Sensors

Research

Jump to: Review

1657 KiB

Open AccessArticle

Use of Wearable Sensors and Biometric Variables in an Artificial Pancreas System

by Kamuran Turksoy, Colleen Monforti, Minsun Park, Garett Griffith, Laurie Quinn and Ali Cinar

Sensors 2017, 17(3), 532; https://doi.org/10.3390/s17030532 - 7 Mar 2017

Cited by 24 | Viewed by 7729

Abstract

An artificial pancreas (AP) computes the optimal insulin dose to be infused through an insulin pump in people with Type 1 Diabetes (T1D) based on information received from a continuous glucose monitoring (CGM) sensor. It has been recognized that exercise is a major [...] Read more.

An artificial pancreas (AP) computes the optimal insulin dose to be infused through an insulin pump in people with Type 1 Diabetes (T1D) based on information received from a continuous glucose monitoring (CGM) sensor. It has been recognized that exercise is a major challenge in the development of an AP system. The use of biometric physiological variables in an AP system may be beneficial for prevention of exercise-induced challenges and better glucose regulation. The goal of the present study is to find a correlation between biometric variables such as heart rate (HR), heat flux (HF), skin temperature (ST), near-body temperature (NBT), galvanic skin response (GSR), and energy expenditure (EE), 2D acceleration-mean of absolute difference (MAD) and changes in glucose concentrations during exercise via partial least squares (PLS) regression and variable importance in projection (VIP) in order to determine which variables would be most useful to include in a future artificial pancreas. PLS and VIP analyses were performed on data sets that included seven different types of exercises. Data were collected from 26 clinical experiments. Clinical results indicate ST to be the most consistently important (important for six out of seven tested exercises) variable over all different exercises tested. EE and HR are also found to be important variables over several types of exercise. We also found that the importance of GSR and NBT observed in our experiments might be related to stress and the effect of changes in environmental temperature on glucose concentrations. The use of the biometric measurements in an AP system may provide better control of glucose concentration. Full article

(This article belongs to the Special Issue Glucose Sensors: Revolution in Diabetes Management 2016)

► Show Figures

Figure 1

Figure 1
Linear regressions between biometric variables for 1 treadmill exercise session. Red colored correlation coefficients indicate statistical correlation. The diagonal figures show histograms for each biometric variable. Full article ">Figure 2
Distribution of VIP values for each biometric variable measured during treadmill exercise sessions. Full article ">Figure 3
Distribution of VIP values for each biometric variable measured during treadmill exercise- interval training sessions. Full article ">Figure 4
Distribution of VIP values for each biometric variable measured during exercise stress test sessions. Full article ">Figure 5
Distribution of VIP values for each biometric variable measured during submaximal resistance training sessions. Full article ">Figure 6
Distribution of VIP values for each biometric variable measured during maximal resistance training sessions. Full article ">Figure 7
Distribution of VIP values for each biometric variable measured during bike exercise sessions. Full article ">Figure 8
Distribution of VIP values for each biometric variable measured during workout video sessions. Full article ">

455 KiB

Open AccessArticle

Continuous Glucose Monitoring Enables the Detection of Losses in Infusion Set Actuation (LISAs)

by Daniel P. Howsmon, Faye Cameron, Nihat Baysal, Trang T. Ly, Gregory P. Forlenza, David M. Maahs, Bruce A. Buckingham, Juergen Hahn and B. Wayne Bequette

Sensors 2017, 17(1), 161; https://doi.org/10.3390/s17010161 - 15 Jan 2017

Cited by 20 | Viewed by 6780

Abstract

Reliable continuous glucose monitoring (CGM) enables a variety of advanced technology for the treatment of type 1 diabetes. In addition to artificial pancreas algorithms that use CGM to automate continuous subcutaneous insulin infusion (CSII), CGM can also inform fault detection algorithms that alert [...] Read more.

Reliable continuous glucose monitoring (CGM) enables a variety of advanced technology for the treatment of type 1 diabetes. In addition to artificial pancreas algorithms that use CGM to automate continuous subcutaneous insulin infusion (CSII), CGM can also inform fault detection algorithms that alert patients to problems in CGM or CSII. Losses in infusion set actuation (LISAs) can adversely affect clinical outcomes, resulting in hyperglycemia due to impaired insulin delivery. Prolonged hyperglycemia may lead to diabetic ketoacidosis—a serious metabolic complication in type 1 diabetes. Therefore, an algorithm for the detection of LISAs based on CGM and CSII signals was developed to improve patient safety. The LISA detection algorithm is trained retrospectively on data from 62 infusion set insertions from 20 patients. The algorithm collects glucose and insulin data, and computes relevant fault metrics over two different sliding windows; an alarm sounds when these fault metrics are exceeded. With the chosen algorithm parameters, the LISA detection strategy achieved a sensitivity of 71.8% and issued 0.28 false positives per day on the training data. Validation on two independent data sets confirmed that similar performance is seen on data that was not used for training. The developed algorithm is able to effectively alert patients to possible infusion set failures in open-loop scenarios, with limited evidence of its extension to closed-loop scenarios. Full article

(This article belongs to the Special Issue Glucose Sensors: Revolution in Diabetes Management 2016)

► Show Figures

Figure 1

888 KiB

Open AccessArticle

Continuous Glucose Monitoring Sensors: Past, Present and Future Algorithmic Challenges

by Andrea Facchinetti

Sensors 2016, 16(12), 2093; https://doi.org/10.3390/s16122093 - 9 Dec 2016

Cited by 127 | Viewed by 14556

Abstract

Continuous glucose monitoring (CGM) sensors are portable devices that allow measuring and visualizing the glucose concentration in real time almost continuously for several days and are provided with hypo/hyperglycemic alerts and glucose trend information. CGM sensors have revolutionized Type 1 diabetes (T1D) management, [...] Read more.

Continuous glucose monitoring (CGM) sensors are portable devices that allow measuring and visualizing the glucose concentration in real time almost continuously for several days and are provided with hypo/hyperglycemic alerts and glucose trend information. CGM sensors have revolutionized Type 1 diabetes (T1D) management, improving glucose control when used adjunctively to self-monitoring blood glucose systems. Furthermore, CGM devices have stimulated the development of applications that were impossible to create without a continuous-time glucose signal, e.g., real-time predictive alerts of hypo/hyperglycemic episodes based on the prediction of future glucose concentration, automatic basal insulin attenuation methods for hypoglycemia prevention, and the artificial pancreas. However, CGM sensors’ lack of accuracy and reliability limited their usability in the clinical practice, calling upon the academic community for the development of suitable signal processing methods to improve CGM performance. The aim of this paper is to review the past and present algorithmic challenges of CGM sensors, to show how they have been tackled by our research group, and to identify the possible future ones. Full article

(This article belongs to the Special Issue Glucose Sensors: Revolution in Diabetes Management 2016)

► Show Figures

Figure 1

3522 KiB

Open AccessArticle

Remote Blood Glucose Monitoring in mHealth Scenarios: A Review

by Giordano Lanzola, Eleonora Losiouk, Simone Del Favero, Andrea Facchinetti, Alfonso Galderisi, Silvana Quaglini, Lalo Magni and Claudio Cobelli

Sensors 2016, 16(12), 1983; https://doi.org/10.3390/s16121983 - 24 Nov 2016

Cited by 30 | Viewed by 9747

Abstract

Glucose concentration in the blood stream is a critical vital parameter and an effective monitoring of this quantity is crucial for diabetes treatment and intensive care management. Effective bio-sensing technology and advanced signal processing are therefore of unquestioned importance for blood glucose monitoring. [...] Read more.

Glucose concentration in the blood stream is a critical vital parameter and an effective monitoring of this quantity is crucial for diabetes treatment and intensive care management. Effective bio-sensing technology and advanced signal processing are therefore of unquestioned importance for blood glucose monitoring. Nevertheless, collecting measurements only represents part of the process as another critical task involves delivering the collected measures to the treating specialists and caregivers. These include the clinical staff, the patient’s significant other, his/her family members, and many other actors helping with the patient treatment that may be located far away from him/her. In all of these cases, a remote monitoring system, in charge of delivering the relevant information to the right player, becomes an important part of the sensing architecture. In this paper, we review how the remote monitoring architectures have evolved over time, paralleling the progress in the Information and Communication Technologies, and describe our experiences with the design of telemedicine systems for blood glucose monitoring in three medical applications. The paper ends summarizing the lessons learned through the experiences of the authors and discussing the challenges arising from a large-scale integration of sensors and actuators. Full article

(This article belongs to the Special Issue Glucose Sensors: Revolution in Diabetes Management 2016)

► Show Figures

Figure 1

Figure 1
The early architecture adopted for the remote monitoring of Type 1 Diabetes Patients. The architecture encompassed two separate units, each one hosting different services, asynchronously communicating using modems operating over landlines. Full article ">Figure 2
The web-centric architecture emerged during the first decade of the new century. A large number of devices accessed a central server using multimodal techniques. Full article ">Figure 3
The architecture adopted for a Body Area Network sees multiple wearable devices coordinated by a Body Gateway. The Body Gateway interacts using Bluetooth with the Network Hub that enacts remote monitoring. Full article ">Figure 4
The architecture illustrating the components used in the final trial of AP@home, with the Diabetes Assistant acting both as a Body Gateway and as a Network Hub. Full article ">Figure 5
The remote monitoring architecture used for the adolescents camp held in Bardonecchia. The system was used by the clinical and technical staff for safety and research purposes and was proposed to the parents as a means of managing the disease of their children. Full article ">Figure 6
The components developed for the Neokid mobile application. (a) the smartphone application; (b) the detailed Continuous Glucose Monitoring track for a single patient; and (c) the panel with the suggested glucose infusion rates. Full article ">

3181 KiB

Open AccessArticle

A Robust, Enzyme-Free Glucose Sensor Based on Lysine-Assisted CuO Nanostructures

by Qurrat-ul-Ain Baloach, Aneela Tahira, Arfana Begum Mallah, Muhammad Ishaq Abro, Siraj Uddin, Magnus Willander and Zafar Hussain Ibupoto

Sensors 2016, 16(11), 1878; https://doi.org/10.3390/s16111878 - 14 Nov 2016

Cited by 24 | Viewed by 6180

Abstract

The production of a nanomaterial with enhanced and desirable electrocatalytic properties is of prime importance, and the commercialization of devices containing these materials is a challenging task. In this study, unique cupric oxide (CuO) nanostructures were synthesized using lysine as a soft template [...] Read more.

The production of a nanomaterial with enhanced and desirable electrocatalytic properties is of prime importance, and the commercialization of devices containing these materials is a challenging task. In this study, unique cupric oxide (CuO) nanostructures were synthesized using lysine as a soft template for the evolution of morphology via a rapid and boiled hydrothermal method. The morphology and structure of the synthesized CuO nanomaterial were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The prepared CuO nanostructures showed high potential for use in the electrocatalytic oxidation of glucose in an alkaline medium. The proposed enzyme-free glucose sensor demonstrated a robust response to glucose with a wide linear range and high sensitivity, selectivity, stability, and reproducibility. To explore its practical feasibility, the glucose content of serum samples was successfully determined using the enzyme-free sensor. An analytical recovery method was used to measure the actual glucose from the serum samples, and the results were satisfactory. Moreover, the presented glucose sensor has high chemical stability and can be reused for repetitive measurements. This study introduces an enzyme-free glucose sensor as an alternative tool for clinical glucose quantification. Full article

(This article belongs to the Special Issue Glucose Sensors: Revolution in Diabetes Management 2016)

► Show Figures

Figure 1

2105 KiB

Open AccessArticle

Non-Enzymatic Glucose Sensing Using Carbon Quantum Dots Decorated with Copper Oxide Nanoparticles

by Houcem Maaoui, Florina Teodoresu, Qian Wang, Guo-Hui Pan, Ahmed Addad, Radhouane Chtourou, Sabine Szunerits and Rabah Boukherroub

Sensors 2016, 16(10), 1720; https://doi.org/10.3390/s16101720 - 18 Oct 2016

Cited by 45 | Viewed by 9305

Abstract

Perturbations in glucose homeostasis is critical for human health, as hyperglycemia (defining diabetes) leads to premature death caused by macrovascular and microvascular complications. However, the simple and accurate detection of glucose in the blood at low cost remains a challenging task, although it [...] Read more.

Perturbations in glucose homeostasis is critical for human health, as hyperglycemia (defining diabetes) leads to premature death caused by macrovascular and microvascular complications. However, the simple and accurate detection of glucose in the blood at low cost remains a challenging task, although it is of great importance for the diagnosis and therapy of diabetic patients. In this work, carbon quantum dots decorated with copper oxide nanostructures (CQDs/Cu₂O) are prepared by a simple hydrothermal approach, and their potential for electrochemical non-enzymatic glucose sensing is evaluated. The proposed sensor exhibits excellent electrocatalytic activity towards glucose oxidation in alkaline solutions. The glucose sensor is characterized by a wide concentration range from 6 µM to 6 mM, a sensitivity of 2.9 ± 0.2 µA·µM⁻¹·cm⁻², and a detection limit of 6 µM at a signal-to-noise ratio S/N = 3. The sensors are successfully applied for glucose determination in human serum samples, demonstrating that the CQDs/Cu₂O-based glucose sensor satisfies the requirements of complex sample detection with adapted potential for therapeutic diagnostics. Full article

(This article belongs to the Special Issue Glucose Sensors: Revolution in Diabetes Management 2016)

► Show Figures

Figure 1

Figure 1
Characterization of carbon quantum dots loaded with copper oxide nanoparticles (CQDs/Cu2O NPs): (A) X-ray powder diffraction (XRD) pattern; (B) transmission electron microscopy (TEM) image; (C) high-resolution TEM (HRTEM) image. Full article ">Figure 2
(A) X-ray photoelectron spectroscopy (XPS) survey spectrum; (B) Cu2p core level spectrum; (C) C1s core level spectrum; (D) Raman spectrum; (E) thermogravimetric analysis (TGA) thermogram of CQDs/Cu2O nanocomposite. Full article ">Figure 3
Cyclic voltammograms of (A) glassy carbon electrode (GCE); (B) GCE/Cu2O; and (C) GCE modified with CQDs/Cu2O by drop casting in 0.1 M NaOH aqueous solution in the absence (red) and presence of glucose (black, 100 µM). Full article ">Figure 4
(A) Amperometric response curve of CQDs/Cu2O-modified GCE polarized at +0.55 V vs. Ag/AgCl upon successive additions of glucose (100 µM) in 0.1 M NaOH (up to a total of 500 µM); (B) Calibration curve for CQDs/Cu2O-modified GCE electrodes for the determination of glucose. The inset corresponds to a calibration curve for glucose concentrations of 0–10 µM. Full article ">Figure 5
(A) Interference test of CQDs/Cu2O-modified GCE electrode in 0.1 M NaOH at +0.55 V with 100 µM glucose in the presence 500 µM dopamine (DA), uric acid (UA), ascorbic acid (AA), fructose, galactose; (B) current response to the addition of serum; (C) UV/Vis spectra of different concentrations of glucose as well as of the serum samples (ten times diluted) together with calibration curve (D). Full article ">

3253 KiB

Open AccessArticle

Mid-Infrared Photoacoustic Detection of Glucose in Human Skin: Towards Non-Invasive Diagnostics

by Jonas Kottmann, Julien M. Rey and Markus W. Sigrist

Sensors 2016, 16(10), 1663; https://doi.org/10.3390/s16101663 - 10 Oct 2016

Cited by 85 | Viewed by 13320

Abstract

Diabetes mellitus is a widespread metabolic disease without cure. Great efforts are being made to develop a non-invasive monitoring of the blood glucose level. Various attempts have been made, including a number of non-optical approaches as well as optical techniques involving visible, near- [...] Read more.

Diabetes mellitus is a widespread metabolic disease without cure. Great efforts are being made to develop a non-invasive monitoring of the blood glucose level. Various attempts have been made, including a number of non-optical approaches as well as optical techniques involving visible, near- and mid-infrared light. However, no true breakthrough has been achieved so far, i.e., there is no fully non-invasive monitoring device available. Here we present a new study based on mid-infrared spectroscopy and photoacoustic detection. We employ two setups, one with a fiber-coupled photoacoustic (PA) cell and a tunable quantum cascade laser (QCL), and a second setup with two QCLs at different wavelengths combined with PA detection. In both cases, the PA cells are in direct skin contact. The performance is tested with an oral glucose tolerance test. While the first setup often gives reasonable qualitative agreement with ordinary invasive blood glucose measurements, the dual-wavelength approach yields a considerably improved stability and an uncertainty of only ±30 mg/dL of the blood glucose concentration level at a confidence level of 90%. This result is achieved without advanced data treatment such as principal component analysis involving extended wavelength ranges. Full article

(This article belongs to the Special Issue Glucose Sensors: Revolution in Diabetes Management 2016)

► Show Figures

Figure 1

1828 KiB

Open AccessCommunication

A Human Serum-Based Enzyme-Free Continuous Glucose Monitoring Technique Using a Needle-Type Bio-Layer Interference Sensor

by Dongmin Seo, Sung-Ho Paek, Sangwoo Oh, Sungkyu Seo and Se-Hwan Paek

Sensors 2016, 16(10), 1581; https://doi.org/10.3390/s16101581 - 24 Sep 2016

Cited by 8 | Viewed by 6836

Abstract

The incidence of diabetes is continually increasing, and by 2030, it is expected to have increased by 69% and 20% in underdeveloped and developed countries, respectively. Therefore, glucose sensors are likely to remain in high demand in medical device markets. For the current [...] Read more.

The incidence of diabetes is continually increasing, and by 2030, it is expected to have increased by 69% and 20% in underdeveloped and developed countries, respectively. Therefore, glucose sensors are likely to remain in high demand in medical device markets. For the current study, we developed a needle-type bio-layer interference (BLI) sensor that can continuously monitor glucose levels. Using dialysis procedures, we were able to obtain hypoglycemic samples from commercial human serum. These dialysis-derived samples, alongside samples of normal human serum were used to evaluate the utility of the sensor for the detection of the clinical interest range of glucose concentrations (70–200 mg/dL), revealing high system performance for a wide glycemic state range (45–500 mg/dL). Reversibility and reproducibility were also tested over a range of time spans. Combined with existing BLI system technology, this sensor holds great promise for use as a wearable online continuous glucose monitoring system for patients in a hospital setting. Full article

(This article belongs to the Special Issue Glucose Sensors: Revolution in Diabetes Management 2016)

► Show Figures

Figure 1

Figure 1
Needle-type sensor performance and the influence of membrane size on the detection of glucose concentrations in defined buffer. (a) Schematic of the needle-type sensor. A syringe needle was modified and covered with a semi-permeable membrane to fabricate the needle-type sensor. Bovine serum albumin (BSA)-ligand conjugate was kept outside of the semi-permeable membrane; (b) A glucose sensing profile generated by the sensor. The wavelength shift increases with time as the sensor is exposed to the buffer containing the BSA-ligand conjugates, whereas the shift sharply decreases as the sensor is exposed to a solution of 500 mg/dL glucose (with BSA-ligand conjugate); (c) Membrane pore-size performance. The response of the sensor increased as the pore size increased from 50 nm to 200 nm. Con A: concanavalin A. Full article ">Figure 2
Schematic of the dialysis method and the performance of the sensor for the detection of a broad range of glucose concentrations. (a) Schematic of the dialysis procedure. A dialysis bag containing a mixture of glucose oxidase and human serum was used. This dialysis bag was kept in the container of human serum to reduce the glucose concentration of the serum. The time vs. glucose concentration is the glucose attrition of the serum measured with a standard strip sensor; (b) Performance of the needle-type sensor. The sensor shows a peak at 1800 s for the batch 1 samples (dialyzed human serum: 45 mL/dL, 100 mL/dL, 250 mL/dL, and 500 mL/dL), which have glucose concentrations comparable to that observed in hypoglycemia, whereas this peak is not observed in the profile for batch 2 (normal human serum: 100 mL/dL, 250 mL/dL, and 500 mL/dL). Averaged standard deviation for a constant glucose concentration (i.e., 100 mg/dL and t = 1800–3600 s of batch 2) was measured as 0.005496 nm, corresponding to 2.77% of the wavelength shift; (c) Repeatability test results (n = 3) for glucose concentration range of 100–500 mg/dL. Full article ">Figure 3
Comparison of the needle-type sensor with the standard bio-layer interference (BLI) sensor. Nearly identical profiles were observed when tested with a wide range of glucose concentrations. The profiles indicate that the reproducibility of the needle-type sensor is more stable than the standard BLI sensor. Full article ">

2626 KiB

Open AccessArticle

A Portable Real-Time Ringdown Breath Acetone Analyzer: Toward Potential Diabetic Screening and Management

by Chenyu Jiang, Meixiu Sun, Zhennan Wang, Zhuying Chen, Xiaomeng Zhao, Yuan Yuan, Yingxin Li and Chuji Wang

Sensors 2016, 16(8), 1199; https://doi.org/10.3390/s16081199 - 30 Jul 2016

Cited by 47 | Viewed by 7773

Abstract

Breath analysis has been considered a suitable tool to evaluate diseases of the respiratory system and those that involve metabolic changes, such as diabetes. Breath acetone has long been known as a biomarker for diabetes. However, the results from published data by far [...] Read more.

Breath analysis has been considered a suitable tool to evaluate diseases of the respiratory system and those that involve metabolic changes, such as diabetes. Breath acetone has long been known as a biomarker for diabetes. However, the results from published data by far have been inconclusive regarding whether breath acetone is a reliable index of diabetic screening. Large variations exist among the results of different studies because there has been no “best-practice method” for breath-acetone measurements as a result of technical problems of sampling and analysis. In this mini-review, we update the current status of our development of a laser-based breath acetone analyzer toward real-time, one-line diabetic screening and a point-of-care instrument for diabetic management. An integrated standalone breath acetone analyzer based on the cavity ringdown spectroscopy technique has been developed. The instrument was validated by using the certificated gas chromatography-mass spectrometry. The linear fittings suggest that the obtained acetone concentrations via both methods are consistent. Breath samples from each individual subject under various conditions in total, 1257 breath samples were taken from 22 Type 1 diabetic (T1D) patients, 312 Type 2 diabetic (T2D) patients, which is one of the largest numbers of T2D subjects ever used in a single study, and 52 non-diabetic healthy subjects. Simultaneous blood glucose (BG) levels were also tested using a standard diabetic management BG meter. The mean breath acetone concentrations were determined to be 4.9 ± 16 ppm (22 T1D), and 1.5 ± 1.3 ppm (312 T2D), which are about 4.5 and 1.4 times of the one in the 42 non-diabetic healthy subjects, 1.1 ± 0.5 ppm, respectively. A preliminary quantitative correlation (R = 0.56, p < 0.05) between the mean individual breath acetone concentration and the mean individual BG levels does exist in 20 T1D subjects with no ketoacidosis. No direct correlation is observed in T1D subjects, T2D subjects, and healthy subjects. The results from a relatively large number of subjects tested indicate that an elevated mean breath acetone concentration exists in diabetic patients in general. Although many physiological parameters affect breath acetone, under a specifically controlled condition fast (<1 min) and portable breath acetone measurement can be used for screening abnormal metabolic status including diabetes, for point-of-care monitoring status of ketone bodies which have the signature smell of breath acetone, and for breath acetone related clinical studies requiring a large number of tests. Full article

(This article belongs to the Special Issue Glucose Sensors: Revolution in Diabetes Management 2016)

► Show Figures

Figure 1

2370 KiB

Open AccessArticle

Nitrogen-Doped Carbon Dots as A New Substrate for Sensitive Glucose Determination

by Hanxu Ji, Feng Zhou, Jiangjiang Gu, Chen Shu, Kai Xi and Xudong Jia

Sensors 2016, 16(5), 630; https://doi.org/10.3390/s16050630 - 4 May 2016

Cited by 54 | Viewed by 9333

Abstract

Nitrogen-doped carbon dots are introduced as a novel substrate suitable for enzyme immobilization in electrochemical detection metods. Nitrogen-doped carbon dots are easily synthesised from polyacrylamide in just one step. With the help of the amino group on chitosan, glucose oxidase is immobilized on [...] Read more.

Nitrogen-doped carbon dots are introduced as a novel substrate suitable for enzyme immobilization in electrochemical detection metods. Nitrogen-doped carbon dots are easily synthesised from polyacrylamide in just one step. With the help of the amino group on chitosan, glucose oxidase is immobilized on nitrogen-doped carbon dots-modified carbon glassy electrodes by amino-carboxyl reactions. The nitrogen-induced charge delocalization at nitrogen-doped carbon dots can enhance the electrocatalytic activity toward the reduction of O₂. The specific amino-carboxyl reaction provides strong and stable immobilization of GO_x on electrodes. The developed biosensor responds efficiently to the presence of glucose in serum samples over the concentration range from 1 to 12 mM with a detection limit of 0.25 mM. This novel biosensor has good reproducibility and stability, and is highly selective for glucose determination under physiological conditions. These results indicate that N-doped quantum dots represent a novel candidate material for the construction of electrochemical biosensors. Full article

(This article belongs to the Special Issue Glucose Sensors: Revolution in Diabetes Management 2016)

► Show Figures

Graphical abstract

Graphical abstract
Full article ">Figure 1
Schematic of the N-doped CDs based electrochemical glucose biosensor. Full article ">Figure 2
(a) UV-vis absorption spectrum of N-doped CDs; (b) The typical TEM image of the N-doped CDs; (c) PL spectrum of the N-doped CDs with excitation at 280 nm; (d) XPS full scan spectrum of the N-doped CDs, inset is XPS N 1s spectrum of the N-doped CDs. Full article ">Figure 3
(A): Cyclic voltammograms of (a) non-N-doped CDs modified electrode and (b) N-doped CDs modified electrode in air-saturated 0.1 M pH 7.0 PBS. Scan rate: 100 m·Vs−1 (B): Electrochemical response for two types of CDs (a: non-N-doped CDs and b: N-doped CDs); (C) the picture of modified electrode. Full article ">Figure 4
(a) Cyclic voltammograms N-doped CDs modified electrode in air-saturated PBS containing 10% of serum sample at a scan rate of 100 mV·s−1 with the addition of different concentrations of glucose; (b) Electrochemical response curve for different concentration of glucose. Full article ">Figure 5
Determination of reproducibility of developed GOx/N-doped CDs/chitosan modified GCE in air-saturated PBS containing 10% of serum sample with: (a) 1 mM and (b) 5 mM glucose. Full article ">Figure 6
Determination of reproducibility of developed GOx/N-doped CDs/chitosan modified GCE in air-saturated PBS with 1 mM a glucose and in air-saturated PBS containing 10% of serum samples. Full article ">

Review

Jump to: Research

2605 KiB

Open AccessReview

Current and Emerging Technology for Continuous Glucose Monitoring

by Cheng Chen, Xue-Ling Zhao, Zhan-Hong Li, Zhi-Gang Zhu, Shao-Hong Qian and Andrew J. Flewitt

Sensors 2017, 17(1), 182; https://doi.org/10.3390/s17010182 - 19 Jan 2017

Cited by 228 | Viewed by 52455

Abstract

Diabetes has become a leading cause of death worldwide. Although there is no cure for diabetes, blood glucose monitoring combined with appropriate medication can enhance treatment efficiency, alleviate the symptoms, as well as diminish the complications. For point-of-care purposes, continuous glucose monitoring (CGM) [...] Read more.

Diabetes has become a leading cause of death worldwide. Although there is no cure for diabetes, blood glucose monitoring combined with appropriate medication can enhance treatment efficiency, alleviate the symptoms, as well as diminish the complications. For point-of-care purposes, continuous glucose monitoring (CGM) devices are considered to be the best candidates for diabetes therapy. This review focuses on current growth areas of CGM technologies, specifically focusing on subcutaneous implantable electrochemical glucose sensors. The superiority of CGM systems is introduced firstly, and then the strategies for fabrication of minimally-invasive and non-invasive CGM biosensors are discussed, respectively. Finally, we briefly outline the current status and future perspective for CGM systems. Full article

(This article belongs to the Special Issue Glucose Sensors: Revolution in Diabetes Management 2016)

► Show Figures

Figure 1

Figure 1
The schematic illustration of G1.0 PAMAM-functionalized microgels that can recognize glucose and emit blue fluorescence after injection. Reprinted with permission from [<a href="#B36-sensors-17-00182" class="html-bibr">36</a>]. Full article ">Figure 2
Illustration of the electron transfer steps after illumination of the QD electrode. Reprinted with permission from [<a href="#B40-sensors-17-00182" class="html-bibr">40</a>]. Full article ">Figure 3
Schematic of PDMS chip utilization for monitoring of glucose solutions by a CMOS image sensor. Reprinted with permission from [<a href="#B44-sensors-17-00182" class="html-bibr">44</a>]. Full article ">Figure 4
Illustration of closed-loop glycemic management system utilizing the ‘Sense and Act’ method for optimized insulin delivery. Full article ">Figure 5
Measurement method of tear glucose concentration with a contact lens biosensor. BG levels were simultaneously measured by a commercial BG monitoring kit. Reprinted with permission from [<a href="#B69-sensors-17-00182" class="html-bibr">69</a>]. Full article ">Figure 6
(a) Diagram and photograph (insert) of a physical hydrogel photonic crystal sensing lens; (b) Diffraction wavelength shifts with the variation of the glucose concentration in artificial tear solution. Full article ">Figure 7
(A) Schematic image of the glucose biosensor on the polyethylene terephthalate glycol mouthguard support. Pt and Ag electrodes were formed on the PETG through a sputtering process. Each electrode sensor consisted of a 0.20 mm2 Pt working electrode and a 4.0 mm2 Ag/AgCl reference/counter electrode, both insulated with PDMS on a 0.5 mm thick PETG layer. 30 units of GOD were applied to the sensing region of the working electrode. In order to optimize enzyme entrapment, 2.0 mL of 1.0 wt% PMEH solution was spread over the sensing region to form the PMEH overcoat; (B) Schematic image of the mouth-guard biosensor custom-fit to the patient’s dentition. The device consists of a glucose sensor and wireless transmitter incorporating a potentiostat for stable glucose measurement. The sensor was designed to fit the mandibular dentition from the first premolar up to the third molar. The wireless transmitter was neatly encased in PETG. Reprinted with permission from [<a href="#B94-sensors-17-00182" class="html-bibr">94</a>]. Full article ">

411 KiB

Open AccessReview

The Clinical Benefits and Accuracy of Continuous Glucose Monitoring Systems in Critically Ill Patients—A Systematic Scoping Review

by Sigrid C. J. Van Steen, Saskia Rijkenberg, Jacqueline Limpens, Peter H. J. Van der Voort, Jeroen Hermanides and J. Hans DeVries

Sensors 2017, 17(1), 146; https://doi.org/10.3390/s17010146 - 14 Jan 2017

Cited by 45 | Viewed by 8771

Abstract

Continuous Glucose Monitoring (CGM) systems could improve glycemic control in critically ill patients. We aimed to identify the evidence on the clinical benefits and accuracy of CGM systems in these patients. For this, we performed a systematic search in Ovid MEDLINE, from inception [...] Read more.

Continuous Glucose Monitoring (CGM) systems could improve glycemic control in critically ill patients. We aimed to identify the evidence on the clinical benefits and accuracy of CGM systems in these patients. For this, we performed a systematic search in Ovid MEDLINE, from inception to 26 July 2016. Outcomes were efficacy, accuracy, safety, workload and costs. Our search retrieved 356 articles, of which 37 were included. Randomized controlled trials on efficacy were scarce (n = 5) and show methodological limitations. CGM with automated insulin infusion improved time in target and mean glucose in one trial and two trials showed a decrease in hypoglycemic episodes and time in hypoglycemia. Thirty-two articles assessed accuracy, which was overall moderate to good, the latter mainly with intravascular devices. Accuracy in critically ill children seemed lower than in adults. Adverse events were rare. One study investigated the effect on workload and cost, and showed a significant reduction in both. In conclusion, studies on the efficacy and accuracy were heterogeneous and difficult to compare. There was no consistent clinical benefit in the small number of studies available. Overall accuracy was moderate to good with some intravascular devices. CGM systems seemed however safe, and might positively affect workload and costs. Full article

(This article belongs to the Special Issue Glucose Sensors: Revolution in Diabetes Management 2016)

► Show Figures

Figure 1

4868 KiB

Open AccessReview

A Review on Microfluidic Paper-Based Analytical Devices for Glucose Detection

by Shuopeng Liu, Wenqiong Su and Xianting Ding

Sensors 2016, 16(12), 2086; https://doi.org/10.3390/s16122086 - 8 Dec 2016

Cited by 97 | Viewed by 13895

Abstract

Glucose, as an essential substance directly involved in metabolic processes, is closely related to the occurrence of various diseases such as glucose metabolism disorders and islet cell carcinoma. Therefore, it is crucial to develop sensitive, accurate, rapid, and cost effective methods for frequent [...] Read more.

Glucose, as an essential substance directly involved in metabolic processes, is closely related to the occurrence of various diseases such as glucose metabolism disorders and islet cell carcinoma. Therefore, it is crucial to develop sensitive, accurate, rapid, and cost effective methods for frequent and convenient detections of glucose. Microfluidic Paper-based Analytical Devices (μPADs) not only satisfying the above requirements but also occupying the advantages of portability and minimal sample consumption, have exhibited great potential in the field of glucose detection. This article reviews and summarizes the most recent improvements in glucose detection in two aspects of colorimetric and electrochemical μPADs. The progressive techniques for fabricating channels on μPADs are also emphasized in this article. With the growth of diabetes and other glucose indication diseases in the underdeveloped and developing countries, low-cost and reliably commercial μPADs for glucose detection will be in unprecedentedly demand. Full article

(This article belongs to the Special Issue Glucose Sensors: Revolution in Diabetes Management 2016)

► Show Figures

Figure 1

4806 KiB

Open AccessReview

Conducting Polymers and Their Applications in Diabetes Management

by Yu Zhao, Luyao Cao, Lanlan Li, Wen Cheng, Liangliang Xu, Xinyu Ping, Lijia Pan and Yi Shi

Sensors 2016, 16(11), 1787; https://doi.org/10.3390/s16111787 - 26 Oct 2016

Cited by 28 | Viewed by 8694

Abstract

Advances in conducting polymers (CPs) have promoted the development of diabetic monitoring and treatment, which is of great significance in human healthcare and modern medicine. CPs are special polymers with physical and electrochemical features resembling metals, inorganic semiconductors and non-conducting polymers. To improve [...] Read more.

Advances in conducting polymers (CPs) have promoted the development of diabetic monitoring and treatment, which is of great significance in human healthcare and modern medicine. CPs are special polymers with physical and electrochemical features resembling metals, inorganic semiconductors and non-conducting polymers. To improve and extend their properties, the fabrication of CPs and CP composites has attracted intensive attention in recent decades. Some CPs are biocompatible and suitable for biomedical use. Thus, the intriguing properties of CPs make wearable, noninvasive, continuous diabetes managing devices and other potential applications in diabetes possible in the near future. To highlight the recent advances of CPs and their derived materials (especially in conducting polymer hydrogels), here we discuss their fabrication and characterization, review the current state-of-the-art research in diabetes management based on these materials and describe current challenges as well as future potential research directions. Full article

(This article belongs to the Special Issue Glucose Sensors: Revolution in Diabetes Management 2016)

► Show Figures

Figure 1

4352 KiB

Open AccessReview

Responsive Boronic Acid-Decorated (Co)polymers: From Glucose Sensors to Autonomous Drug Delivery

by Gertjan Vancoillie and Richard Hoogenboom

Sensors 2016, 16(10), 1736; https://doi.org/10.3390/s16101736 - 19 Oct 2016

Cited by 31 | Viewed by 9763

Abstract

Boronic acid-containing (co)polymers have fascinated researchers for decades, garnering attention for their unique responsiveness toward 1,2- and 1,3-diols, including saccharides and nucleotides. The applications of materials that exert this property are manifold including sensing, but also self-regulated drug delivery systems through responsive membranes [...] Read more.

Boronic acid-containing (co)polymers have fascinated researchers for decades, garnering attention for their unique responsiveness toward 1,2- and 1,3-diols, including saccharides and nucleotides. The applications of materials that exert this property are manifold including sensing, but also self-regulated drug delivery systems through responsive membranes or micelles. In this review, some of the main applications of boronic acid containing (co)polymers are discussed focusing on the role of the boronic acid group in the response mechanism. We hope that this summary, which highlights the importance and potential of boronic acid-decorated polymeric materials, will inspire further research within this interesting field of responsive polymers and polymeric materials. Full article

(This article belongs to the Special Issue Glucose Sensors: Revolution in Diabetes Management 2016)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Glucose Sensors: Revolution in Diabetes Management 2016

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Published Papers (15 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI