scholarly journals A cellulose/β-cyclodextrin nanofiber patch as a wearable epidermal glucose sensor

RSC Advances ◽  
2019 ◽  
Vol 9 (40) ◽  
pp. 22790-22794 ◽  
Author(s):  
Kyu Oh Kim ◽  
Geon Jin Kim ◽  
Ji Hye Kim
Keyword(s):  
Interstitial Fluid ◽  
Glucose Sensor ◽  
Noninvasive Monitoring ◽  
Reverse Iontophoresis ◽  
Glucose Levels

In this study, we aimed to develop a cellulose/β-cyclodextrin (β-CD) electrospun immobilized GOx enzyme patch with reverse iontophoresis for noninvasive monitoring of interstitial fluid (ISF) glucose levels (0.1–0.6 mM dm−3).

scholarly journals Novel glucose-responsive of the transparent nanofiber hydrogel patches as a wearable biosensor via electrospinning

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Gun Jin Kim ◽  
Kyu Oh Kim
Keyword(s):  
Continuous Monitoring ◽  
Interstitial Fluid ◽  
High Sensitivity ◽  
Poly Vinyl Alcohol ◽  
High Porosity ◽  
High Permeability ◽  
Reverse Iontophoresis ◽  
Glucose Levels ◽  
Non Invasive ◽  
High Enzyme

Abstract Micro- and nanofiber (NF) hydrogels fabricated by electrospinning to typically exhibit outstanding high porosity and specific surface area under hydrated conditions. However, the high crystallinity of NFs limits the achievement of transparency via electrospinning. Transparent poly(vinyl alcohol)/β-cyclodextrin polymer NF hydrogels contacted with reverse iontophoresis electrodes were prepared for the development of a non-invasive continuous monitoring biosensor platform of interstitial fluid glucose levels reaching ~ 1 mM. We designed the PVA/BTCA/β-CD/GOx/AuNPs NF hydrogels, which exhibit flexibility, biocompatibility, excellent absorptivity (DI water: 21.9 ± 1.9, PBS: 41.91 ± 3.4), good mechanical properties (dried: 12.1 MPa, wetted: 5.33 MPa), and high enzyme activity of 76.3%. Owing to the unique features of PVA/β-CD/GOx containing AuNPs NF hydrogels, such as high permeability to bio-substrates and rapid electron transfer, our biosensors demonstrate excellent sensing performance with a wide linear range, high sensitivity(47.2 μA mM−1), low sensing limit (0.01 mM), and rapid response time (< 15 s). The results indicate that the PVA/BTCA/β-CD/GOx/AuNPs NF hydrogel patch sensor can measure the glucose concentration in human serum and holds massive potential for future clinical applications.

The Artificial Pancreas in Cyborg Bodies

2020 ◽  
pp. 412-430
Author(s):  
Anthony Ryan Hatch ◽  
Julia T. Gordon ◽  
Sonya R. Sternlieb
Keyword(s):  
Glucose Sensor ◽  
Social Inequalities ◽  
Infusion Pump ◽  
Artificial Pancreas ◽  
Small Scale ◽  
Glucose Levels ◽  
Loop Design ◽  
Access To Health ◽  
Do It Yourself ◽  
And Control

The new artificial pancreas system includes a body-attached blood glucose sensor that tracks glucose levels, a worn insulin infusion pump that communicates with the sensor, and features new software that integrates the two systems. The artificial pancreas is purportedly revolutionary because of its closed-loop design, which means that the machine can give insulin without direct patient intervention. It can read a blood sugar and administer insulin based on an algorithm. But, the hardware for the corporate artificial pancreas is expensive and its software code is closed-access. Yet, well-educated, tech-savvy diabetics have been fashioning their own fully automated do-it-yourself (DIY) artificial pancreases for years, relying on small-scale manufacturing, open-source software, and inventive repurposing of corporate hardware. In this chapter, we trace the corporate and DIY artificial pancreases as they grapple with issues of design and accessibility in a content where not everyone can become a diabetic cyborg. The corporate artificial pancreas offers the cyborg low levels of agency and no ownership and control over his or her own data; it also requires access to health insurance in order to procure and use the technology. The DIY artificial pancreas offers patients a more robust of agency but also requires high levels of intellectual capital to hack the devices and make the system work safely. We argue that efforts to increase agency, radically democratize biotechnology, and expand information ownership in the DIY movement are characterized by ideologies and social inequalities that also define corporate pathways.

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.

scholarly journals Non-Invasive Determination of Blood Glucose Levels by Optical Waveguide

2021 ◽  
Author(s):  
Mohsen Askarbioki ◽  
Mojtaba Mortazavi ◽  
Abdolhamid Amooee ◽  
Saeid Kargar ◽  
Mohammad Afkhami-Ardekani ◽  
...  
Keyword(s):  
Blood Glucose ◽  
Optical Waveguide ◽  
Interstitial Fluid ◽  
Evanescent Waves ◽  
The Body ◽  
Statistical Population ◽  
Glucose Levels ◽  
Non Invasive ◽  
Blood Glucose Levels

Objective: Today, there are various non-invasive techniques available for the determination of blood glucose levels. In this study, the level of blood glucose was determined by developing a new device using near-infrared (NIR) wavelength, glass optical waveguide, and the phenomenon of evanescent waves. Materials and Methods: The body's interstitial fluid has made possible the development of new technology to measure the blood glucose. As a result of contacting the fingertip with the body of the borehole rod, where electromagnetic waves are reflected inside, evanescent waves penetrate from the borehole into the skin and are absorbed by the interstitial fluid. The electromagnetic wave rate absorption at the end of the borehole rod is investigated using a detection photodetector, and its relationship to the people's actual blood glucose level. Following precise optimization and design of the glucose monitoring device, a statistical population of 100 participants with a maximum blood glucose concentration of 200 mg/dL was chosen. Before measurements, participants put their index finger for 30 seconds on the device. Results: According to this experimental study, the values measured by the innovative device with Clark grid analysis were clinically acceptable in scales A and B. The Adjusted Coefficient of Determination of the data was estimated to be 0.9064. Conclusion: For future investigations, researchers are recommended to work with a larger statistical population and use error reduction trends to improve the accuracy and expand the range of measurements.

An Interstitial Fluid Transdermal Extraction Chip with Vacuum Generator and Volume Sensor for Continuous Glucose Monitoring

2013 ◽  
Vol 562-565 ◽  
pp. 571-575 ◽  
Author(s):  
Hai Xia Yu ◽  
Da Chao Li ◽  
Yong Jie Ji ◽  
Xiao Li Zhang ◽  
Ke Xin Xu
Keyword(s):  
Continuous Glucose Monitoring ◽  
Microfluidic Chip ◽  
Normal Saline ◽  
Interstitial Fluid ◽  
Glucose Sensor ◽  
Fluid Management ◽  
Glucose Monitoring ◽  
Venturi Tube ◽  
Sensor Integration ◽  
Volume Sensor

A five layer microfluidic chip which is designed and fabricated for interstitial fluid (ISF) transdermal extraction, collection, and measurement toward the application of continuous and real-time glucose monitoring is presented in this paper. The microfluidic chip consists of a Venturi tube generating vacuum for ISF extraction and fluid manipulation, a novel volume sensor of electrolytic fluid for normal saline input volume control and ISF volume measurement, pneumatic valves for fluid management, and access ports for glucose sensor integration. The output vacuum of the Venturi tube is tested, and a less than 88kPa vacuum has been achieved, when 220kPa external pressure is applied. The feasibility of using the volume sensor to control and measure the normal saline input volume is confirmed by high accuracy and low coefficient of variation (CV=0.0040, n=12). The microfluidic chip is ready for glucose sensor integration in continuous glucose monitoring.

The Role of Biomaterials in Insulin Delivery Systems

1980 ◽  
Vol 3 (5) ◽  
pp. 299-304 ◽  
Author(s):  
S.D. Bruck
Keyword(s):  
Blood Glucose ◽  
Glucose Sensor ◽  
Insulin Delivery ◽  
The United States ◽  
Delivery Systems ◽  
Open Loop ◽  
Health Concern ◽  
Glucose Levels ◽  
Blood Glucose Levels

The control of blood glucose levels in diabetes involving devices are critically reviewed, and the role of blood-contacting biomaterial components analyzed. These include mechanical insulin-delivery systems of the closed-loop type that require an electronic glucose sensor and feedback, and open-loop systems that deliver insulin without a sensor and feedback. Whole pancreatic and islet transplantations, islet encapsulation, and the potential role of polymeric sustained drug delivery systems are discussed. The medical and social impacts of diabetes mellitus are of prime public health concern and of even greater magnitude than those of heart disease in the United States. While future advances in device design, miniaturization, and biometrials technology will significantly add to the arsenal of therapeutic alternatives, devices capable of controlling blood glucose levels ought to be viewed as mere interim phases rather than as final goals of the problem.

Comparison of Glucose Concentration in Interstitial Fluid, and Capillary and Venous Blood During Rapid Changes in Blood Glucose Levels

2001 ◽  
Vol 3 (3) ◽  
pp. 357-365 ◽  
Author(s):  
Suresh N. Thennadil ◽  
Jessica L. Rennert ◽  
Brian J. Wenzel ◽  
Kevin H. Hazen ◽  
Timothy L. Ruchti ◽  
...  
Keyword(s):  
Blood Glucose ◽  
Glucose Concentration ◽  
Interstitial Fluid ◽  
Venous Blood ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
Rapid Changes

scholarly journals Effects of Liraglutide on β-Cell-Specific Glucokinase-Deficient Neonatal Mice

Endocrinology ◽  
2012 ◽  
Vol 153 (7) ◽  
pp. 3066-3075 ◽  
Author(s):  
Jun Shirakawa ◽  
Ritsuko Tanami ◽  
Yu Togashi ◽  
Kazuki Tajima ◽  
Kazuki Orime ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Glucose Sensor ◽  
Liver Steatosis ◽  
Survival Rates ◽  
Glycolytic Enzyme ◽  
Β Cells ◽  
Β Cell ◽  
Newborn Mice ◽  
Glucose Levels ◽  
Glucagon Like Peptide 1

The glucagon-like peptide-1 receptor agonist liraglutide is used to treat diabetes. A hallmark of liraglutide is the glucose-dependent facilitation of insulin secretion from pancreatic β-cells. In β-cells, the glycolytic enzyme glucokinase plays a pivotal role as a glucose sensor. However, the role of glucokinase in the glucose-dependent action of liraglutide remains unknown. We first examined the effects of liraglutide on glucokinase haploinsufficient (Gck+/−) mice. Single administration of liraglutide significantly improved glucose tolerance in Gck+/− mice without increase of insulin secretion. We also assessed the effects of liraglutide on the survival rates, metabolic parameters, and histology of liver or pancreas of β-cell-specific glucokinase-deficient (Gck−/−) newborn mice. Liraglutide reduced the blood glucose levels in Gck−/− neonates but failed to prolong survival, and all the mice died within 1 wk. Furthermore, liraglutide did not improve glucose-induced insulin secretion in isolated islets from Gck−/− neonates. Liraglutide initially prevented increases in alanine aminotransferase, free fatty acids, and triglycerides in Gck−/− neonates but not at 4 d after birth. Liraglutide transiently prevented liver steatosis, with reduced triglyceride contents and elevated glycogen contents in Gck−/− neonate livers at 2 d after birth. Liraglutide also protected against reductions in β-cells in Gck−/− neonates at 4 d after birth. Taken together, β-cell glucokinase appears to be essential for liraglutide-mediated insulin secretion, but liraglutide may improve glycemic control, steatosis, and β-cell death in a glucokinase-independent fashion.

Co3O4 Nanoparticles as a Noninvasive Electrochemical Sensor for Glucose Detection in Saliva

NANO ◽  
2020 ◽  
pp. 2150009
Author(s):  
Mei Wang ◽  
Fang Liu ◽  
Zhifeng Zhang ◽  
Erchao Meng ◽  
Feilong Gong ◽  
...  
Keyword(s):  
Glucose Sensor ◽  
Saliva Sample ◽  
High Sensitivity ◽  
Single Step ◽  
Uniform Structure ◽  
Glucose Detection ◽  
Co3o4 Nanoparticles ◽  
Glucose Levels ◽  
Maximal Sensitivity ◽  
Sensitivity And Selectivity

A new noninvasive glucose sensor is developed based on Co3O4 particles (Co3O4 NPs), which are synthesized by a single-step hydrothermal method with uniform structure and size. The electrochemical measurements reveal that the device exhibits outstanding performance for glucose detection, achieving a maximal sensitivity of 2495.79[Formula: see text][Formula: see text]A mM[Formula: see text] cm[Formula: see text] with a high [Formula: see text] of 0.99575, a ultra-low detection limit of 9.3[Formula: see text]nM with a signal-to-noise of 3 and linear range up to 3[Formula: see text]mM. The noninvasive glucose sensor can respond swiftly and selectively due to the high electrocatalytic activity of Co3O4 NPs. The sensor also shows its high sensitivity and selectivity in detecting glucose levels in human blood serum and saliva sample, confirming the application potential of Co3O4 NPs in noninvasive detection of glucose.

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