scholarly journals Porous Platinum Black-Coated Minimally Invasive Microneedles for Non-Enzymatic Continuous Glucose Monitoring in Interstitial Fluid

Nanomaterials ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 37
Author(s):  
Somasekhar R. Chinnadayyala ◽  
Sungbo Cho
Keyword(s):  
Continuous Glucose Monitoring ◽  
Photoelectron Spectroscopy ◽  
Interstitial Fluid ◽  
Dynamic Range ◽  
Glucose Monitoring ◽  
Stability Loss ◽  
Blood Glucose Monitoring ◽  
Platinum Black ◽  
X Ray ◽  
Relative Standard

Individuals with diabetes can benefit considerably from continuous blood glucose monitoring. To address this challenge, a proof-of-concept was performed for continuous glucose monitoring (CGM) based on an enzymeless porous nanomaterial (pNM)-modified microneedle electrode array (MNEA). The pNM sensing layer was electrochemically deposited on MNs by applying a fixed negative current of −2.5 mA cm˗2 for 400 s. The pNM-modified MNEA was packed using a biocompatible Nafion ionomer. The fabricated MNEAs were 600 × 100 × 150 µm in height, width, and thickness, respectively. The surfaces of the modified MNs were characterized by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The fabricated MNEAs showed a wide dynamic range (1–30 mM) in phosphate-buffered saline (PBS) and in artificial interstitial fluid (ISF), with good sensitivities (PBS: 1.792 ± 0.25 µA mM−1 cm−2, ISF: 0.957 ± 0.14 µA mM−1 cm−2) and low detection limits (PBS: 7.2 µM, ISF: 22 µM). The sensor also showed high stability (loss of 3.5% at the end of 16 days), selectivity, and reproducibility (Relative standard deviations (RSD) of 1.64% and 0.70% for intra- and inter-assay, respectively) and a good response time (2 s) with great glucose recovery rates in ISF (98.7–102%).

Interstitial fluid glucose time-lag correction for real-time continuous glucose monitoring

2013 ◽  
Vol 8 (1) ◽  
pp. 81-89 ◽  
Author(s):  
D. Barry Keenan ◽  
John J. Mastrototaro ◽  
Stuart A. Weinzimer ◽  
Garry M. Steil
Keyword(s):  
Real Time ◽  
Continuous Glucose Monitoring ◽  
Interstitial Fluid ◽  
Time Lag ◽  
Glucose Monitoring

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.

scholarly journals Accuracy of flash glucose monitoring and continuous glucose monitoring technologies: Implications for clinical practice

2018 ◽  
Vol 15 (3) ◽  
pp. 175-184 ◽  
Author(s):  
Ramzi A Ajjan ◽  
Michael H Cummings ◽  
Peter Jennings ◽  
Lalantha Leelarathna ◽  
Gerry Rayman ◽  
...  
Keyword(s):  
Continuous Glucose Monitoring ◽  
Diabetes Care ◽  
Interstitial Fluid ◽  
Glucose Monitoring ◽  
Relative Difference ◽  
Glucose Sensing ◽  
Sensor Data ◽  
Flash Glucose Monitoring ◽  
Fluid Sensor ◽  
Monitoring Technologies

Continuous glucose monitoring and flash glucose monitoring technologies measure glucose in the interstitial fluid and are increasingly used in diabetes care. Their accuracy, key to effective glycaemic management, is usually measured using the mean absolute relative difference of the interstitial fluid sensor compared to reference blood glucose readings. However, mean absolute relative difference is not standardised and has limitations. This review aims to provide a consensus opinion on assessing accuracy of interstitial fluid glucose sensing technologies. Mean absolute relative difference is influenced by glucose distribution and rate of change; hence, we express caution on the reliability of comparing mean absolute relative difference data from different study systems and conditions. We also review the pitfalls associated with mean absolute relative difference at different glucose levels and explore additional ways of assessing accuracy of interstitial fluid devices. Importantly, much data indicate that current practice of assessing accuracy of different systems based on individualised mean absolute relative difference results has limitations, which have potential clinical implications. Healthcare professionals must understand the factors that influence mean absolute relative difference as a metric for accuracy and look at additional assessments, such as consensus error grid analysis, when evaluating continuous glucose monitoring and flash glucose monitoring systems in diabetes care. This in turn will ensure that management decisions based on interstitial fluid sensor data are both effective and safe.

scholarly journals Continuous Glucose Monitoring in Critically Ill Patients With COVID-19: Results of an Emergent Pilot Study

2020 ◽  
Vol 14 (6) ◽  
pp. 1065-1073
Author(s):  
Archana R. Sadhu ◽  
Ivan Alexander Serrano ◽  
Jiaqiong Xu ◽  
Tariq Nisar ◽  
Jessica Lucier ◽  
...  
Keyword(s):  
Blood Glucose ◽  
Pilot Study ◽  
Insulin Therapy ◽  
Critically Ill ◽  
Continuous Glucose Monitoring ◽  
Critically Ill Patients ◽  
Point Of Care ◽  
Glucose Monitoring ◽  
Blood Glucose Monitoring ◽  
Target Range

Background: Amidst the coronavirus disease 2019 (COVID-19) pandemic, continuous glucose monitoring (CGM) has emerged as an alternative for inpatient point-of-care blood glucose (POC-BG) monitoring. We performed a feasibility pilot study using CGM in critically ill patients with COVID-19 in the intensive care unit (ICU). Methods: Single-center, retrospective study of glucose monitoring in critically ill patients with COVID-19 on insulin therapy using Medtronic Guardian Connect and Dexcom G6 CGM systems. Primary outcomes were feasibility and accuracy for trending POC-BG. Secondary outcomes included reliability and nurse acceptance. Sensor glucose (SG) was used for trends between POC-BG with nursing guidance to reduce POC-BG frequency from one to two hours to four hours when the SG was in the target range. Mean absolute relative difference (MARD), Clarke error grids analysis (EGA), and Bland-Altman (B&A) plots were calculated for accuracy of paired SG and POC-BG measurements. Results: CGM devices were placed on 11 patients: Medtronic ( n = 6) and Dexcom G6 ( n = 5). Both systems were feasible and reliable with good nurse acceptance. To determine accuracy, 437 paired SG and POC-BG readings were analyzed. For Medtronic, the MARD was 13.1% with 100% of readings in zones A and B on Clarke EGA. For Dexcom, MARD was 11.1% with 98% of readings in zones A and B. B&A plots had a mean bias of −17.76 mg/dL (Medtronic) and −1.94 mg/dL (Dexcom), with wide 95% limits of agreement. Conclusions: During the COVID-19 pandemic, CGM is feasible in critically ill patients and has acceptable accuracy to identify trends and guide intermittent blood glucose monitoring with insulin therapy.

scholarly journals Electrochemically Activated Conductive Ni-Based MOFs for Non-enzymatic Sensors Toward Long-Term Glucose Monitoring

2020 ◽  
Vol 8 ◽  
Author(s):  
Yating Chen ◽  
Yulan Tian ◽  
Ping Zhu ◽  
Liping Du ◽  
Wei Chen ◽  
...  
Keyword(s):  
Continuous Glucose Monitoring ◽  
Glucose Sensor ◽  
Glucose Monitoring ◽  
Glucose Sensors ◽  
Blood Glucose Monitoring ◽  
Diabetic Patients ◽  
Potential Range ◽  
Potential Applications ◽  
Naoh Solution

Continuous intensive monitoring of glucose is one of the most important approaches in recovering the quality of life of diabetic patients. One challenge for electrochemical enzymatic glucose sensors is their short lifespan for continuous glucose monitoring. Therefore, it is of great significance to develop non-enzymatic glucose sensors as an alternative approach for long-term glucose monitoring. This study presented a highly sensitive and selective electrochemical non-enzymatic glucose sensor using the electrochemically activated conductive Ni3(2,3,6,7,10,11-hexaiminotriphenylene)2 MOFs as sensing materials. The morphology and structure of the MOFs were investigated by scanning SEM and FTIR, respectively. The performance of the activated electrode toward the electrooxidation of glucose in alkaline solution was evaluated with cyclic voltammetry technology in the potential range from 0.2 V to 0.6 V. The electrochemical activated Ni-MOFs exhibited obvious anodic (0.46 V) and cathodic peaks (0.37 V) in the 0.1 M NaOH solution due to the Ni(II)/Ni(III) transfer. A linear relationship between the glucose concentrations (ranging from 0 to 10 mM) and anodic peak currents with R2 = 0.954 was obtained. It was found that the diffusion of glucose was the limiting step in the electrochemical reaction. The sensor exhibited good selectivity toward glucose in the presence of 10-folds uric acid and ascorbic acid. Moreover, this sensor showed good long-term stability for continuous glucose monitoring. The good selectivity, stability, and rapid response of this sensor suggests that it could have potential applications in long-term non-enzymatic blood glucose monitoring.

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