of silver nano-cluster was accomplished using SEM, UV-spectra and Raman spectra. The silver nano-cluster has successfully catalysis the process of oxidation using TMB, 3,3′,5,5′-tetramethylbenzidine in the existence of hydrogen peroxidase and this has demonstrated an outstanding peroxidase like activity. The UV absorption spectra expose a peak at 651 nm and the silver nano-cluster's peroxidase activity was validated. The colorimetric sensing mechanism was recognized by electron transfer process. Silver nano-cluster and glucose oxidase is the base for colorimetric bio-sensor and it has illustrated excellent sensitivity and selectivity for the recognition of glucose. The synthesized glucose biosensor showed a good linearity for glucose in a range of 0.020 to 80.0 µM with a detection limit of 40.0 nM. The peroxidase mimic has been successfully validated for analysing different concentration of glucose samples. The machine learning approach has supported the effective monitoring of glucose at low concentration. [ABSTRACT FROM AUTHOR]

Due to technical availability, different thermal processing techniques has been adopted to finalise the preparation of wheat-based dough in Indonesia. This study aimed to compare dough that have been prepared using different final thermal process namely baking, frying, and steaming. Chemical composition and starch hydrolysis of the dough were used as the basis of the comparison. The chemical composition comprising solid, protein, and lipid were analysed by mean of gravimetry, Kjeldahl, and solvent extraction methods respectively. Subsequently, dough was subjected to hydrolysis in a mixture of alpha-amylase and glucoamylase for 60 min at 37 °C at an optimum pH and enzymes ratio. At the end of reaction, glucose release was assayed by mean of glucose oxidase to indicate the degree of hydrolysis. Pattern recognition analysis was then conducted by mean of principal component analysis (PCA) on the chemical composition and the starch hydrolysis to observe the dissimilarity and similarity among the products. As results, the first and the second principal components were able to explain 88% of variances determining the dissimilarities of the three products. Briefly, fried product was found to be associated with solid, lipid, and starch hydrolysis and is distinct compared to the other products. Furthermore, baked product was found to be associated with protein. Thus, dough prepared under baking, steaming, and frying as final processes do have dissimilarities in chemical composition and starch hydrolysis. [ABSTRACT FROM AUTHOR]

The use of magnetic nanoparticles in biocatalysis, due to their unique properties, such as controlled particle size, large surface area, and ease of separating them and the reaction mixture by applying an external magnetic field, makes it possible to reuse enzymes immobilized on magnetic nanoparticles for catalytic processes. In this work, horseradish root peroxidase was immobilized on Fe3O4 magnetic nanoparticles. The carrier surface was modified and activated before enzyme immobilization using 3-aminopropyltriethoxysilane and glutaraldehyde. Testing of biocatalytic systems was carried out in the oxidation reaction of 2,2'-azino-bis-(3-ethylbenzthiozolin-6-sulfonic acid) diammonium salt with hydrogen peroxide. The immobilized enzyme showed high efficiency and stability compared to the native enzyme. Also, in the work, the joint immobilization of peroxidase and glucose oxidase on magnetically attached carriers was studied. Enzymes were immobilized on Fe3O4 magnetic nanoparticles and SiO2. Optimal conditions (temperature, pH) were selected for all biocatalytic systems. [ABSTRACT FROM AUTHOR]

In the present study, we report the kinetic analysis of the polyindole modified metal (Au) as a glucose sensor utilizing Surface Plasmon Resonance (SPR) technique. Polyindole (PIn) was deposited by spin coating to modify the surface of the gold disc. Sensor surface was prepared by immobilizing glucose oxidase (GOD) on the polyindole modified gold disc. Different concentrations of glucose were taken to analyze the sensor response. A change in refractive index of the film was observed due to the chemical reactions of glucose with glucose oxidase. The response of the sensor is fast and highly sensitive to low concentrations of glucose and the sensitivity increases in the range of 0.1-0.5 µM.The sensogram of glucose sensor on Polyindole active surface was analyzed using kinetic evaluation software for three different concentration of glucose 0.1μM, 0.25μM, and 0.5μM. Association phase analysis was done on analysis wizard using both integration and numerical integration rate method and it was done for monophasic and biphasic system of interaction for all the three concentration of glucose. The kinetic evaluation is done invariably using monophasic model, which involves 1:1 interaction. In the present study, the biphasic model of interaction, which involves a non-linear fitting, is giving a better analysis. This change can be attributed to the binding sites with different affinities. [ABSTRACT FROM AUTHOR]

Enzymatic biofuel cells (EFCs) are bioelectronic devices that use oxidoreductase enzymes as electrocatalysts for the oxidation of an organic substrate and/or the reduction of oxygen or peroxide, finalized to direct energy conversion to electricity. Enzymes provide excellent specificity towards the substrates, avoiding, in some cases, the need of membranes and noble metals, thus realizing very compact systems suitable for miniaturization. Other advantages include high catalytic activity with low overvoltage for substrate conversion, mild operating conditions, like ambient temperature and near-neutral pH and low cost. EFCs can be utilized in a variety of applications, which need low power input and the biocompatibility of the device, including implantable or wearable biofuel cells, self-powered biosensors and, generally, portable battery-free power solutions. For enzymatic biofuel cell design, an effective immobilization of enzymes on the electrodes is an important challenge to obtain direct electron transfer without mediators, resulting in higher performance and improved long term stability. The use of conductive nanomaterials and different types of polymers as electrodes allow to achieve high specific surface, increasing the number of wired enzymes per volume unit, and facilitate the electron transfer between enzyme active site and electrode. The present paper focuses on glucose fuel cells (GFCs), a subtype of conventional EFCs able to oxidize glucose provided by a lot of metabolic processes. The designs of bioanodes are focused on the use of glucose oxidase (GOx), while biocathodes are based on laccase. The realization of a preliminary prototype on lab scale is presented based on glucose oxidase immobilized on conductive polymer, which already exhibited stability over time (several months) once immobilized through innovative techniques. Since glucose is an essential, relatively abundant and almost unlimited source of energy in living organisms, possible applications are the development of implantable GFCs as well as the exploitation of agro-industrial wastes. [ABSTRACT FROM AUTHOR]

Here we report immobilization of GOx on magnetic silica: (i) nanoparticles Fe3O4 with silica coating (Fe3O4-SiO2) and (ii) mesoporous silica with incorporated nanoparticles Fe3O4 (SiO2-Fe3O4) functionalized with amino groups using glutaraldehyde as a linker. Magnetic support based biocatalysts demonstrate high catalytic activity in D-glucose oxidation to D-gluconic acid at pH 5-7.5 and temperature of 30-50°C with the best activities of 95% and 94% for SiO2-Fe3O4-GOx and Fe3O4-SiO2-GOx, respectively. A comparison of magnetic and non-magnetic silica shows a significant enhancement of the relative catalytic activity for magnetic supports. Noticeably higher activity of GOx immobilized on magnetic supports is explained by the synergy of the GOx inherent activity and enzyme-like activity of iron oxide nanoparticles. Excellent relative activity of SiO2-Fe3O4-GOx (95% of native GOx) in a tolerant pH and temperature range, as well as high stability in a repeated use (6% relative activity loss after ten catalytic cycles), makes this catalyst promising for practical applications. [ABSTRACT FROM AUTHOR]

Here, we developed an effective D-glucose oxidation with magnetically recoverable biocatalysts. These biocatalysts were synthesized on magnetite particles obtained by different methods, polyol and co-precipitation. These MPs were coated with a layer of silica modified with amino groups. The GOx covalent attachment has been carried out via the reaction with glutaraldehyde. We established that the method of MPs synthesis affect the enzyme catalytic activity. It should be noted that the magnetically recoverable biocatalyst Fe3O4-polyol/GOx showed high activity - 86% of the activity of the native enzyme. [ABSTRACT FROM AUTHOR]

The insulin resistance models of mouse liver epithelial and rat myoblasts cells were induced by three kinds of inducers: dexamethasone, high insulin and high glucose. The purpose is to select the optimal insulin resistance model, to provide a simple and reliable IR cell model for the study of the pathogenesis of IR and the improvement of IR drugs and functional foods. The MTT method is used for toxicity screening of three compounds, selecting security and suitable concentration. We performed a Glucose oxidase peroxidase (GOD-POD) method involving FL83B and L6 cell with dexamethasone, high insulin and high glucose-induced insulin resistance. Results suggested that FL83B cells with dexamethasone-induced (0.25uM) were established insulin resistance and L6 cells with high-glucose (30mM) and dexamethasone-induced (0.25uM) were established insulin resistance. [ABSTRACT FROM AUTHOR]

The influence of nanosized particles on the glucose oxidase loading and the performance of amperometric glucose bionsensors were studied. Four enzyme electrodes (Pt/PAN/GOD, Pt/PAN/NZ/GOD, Pt/PAN/NZ/MNP/GOD, Pt/PAN/NZ/MWNT/GOD) were prepared by cross-linking of glucose oxidase (GOD) on nanocomposite material. Nanocomposites were prepared by entrapping nanozeolite (NZ), multiwalled carbon nanotubes (MWNT) and magnetic nanoparticles (MNP) in polyacrylonitrile (PAN) film. Cyclic voltammetric kinetic studies have been carried out with the four biosensors and the surface concentration of the adsorbed electroactive species on the electrodes was estimated. The highest enzyme concentration on the electrode surface corresponded to the electrodes prepared by nanozeolite separate (Pt/PAN/NZ/GOD) and combined with multi-walled carbon nanotubes (Pt/PAN/NZ/MWNT/GOD). The sensitivity of these two biosensors was the highest and that is in accordance with the greater amount of the adsorbed electroactive species on the electrodes (0.373 mol.cm-2). This was indication that a good synergistic effect happened when MWNTs and NZ were combined and these greatly improve the electron transfer ability of the sensor interface. Amperometric measurement of the two glucose oxidase electrodes (Pt/PAN/NZ/GOD and Pt/PAN/NZ/MWNT/GOD) with best results was carried out. The linear concentration interval of the Pt/PAN/NZ/MWNT/GOD biosensor was up to 3 mM, the detection limit - 0.02 mM glucose and the storage stability - 81% of its initial current response after 30 days. [ABSTRACT FROM AUTHOR]

The influence of nanosized particles on the glucose oxidase loading and the performance of amperometric glucose bionsensors were studied. Four enzyme electrodes (Pt/PAN/GOD, Pt/PAN/NZ/GOD, Pt/PAN/NZ/MNP/GOD, Pt/PAN/NZ/MWNT/GOD) were prepared by cross-linking of glucose oxidase (GOD) on nanocomposite material. Nanocomposites were prepared by entrapping nanozeolite (NZ), multiwalled carbon nanotubes (MWNT) and magnetic nanoparticles (MNP) in polyacrylonitrile (PAN) film. Cyclic voltammetric kinetic studies have been carried out with the four biosensors and the surface concentration of the adsorbed electroactive species on the electrodes was estimated. The highest enzyme concentration on the electrode surface corresponded to the electrodes prepared by nanozeolite separate (Pt/PAN/NZ/GOD) and combined with multi-walled carbon nanotubes (Pt/PAN/NZ/MWNT/GOD). The sensitivity of these two biosensors was the highest and that is in accordance with the greater amount of the adsorbed electroactive species on the electrodes (0.373 mol.cm-2). This was indication that a good synergistic effect happened when MWNTs and NZ were combined and these greatly improve the electron transfer ability of the sensor interface. Amperometric measurement of the two glucose oxidase electrodes (Pt/PAN/NZ/GOD and Pt/PAN/NZ/MWNT/GOD) with best results was carried out. The linear concentration interval of the Pt/PAN/NZ/MWNT/GOD biosensor was up to 3 mM, the detection limit - 0.02 mM glucose and the storage stability - 81% of its initial current response after 30 days. [ABSTRACT FROM AUTHOR]

This study used a fast, simple, and low-cost method to fabricate arrayed flexible glucose biosensor, and the glucose biosensor was integrated with microfluidic framework for investigating sensing characteristics of glucose biosensor at the dynamic conditions. The indium gallium zinc oxide (IGZO) was adopted as sensing membrane and it was deposited on aluminum electrodes / polyethylene terephthalate (PET) substrate by the radio frequency sputtering system. Then, we utilized screen-printed technology to accomplish miniaturization of glucose biosensor. Finally, the glucose sensing membrane was composed of glucose oxidase (GOx) and nafion, which was dropped on IGZO sensing membrane to complete glucose biosensor. According to the experimental results, we found that optimal sensing characteristics of arrayed flexible IGZO glucose biosensor at the dynamic conditions were better than at the static conditions. The optimal average sensitivity and linearity of the arrayed flexible IGZO glucose biosensor were 7.255 mV/mM and 0.994 at 20 µL/min flow rate, respectively. [ABSTRACT FROM AUTHOR]

Large surface area of porous structure cryogel showed an excellent matrix for enzyme immobilization, especially in the biosensor development. A chitosan cryogel beads was prepare by cross-linking chitosan with sodium tripolyphosphate at subzero temperature. This chitosan cryogel beads was then used to immobilize glucose oxidase for glucose biosensor fabrication. The biosensor was simple design and operation, using a micropipette tip to hold the immobilized enzyme, where the reaction can be performed by suck-hold-release the analyte using micropipette. The detection was based on the reaction between hydrogen peroxide, enzymatic product, with titanium (IV) oxysulfate to produce color change, which finally recorded using commercial scanner. The digital image obtained was then analyze using freeware of ImageJ to get the relationship between color change and the analyte concentration. The result showed a linear response in the glucose detection of 1.0 to 5.0 and 10 mM, with a regression of y = 11.33x + 46.02 and R2 of 0.983. The great enzyme immobilization was showed in the fabricated biosensor with 12 times uninterrupted analysis without reducing significant responses. [ABSTRACT FROM AUTHOR]

Well aligned PPy nanowire arrays with diameter about 20 nm have been accomplished by electrochemical polymerization within anodized aluminum oxide (AAO) template. Glucose oxidase (GOx) was galvanostatically entrapped within the PPy nanoarrays. Scanning electron microscopy (SEM) confirmed the presence of PPy nanowire arrays. The electrochemical properties and response of the PPy-GOx nanowire arrays biosensor to glucose were characterized by cyclic voltammetry and amperometry. Evident current response can be observed in the cyclic voltammogram of the PPy-GOx nanowire arrays biosensor when exposed to glucose in a phosphate buffer solution. Amperometric detection of glucose was successfully achieved and the established optimum conditions with the PPy(GOx) biosensor were 0.4 M pyrrole, 200 U/ml GOx, applied current density of 0.1 mA/cm2, polymerization time of 600 s. The biosensor achieved a detection limit of 50 µM, a linear concentration range of 0.1 mM to 8 mM, and sensitivity of 9.97 µA cm#x2212;2 mM−1. [ABSTRACT FROM PUBLISHER]

The integration of biology and electronics is crucial to developing advanced medical diagnostics and biological experimentation devices. To this end, we investigated the generation of hydrogels from the “biocompatible” polymer chitosan. Specifically, we imposed electrical signals at the biology electronics interface within microfabricated fluidic devices to electrodeposit chitosan hydrogels. Chitosan's unique properties enable electrodeposited hydrogels to be reversibly swollen and de-swollen providing a means for microfluidic valving or for controlled release of entrapped components. Furthermore, the method of anodic deposition reported here allows for one-step biofunctionalization of components for multiplexed electrochemical biosensing. Thus, we believe this electrodeposition method will provide a means to generate hydrogels capable of integrating biology with microelectromechanical systems. [ABSTRACT FROM PUBLISHER]