scholarly journals Continuous Non-Invasive Glucose Monitoring via Contact Lenses: Current Approaches and Future Perspectives

Biosensors ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 189
Author(s):  
David Bamgboje ◽  
Iasonas Christoulakis ◽  
Ioannis Smanis ◽  
Gaurav Chavan ◽  
Rinkal Shah ◽  
...  
Keyword(s):  
Embedded System ◽  
Contact Lenses ◽  
Glucose Monitoring ◽  
Ease Of Use ◽  
Biofuel Cell ◽  
Glucose Measurement ◽  
Rf Power ◽  
Lacrimal Fluid ◽  
Non Invasive ◽  
Invasive Techniques

Diabetes mellitus (DM) is a chronic disease that must be carefully managed to prevent serious complications such as cardiovascular disease, retinopathy, nephropathy and neuropathy. Self-monitoring of blood glucose is a crucial tool for managing diabetes and, at present, all relevant procedures are invasive while they only provide periodic measurements. The pain and measurement intermittency associated with invasive techniques resulted in the exploration of painless, continuous, and non-invasive techniques of glucose measurement that would facilitate intensive management. The focus of this review paper is the existing solutions for continuous non-invasive glucose monitoring via contact lenses (CLs) and to carry out a detailed, qualitative, and comparative analysis to inform prospective researchers on viable pathways. Direct glucose monitoring via CLs is contingent on the detection of biomarkers present in the lacrimal fluid. In this review, emphasis is given on two types of sensors: a graphene-AgNW hybrid sensor and an amperometric sensor. Both sensors can detect the presence of glucose in the lacrimal fluid by using the enzyme, glucose oxidase. Additionally, this review covers fabrication procedures for CL biosensors. Ever since Google published the first glucose monitoring embedded system on a CL, CL biosensors have been considered state-of-the-art in the medical device research and development industry. The CL not only has to have a sensory system, it must also have an embedded integrated circuit (IC) for readout and wireless communication. Moreover, to retain mobility and ease of use of the CLs used for continuous glucose monitoring, the power supply to the solid-state IC on such CLs must be wireless. Currently, there are four methods of powering CLs: utilizing solar energy, via a biofuel cell, or by inductive or radiofrequency (RF) power. Although, there are many limitations associated with each method, the limitations common to all, are safety restrictions and CL size limitations. Bearing this in mind, RF power has received most of the attention in reported literature, whereas solar power has received the least attention in the literature. CLs seem a very promising target for cutting edge biotechnological applications of diagnostic, prognostic and therapeutic relevance.

Indole as a new tentative marker in exhaled breath for non-invasive blood glucose monitoring of diabetic subjects

2021 ◽  
Author(s):  
Herbert Fink ◽  
Tim Maihöfer ◽  
Jeffrey Bender ◽  
Jochen Schulat
Keyword(s):  
Blood Glucose ◽  
Diabetes Management ◽  
Glucose Monitoring ◽  
Blood Glucose Monitoring ◽  
Glucose Measurement ◽  
Diabetic Patients ◽  
Exhaled Breath ◽  
Invasive Approach ◽  
Test Strips ◽  
Non Invasive

Abstract Blood glucose monitoring (BGM) is the most important part of diabetes management. In classical BGM, glucose measurement by test strips involves invasive finger pricking. We present results of a clinical study that focused on a non-invasive approach based on volatile organic compounds (VOCs) in exhaled breath. Main objective was the discovery of markers for prediction of blood glucose levels (BGL) in diabetic patients. Exhaled breath was measured repeatedly in 60 diabetic patients (30 type 1, 30 type 2) in fasting state and after a standardized meal. Proton Transfer Reaction Time of Flight Mass Spectrometry (PTR-ToF-MS) was used to sample breath every 15 minutes for a total of six hours. BGLs were tested in parallel via BGM test strips. VOC signals were plotted against glucose trends for each subject to identify correlations. Exhaled indole (a bacterial metabolite of tryptophan) showed significant mean correlation to BGL (with negative trend) and significant individual correlation in 36 patients. The type of diabetes did not affect this result. Additional experiments of one healthy male subject by ingestion of lactulose and 13C-labeled glucose (n=3) revealed that exhaled indole does not directly originate from food digestion by intestinal microbiota. As indole has been linked to human glucose metabolism, it might be a tentative marker in breath for non-invasive BGM. Clinical studies with greater diversity are required for confirmation of such results and further investigation of metabolic pathways.

scholarly journals Design and Dimensional Measurement of Interdigital Sensor for Blood Glucose Measurement through Non-Invasive Method

2019 ◽  
Vol 8 (4) ◽  
pp. 6437-6441
Keyword(s):  
Glucose Monitoring ◽  
Blood Glucose Measurement ◽  
World Health ◽  
Glucose Measurement ◽  
Noninvasive Technique ◽  
Glucose Levels ◽  
Non Invasive ◽  
Reduced Physical Activity ◽  
Invasive Method ◽  
Health Organization

Diabetes has shown to be a chronic disease world over, mainly caused due to reduced physical activity and increased obesity. World health organization statistics show diabetes as a leading cause of disability universally. To avoid extreme medical conditions of subjects, regular monitoring of their glucose levels has been suggested. The most common method that has been in use is the pinprick method for glucose monitoring which carries the risk of contamination as well as irritation. One possible approach called noninvasive technique can be adopted to avoid this major concern. This paper presents designing Inter-Digital-Sensor (IDS) for non-invasive sensing of the glucose level. The sensor-based chip once mounted onto the upper arm or pinkie finger of diabetes subject, is able to sense different glucose levels concentration as impedance plots. A set of several simulation results has been obtained using COMSOL for getting optimized dimensions of the sensor digits. This research has presented the generation of an electric field and intensity by using electrode of known length with element spacing varying from 250µm to 600µm developed over 15mm x 20mm sensor area. An ID of 475µm width spacing with ten (10) digits producing 2.33 pF of capacitance value with impedance resonating at 13 GHz of frequency is reported in this paper

Depth-selective photothermal IR spectroscopy of skin: potential application for non-invasive glucose measurement

The Analyst ◽  
2017 ◽  
Vol 142 (3) ◽  
pp. 495-502 ◽  
Author(s):  
Otto Hertzberg ◽  
Alexander Bauer ◽  
Arne Küderle ◽  
Miguel A. Pleitez ◽  
Werner Mäntele
Keyword(s):  
Ir Spectroscopy ◽  
Total Internal Reflection ◽  
Depth Profiling ◽  
Glucose Monitoring ◽  
Glucose Measurement ◽  
Skin Potential ◽  
Non Invasive ◽  
Photothermal Deflection Spectroscopy ◽  
Photothermal Deflection

Photothermal depth profiling is applied to total internal reflection enhanced photothermal deflection spectroscopy (TIR-PTDS) in order to study skin characteristicsin vivoand to improve the sensing technique for non-invasive glucose monitoring.

scholarly journals Glucose detection of ringer-lactate solution using electrical bioimpedance: preliminary results

2021 ◽  
Vol 2008 (1) ◽  
pp. 012003
Author(s):  
B G Pedro ◽  
P Bertemes-Filho
Keyword(s):  
Analytical Model ◽  
Glucose Monitoring ◽  
Training Sample ◽  
Glucose Measurement ◽  
Future Research ◽  
Non Invasive ◽  
Relaxation Coefficient ◽  
Electrical Bioimpedance ◽  
Measurement Devices ◽  
The Right

Abstract Continuous glucose monitoring is essential to reduce the damages caused by diabetes and for choosing the right treatment approach. In most cases, non-invasive glucose measurement devices generate their results through statistical tools (e.g., artificial neural networks) with an error that increases the further away from the training sample the measurement is. An analytical model would contain only propagated errors. Impedance measurements of lactate ringer’s solutions with egg albumin containing different concentrations of sugar were performed to validate the model proposed for measuring glycemia in human blood using the electrical bioimpedance meter AD5933. The curve fitting showed errors lower than 1.5%. Chemical phenomena, such as reduced sugar, fructosamine and solvation, might explain the behaviors observed in the experiments. The results suggest that the relaxation coefficient has significant changes with the increase of sugar in the solutions. The findings encourage future research with bovine blood for a more realistic analytical model.

Evaluation of the Accuracy and Safety of a Portable Metabolic Heat Conformation-Based Non-invasive Glucose Meter: A Multicentre Clinical Study. (Preprint)

2021 ◽  
Author(s):  
Yuanmeng Xu ◽  
Ang Li ◽  
Chenyang Wu ◽  
Zhanxiao Geng ◽  
Junqing Zhang ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Blood Glucose ◽  
Clinical Study ◽  
Glucose Monitoring ◽  
Blood Glucose Monitoring ◽  
Glucose Measurement ◽  
Non Invasive ◽  
Metabolic Heat ◽  
Fasted State ◽  
Glucose Meter

BACKGROUND Non-invasive blood glucose measurement is expected to be an ideal way for glucose monitoring, although most of the methods are under study and yet to be verified in large-scale clinical trials. OBJECTIVE We intend to evaluate the stability, accuracy of the metabolic heat conformation (MHC)-based non-invasive glucometer in a multicentre, self-controlled clinical trial. This device obtained the first medical device registration certificate awarded by the National Medical Products Administration of China (NMPA). METHODS The clinical study was conducted at three sites on 200 subjects who received glucose measurement with a non-invasive glucometer, the Contour Plus blood glucose monitoring system, and venous plasma glucose (VPG) measurements, in a fasted state and at 2 and 4 hours after meals. Trial Registration: ChiCTR1900020523. RESULTS The non-invasive and VPG measurements showed 93.9% (95% CI, 91.7–95.6%) of the values in zone A + B in a Consensus Error Grid. The measurements obtained in a fasted state and at 2 hours after meals are more accurate, with 99.0% and 97.0% of the values in zone A + B, respectively. The proportion of values in zone A + B and the correlation coefficients in subjects who did not receive insulin were 3.1% and 0.0596 higher than in those who received insulin. The accuracy of the non-invasive glucometer was influenced by the level of islet cell function and insulin resistance, which had a correlation coefficient with the MARD of -0.0961 (p=0.020) and -0.1577 (p=0.00012), respectively. CONCLUSIONS The MHC-based non-invasive glucometer demonstrates generally high stability and accuracy in the glucose monitoring of diabetic patients. The calculation model needs to be further explored and optimised for patients with different diabetes subtypes, levels of insulin resistance and insulin secretion capacity. CLINICALTRIAL the name of the trial registry : A multi-center study for evaluating the accuracy and safety of noninvasive glucose meter in people with diabetes or impaired glucose regulation (impaired fasting glucose and impaired glucose tolerance), using an experimental test system as a reference. registration number : ChiCTR1900020523 URL : https://www.chictr.org.cn/showproj.aspx?proj=33857

scholarly journals The Progress of Glucose Monitoring—A Review of Invasive to Minimally and Non-Invasive Techniques, Devices and Sensors

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 800 ◽  
Author(s):  
Wilbert Villena Gonzales ◽  
Ahmed Mobashsher ◽  
Amin Abbosh
Keyword(s):  
New Technologies ◽  
Accuracy Assessment ◽  
Glucose Monitoring ◽  
Future Trend ◽  
Electromagnetic Spectrum ◽  
Glucose Detection ◽  
Monitoring Methods ◽  
Value Prediction ◽  
Non Invasive ◽  
Invasive Techniques

Current glucose monitoring methods for the ever-increasing number of diabetic people around the world are invasive, painful, time-consuming, and a constant burden for the household budget. The non-invasive glucose monitoring technology overcomes these limitations, for which this topic is significantly being researched and represents an exciting and highly sought after market for many companies. This review aims to offer an up-to-date report on the leading technologies for non-invasive (NI) and minimally-invasive (MI) glucose monitoring sensors, devices currently available in the market, regulatory framework for accuracy assessment, new approaches currently under study by representative groups and developers, and algorithm types for signal enhancement and value prediction. The review also discusses the future trend of glucose detection by analyzing the usage of the different bands in the electromagnetic spectrum. The review concludes that the adoption and use of new technologies for glucose detection is unavoidable and closer to become a reality.

scholarly journals Advances in Biosensors for Continuous Glucose Monitoring Towards Wearables

2021 ◽  
Vol 9 ◽  
Author(s):  
Lucy Johnston ◽  
Gonglei Wang ◽  
Kunhui Hu ◽  
Chungen Qian ◽  
Guozhen Liu
Keyword(s):  
Contact Lenses ◽  
Glucose Monitoring ◽  
Non Invasive ◽  
Bodily Fluids ◽  
Recent Developments ◽  
Low Glucose ◽  
Continuous Glucose Monitors ◽  
Diabetic Person ◽  
Glucose Biosensing ◽  
Blood Glucose Concentrations

Continuous glucose monitors (CGMs) for the non-invasive monitoring of diabetes are constantly being developed and improved. Although there are multiple biosensing platforms for monitoring glucose available on the market, there is still a strong need to enhance their precision, repeatability, wearability, and accessibility to end-users. Biosensing technologies are being increasingly explored that use different bodily fluids such as sweat and tear fluid, etc., that can be calibrated to and therefore used to measure blood glucose concentrations accurately. To improve the wearability of these devices, exploring different fluids as testing mediums is essential and opens the door to various implants and wearables that in turn have the potential to be less inhibiting to the wearer. Recent developments have surfaced in the form of contact lenses or mouthguards for instance. Challenges still present themselves in the form of sensitivity, especially at very high or low glucose concentrations, which is critical for a diabetic person to monitor. This review summarises advances in wearable glucose biosensors over the past 5 years, comparing the different types as well as the fluid they use to detect glucose, including the CGMs currently available on the market. Perspectives on the development of wearables for glucose biosensing are discussed.

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