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El Housseini W, Baiarashov E, Gerulskis R, Milam A, Minteer SD. Harnessing Redox Polymer Dynamics for Enhanced Glucose-Oxygen Coupling in Dual Biosensing and Therapeutic Applications. ACS Sens 2024. [PMID: 38842796 DOI: 10.1021/acssensors.4c00685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2024]
Abstract
The burgeoning field of continuous glucose monitoring (CGM) for diabetes management faces significant challenges, particularly in achieving precise and stable biosensor performance under changing environmental conditions such as varying glucose concentrations and O2 levels. To address this, we present a novel biosensor based on the electroless coupling of glucose oxidation catalyzed by flavin-dependent glucose dehydrogenase (FAD-GDH) and O2 reduction catalyzed by bilirubin oxidase (BOD) via a redox polymer, dimethylferrocene-modified linear poly(ethylenimine), FcMe2-LPEI. Initial cyclic voltammetry tests confirm the colocalization of both enzymatic reactions within the potential range of the polymer, indicating an effective electron shuttle mechanism. As a result, we created a hybrid biosensor that operates at open-circuit potential (OCP). It can detect glucose concentrations of up to 100 mM under various O2 conditions, including ambient air. This resulted from optimizing the enzyme ratio to 120 ± 10 mUBOD·UFAD-GDH-1·atmO2-1. This biosensor is highly sensitive, a crucial feature for CGM applications. This distinguishes it from FAD-GDH traditional biosensors, which require a potential to be applied to measure glucose concentrations up to 30 mM. In addition, this biosensor demonstrates the ability to function as a noninvasive, external device that can adapt to changing glucose levels, paving the way for its use in diabetes care and, potentially, personalized healthcare devices. Furthermore, by leveraging the altered metabolic pathways in tumor cells, this system architecture opened up new avenues for targeted glucose scavenging and O2 reduction in cancer therapy.
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Affiliation(s)
- Wassim El Housseini
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
- Kummer Institute Center for Resource Sustainability, Missouri University of Science and Technology, Rolla, Missouri 65409, United States
| | - Egor Baiarashov
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
- Kummer Institute Center for Resource Sustainability, Missouri University of Science and Technology, Rolla, Missouri 65409, United States
| | - Rokas Gerulskis
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Adam Milam
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Shelley D Minteer
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
- Kummer Institute Center for Resource Sustainability, Missouri University of Science and Technology, Rolla, Missouri 65409, United States
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2
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Zhu B, Li X, Zhu L, Qi M, Cao J, Zhou L, Su B. In Vivo Electrochemical Measurement of Glucose Variation in the Brain of Early Diabetic Mice. ACS Sens 2023; 8:4064-4070. [PMID: 37950693 DOI: 10.1021/acssensors.3c01165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2023]
Abstract
Diabetes is a chronic disease caused by a decrease in insulin level or insulin resistance. Diabetes also has detrimental effects on the brain, which can lead to the injury of the blood-brain barrier and influence the glucose transport. In this study, we use in vivo electrochemical measurement to explore the glucose variation in the brain of early diabetic mice. The glucose level in mice brain is measured using a carbon fiber microelectrode modified with the osmium-derivatized polymer and glucose oxidase. The electrode shows an excellent electrochemical performance, antibiofouling ability, and high stability, which can work stably in the mice brain for 2 h. By monitoring the glucose level in the brain of normal and diabetic mice after injection of concentrated glucose solution into the abdominal cavity, it is found that the variation of cerebral glucose decreases by ∼2 fold for diabetic mice. It is proposed that diabetes can downregulate the activity of glucose transporter in the brain and finally inhibit the brain glucose uptake.
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Affiliation(s)
- Boyu Zhu
- Key Laboratory of Excited-State Materials of Zhejiang Province, Institute of Analytical Chemistry, Department of Chemistry, Zhejiang University, Hangzhou 310058, China
| | - Xinru Li
- Key Laboratory of Excited-State Materials of Zhejiang Province, Institute of Analytical Chemistry, Department of Chemistry, Zhejiang University, Hangzhou 310058, China
| | - Lihang Zhu
- Department of Biomedical Engineering, Zhejiang University, Hangzhou 310027, China
| | - Min Qi
- Key Laboratory of Excited-State Materials of Zhejiang Province, Institute of Analytical Chemistry, Department of Chemistry, Zhejiang University, Hangzhou 310058, China
| | - Jiayi Cao
- Key Laboratory of Excited-State Materials of Zhejiang Province, Institute of Analytical Chemistry, Department of Chemistry, Zhejiang University, Hangzhou 310058, China
| | - Lin Zhou
- Key Laboratory of Excited-State Materials of Zhejiang Province, Institute of Analytical Chemistry, Department of Chemistry, Zhejiang University, Hangzhou 310058, China
| | - Bin Su
- Key Laboratory of Excited-State Materials of Zhejiang Province, Institute of Analytical Chemistry, Department of Chemistry, Zhejiang University, Hangzhou 310058, China
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Design of a Sandwich Hierarchically Porous Membrane with Oxygen Supplement Function for Implantable Glucose Sensor. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10082848] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
This study aims to develop an oxygen regeneration layer sandwiched between multiple porous polyurethanes (PU) to improve the performance of implantable glucose sensors. Sensors were prepared by coating electrodes with platinum nanoparticles, Nafion, glucose oxidase and sandwich hierarchically porous membrane with an oxygen supplement function (SHPM-OS). The SHPM-OS consisted of a hierarchically porous structure synthesized by polyethylene glycol and PU and a catalase (Cat) layer that was coated between hierarchical membranes and used to balance the sensitivity and linearity of glucose sensors, as well as reduce the influence of oxygen deficiency during monitoring. Compared with the sensitivity and linearity of traditional non-porous (NO-P) sensors (35.95 nA/mM, 0.9987, respectively) and single porous (SGL-P) sensors (45.3 nA /mM, 0.9610, respectively), the sensitivity and linearity of the SHPM-OS sensor was 98.45 nA/mM and 0.9989, respectively, which was more sensitive with higher linearity. The sensor showed a response speed of five seconds and a relative sensitivity of 90% in the first 10 days and remained 78% on day 20. This sensor coated with SHPM-OS achieved rapid responses to changes of glucose concentration while maintaining high linearity for long monitoring times. Thus, it may reduce the difficulty of back-end hardware module development and assist with effective glucose self-management for people with diabetes.
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Gray ME, Meehan J, Blair EO, Ward C, Langdon SP, Morrison LR, Marland JRK, Tsiamis A, Kunkler IH, Murray A, Argyle D. Biocompatibility of common implantable sensor materials in a tumor xenograft model. J Biomed Mater Res B Appl Biomater 2019; 107:1620-1633. [PMID: 30367816 PMCID: PMC6767110 DOI: 10.1002/jbm.b.34254] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 08/30/2018] [Accepted: 09/09/2018] [Indexed: 12/22/2022]
Abstract
Real-time monitoring of tumor microenvironment parameters using an implanted biosensor could provide valuable information on the dynamic nature of a tumor's biology and its response to treatment. However, following implantation biosensors may lose functionality due to biofouling caused by the foreign body response (FBR). This study developed a novel tumor xenograft model to evaluate the potential of six biomaterials (silicon dioxide, silicon nitride, Parylene-C, Nafion, biocompatible EPOTEK epoxy resin, and platinum) to trigger a FBR when implanted into a solid tumor. Biomaterials were chosen based on their use in the construction of a novel biosensor, designed to measure spatial and temporal changes in intra-tumoral O2 , and pH. None of the biomaterials had any detrimental effect on tumor growth or body weight of the murine host. Immunohistochemistry showed no significant changes in tumor necrosis, hypoxic cell number, proliferation, apoptosis, immune cell infiltration, or collagen deposition. The absence of biofouling supports the use of these materials in biosensors; future investigations in preclinical cancer models are required, with a view to eventual applications in humans. To our knowledge this is the first documented investigation of the effects of modern biomaterials, used in the production of implantable sensors, on tumor tissue after implantation. © 2018 The Authors. Journal of Biomedical Materials Research Part B: Applied Biomaterials published by Wiley Periodicals, Inc. J Biomed Mater Res Part B, 2018. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1620-1633, 2019.
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Affiliation(s)
- Mark E. Gray
- The Royal (Dick) School of Veterinary Studies and Roslin InstituteUniversity of EdinburghEdinburghEH25 9RGUK
- Cancer Research UK Edinburgh Centre and Division of Pathology Laboratories, Institute of Genetics and Molecular MedicineUniversity of EdinburghEdinburghEH4 2XUUK
| | - James Meehan
- Cancer Research UK Edinburgh Centre and Division of Pathology Laboratories, Institute of Genetics and Molecular MedicineUniversity of EdinburghEdinburghEH4 2XUUK
- Institute of Sensors, Signals and Systems, School of Engineering and Physical SciencesHeriot‐Watt UniversityEdinburghEH14 4ASUK
| | - Ewen O. Blair
- School of Engineering, Faraday BuildingEdinburghEH9 3JLUK
| | - Carol Ward
- The Royal (Dick) School of Veterinary Studies and Roslin InstituteUniversity of EdinburghEdinburghEH25 9RGUK
- Cancer Research UK Edinburgh Centre and Division of Pathology Laboratories, Institute of Genetics and Molecular MedicineUniversity of EdinburghEdinburghEH4 2XUUK
| | - Simon P. Langdon
- Cancer Research UK Edinburgh Centre and Division of Pathology Laboratories, Institute of Genetics and Molecular MedicineUniversity of EdinburghEdinburghEH4 2XUUK
| | - Linda R. Morrison
- The Royal (Dick) School of Veterinary Studies and Roslin InstituteUniversity of EdinburghEdinburghEH25 9RGUK
| | | | | | - Ian H. Kunkler
- Cancer Research UK Edinburgh Centre and Division of Pathology Laboratories, Institute of Genetics and Molecular MedicineUniversity of EdinburghEdinburghEH4 2XUUK
| | - Alan Murray
- School of Engineering, Faraday BuildingEdinburghEH9 3JLUK
| | - David Argyle
- The Royal (Dick) School of Veterinary Studies and Roslin InstituteUniversity of EdinburghEdinburghEH25 9RGUK
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Lee I, Loew N, Tsugawa W, Ikebukuro K, Sode K. Development of a third-generation glucose sensor based on the open circuit potential for continuous glucose monitoring. Biosens Bioelectron 2018; 124-125:216-223. [PMID: 30388564 DOI: 10.1016/j.bios.2018.09.099] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 09/10/2018] [Accepted: 09/29/2018] [Indexed: 10/28/2022]
Abstract
Continuous glucose monitoring (CGM) systems are most important in the current Type I diabetes care and as component for the development of artificial pancreas systems because the amount of insulin being supplied is calculated based on the CGM results. Therefore, to stably and accurately control the blood glucose level, CGM should be stable and accurate for a long period. We have been engaged in the biomolecular engineering and application of FAD dependent glucose dehydrogenase complex (FADGDH) which is capable of direct electron transfer. In this study, we report the development of the third-generation type open circuit potential (OCP) principle-based glucose sensor with direct electron transfer FADGDH immobilized on gold electrodes using a self-assembled monolayer (SAM). We developed a novel algorithm for OCP-based glucose sensors. By employing this new algorithm, high reproducibility of measurement and sensor preparation were achieved. In addition, the signal was not affected by the presence of acetaminophen and ascorbic acid in the sample solution. The thus optimized third-generation OCP-based glucose sensor could be operated continuously for more than 9 days without significant change in the signal, sensitivity and dynamic range, indicating its potential application for CGM systems.
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Affiliation(s)
- Inyoung Lee
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan; Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 and North Carolina State University, Raleigh, NC 27695, USA
| | - Noya Loew
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 and North Carolina State University, Raleigh, NC 27695, USA
| | - Wakako Tsugawa
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Kazunori Ikebukuro
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Koji Sode
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan; Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 and North Carolina State University, Raleigh, NC 27695, USA.
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6
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Maahs DM, DeSalvo D, Pyle L, Ly T, Messer L, Clinton P, Westfall E, Wadwa RP, Buckingham B. Effect of acetaminophen on CGM glucose in an outpatient setting. Diabetes Care 2015; 38:e158-9. [PMID: 26269199 PMCID: PMC4876736 DOI: 10.2337/dc15-1096] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 07/02/2015] [Indexed: 02/03/2023]
Affiliation(s)
- David M. Maahs
- Barbara Davis Center for Childhood Diabetes, University of Colorado, Aurora, CO,Corresponding author: David M. Maahs,
| | - Daniel DeSalvo
- Division of Endocrinology and Diabetes, Department of Pediatrics, Stanford University School of Medicine, Stanford, CA
| | - Laura Pyle
- Barbara Davis Center for Childhood Diabetes, University of Colorado, Aurora, CO
| | - Trang Ly
- Division of Endocrinology and Diabetes, Department of Pediatrics, Stanford University School of Medicine, Stanford, CA
| | - Laurel Messer
- Barbara Davis Center for Childhood Diabetes, University of Colorado, Aurora, CO
| | - Paula Clinton
- Division of Endocrinology and Diabetes, Department of Pediatrics, Stanford University School of Medicine, Stanford, CA
| | - Emily Westfall
- Barbara Davis Center for Childhood Diabetes, University of Colorado, Aurora, CO
| | - R. Paul Wadwa
- Barbara Davis Center for Childhood Diabetes, University of Colorado, Aurora, CO
| | - Bruce Buckingham
- Division of Endocrinology and Diabetes, Department of Pediatrics, Stanford University School of Medicine, Stanford, CA
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7
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Cordeiro C, de Vries M, Ngabi W, Oomen P, Cremers T, Westerink B. In vivo continuous and simultaneous monitoring of brain energy substrates with a multiplex amperometric enzyme-based biosensor device. Biosens Bioelectron 2015; 67:677-86. [DOI: 10.1016/j.bios.2014.09.101] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Revised: 08/27/2014] [Accepted: 09/22/2014] [Indexed: 01/30/2023]
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8
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Du X, Durgan CJ, Matthews DJ, Motley JR, Tan X, Pholsena K, Árnadóttir L, Castle JR, Jacobs PG, Cargill RS, Ward WK, Conley JF, Herman GS. Fabrication of a Flexible Amperometric Glucose Sensor Using Additive Processes. ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY : JSS 2015; 4:P3069-P3074. [PMID: 26634186 PMCID: PMC4664458 DOI: 10.1149/2.0101504jss] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
This study details the use of printing and other additive processes to fabricate a novel amperometric glucose sensor. The sensor was fabricated using a Au coated 12.7 μm thick polyimide substrate as a starting material, where micro-contact printing, electrochemical plating, chloridization, electrohydrodynamic jet (e-jet) printing, and spin coating were used to pattern, deposit, chloridize, print, and coat functional materials, respectively. We have found that e-jet printing was effective for the deposition and patterning of glucose oxidase inks with lateral feature sizes between ~5 to 1000 μm in width, and that the glucose oxidase was still active after printing. The thickness of the permselective layer was optimized to obtain a linear response for glucose concentrations up to 32 mM and no response to acetaminophen, a common interfering compound, was observed. The use of such thin polyimide substrates allow wrapping of the sensors around catheters with high radius of curvature ~250 μm, where additive and microfabrication methods may allow significant cost reductions.
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Affiliation(s)
- Xiaosong Du
- School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, Oregon 97331, USA
| | - Christopher J. Durgan
- School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, Oregon 97331, USA
| | - David J. Matthews
- School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, Oregon 97331, USA
| | - Joshua R. Motley
- School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, Oregon 97331, USA
| | - Xuebin Tan
- School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, Oregon 97331, USA
| | - Kovit Pholsena
- School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, Oregon 97331, USA
| | - Líney Árnadóttir
- School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, Oregon 97331, USA
| | | | - Peter G. Jacobs
- Pacific Diabetes Technologies, Portland, Oregon 97201, USA
- Oregon Health & Science University, Portland, Oregon 97239, USA
| | | | | | - John F. Conley
- School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, Oregon 97331, USA
| | - Gregory S. Herman
- School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, Oregon 97331, USA
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9
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Adamson TL, Cook CB, LaBelle JT. Detection of 1,5-Anhydroglucitol by Electrochemical Impedance Spectroscopy. J Diabetes Sci Technol 2014; 8:350-355. [PMID: 24876587 PMCID: PMC4455417 DOI: 10.1177/1932296814523874] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Multiple markers are used to assess glycemic control in patients with diabetes mellitus (DM). New technology that permits simultaneous detection of multiple biomarkers combined with those used at the point of care indicative of glycemic control, including glycemic variability determined from 1,5-anhydroglucitol measurement, could provide better management and further insight into the disease. This platform was based on previous research involving glucose detection and uses electrochemical impedance spectroscopy to detect a range of 1,5-anhydroglucitol concentrations at an optimal binding frequency. The enzyme pyranose oxidase was fixed to gold electrodes while a sine wave of sweeping frequencies was induced in purified solutions and in variable presence of whole blood. The optimal binding frequency for the detection of 1,5-anhydroglucitol was found to be 3.71 kHz. The impedance response compared to the concentration of target present was found to have a logarithmic slope of 7.04 with an R-squared value of 0.96. This response includes 2 experimental sets, a single test of a low concentration range and a high concentration range with 5 replicates. The relative standard deviation of the high range varied from 28% to 27% from lowest to highest concentrations. Best detection in complex solutions was found in lower blood concentrations of 0.5% and 1%, but maintained relatively high accuracy in concentrations 5% and 10%. The sensor platform was successfully evaluated at a high dynamic range of 1,5-AG in purified solutions. In the presence of whole blood, lowest percentages yielded the best results indicating that filtering interferents may be necessary in final device architecture.
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Affiliation(s)
- Teagan L Adamson
- Harrington Biomedical Engineering Program in the School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, USA
| | - Curtiss B Cook
- Division of Endocrinology and Division of Preventive, Occupational, and Aerospace Medicine, Mayo Clinic Arizona, Scottsdale, AZ, USA
| | - Jeffrey T LaBelle
- Harrington Biomedical Engineering Program in the School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, USA
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10
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Adamson TL, Eusebio FA, Cook CB, LaBelle JT. The promise of electrochemical impedance spectroscopy as novel technology for the management of patients with diabetes mellitus. Analyst 2012; 137:4179-87. [PMID: 22842610 DOI: 10.1039/c2an35645g] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Self-monitoring of blood glucose is the standard of care in management of hyperglycemia among patients with diabetes mellitus. To increase the sensitivity and specificity of current devices, a novel method of detecting glucose using electrochemical impedance spectroscopy (EIS) technology is explored. The enzyme glucose oxidase (GOx) was fixed to gold electrodes and a sine wave of sweeping frequencies was induced using a wide range of concentrations of glucose. Each frequency in the impedance sweep was analyzed for the highest response and R-squared value. The frequency with both factors optimized is specific for the glucose-GOx binding interaction and was determined to be 1.17 kHz in purified solutions in both higher and lower ranges of glucose. The correlation between the impedance response and concentration at the low range of detection (0-100 mg dL(-1) of glucose) was determined to be 3.53 ohm/ln (mg dL(-1)) with an R-squared value of 0.90 with a 39 mg dL(-1) lower limit of detection. The same frequency of 1.17 kHz was verified in whole blood under the same glucose range. The above data confirm that EIS offers a new method of glucose detection as an alternative to current technology in use by patients. Additionally, the unique frequency response of individual markers allows for modulation of signals so that several other markers important in the management of diabetes could be measured with a single sensor.
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Affiliation(s)
- Teagan Leigh Adamson
- Harrington Biomedical Engineering Program in the School of Biological and Health Systems Engineering, Arizona State University, The Biodesign Institute, Tempe, 85287-9709, USA
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11
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Li Q, Cheng K, Weng W, Du P, Han G. Highly sensitive hydrogen peroxide biosensors based on TiO2 nanodots/ITO electrodes. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm30853c] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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12
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Peng Y, Wei CW, Liu YN, Li J. Nafion coating the ferrocenylalkanethiol and encapsulated glucose oxidase electrode for amperometric glucose detection. Analyst 2011; 136:4003-7. [DOI: 10.1039/c1an15292k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Heinemann L. Quality of glucose measurement with blood glucose meters at the point-of-care: relevance of interfering factors. Diabetes Technol Ther 2010; 12:847-57. [PMID: 20879962 DOI: 10.1089/dia.2010.0076] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AIM A good understanding of the relevance of interfering factors having an impact on blood glucose (BG) measurement is needed to obtain the required quality. This depends on the application in which meters designed for self-monitoring of BG (SMBG) are used. METHODS By means of a literature search all publications (from January 1, 1980 to August 10, 2009) were identified that report about the influence of potentially interfering substances/factors on the measurement quality of BG meters. RESULTS Certain substances (e.g., maltose) can have a profound and misleading impact on the BG measurement result when the enzymatic reaction embedded on the given test strips cross-reacts. Also, a number of other drugs (e.g., acetaminophen) and factors (like temperature and altitude) affect the reliability of BG measurement massively. However, the susceptibility of the BG meter (depending on the enzyme technology of the test strips) differs significantly. CONCLUSIONS In daily practice the factors that have a relevant impact on the reliability of BG measurements with modern BG meters are rarely met. Clearly this also depends on the intended use (SMBG in patient hands vs. point-of-care testing in hospitals). To avoid misleading measurement results requires adequate training of all people involved.
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Affiliation(s)
- Lutz Heinemann
- Profil Institut für Stoffwechselforschung GmbH, Hellersbergstrasse 9, Neuss, Germany.
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14
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Peng Y, Jiang D, Su L, Zhang L, Yan M, Du J, Lu Y, Liu YN, Zhou F. Mixed monolayers of ferrocenylalkanethiol and encapsulated horseradish peroxidase for sensitive and durable electrochemical detection of hydrogen peroxide. Anal Chem 2009; 81:9985-92. [PMID: 19928778 PMCID: PMC2795022 DOI: 10.1021/ac901833s] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
This paper describes the construction of a mixed monolayer of ferrocenylalkanethiol and encapsulated horseradish peroxidase (HRP) at a gold electrode for amperometric detection of H(2)O(2) at trace levels. By tuning the alkanethiol chain lengths that tether the HRP enzyme and the ferrocenylalkanethiol (FcC(11)SH) mediator, facile electron transfer between FcC(11)SH and HRP can be achieved. Unlike most HRP-based electrochemical sensors, which rely on HRP-facilitated H(2)O(2) reduction (to H(2)O), the electrocatalytic current is resulted from an HRP-catalyzed oxidation reaction of H(2)O(2) (to O(2)). Upon optimizing other experimental conditions (surface coverage ratio, pH, and flow rate), the electrocatalytic reaction proceeding at the electrode was used to attain a low amperometric detection level (0.64 nM) and a dynamic range spanning over 3 orders of magnitude. Not only does the thin hydrophilic porous HRP capsule allow facile electron transfer, it also enables H(2)O(2) to permeate. More significantly, the enzymatic activity of the encapsulated HRP is retained for a considerably longer period (>3 weeks) than naked HRP molecules attached to an electrode or those wired to a redox polymer thin film. By comparing to electrodes modified with denatured HRP that are subsequently encapsulated or embedded in a poly-L-lysine matrix, it is concluded that the encapsulation has significantly preserved the native structure of HRP and therefore its enzymatic activity. The electrode covered with FcC(11)SH and encapsulated HRP is shown to be capable of rapidly and reproducibly detecting H(2)O(2) present in complex sample media.
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Affiliation(s)
- Yong Peng
- Department of Chemistry and Biochemistry, California State University, Los Angeles, Los Angeles, California 90032, USA
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15
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Rowinski P, Rowinska M, Heller A. Liquid Crystal Membranes for Serum-Compatible Diabetes Management-Assisting Subcutaneously Implanted Amperometric Glucose Sensors. Anal Chem 2008; 80:1746-55. [DOI: 10.1021/ac702151u] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Pawel Rowinski
- Department of Chemical Engineering, University of Texas, Austin, Texas 78712
| | - Magdalena Rowinska
- Department of Chemical Engineering, University of Texas, Austin, Texas 78712
| | - Adam Heller
- Department of Chemical Engineering, University of Texas, Austin, Texas 78712
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16
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Klueh U, Dorsky DI, Kreutzer DL. Use of vascular endothelial cell growth factor gene transfer to enhance implantable sensor function
in vivo. J Biomed Mater Res A 2003; 67:1072-86. [PMID: 14666925 DOI: 10.1002/jbm.a.20041] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In the current study, we developed and validated a simple, rapid and safe in vivo model to test gene transfer and sensor function in vivo. Using the model, we tested the specific hypothesis that in vivo gene transfer of angiogenic factors at sites of biosensor implantation would induce neovascularization surrounding the sensor and thereby enhance biosensor function in vivo. As the in vivo site for testing of our gene transfer cell and biosensor function systems, the developing chorioallantoic membrane (CAM) of the embryo was utilized. Vascular endothelial cell growth factor (VEGF) was used as a prototype for angiogenic factor gene transfer. A helper-independent retroviral vector derived from Rous sarcoma virus (RSV), designated RCAS, was used for gene transfer of the murine VEGF (mVEGF) gene (mVEGF:RCAS) into the DF-1 chicken cell line (designated mVEGF:DF-1). Initially, the ability of VEGF:DF-1 cells to produce VEGF and RCAS viral vectors containing the mVEGF gene (mVEGF:RCAS) was validated in vitro and in vivo, as was the ability of the mVEGF:DF-1 cells to induce neovascularization in the ex ova CAM model. Using the system, we determined the ability of mVEGF:DF-1 cells to enhance acetaminophen sensor function in vivo, by inducing neovascularization at sites of sensor implantation in the ex ova CAM model. For these studies, acetaminophen sensors were placed on 8-day-old ex ova CAMs, followed by addition of media or cells (mVEGF:DF-1 cells or GFP:DF-1 cells) at the sites of biosensor implantation on the CAM. At 4 to 10 days after sensor placement, the biosensor function was determined by measuring sensor response to an intravenous injection of acetaminophen. Sensors implanted on CAMs with buffer or control cells (GFP:DF-1 cells) displayed no induced neovascularization around the sensor and had minimal/baseline sensor responses to intravenous acetaminophen injection (media, 133.33 +/- 27.64 nA; GFP:DF-1, 187.50 +/- 55.43 nA). Alternatively, the sensors implanted with mVEGF:DF-1 cells displayed massive neovascularization and equally massive sensor response to intravenous injection of acetaminophen (VEGF:DF-1, 1387.50 +/- 276.42 nA). These data clearly demonstrate that enhancing vessel density (i.e., neovascularization) around an implanted sensor dramatically enhances sensor function in vivo.
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Affiliation(s)
- U Klueh
- Center for Molecular Tissue Engineering, University of Connecticut, School of Medicine, Farmington 06030, USA
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17
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Abel PU, von Woedtke T. Biosensors for in vivo glucose measurement: can we cross the experimental stage. Biosens Bioelectron 2002; 17:1059-70. [PMID: 12392956 DOI: 10.1016/s0956-5663(02)00099-4] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The development of in vivo working glucose sensors needs two decades, so far. The availability of long term functional implantable biosensors for continuous glucose measurings is a basic prerequisite for the individualized optimum insulin treatment of diabetics. Enzymatic electrochemical sensors are described which realize a functional stability over more than 2 years in vitro, however their function in vivo is limited due to certain bioincompatibility expressed by inflammation of the surrounding tissue, exudates, and immun reactions. The paper reflects an overview concerning different sensor covering materials used as more or less suitable diffusion membranes. From experimental studies in animals and human volunteers conclusions are drawn for further developmental steps of biosensors for in vivo use and for the applicability of glucose sensors for transient diagnostic purposes and as a basis for glucose controlled therapeutic measures. The results demonstrate that further progress aimed at long term biostability of implanted biosensors needs to solve technological problems and the serial production of sensors with really comparable qualities as a prerequisite for clinical trials.
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Affiliation(s)
- P U Abel
- Institute of Pathophysiology of the Ernst Moritz Arndt, University of Greifswald, Greifswalder Strasse 11b, D-17495 Karlsburg, Germany.
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18
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Ward WK, Jansen LB, Anderson E, Reach G, Klein JC, Wilson GS. A new amperometric glucose microsensor: in vitro and short-term in vivo evaluation. Biosens Bioelectron 2002; 17:181-9. [PMID: 11839471 DOI: 10.1016/s0956-5663(01)00268-8] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
For biosensor fabrication, it is important to optimize materials and methods in order to create predictable function in vitro and in vivo. For this reason, we designed a new glucose sensor ('revised protocol') that utilized an outer permselective membrane made of amphiphobic polyurethane which allows glucose passage through hydrophilic segments. An inner polyethersulfone membrane, stabilized with a trimethoxysilane, provided specificity. Before application of the inner membrane, it was necessary to etch the platinum electrode with a radio frequency oxygen plasma. The revised protocol sensors (n=185) were compared with sensors fabricated with an earlier ('original') protocol (n=204) which used an outer polyurethane without hydrophilic segments and a complex inner membrane of cellulose acetate and Nafion. The function of revised protocol sensors was more predictable in vitro as evidenced by a much lower variation of glucose sensitivity than the original protocol sensors. Revised and original protocol sensors were nearly linear up to a glucose concentration of 20 mM. In vitro interference from 0.1 mM acetaminophen was minimal in both groups of sensors and would be expected to represent about 2% of the total sensor response at normal glucose levels for revised protocol sensors. Prolonged testing of the revised protocol sensors for 11 days during immersion in buffer revealed stable sensitivities (day 1: 6.12+/-1.34 nA/mM; day 3: 6.33+/-1.40; day 8: 7.13+/-1.39; and day 11: 7.56+/-1.47; sensitivity for day 1 vs. each other day: not significant) and no critical loss of glucose oxidase activity. The response of the revised protocol sensors (n=7) to intraperitoneal glucose was tested in rats approximately one day after subcutaneous implantation and the sensors tracked glucose closely with a slight lag of 3-6 min.
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Affiliation(s)
- W Kenneth Ward
- iSense Corporation, 16125 SW 72nd Avenue, Portland, OR 97224, USA.
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19
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Affiliation(s)
- G S Wilson
- Department of Chemistry and the Center for Neurobiology and Immunology Research, University of Kansas, Lawrence, Kansas 66045
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20
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Aussedat B, Dupire-Angel M, Gifford R, Klein JC, Wilson GS, Reach G. Interstitial glucose concentration and glycemia: implications for continuous subcutaneous glucose monitoring. Am J Physiol Endocrinol Metab 2000; 278:E716-28. [PMID: 10751207 DOI: 10.1152/ajpendo.2000.278.4.e716] [Citation(s) in RCA: 140] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The changes in plasma glucose concentration and in interstitial glucose concentration, determined with a miniaturized subcutaneous glucose sensor, were investigated in anesthetized nondiabetic rats. Interstitial glucose was estimated through two different calibration procedures. First, after a glucose load, the magnitude of the increase in interstitial glucose, estimated through a one-point calibration procedure, was 70% of that in plasma glucose. We propose that this is due to the effect of endogenous insulin on peripheral glucose uptake. Second, during the spontaneous secondary decrease in plasma glucose after the glucose load, interstitial glucose decreased faster than plasma glucose, which may also be due to the effect of insulin on peripheral glucose uptake. Third, during insulin-induced hypoglycemia, the decrease in interstitial glucose was less marked than that of plasma glucose, suggesting that hypoglycemia suppressed transfer of glucose into the interstitial tissue; subsequently, interstitial glucose remained lower than plasma glucose during its return to basal value, suggesting that the stimulatory effect of insulin on peripheral glucose uptake was protracted. If these observations obtained in rats are relevant to human physiology, such discrepancies between plasma and interstitial glucose concentration may have major implications for the use of a subcutaneous glucose sensor in continuous blood glucose monitoring in diabetic patients.
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Affiliation(s)
- B Aussedat
- Department of Diabetology, Institut National de la Santé et de la Recherche Médicale U341, Hôtel-Dieu, 75004 Paris, France
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21
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Ward WK, Wood MD, Troupe JE. Rise in background current over time in a subcutaneous glucose sensor in the rabbit: relevance to calibration and accuracy. Biosens Bioelectron 2000; 15:53-61. [PMID: 10826643 DOI: 10.1016/s0956-5663(00)00051-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In order to calibrate a continuous glucose monitor, accurate determination of the background current (I0) is necessary, in part because I0 could change over time. We compared two methods of I0 measurement: (1), extrapolation of sensor output data (as a function of glucose level) to the intercept at zero glucose and (2) direct measurement of the output of a blank anode with no enzyme coat. We implanted telemetric sensors subcutaneously in rabbits and measured their outputs during tri-level glucose clamps once per week for 5 weeks. The two methods yielded similar results. I0 rose substantially over time and this increase reached significance during week 3 by the direct method but not until week 5 by the extrapolation method. Using the direct method, I0 rose from 3.41 (0.60-8.48 nanoamperes (nA), median and range) during week 1 to 13.42 (9.1-14.3) during week 5. Using the extrapolation method, I0 rose from 0.57 (0-16.7) during week 1 to 15.3 (12.2-21.6) during week 5. We conclude that I0 can rise over time. If this rise went undetected and was assumed to be stable, a one-point calibration procedure would overestimate glycemia in the hypoglycemic range, i.e. fail to appreciate the severity of hypoglycemia. It is recommended that during validation of a chronic glucose sensor, I0 be measured sequentially over time.
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Affiliation(s)
- W K Ward
- Legacy Health System, Holladay Park Research Center, Portland, OR 97232, USA.
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22
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Thomé-Duret V, Aussedat B, Reach G, Gangnerau MN, Lemonnier F, Klein JC, Zhang Y, Hu Y, Wilson GS. Continuous glucose monitoring in the free-moving rat. Metabolism 1998; 47:799-803. [PMID: 9667224 DOI: 10.1016/s0026-0495(98)90115-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The aim of this work was to set up an experimental model of glycemic fluctuations for assessing in the conscious freely moving rat, the performance of a continuous glucose-monitoring system, using a pocket-calculator-size electronic control unit and a miniaturized subcutaneous glucose sensor. The well-known triphasic glycemic pattern following streptozotocin injection (initial peak and secondary hypoglycemia preceding the establishment of permanent hyperglycemia) was used as a way to obtain spontaneous changes in blood glucose level over a wide concentration range. This report demonstrates that streptozotocin injection produced highly reproducible changes in the current generated by the sensor: an initial peak and a secondary nadir, during which blood sampling provided the evidence of hyperglycemia associated with immunoreactive hypoinsulinemia, and of hypoglycemia associated with hyperinsulinemia, respectively. This reproducible experimental model should be valuable for the assessment of a continuous glucose-monitoring system.
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Affiliation(s)
- V Thomé-Duret
- INSERM U341, Département de Diabétologie, Hôtel-Dieu, Paris, France
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23
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Gerritsen M, Jansen JA, Kros A, Nolte RJ, Lutterman JA. Performance of subcutaneously implanted glucose sensors: a review. J INVEST SURG 1998; 11:163-74. [PMID: 9743484 DOI: 10.3109/08941939809098031] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Despite a considerable amount of research attributed to the development of an implantable glucose sensor, to date there is no clinically applicable concept for continuous glucose monitoring. Investigations to validate the subcutaneous tissue for continuous glucose sensing mostly comprise short-term implantations of glucose sensors. Most implanted glucose sensors showed a significant decay in sensitivity over the implantation period. This bioinstability was not to be expected from the in vitro performance of the sensors. In this article, the influence of possible failure mechanisms on the poor in vivo performance of subcutaneously implanted glucose sensors is reviewed.
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Affiliation(s)
- M Gerritsen
- Department of Biomaterials, University of Nijmegen, The Netherlands
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24
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Cartier LJ, Leclerc P, Pouliot M, Nadeau L, Turcotte G, Fruteau-de-Laclos B. Toxic Levels of Acetaminophen Produce a Major Positive Interference on Glucometer Elite and Accu-chek Advantage Glucose Meters. Clin Chem 1998. [DOI: 10.1093/clinchem/44.4.893] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
| | | | | | | | | | - Bernard Fruteau-de-Laclos
- Service de biochimie, Centre Hospitalier Affilié Univ. de Québec, 1401, 18e rue Québec, Quebec G1J 1Z4, Canada
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25
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Aussedat B, Thomé-Duret V, Reach G, Lemmonier F, Klein JC, Hu Y, Wilson GS. A user-friendly method for calibrating a subcutaneous glucose sensor-based hypoglycaemic alarm. Biosens Bioelectron 1998; 12:1061-71. [PMID: 9451795 DOI: 10.1016/s0956-5663(97)00083-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A crucial step in developing a glucose monitoring system using a subcutaneous implanted glucose sensor is the transformation of the sensor signal (a current) into an estimation of a blood glucose concentration. We have developed an Electronic Control Unit (ECU) able to recognize, before and after a glucose load, that the sensor current presents a plateau, thus triggering an alarm asking for blood glucose determination. The system, fed with these results, subsequently transforms the current into an estimation of glucose concentration by linear extrapolation based on the sensor sensitivity and the background current computed from the two sets of current and glycaemia values (two-point calibration). In addition, the system is able to trigger an alarm when this estimation decreases below a threshold that can be set by the user. This system was evaluated in experiments performed in 12 normal rats. The quality of the calibration was assessed by comparing, by error grid analysis, the data displayed on the liquid-crystal display of the ECU to concomitant plasma glucose concentration determined at frequent intervals, 65 +/- 6 and 26 +/- 5% of the values were in zones A (good) and B (acceptable estimation) of the grid, respectively. The system was set to trigger an alarm when the estimation of glucose concentration decreased below 70 mg/dl. Following an insulin administration, the alarm was triggered when the system displayed a 64 +/- 2 mg/dl glucose concentration. The concomitant plasma glucose concentration was 59 +/- 5 mg/dl (NS). In conclusion, this work validates experimentally the new, user-friendly method for calibrating the glucose sensor integrated into the ECU, based on an automatic detection of plateaus. The quality of the sensor calibration performed with this procedure is compatible with the appropriate functioning of this continuous glucose monitoring system, which was demonstrated by its ability to detect mild hypoglycaemia following insulin injection.
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Affiliation(s)
- B Aussedat
- INSERM U 341, Department of Diabetology, Hôtel-Dieu, Paris, France
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26
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Atanasov P, Yang S, Salehi C, Ghindilis AL, Wilkins E, Schade D. Implantation of a refillable glucose monitoring-telemetry device. Biosens Bioelectron 1997; 12:669-80. [PMID: 9366023 DOI: 10.1016/s0956-5663(97)00025-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This study describes the components and short-term in vivo evaluation of an integrated implantable system consisting of an amperometric glucose biosensor, a miniature potentiostat, a FM signal transmitter, and a power supply. The device (dimensions: 5.0 x 7.0 x 1.5 cm) was implanted subcutaneously in healthy mongrel dogs. The biosensor performance was evaluated in vitro prior to implantation using standard solutions simulating the physiological environment. A linear response to glucose concentration was observed throughout the physiological and pathophysiological range (with an upper limit of 25 mM glucose, and a sensitivity of 0.5 microA/mM). The results of short-term subcutaneous implantation of the integrated system demonstrated good agreement between the glucose concentration measured by the biosensor and that obtained using standard glucose determination methods. The delay-time between the tissue glucose level (measured by the biosensor) and the blood glucose level (obtained by standard methodology) was 3-7 min. These results demonstrated the feasibility of data transmission by a telemetry system through the skin of a dog and allowed the commencement of chronic in vivo testing. During the chronic implantation the biosensor was refilled in vivo. A rejuvenation of the sensor's response after refilling was observed suggesting the potential of such sensors for long-term implantation.
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Affiliation(s)
- P Atanasov
- Department of Chemical and Nuclear Engineering, School of Engineering, University of New Mexico, Albuquerque 87131, USA
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27
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Atanasov P, Yang S, Salehi C, Ghindilis AL, Wilkins E. Short-term canine implantation of a glucose monitoring-telemetry device. Med Eng Phys 1996; 18:632-40. [PMID: 8953555 DOI: 10.1016/s1350-4533(96)00024-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In this study we report the development and short-term in vivo evaluation of an integrated implantable device consisting of an amperometric glucose biosensor, a miniature potentiostat, a FM signal transmitter, and power supply. The device (dimensions: 5.0 x 7.0 x 1.5 cm) was implanted under the skin of medium-size anaesthetized dog. The experimental set-up included several methods for data collection: analog recording via wired X-T chart recorders; data collection by wearable microprocessor--data logger, and remote data collection via antenna and receiver linked to a computer-based data acquisition system. The device (sensor) performance was evaluated in vitro prior to implantation, using different model solutions simulating the physiological environment. A linear response to glucose concentration was obtained up to 25 mM glucose, with a sensitivity of 0.5 microA/mM. The results of short-term subcutaneous implantation of the integrated device reveal adequate monitoring of an artificially-induced glycaemia. The delay-time was 3-7 minutes. These tests demonstrate the feasibility of data transmission by the telemetry system through the skin of a medium-sized dog and allow the commencement of chronic in vivo experimentation.
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Affiliation(s)
- P Atanasov
- Department of Chemical and Nuclear Engineering, School of Engineering, University of New Mexico, Albuquerque 87131, USA
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28
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Carlsson T, Adamson U, Lins PE, Danielsson B. Use of an enzyme thermistor for semi-continuous blood glucose measurements. Clin Chim Acta 1996; 251:187-200. [PMID: 8862473 DOI: 10.1016/0009-8981(96)06306-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A method to monitor glucose in whole blood is presented. The aim of the project was to develop a prototype for a bedside monitor system for semi-continuous monitoring of the blood glucose concentration, requiring only one calibration. This was made possible by using the special advantage of the thermal sensor technique in combination with the adjustment of flow. The glucose concentration was determined from the difference between the sensor response and an estimated background signal. Using standard addition technique, calibration factors for background and sensitivity were set and remained unchanged during the monitoring. The background signal was 45 +/- 8 mV (mean +/- S.D., n = 8) and the sensitivity was 28 +/- 1 mV/mmol (mean +/- S.D., n = 4). Recovery in whole blood was 90-98% (mean 94%, n = 12). With an injection interval of 3 min the precision with the sensor was < 3% over more than 100 blood samples. Response time was about 60 s. The calculated glucose values correlated, r = 0.98, with the values obtained with an YSI glucose analyser (Yellow Springs Instruments. Yellow Springs, OH, USA), over the range 2-20 mmol/l.
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Affiliation(s)
- T Carlsson
- Department of Medicine, Karolinska Institutet, Danderyd Hospital, Stockholm, Sweden
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29
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Abstract
Over the past 18 months, our understanding of the chemistry and engineering principles of amperometric biosensors, including bioaffinity sensors, has deepened. In addition, several novel amperometric biosensors have been commercialized and progress has been made in the design of subcutaneous sensors, particularly those for glucose.
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Affiliation(s)
- A Heller
- Department of Chemical Engineering, University of Texas at Austin 78712-1062, USA
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