scholarly journals Performance-Enhanced Non-Enzymatic Glucose Sensor Based on Graphene-Heterostructure

Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 145 ◽  
Author(s):  
Mahmoud A. Sakr ◽  
Karim Elgammal ◽  
Anna Delin ◽  
Mohamed Serry
Keyword(s):  
Film Thickness ◽  
Layer Thickness ◽  
Active Sites ◽  
Glucose Oxidation ◽  
Glucose Sensor ◽  
Schottky Diodes ◽  
Glucose Monitoring ◽  
Platinum Oxide ◽  
Glucose Sensing ◽  
Market Demand

Non-enzymatic glucose sensing is a crucial field of study because of the current market demand. This study proposes a novel design of glucose sensor with enhanced selectivity and sensitivity by using graphene Schottky diodes, which is composed of graphene (G)/platinum oxide (PtO)/n-silicon (Si) heterostructure. The sensor was tested with different glucose concentrations and interfering solutions to investigate its sensitivity and selectivity. Different structures of the device were studied by adjusting the platinum oxide film thickness to investigate its catalytic activity. It was found that the film thickness plays a significant role in the efficiency of glucose oxidation and hence in overall device sensitivity. 0.8–2 μA output current was obtained in the case of 4–10 mM with a sensitivity of 0.2 μA/mM.cm2. Besides, results have shown that 0.8 μA and 15 μA were obtained by testing 4 mM glucose on two different PtO thicknesses, 30 nm and 50 nm, respectively. The sensitivity of the device was enhanced by 150% (i.e., up to 30 μA/mM.cm2) by increasing the PtO layer thickness. This was attributed to both the increase of the number of active sites for glucose oxidation as well as the increase in the graphene layer thickness, which leads to enhanced charge carriers concentration and mobility. Moreover, theoretical investigations were conducted using the density function theory (DFT) to understand the detection method and the origins of selectivity better. The working principle of the sensors puts it in a competitive position with other non-enzymatic glucose sensors. DFT calculations provided a qualitative explanation of the charge distribution across the graphene sheet within a system of a platinum substrate with D-glucose molecules above. The proposed G/PtO/n-Si heterostructure has proven to satisfy these factors, which opens the door for further developments of more reliable non-enzymatic glucometers for continuous glucose monitoring systems.

scholarly journals Performance-Enhanced Non-Enzymatic Glucose Sensor Based on Graphene-Heterostructure

2019 ◽  
Author(s):  
Mahmoud A Sakr ◽  
Karim Elgammal ◽  
Anna Delin ◽  
Mohamed Serry
Keyword(s):  
Film Thickness ◽  
Glucose Sensor ◽  
Schottky Diodes ◽  
Glucose Monitoring ◽  
Platinum Oxide ◽  
Glucose Sensing ◽  
Market Demand ◽  
Theoretical Investigations ◽  
Sensitivity And Selectivity ◽  
Working Principle

Non-enzymatic glucose sensing is a crucial field of study because of the current market demand. This study proposes a novel design of glucose sensor with enhanced selectivity and sensitivity by using graphene Schottky diodes, which is composed of Graphene/Platinum Oxide/n-Silicon heterostructure. The sensor was tested with different glucose concentrations and interfering solutions to investigate its sensitivity and selectivity. Different structures of the device were studied by adjusting the platinum oxide film thickness to investigate its catalytic activity. It was found that the film thickness plays a significant role in the efficiency of glucose oxidation and hence in overall device sensitivity. Moreover, theoretical investigations were conducted using Density Function Theory (DFT) to better understand the detection method and the origins of selectivity. The working principle of the sensors puts it in a competitive position with other non-enzymatic glucose sensors. DFT calculations provided a qualitative explanation of the charges distributed across the graphene sheet within a system of a platinum substrate with D-glucose molecules above. The proposed graphene/PtO/n-Si heterostructure has proven to satisfy these factors, which opens the door for further developments of more reliable non-enzymatic glucometers for continuous glucose monitoring systems.

scholarly journals Recent Advances in Non-Enzymatic Glucose Sensors Based on Metal and Metal Oxide Nanostructures for Diabetes Management- A Review

2021 ◽  
Vol 9 ◽  
Author(s):  
Gowhar A. Naikoo ◽  
Hiba Salim ◽  
Israr U. Hassan ◽  
Tasbiha Awan ◽  
Fareeha Arshad ◽  
...  
Keyword(s):  
Active Sites ◽  
Glucose Oxidation ◽  
Diabetes Management ◽  
Glucose Sensing ◽  
Glucose Sensors ◽  
Glucose Detection ◽  
Hydrous Oxide ◽  
Oxide Nanostructures ◽  
Metal Oxide Nanostructures ◽  
Glucose Electrooxidation

There is an undeniable growing number of diabetes cases worldwide that have received widespread global attention by many pharmaceutical and clinical industries to develop better functioning glucose sensing devices. This has called for an unprecedented demand to develop highly efficient, stable, selective, and sensitive non-enzymatic glucose sensors (NEGS). Interestingly, many novel materials have shown the promising potential of directly detecting glucose in the blood and fluids. This review exclusively encompasses the electrochemical detection of glucose and its mechanism based on various metal-based materials such as cobalt (Co), nickel (Ni), zinc (Zn), copper (Cu), iron (Fe), manganese (Mn), titanium (Ti), iridium (Ir), and rhodium (Rh). Multiple aspects of these metals and their oxides were explored vis-à-vis their performance in glucose detection. The direct glucose oxidation via metallic redox centres is explained by the chemisorption model and the incipient hydrous oxide/adatom mediator (IHOAM) model. The glucose electrooxidation reactions on the electrode surface were elucidated by equations. Furthermore, it was explored that an effective detection of glucose depends on the aspect ratio, surface morphology, active sites, structures, and catalytic activity of nanomaterials, which plays an indispensable role in designing efficient NEGS. The challenges and possible solutions for advancing NEGS have been summarized.

scholarly journals Solvothermal synthesis of Fe3O4 nanospheres for high-performance electrochemical non-enzymatic glucose sensor

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jiasheng Xu ◽  
Yuting Sun ◽  
Jie Zhang
Keyword(s):  
Active Sites ◽  
High Performance ◽  
Glucose Sensor ◽  
Limit Of Detection ◽  
Glucose Monitoring ◽  
High Sensitivity ◽  
Blood Glucose Monitoring ◽  
Glucose Detection ◽  
Uniform Size ◽  
Long Term Stability

Abstract Ferroferric oxide (Fe3O4) nanospheres have been synthesized via a facile solvothermal procedure to serve as an electrode material for high performance non-enzymatic glucose sensor. The as-synthesized Fe3O4 nanospheres with a uniform size from 16 to 18 nm, which can increase the reaction contact area and the active sites in the process of glucose detection. Benefiting from the particular nanoscale structure, the Fe3O4 nanospheres obviously enhanced the activity of electrocatalytic oxidation towards glucose. When the Fe3O4 nanospheres material was used for non-enzymatic glucose sensor, several electrochemical properties including the high sensitivity 6560 μA mM−1 cm−2 (0.1–1.1 mM), limit of detection 33 μM (S/N = 3) and good long-term stability were well demonstrated. Furthermore, Fe3O4 nanospheres electrode confirmed the excellent performance of selectivity in glucose detection with the interfering substances existed such as urea, citric acid, ascorbic acid, and NaCl. Due to the excellent electrocatalytic activity in alkaline solution, the Fe3O4 nanospheres material can be considered as a promising candidate in blood glucose monitoring.

scholarly journals Noninvasive Glucose Monitoring with a Contact Lens and Smartphone

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3208 ◽  
Author(s):  
You-Rong Lin ◽  
Chin-Chi Hung ◽  
Hsien-Yi Chiu ◽  
Bo-Han Chang ◽  
Bor-Ran Li ◽  
...  
Keyword(s):  
Contact Lens ◽  
Glucose Sensor ◽  
Phenylboronic Acid ◽  
Glucose Monitoring ◽  
Glucose Sensing ◽  
Covalent Interaction ◽  
Simple Implementation ◽  
The Difference ◽  
Reversible Covalent ◽  
Diabetes Patients

Diabetes has become a chronic metabolic disorder, and the growing diabetes population makes medical care more important. We investigated using a portable and noninvasive contact lens as an ideal sensor for diabetes patients whose tear fluid contains glucose. The key feature is the reversible covalent interaction between boronic acid and glucose, which can provide a noninvasive glucose sensor for diabetes patients. We present a phenylboronic acid (PBA)-based HEMA contact lens that exhibits a reversible swelling/shrinking effect to change its thickness. The difference in thickness can be detected in a picture taken with a smartphone and analyzed using software. Our novel technique offers the following capabilities: (i) non-enzymatic and continuous glucose detection with the contact lens; (ii) no need for an embedded circuit and power source for the glucose sensor; and (iii) the use of a smartphone to detect the change in thickness of the contact lens with no need for additional photo-sensors. This technique is promising for a noninvasive measurement of the glucose level and simple implementation of glucose sensing with a smartphone.

scholarly journals Advanced Binder-Free Electrode Based on CuCo2O4 Nanowires Coated with Polypyrrole Layer as a High-Performance Nonenzymatic Glucose Sensing Platform

Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1462
Author(s):  
Mohammad Rafe Hatshan ◽  
Sadia Aslam ◽  
Dmitry Bokov ◽  
Ahmed Jaber Ibrahim ◽  
Yasser Fakri Mustafa ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Active Sites ◽  
High Performance ◽  
Glucose Sensor ◽  
3D Structure ◽  
Glucose Sensing ◽  
Structure Characterization ◽  
Carbon Cloth ◽  
Great Ability ◽  
X Ray

In this work, the CuCo2O4 nanowires (CuCo2O4 NWs) were grown on carbon cloth electrode (CCE) and then coated with polypyrrole (pPy) layer (CuCo2O4 NWs-pPy@CCE). The morphology and structure characterization of as-prepared CuCo2O4 NWs-pPy@CCE were carried out using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), field-emission scanning electron microscope (FESEM), thermogravimetric analysis (TGA), and transmission electron microscope (TEM). The CuCo2O4 NWs-pPy@CCE was applied directly as an electrocatalyst toward nonenzymatic glucose oxidation. Due to the advantages of this 3D structure, it offer high availability to the analyte/electrolyte, abundant electrochemical-active sites, and high stability and conductivity. As a glucose sensor, the CuCo2O4 NWs-pPy@CCE shows wide linear range (0.01 to 21.3 mM), excellent sensitivity (4.41 μA μM−1 cm−2), good selectivity, low detection limit (0.2 μM), and rapid response time (<1 s) toward glucose detection. Furthermore, the designed sensor shows a great ability in detection of glucose in biological real samples.

scholarly journals Waste eggshell membrane-templated synthesis of functional Cu2+–Cu+/biochar for an ultrasensitive electrochemical enzyme-free glucose sensor

RSC Advances ◽  
2021 ◽  
Vol 11 (31) ◽  
pp. 18994-18999
Author(s):  
Linzhi Li ◽  
Tianzeng Huang ◽  
Saijun He ◽  
Xing Liu ◽  
Qi Chen ◽  
...  
Keyword(s):  
Glucose Sensor ◽  
Glucose Sensing ◽  
Fabrication Process ◽  
Eggshell Membrane ◽  
Templated Synthesis ◽  
Free Glucose

The fabrication process of the nonenzyme glucose sensing based Cu2+–Cu+/biochar.

scholarly journals N, S and Transition-Metal Co-Doped Graphene Nanocomposites as High-Performance Catalyst for Glucose Oxidation in a Direct Glucose Alkaline Fuel Cell

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 202
Author(s):  
Yexin Dai ◽  
Jie Ding ◽  
Jingyu Li ◽  
Yang Li ◽  
Yanping Zong ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Active Sites ◽  
High Performance ◽  
Glucose Oxidation ◽  
Alkaline Fuel Cell ◽  
Blank Group ◽  
Graphene Nanocomposites ◽  
Doped Graphene ◽  
One Step ◽  
Hydrothermal Approach

In this work, reduced graphene oxide (rGO) nanocomposites doped with nitrogen (N), sulfur (S) and transitional metal (Ni, Co, Fe) were synthesized by using a simple one-step in-situ hydrothermal approach. Electrochemical characterization showed that rGO-NS-Ni was the most prominent catalyst for glucose oxidation. The current density of the direct glucose alkaline fuel cell (DGAFC) with rGO-NS-Ni as the anode catalyst reached 148.0 mA/cm2, which was 40.82% higher than the blank group. The DGAFC exhibited a maximum power density of 48 W/m2, which was more than 2.08 folds than that of blank group. The catalyst was further characterized by SEM, XPS and Raman. It was speculated that the boosted performance was due to the synergistic effect of N, S-doped rGO and the metallic redox couples, (Ni2+/Ni3+, Co2+/Co3+ and Fe2+/Fe3+), which created more active sites and accelerated electron transfer. This research can provide insights for the development of environmental benign catalysts and promote the application of the DGAFCs.

scholarly journals Two glucose sensing/signaling pathways stimulate glucose-induced inactivation of maltose permease in Saccharomyces.

1997 ◽  
Vol 8 (7) ◽  
pp. 1293-1304 ◽  
Author(s):  
H Jiang ◽  
I Medintz ◽  
C A Michels
Keyword(s):  
Signaling Pathways ◽  
Glucose Transport ◽  
Glucose Sensor ◽  
Constitutive Expression ◽  
Glucose Sensing ◽  
Regulation Of Transcription ◽  
Carbohydrate Utilization ◽  
Maltose Permease ◽  
Glucose Levels ◽  
Dependent Signal

Glucose is a global metabolic regulator in Saccharomyces. It controls the expression of many genes involved in carbohydrate utilization at the level of transcription, and it induces the inactivation of several enzymes by a posttranslational mechanism. SNF3, RGT2, GRR1 and RGT1 are known to be involved in glucose regulation of transcription. We tested the roles of these genes in glucose-induced inactivation of maltose permease. Our results suggest that at least two signaling pathways are used to monitor glucose levels. One pathway requires glucose sensor transcript and the second pathway is independent of glucose transport. Rgt2p, which along with Snf3p monitors extracellular glucose levels, appears to be the glucose sensor for the glucose-transport-independent pathway. Transmission of the Rgt2p-dependent signal requires Grr1p. RGT2 and GRR1 also play a role in regulating the expression of the HXT genes, which appear to be the upstream components of the glucose-transport-dependent pathway regulating maltose permease inactivation. RGT2-1, which was identified as a dominant mutation causing constitutive expression of several HXT genes, causes constitutive proteolysis of maltose permease, that is, in the absence of glucose. A model of these glucose sensing/signaling pathways is presented.

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