A New Bio-Inorganic Nanocomposite Membrane for Glucose-Modulated Release of Insulin

2009 ◽  
Vol 1234 ◽  
Author(s):  
Claudia Regina Gordijo ◽  
Adam Jason Shuhendler ◽  
Xiao Yu Wu
Keyword(s):  
Insulin Release ◽  
Glucose Level ◽  
Release Rate ◽  
Glucose Concentration ◽  
Glucose Sensor ◽  
Fold Increase ◽  
Ph Responsive ◽  
Long Term Stability ◽  
Isopropyl Acrylamide

AbstractThis work focuses on the development of a new bio-inorganic nanocomposite glucose-responsive membrane to be applied as a single self-regulated platform for insulin delivery. Crosslinked bovine serum albumin (BSA)-based membranes were prepared containing impregnated pH-responsive poly(N-isopropyl acrylamide-co-methacrylic acid) nanoparticles (hydrogel NPs), glucose oxidase (GOx), catalase (CAT), with or without MnO2 NPs. The membrane acts as a glucose sensor and insulin release attenuator. In this system glucose is oxidized by GOx to produce gluconic acid, which regulates the permeability of the membrane to insulin. CAT and/or MnO2 NPs are introduced into the membrane in order to quench unwanted H2O2 produced by GOx turnover cycles, which can cause inactivation of GOx and toxicity. The glucose-modulated insulin release through the membrane is determined by alternating glucose concentration between 100 – 400 mg/dL (normal and hyperglycemic levels, respectively). The results show that the combination of CAT and MnO2 NPs in the membrane formulation leads to better efficiency in quenching the H2O2 and better long-term stability of GOx than using either alone. Very small amounts of insulin permeate though the membrane at the normal blood glucose level while a four-fold increase in the release rate is observed when glucose concentration is raised to a hyperglycemic level. The release rate of insulin drops when the glucose level is reduced to a normal value. These results demonstrate the self-regulated capability of the system.

A long-term stable paper-based glucose sensor using a glucose oxidase-loaded, Mn2BPMP-conjugated nanocarrier with a smartphone readout

Nanoscale ◽  
2021 ◽  
Author(s):  
Soyeon Yoo ◽  
Kiyoon Min ◽  
Giyoong Tae ◽  
Min Su Han
Keyword(s):  
Glucose Oxidase ◽  
Glucose Sensor ◽  
Sensor System ◽  
Term Stability ◽  
Long Term Stability

A paper-type sensor system was devised using an enzyme-loaded, artificial peroxidase-conjugated nanocarrier to maintain long-term stability with smartphone readout.

scholarly journals Highly Responsive and Ultrasensitive Non-Enzymatic Electrochemical Glucose Sensor Based on Au Foam

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1203 ◽  
Author(s):  
Nannan Shen ◽  
Haijun Xu ◽  
Weichen Zhao ◽  
Yongmei Zhao ◽  
Xin Zhang
Keyword(s):  
High Selectivity ◽  
Glucose Sensor ◽  
Limit Of Detection ◽  
Surface Enhanced Raman Spectroscopy ◽  
Au Nanoparticle ◽  
Quantitative Detection ◽  
Term Stability ◽  
Long Term Stability ◽  
Surface Enhanced Raman

Glucose concentration is an important physiological index, therefore methods for sensitive detection of glucose are important. In this study, Au foam was prepared by electrodeposition with a dynamic gas template on an Au nanoparticle/Si substrate. The Au foam showed ultrasensitivity, high selectivity, and long-term stability in the quantitative detection of glucose. The foam was used as an electrode, and the amperometric response indicated excellent catalytic activity in glucose oxidation, with a linear response across the concentration range 0.5 μM to 12 mM, and a limit of detection of 0.14 μM. High selectivity for interfering molecules at six times the normal level and long-term stability for 30 days were obtained. The results for electrochemical detection with Au foam of glucose in human serum were consistent with those obtained with a sensor based on surface-enhanced Raman spectroscopy and a commercial sensor. This proves that this method can be used with real samples. These results show that Au foam has great potential for use as a non-enzymatic glucose sensor.

scholarly journals The pentose cycle and insulin release in mouse pancreatic islets

1972 ◽  
Vol 126 (3) ◽  
pp. 525-532 ◽  
Author(s):  
S. J. H. Ashcroft ◽  
L. C. C. Weerasinghe ◽  
J. M. Bassett ◽  
P. J. Randle
Keyword(s):  
Glucose Metabolism ◽  
Pancreatic Islets ◽  
Insulin Release ◽  
Glucose Concentration ◽  
Glucose Utilization ◽  
Fold Increase ◽  
Primary Role ◽  
Mouse Pancreatic Islets ◽  
Oxidation Of Glucose

1. Rates of insulin release, glucose utilization (measured as [3H]water formation from [5-3H]glucose) and glucose oxidation (measured as14CO2 formation from [1-14C]- or [6-14C]-glucose) were determined in mouse pancreatic islets incubated in vitro, and were used to estimate the rate of oxidation of glucose by the pentose cycle pathway under various conditions. Rates of oxidation of [U-14C]ribose and [U-14C]xylitol were also measured. 2. Insulin secretion was stimulated fivefold when the medium glucose concentration was raised from 3.3 to 16.7mm in the absence of caffeine; in the presence of caffeine (5mm) a similar increase in glucose concentration evoked a much larger (30-fold) increase in insulin release. Glucose utilization was also increased severalfold as the intracellular glucose concentration was raised over this range, particularly between 5 and 11mm, but the rate of oxidation of glucose via the pentose cycle was not increased. 3. Glucosamine (20mm) inhibited glucose-stimulated insulin release and glucose utilization but not glucose metabolism via the pentose cycle. No evidence was obtained for any selective effect on the metabolism of glucose via the pentose cycle of tolbutamide, glibenclamide, dibutyryl 3′:5′-cyclic AMP, glucagon, caffeine, theophylline, ouabain, adrenaline, colchicine, mannoheptulose or iodoacetamide. Phenazine methosulphate (5μm) increased pentose-cycle flux but inhibited glucose-stimulated insulin release. 4. No formation of14CO2 from [U-14C]ribose could be detected: [U-14C]xylitol gave rise to small amounts of14CO2. Ribose and xylitol had no effect on the rate of oxidation of glucose; ribitol and xylitol had no effect on the rate of glucose utilization. Ribose, ribitol and xylitol did not stimulate insulin release under conditions in which glucose produced a large stimulation. 5. It is concluded that in normal mouse islets glucose metabolism via the pentose cycle does not play a primary role in insulin-secretory responses.

Preparation of Glucose Sensor Using Polydimethylsiloxane / Polypyrrole Complex

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1217-1222 ◽  
Author(s):  
Mikito Yasuzawa ◽  
Shigeru Inoue ◽  
Shinji Imai
Keyword(s):  
Glucose Sensor ◽  
Platelet Rich Plasma ◽  
Glucose Sensors ◽  
Wire Electrode ◽  
Term Stability ◽  
Long Term Stability ◽  
Response Current ◽  
And Storage ◽  
Storage Temperatures

New glucose oxidase (GOD) immobilized glucose sensors were prepared by the electropolymerization of 1-(6-D-gluconamidohexyl) pyrrole (GHP) on the platinum wire electrode precoated with the mixture solution of pyrrole derivative GHP, polydimethylsiloxane (PDS) and Nafion. The addition of Nafion into the precoating mixture solution was essential to obtain suitable sensor sensitivity. However, the sensitivity was about the half of that of the electrode without PDS precoating. Although, the introduction of Nafion was effective to improve the long-term stability of the enzyme-immobilized electrode, the electrode prepared using Nafion, PDS and GHP performed excellent long-term stability even at the measurement and storage temperatures of 40°C. Relatively constant response current was obtained over 30 days under the condition of 40°C and over 9 months measured at 25°C. Moreover, the GOD-immobilized GHP polymer film prepared on the electrode precoated with GHP, PDS and Nafion solution, was found to have excellent hemocompatibility from the result of platelet rich plasma contacting test.

Preparation and Characterization of Electrochemical Glucose Sensor Based on Nickel Electrodes Supported by Silicon Microchannel Plates

2011 ◽  
Vol 138-139 ◽  
pp. 1126-1131
Author(s):  
Bai Rui Tao ◽  
Feng Juan Miao ◽  
Yong Jie Zheng
Keyword(s):  
Glucose Sensor ◽  
Electrochemical Etching ◽  
Alkaline Solutions ◽  
X Ray Diffraction ◽  
Long Term Stability ◽  
Microchannel Plates ◽  
Electro Oxidation ◽  
Oxidation Of Glucose

A novel nickel nanocomposite electrode supported by 3D ordered silicon microchannel plates (MCP) had been reported and its electrocatalytic toward the oxidation of glucose for sensor had been studied. The 3D ordered Si MCP electrodes were first fabricated by electrochemical etching and then Nickel nanoparticles were deposited onto the sidewall of the MCP via electroless deposition followed by annealing at 300°C for 300 s under argon to stabilize the structure. The morphology of the Ni/Si-MCP electrode was characterized by Scanning electron microscope (SEM) and X-ray diffraction (XRD). The electrochemical methods were employed to investigate the Ni/Si-MCP materials. The Ni/Si-MCP nanocomposites exhibit superior electrocatalytic properties towards glucose electro-oxidation in alkaline solutions, in addition to showing excellent long-term stability and good reproducibility.

Long-term stability of glucose: 96-h study using Terumo Glycaemia tubes

2016 ◽  
Vol 54 (3) ◽  
Author(s):  
Theresa Winter ◽  
Anne Greiser ◽  
Matthias Nauck ◽  
Astrid Petersmann
Keyword(s):  
Glucose Concentration ◽  
Room Temperature ◽  
Venous Blood ◽  
Sample Collection ◽  
Multicenter Studies ◽  
Entire Study ◽  
Blood Samples ◽  
Term Stability ◽  
Long Term Stability

AbstractLong transportation times of samples can occur due to centralization of laboratories, and also in, for instance epidemiological multicenter studies with one core laboratory. Unsatisfactory glycolysis inhibition is known to threaten the correct measurements of glucose concentration in patient samples. In former studies Terumo Glycaemia tubes proved to be superior to other anticoagulant systems for time periods of up to 24 h. We investigated long-term stability of glucose concentration in Terumo Glycaemia tubes for up to 96 h at room temperature and imitated transport conditions by continuous sample shaking.Human venous blood samples were collected from 40 healthy blood donors using Terumo Glycaemia tubes. Immediately after sampling, tubes were mixed according to the manufactures recommendations. To simulate transportation conditions samples were placed on a shaker for the entire study period and maintained at room temperature. Samples were (re)centrifuged at 0, 24, 36, 48, 72 and 96 h prior to measuring glucose concentration. The glucose concentration at 0 h was used as baseline for evaluation of long-term stability.The recovery of glucose was 100% throughout the study, including the 96-h measurements. Deviations of single glucose measurements were within the imprecision of the measurement procedure.Terumo Glycaemia tubes can effectively stabilize glucose in whole blood samples kept at room temperature on a shaker during a 96-h time period. Therefore, we consider Terumo Glycaemia tubes as a suitable glucose stabilizing tube for long intervals between sample collection and glucose quantification.

Long-term stability of glucose: glycolysis inhibitor vs. gel barrier tubes

2018 ◽  
Vol 56 (8) ◽  
pp. 1251-1258 ◽  
Author(s):  
Theresa Winter ◽  
Anke Hannemann ◽  
Juliane Suchsland ◽  
Matthias Nauck ◽  
Astrid Petersmann
Keyword(s):  
Glucose Concentration ◽  
Room Temperature ◽  
Venous Blood ◽  
Blood Samples ◽  
Long Term Stability ◽  
Acceptable Alternative ◽  
Glycolysis Inhibitor ◽  
The Stability ◽  
Gel Barrier

AbstractBackground:Measuring the glucose concentration in whole blood samples is critical due to unsatisfactory glycolysis inhibition. Previous studies showed that Terumo tubes were superior, but they were taken off the European market in 2016 and alternatives were required. This initiated the present evaluation of glucose stability in five available tube types.Methods:Venous blood samples were collected from 61 healthy volunteers to test tubes supplied by Terumo (two sets), Greiner FC-Mix, BD FX-Mixture and BD serum. After sampling, the contents were thoroughly mixed and centrifuged within an hour. The glucose concentrations were determined and the samples resuspended except for BD serum tubes (gel barrier). The first 30 samples were stored at room temperature and the remaining 31 at 4°C. After 24, 48, 72 and 96 h, all tubes were (re)centrifuged, and glucose concentration measurements were repeated.Results:Changes in glucose concentrations over time differed significantly between the investigated tube types and to a certain extent between the two storing conditions. Glycolysis was most evident in the BD FX-mixture tubes. Good glucose stability was observed in samples retrieved form BD serum and Greiner tubes. The stability in both Terumo tubes was comparable to that in other studies. Although Greiner and both Terumo tubes are supposed to contain the same glycolysis inhibitor, glucose stability differed between these tubes.Conclusions:We showed that Greiner is an acceptable alternative to Terumo and that glucose in serum that was rapidly separated from corpuscles by a gel barrier is stable for an extended time.

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