Glucose In Human Serum Research Articles

Determination of glucose in human serum based on an onion primary cuticula biosensor immobilized glucose oxidase

A glucose biosensor based on onion primary cuticula immobilized glucose oxidase has been developed. The glucose concentration was quantified by the decrease of dissolved oxygen. The effects of enzyme loading, pH, temperature, buffer concentration and interference have been studied in detail. The biosensor showed a wide linear relationship with a concentration range of 20 μM–1.1 mM, a fast response time (70 s), good repeatability (2.8%, n = 10) and satisfactory reproducibility (0.91%, n = 3). The biosensor retained 90% of its initial response after 3 months at 25 °C. The apparent Michaelis-Menten constant Km was estimated to be 0.042 mM, which revealed higher biological affinity to glucose. The proposed biosensor method has been successfully applied to the determination of glucose concentration in human blood serum and obtained results were agreement with the colorimetric assay kit. The recoveries of proposed method are 95.2–106.3%.

A nonenzymatic glucose sensing platform based on Ni nanowire modified electrode

Glucose detection is very important for the diagnosis and management of diabetes, and nonenzymatic glucose sensors have attracted considerable attention due to their excellent stability, high sensitivity, and so on. Herein, a sensitive, cost-effective nonenzymatic glucose sensor using ultralong Ni nanowire (NW) modified glassy carbon electrode is presented. The current–time curve shows that the catalytic oxidation current is linearly dependent on glucose concentration in the range from 1 μM to 5 mM with a correlation coefficient 0.994, and a sensitivity of 367 μA mM−1 cm−2. The relative standard deviation is 3.7% for 8 successive measurements for 1 mM glucose. After 2-weeks storage in air at room temperature, the signal for 1 mM glucose maintains 97.2% of its initial value. What is more, the present Ni NW-based electrochemical sensing platform can successfully be used to detect glucose in human serum with satisfactory results.

Development of quantitative enzymatic method and its validation for the assay of glucose in human serum

ObjectiveTo develop a simple, rapid, sensitive and affordable assay method for the determination of glucose in blood samples using a novel approach. Design and methodsA spectrophotometric method for glucose quantification in human serum samples based on self-coupling of activated 2,5-dimethoxyaniline (DMA) in the presence of peroxidase (POD)/glucose oxidase (GOD) and H2O2 is described. H2O2 generated in situ by catalytic reaction between GOD and glucose, activates DMA in the presence of POD to form a green-colored product, which has a strong absorption at λmax=740nm at room temperature (30°C) in a 100mmol/L acetate/acetic acid buffer of pH 4.2. ResultsThe linearity ranges for the quantification of glucose by rate and one-time detection method are 0.017–0.740 and 0.017–0.478mmol/L, respectively. Within-day and day-to-day precision were 0.98–1.4% (n=10) and 1.33–2.89% (n=15), respectively. Glucose recoveries ranged from 96.6 to 102%, indicating minimal interference by commonly present interferants in serum samples. Accuracy results were between 90 and 102%. The detection and quantification limits of glucose were 2.376 and 7.923μmol/L, respectively. The proposed method has good correlation coefficient of 0.999 with the enzymatic kit method. ConclusionsThis is a rapid and convenient method to determine serum glucose using simple spectrophotometer with excellent recovery and minimal interference by interferants in serum samples with low detection limit. Therefore, this method can be considered for adoption by the clinical diagnostic laboratories.

Nonenzymatic continuous glucose monitoring in human whole blood using electrified nanoporous Pt

This paper describes the first devised method for the nonenzymatic and electrochemical glucose monitoring in 100% human whole blood and serum. The nanoporous Pt electrode allows for the selective amplification of glucose oxidation in the presence of electroactive interfering species without the need for enzymatic reaction. The outer membrane was particularly optimized to allow glucose molecules to be electrochemically detected against the numerous constituents of human blood. The proposed sensor provided reproducible amperometric responses to glucose in human serum and whole blood. Its sensitivity was maintained for at least 7h under constantly electrified conditions, and continued to work properly after 30 days of storage in human whole blood and serum. Unlike the enzyme-based glucose sensors, it was found to be minimally affected by thermal fluctuation, so as to remain successful even after steam sterilization at high temperature (134°C) and pressure (0.22Mpa). The unprecedented long-term stability and sterilization compatibility observed herein suggest a promising alternative to conventional enzymatic glucose sensors for many analytical and clinical applications, particularly for continuous glucose monitoring devices designed to potentially lead to a closed-loop artificial pancreas by combining them with an insulin pump.

Sensitive and selective determination of glucose in human serum and urine based on the peroxyoxalate chemiluminescence reaction of a new Fluorophore

A novel method for simple and sensitive determination of glucose based on the peroxyoxalate chemiluminescence (PO-CL) detection of enzymatically generated H 2O 2 was investigated. Influence of various experimental parameters on glucose sensing, including the action time of the enzyme, solution pH, interferents and the concentration of CL reagents was investigated. Under the optimum condition, the linear response range of glucose was found to be 2.50 × 10 −6 to 1.75 × 10 −4 mol/L, and the detection limit (defined as the concentration that could be detected at the signal-to-noise ratio of 3) was 1.10 × 10 −6 mol/L. The present method has been used to determine the glucose concentrations in real serum and urine samples with satisfactory results.

Cobalt oxide acicular nanorods with high sensitivity for the non-enzymatic detection of glucose

Acicular cobalt oxide nanorods (CoONRs) were prepared for the non-enzymatic detection of glucose, first by directly growing layered cobalt carbonate hydroxide (LCCH) on a conducting fluorine-doped tin oxide (FTO) substrate using a simple chemical bath deposition (CBD) technique and then by transforming the LCCH into CoONRs through pyrolysis. The composition and grain size of the films of LCCH and CoONRs were verified by X-ray diffraction (XRD); their morphologies were examined by scanning electron microscopic (SEM) and transmission electron microscopic (TEM) images. CoONRs showed high electrocatalytic activity for the electro-oxidation of glucose in alkaline media, and the activity was strongly influenced by NaOH concentration, annealing temperature of CoONRs, and thickness of CoONRs film. The pertinent sensor could be successfully used for the quantification of glucose by amperometric method. The sensing parameters include wide linear range up to 3.5 mM, a high sensitivity of 571.8 μA/(cm 2 mM), and a remarkable low detection limit of 0.058 μM. The CoONRs modified electrode exhibited a high selectivity for glucose in human serum, against ascorbic acid, uric acid, and acetaminophen.

Paper Bioassay Based on Ceria Nanoparticles as Colorimetric Probes

We report the first use of redox nanoparticles of cerium oxide as colorimetric probes in bioanalysis. The method is based on changes in the physicochemical properties of ceria nanoparticles, used here as chromogenic indicators, in response to the analyte. We show that these particles can be fully integrated in a paper-based bioassay. To construct the sensor, ceria nanoparticles and glucose oxidase were coimmobilized onto filter paper using a silanization procedure. In the presence of glucose, the enzymatically generated hydrogen peroxide induces a visual color change of the ceria nanoparticles immobilized onto the bioactive sensing paper, from white-yellowish to dark orange, in a concentration-dependent manner. A detection limit of 0.5 mM glucose with a linear range up to 100 mM and a reproducibility of 4.3% for n = 11 ceria paper strips were obtained. The assay is fully reversible and can be reused for at least 10 consecutive measurement cycles, without significant loss of activity. Another unique feature is that it does not require external reagents, as all the sensing components are fixed onto the paper platform. The bioassay can be stored for at least 79 days at room temperature while maintaining the same analytical performance. An example of analytical application was demonstrated for the detection of glucose in human serum. The results demonstrate the potential of this type of nanoparticles as novel components in the development of robust colorimetric bioassays.

Glucose in human serum determined by capillary electrophoresis with glucose micro-biosensor

A glucose micro-biosensor was employed as detector in capillary electrophoresis (CE) for determining the concentration of glucose in human serum. The micro-biosensor was based on the immobilization of the SWNTs-glucose oxidase-chitosan biocomposite at a platinized Au electrode by electrodeposition. The influencing factors including separation voltage, detection potential, pH value, and the concentration of the buffer were studied. Suitable conditions were obtained for the determination of glucose: running buffer, 25 mM PBS (pH 8.0); separation field strength, 250 V cm(-1); detection potential, 0.80 V vs. saturated calomel electrode. Under optimized detection conditions, glucose responded linearly from the range of 5 μM to 1 mM with a correlation coefficient of 0.9986 for the injection voltage of 5.0 kV and injection time of 10 s. The concentration limit of detection of the method was 1 μM (S/N = 3). The micro-biosensor exhibited good stability and durability in the analytical procedures. The relative standard deviation of the migration time and peak current were 1.7% and 2.6%, respectively. Glucose in human serum from two healthy individuals and two diabetics was successfully determined, giving a good prospect for a new clinical diagnostic instrument.

Equidistant Five Wavenumbers Selection for NIR Spectroscopy Analysis of Glucose in Human Serum

Using Fourier transform near-infrared (FTNIR) transmission spectroscopy and multiple linear regression (MLR) method of the equidistant wavenumbers combination, the quantitative analysis models of human serum glucose were established, and discrete wavenumbers combination was optimized. The optimal models were found in the five equidistant wavenumbers combinations with 7 and 40 gaps.The center wavenumber of the optimal models with 40 gaps in the first overtone region and combination region were 7970 and 5880 cm-1 respectively, and the corresponding RMSEP were 0.371 and 0.389 mmol/L respectively. While the center wavenumber of the optimal models with 7 gaps in the combination region and first overtone region were 5795 and 8041 cm-1 respectively, and the corresponding RMSEP were 0.395 and 0.407 mmol/L respectively. The above four models had a good prediction effect, and could provide basis for designing minitype special NIR spectroscopy instrument.

Functionalization of graphene nanoribbons with porphyrin for electrocatalysis and amperometric biosensing

A direct electrochemical method to reduce graphene oxide nanoribbons was proposed. The reduced graphene nanoribbons (RGNRs) could be functionalized with water-soluble iron(III) meso-tetrakis(N-methylpyridinum-4-yl) porphyrin (FeTMPyP) via π–π noncovalent interaction on electrode surface. The resulting FeTMPyP/RGNRs film showed excellent electrocatalysis toward the reduction of dissolved oxygen at peak potential of −0.28 V. Using glucose oxidase as model enzyme, a biosensor based on the consumption of O 2 was developed for amperometric detection of glucose ranging from 0.5 mM to 10 mM. This biosensor could be successfully applied in the detection of glucose in human serum. The FeTMPyP functionalized RGNRs provided a platform for electrocatalysis and biosensing of oxidase substrates.

Thin-Walled Graphitic Nanocages As a Unique Platform for Amperometric Glucose Biosensor

A thin-walled graphitic nanocages material with well-developed graphitic structure, large specific surface area and pronounced mesoporosity was synthesized and used to construct a sensing interface for an amperometric glucose biosensor, showing a high and reproducible sensitivity of 13.3 μA mM(-1) cm(-2), linear dynamic range of 0.02-6.2 mM, and fast response time of 5 s. It was successfully used to accurately detect glucose in human serum with effective discrimination to common interference species such as dopamine, ascorbic acid, acetaminophen, and uric acid.

Pt-dispersed flower-like carbon nanosheet aggregation for low-overpotential electrochemical biosensing

A Pt nanoparticle-decorated flower-like carbon nanosheet aggregation (FCNA) was prepared via one-step ethylene glycol method. The aggregation was characterized with scanning electron micrographs, X-ray photoelectron spectra, X-ray diffraction and electrochemical impedance spectra. When the aggregation was immobilized on a glassy carbon electrode, the dense dispersion of Pt nanoparticles (Pt NPs) on the carbon nanosheets of FCNA could combine the good conductivity of FCNA with the excellent catalytic activity of Pt NPs for the electroreduction of oxygen at a low overpotential, which led to a method for electrochemical detection of oxygen from 6.3 to 69.3 μM. Using glucose oxidase (GOx) as a model, the resulting GOx/Pt/FCNA nanocomposite-based amperometric biosensor showed a linear response to glucose ranging from 0.5 to 8.0 mM with a detection limit of 0.3 mM at a S/N ratio of 3. The designed biosensor was of excellent performance with high selectivity, acceptable recovery and good repeatability, and could be successfully applied in the detection of glucose in human serum. The FCNA could be expected as a carrier for the preparation of other metal nanoparticle-dispersed aggregations and biosensing applications.

Amperometric glucose sensor based on glucose oxidase immobilized on gelatin-multiwalled carbon nanotube modified glassy carbon electrode

We investigated the direct electrochemistry of glucose oxidase (GOx) at gelatin-multiwalled carbon nanotube (GCNT) modified glassy carbon electrode (GCE). GOx was covalently immobilized onto GCNT modified GCE through the well known glutaraldehyde (GAD) chemistry. The immobilized GOx showed a pair of well-defined reversible redox peaks with a formal potential (E 0′) of − 0.40 V and a peak to peak separation (ΔE p) of 47 mV. The surface coverage concentration (Г) of GOx in GCNT/GOx/GAD composite film modified GCE was 3.88 × 10 − 9 mol cm − 2 which indicates the high enzyme loading. The electron transfer rate constant ( k s) of GOx immobilized onto GCNT was 1.08 s − 1 which validates a rapid electron transfer processes. The composite film shows linear response towards 6.30 to 20.09 mM glucose. We observed a good sensitivity of 2.47 μA mM − 1 cm − 2 for glucose at the composite film. The fabricated biosensor displayed two weeks stability. Moreover, it shows no response to 0.5 mM of ascorbic acid (AA), uric acid (UA), acetaminophen (AP), pyruvate (PA) and lactate (LA) which shows its potential application in the determination of glucose from human serum samples. The composite film exhibits excellent recovery for glucose in human serum at physiological pH with good practical applicability.

A Novel Glucose Biosensor Based on Glucose Oxidase Immobilized on AuPt Nanoparticle – Carbon Nanotube – Ionic Liquid Hybrid Coated Electrode

AbstractA novel amperometric glucose biosensor is presented in this article, which is based on the adsorption of glucose oxidase on gold‐platinum nanoparticle (AuPt NP)‐multiwalled carbon nanotube (MWNT) – ionic liquid (i.e., 1‐octyl‐3‐methylimidazolium hexafluorophosphate, [OMIM]PF6) composite. The gold‐platinum nanoparticles is prepared through direct electrodeposition. Owing to the synergistic action of AuPt nanoparticle, MWNT and [OMIM]PF6, the biosensor shows good response to glucose, with wide linear range (0.01 to 9.49 mM), short response time (3 s), and high sensitivity (3.47 μA mM−1). With the biosensor the determination of glucose in human serum is performed.

Activation of nylon net and its application to a biosensor for determination of glucose in human serum

A glucose biosensor using a glucose oxidase (GO x)-immobilized nylon net with glutaraldehyde as cross-linking reagent and an oxygen (O 2) electrode for the determination of glucose has been fabricated. The detection scheme was based on the utilization of dissolved O 2 in oxidation of glucose by the membrane bound GO x. Crucial factors including O-alkylation temperature, reaction times of nylon net with dimethyl sulfate, l-lysine, and glutaraldehyde, and enzyme loading were examined to determine the optimal enzyme immobilization conditions for the best sensitivity of the developed glucose biosensor. In addition, the effects of pH and concentration of phosphate buffer on the response of the biosensor were studied. The glucose biosensor had a linear range of 18 μM to 1.10 mM with the detection limit of 9.0 μM (S/N = 3) and response time of 80 s. The biosensor exhibited both good operational stability with over 200 measurements and long-term storage stability. The results from this biosensor compared well with those of a commercial glucose assay kit in analyzing human serum glucose samples.

Chemiluminescence flow biosensor for glucose based on gold nanoparticle-enhanced activities of glucose oxidase and horseradish peroxidase

In this work, a novel chemiluminescence (CL) flow biosensor for glucose was proposed. Glucose oxidase (GOD), horseradish peroxidase (HRP) and gold nanoparticles were immobilized with sol–gel method on the inside surface of the CL flow cell. The CL detection involved enzymatic oxidation of glucose to d-gluconic acid and H 2O 2, and then the generated H 2O 2 oxidizing luminol to produce CL emission in the presence of HRP. It was found that gold nanoparticles could remarkably enhance the CL respond of the glucose biosensor. The enhanced effect was closely related to the sizes of gold colloids, and the smaller the size of gold colloids had the higher CL respond. The immobilization condition and the CL condition were studied in detail. The CL emission intensity was linear with glucose concentration in the range of 1.0 × 10 −5 mol L −1 to 1.0 × 10 −3 mol L −1, and the detection limit was 5 × 10 −6 mol L −1 (3 σ). The apparent Michaelis–Menten constant of GOD in gold nanoparticles/sol–gel matrix was evaluated to be 0.3 mmol L −1, which was smaller than that of GOD immobilized in sol–gel matrix without gold nanoparticles. The proposed biosensor exhibited short response time, easy operation, low cost and simple assembly, and the proposed biosensor was successfully applied to the determination of glucose in human serum.

Fabrication of microband glucose biosensors using a screen-printing water-based carbon ink and their application in serum analysis

Microband glucose biosensors were fabricated by screen-printing a water-based carbon ink formulation containing cobalt phthalocyanine redox mediator and glucose oxidase (GOD) enzyme, then insulating and sectioning through the thick (20 μm) film to expose a 3 mm-long working electrode edge. The performance of these biosensors for glucose analysis was investigated at 25 °C. Voltammetry in glucose-containing buffer solutions established that an operating potential of +0.4 V vs. Ag/AgCl was suitable for analysis under both stirring and quiescent conditions. The influence of pH on biosensor performance was established and an operational pH of 8.0 was selected. Steady-state responses were obtained under quiescent conditions, suggesting a mixed mechanism predominated by radial diffusion, indicative of microelectrode behaviour. Calibration studies obtained with these biosensors showed steady-state currents that were linearly dependent on glucose concentration from the limit of detection (0.27 mM) up to 2.0 mM, with a precision for replicate biosensors of 6.2–10.7%. When applied to the determination of glucose in human serum, the concentration compared favourably to that determined by a spectroscopic method. These results have demonstrated a simple means of fabricating biosensors for glucose measurement and determination in situations where low-current real-time monitoring under quiescent conditions would be desirable.

Clinical determination of glucose in human serum by a tomato skin biosensor

Background Glucose biosensors based on enzyme reaction of glucose oxidase were studied because the symptomatic therapy of diabetes mellitus requires reliable assessment of blood glucose level at frequent intervals. Tomato skin membranes have been successfully employed to entrap glucose oxidase for fabrication of glucose biosensor. Methods Glucose oxidase was immobilized onto the tomato skin and the enzyme membrane was then positioned on the surface of an oxygen electrode. The glucose concentration was quantified by the change of dissolved oxygen. All the serum samples were also simultaneously determined by a Hitachi 7060 chemistry analyzer. Results The response of the biosensor showed a linear relationship with a concentration range of 1.0–30.0 mmol/l glucose. The limit of detection was 0.20 mmol/l. Error Grid analysis demonstrated that 100% of the results fell within clinically acceptable zones A and B. The F- and t-tests showed no significant differences between the 2 methods. The recovery was 95.0–110.0% for 30 serum samples analysis. Conclusions The tomato skin biosensor possesses the advantages of simple fabrication, fast response time, low cost and high sensitivity. The results of our method are more accurate than and match well with the current clinical instrument method.

Chemiluminescence flow-through biosensor for glucose with eggshell membrane as enzyme immobilization platform

In this study, a new chemiluminescence (CL) flow-through biosensor for glucose was developed by immobilizing glucose oxidase (GOD) and horseradish peroxidase (HRP) on the eggshell membrane with glutaraldehyde as a cross-linker. The CL detection involved enzymatic oxidation of glucose to d-gluconic acid and hydrogen peroxide (H 2O 2) and then H 2O 2 oxidizing luminol to produce CL emission in the presence of HRP. The immobilization condition (e.g., immobilization time, GOD/HRP ratio, glutaraldehyde concentration) was studied in detail. It showed good storage stability at 4 °C over a 5-month period. The proposed biosensor exhibited short response time, high sensitivity, easy operation, and simple sensor assembly, and the proposed biosensor was successfully applied to the determination of glucose in human serum.

An optical biosensor for the rapid determination of glucose in human serum

Abstract An optical glucose biosensor based on the immobilization of glucose oxidase in a sensing film was developed. The sensing film consisted of an organically modified silicate film embedded with tri(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) perchlorate and a polyvinyl alcohol sol–gel matrix with immobilized glucose oxidase. A kinetic curve simulation method was employed for glucose measurements, as a result of which the measurement time was less than 1 min for each sample analysis. The detection limit (S/N = 3) of the glucose optical sensor was 3.6 × 10−6 mol L−1 with linear ranges from 0.00 to 0.50 mmol L−1 (Y = 358.25X−2.93, R2 = 0.9954) and 0.50 to 3.00 mmol L−1 (Y = 430.12X−46.43, R2 = 0.9972). In addition, the appearance of the sensing film, and effects of the amounts of immobilized enzyme, pH, temperature, ionic strength, and co-existing substances (including heavy metal ions and organic compounds) were investigated. The glucose values estimated by this optical biosensor correlated well with those determined using the conventional method for human serum samples.