Glucose Sensor Research Articles

Design and analysis of glucose sensor based on Sagnac interferometer utilizing photonic crystal fiber with micro-holes

Design and analysis of glucose sensor based on Sagnac interferometer utilizing photonic crystal fiber with micro-holes

Fabrication of Supported and Unsupported Gold Nanorods for Nonenzymatic Glucose Sensing and Study of Their Growth Kinetics.

This work includes a novel approach for synthesis/fabrication of AuNRs of varied aspect ratios leading to investigation on the kinetics of their growth mechanism. The synthesized AuNRs were further functionalized with MWCNTs (AuNRs@MWCNTs) by one-pot synthesis. The synthesized AuNRs and AuNRs@MWCNTs were characterized by employing UV-vis spectroscopy. Red shifts in the spectra of AuNRs confirmed the formation of nanorods of higher aspect ratios. Morphology of AuNRs and functionalized AuNRs was confirmed by high-resolution scanning electron microscopy. Biological studies were carried out by fabricating efficient nonenzymatic glucose sensors for optical and electrochemical sensing via UV and cyclic voltammetry in the detection ranges of 0.7-28 mM glucose (UV) and 5.5 μM-0.33 mM (CV). An electrochemical sensing study was carried out via AuNR- and AuNRs@MWCNT-modified GCEs in a 0.1 M NaOH electrolyte solution. The modified electrodes exhibited very high sensitivity with a broad linear range. The order of sensitivity (via CV) was found to be AuNRX0@MWCNTs > AuNRD5@MWCNTs > AuNRD5 > AuNRX0.

Hydrogen peroxide and glucose detection using surface plasmon resonance imaging biosensor with corrodible silver thin film

A surface plasmon resonance imaging (SPRI)-based biosensor is demonstrated for the detection of both hydrogen peroxide (H2O2) and glucose. The H2O2 to be detected acts as an oxidant and etch the silver film. This process gradually effects on resonance condition and consequently the reflected light intensity at a fixed angle. The etching rate of the silver film shows a clear relation with the H2O2 concentration. Therefore, monitoring the reflected light intensity progressively changing over a few minutes, enables accurate detection of H2O2 concentrations ranging from 0 to 200 μM (within physiological range of 0.25–50 μM), with a remarkable limit of detection (LOD) as low as 40 nM. In this regard, the behavior of the surface plasmon resonance (SPR) dip in response to the reduction of the silver film thickness is predicted by Winspall simulation software. These simulation results are in good agreement with the experimental results. Moreover, the proposed method can be applied to determine glucose concentrations ranging from 0 to 10 mM, encompassing the physiological range of 3–8 mM. This is achieved by observing the generated H2O2 through the enzymatic oxidation reaction between glucose and glucose oxidase (Gox). The sensor demonstrates remarkable sensitivity and selectivity, with a detection limit as low as 175 μM for glucose concentration. Furthermore, accurate measurement of glucose concentration in an actual human serum sample is achievable with the proposed sensor, using the standard addition method. The suggested glucose sensor shows promising prospects for use in routine glucose testing, employing a label-free, real-time, and multiplex detection approach.© 2017 Elsevier Inc. All rights reserved.

Flexible cellulose paper-based biosensor from inkjet printing for non-invasive glucose monitoring

Wearable glucose sensors have attracted significant attention for enabling non-invasive blood glucose measurement without discomfort and risk of infection. However, it is a challenge to simultaneously realize wearable adaptability, biodegradability, and excellent sensing performance. Herein, a cellulose paper-based non-invasive biosensor relying on reverse iontophoresis was designed to detect glucose in interstitial fluid (ISF), and two different enzyme immobilization strategies have been compared. The results showed inkjet-printed cellulose paper-based biosensor (IPB) performances better than the drop-coated cellulose paper-based biosensor (DPB). IPB has twice response current more than DPB in detection range (0–10 mM). In sensitivity, IPB is 1.170 μA/mM three times higher than the DPB (0.376 μA/mM). Besides, IPB's electron-transfer resistance (Rct) is 7.27 kΩ smaller than DPB (Rct = 10.51 kΩ) about 30 %. More importantly, IPB exhibited a good reproducibility (RSD, 4.82 %), which was much less than DPB (RSD, 18.35 %). Furthermore, the IPB realizes noninvasive continuous glucose monitoring over 6 h in volunteer experiments with great analytical performance comparable to commercial devices (Pearson correlation 0.732). Cellulose paper-based glucose sensors with inkjet printing provide non-invasive access to statistically significant diagnostic information, simple and cost-effective, which promotes the application of flexible, wearable, degradable bioelectrodes in continuous glucose monitoring at home, providing a concept for full integration in a compact and portable way in the future.

Directionally Exfoliated Ni/Co Hydroxide-Organic Framework Nanosheets for Enhanced Wearable Glucose Sensing.

We report two-dimensional (2D) Ni/Co-based metal hydroxide-organic framework nanosheets (Ni/Co-MHOF NSs) for the construction of an efficient electrochemical nonenzymatic glucose sensor. The nanosheet architecture maximizes the exposure of coordinatively unsaturated metal sites, which enables a largely improved electrocatalytic performance toward the glucose oxidation reaction. The as-designed nonenzymatic sensor exhibits a high sensitivity of 235.71 μA·mM-1·cm-2 and a wide linear range of 1-3000 μM. The sensor presents excellent selectivity against several potential interferences and a short response time of 3.0 s. Of interest, a high-performance flexible sensor is developed by depositing the Ni/Co-MHOF NSs on screen-printed electrodes, which reveal decent bending stability. The designed glucose sensor patch can attach to the human body and realize noninvasive glucose monitoring in human sweat. This work may shed light on the application of novel MHOFs in the field of wearable electrochemical sensing.

Heterogeneous CuxO Nano-Skeletons from Waste Electronics for Enhanced Glucose Detection

HighlightsNovel laser-induced transfer method for fabricating glucose sensors from recycled e-waste copper, offering a sustainable and cost-effective solution.Unique heterogeneous CuxO nano-skeletons derived from discarded printed circuit boards exhibiting exceptional glucose-sensing performance (sensitivity: 9.893 mA mM−1 cm−2, detection limit: 0.34 μM).Miniaturized glucose detection device, optimized for scalability and portability, revolutionizing diabetes management and patient care.

Evaluation of Electrochemical Sensor Using Microfluidic System

This paper presents the characterization and testing of electrochemical sensor using microfluidic system. Various geometric patterns were laser cut into the platinum working electrode of a biosensor. In this work, a microfluidic chamber was designed that allows phosphate buffer solution (PBS) to flow across the sensor, using a peristaltic pump, while varying the concentration of hydrogen peroxide. The amperometric characterization of the electrochemical sensor with 25, 50, 75, and 100[Formula: see text][Formula: see text]m perforation and 75[Formula: see text][Formula: see text]m spacing showed the highest sensitivity. This result was to be expected the purpose of patterning the sensors was to provide a 3-dimensional structure to the planar electrode in order for the enzyme, glucose oxidase, to be immobilized. Future work will include selecting one of the patterns for immobilization of glucose oxidase allowing us to realize a fully functional glucose sensor.

All-Fiber Flexible Electrochemical Sensor for Wearable Glucose Monitoring.

Wearable sensors, specifically microneedle sensors based on electrochemical methods, have expanded extensively with recent technological advances. Today's wearable electrochemical sensors present specific challenges: they show significant modulus disparities with skin tissue, implying possible discomfort in vivo, especially over extended wear periods or on sensitive skin areas. The sensors, primarily based on polyethylene terephthalate (PET) or polyimide (PI) substrates, might also cause pressure or unease during insertion due to the skin's irregular deformation. To address these constraints, we developed an innovative, wearable, all-fiber-structured electrochemical sensor. Our composite sensor incorporates polyurethane (PU) fibers prepared via electrospinning as electrode substrates to achieve excellent adaptability. Electrospun PU nanofiber films with gold layers shaped via thermal evaporation are used as base electrodes with exemplary conductivity and electrochemical catalytic attributes. To achieve glucose monitoring, gold nanofibers functionalized by gold nanoflakes (AuNFs) and glucose oxidase (GOx) serve as the working electrode, while Pt nanofibers and Ag/AgCl nanofibers serve as the counter and reference electrode. The acrylamide-sodium alginate double-network hydrogel synthesized on electrospun PU fibers serves as the adhesive and substance-transferring layer between the electrodes. The all-fiber electrochemical sensor is assembled layer-by-layer to form a robust structure. Given the stretchability of PU nanofibers coupled with a high specific surface area, the manufactured porous microneedle glucose sensor exhibits enhanced stretchability, superior sensitivity at 31.94 μA (lg(mM))-1 cm-2, a broad detection range (1-30 mM), and a significantly low detection limit (1 mM, S/N = 3), as well as satisfactory biocompatibility. Therefore, the novel electrochemical microneedle design is well-suited for wearable or even implantable continuous monitoring applications, thereby showing promising significant potential within the global arena of wearable medical technology.

Advancements of Glucose Monitoring Biosensor: Current State, Generations of Technological Progress, and Innovation Dynamics.

Glucose monitoring is essential for managing diabetes, and continuous glucose monitoring biosensors can offer real-time monitoring with little invasiveness. However, challenges remain in improving sensor accuracy, selectivity, and overall performance. This article aims to review current trends and recent advancements in glucose-monitoring biosensors while evaluating their benefits and limitations for diabetes monitoring. An analysis of current literature on transdermal glucose sensors was conducted, focusing on detection techniques, novel nanomaterials, and integrated sensor systems. Recent research has led to advancements in electrochemical, optical, electromagnetic, and sonochemical sensors for transdermal glucose detection. The use of novel nanomaterials and integrated sensor designs has improved sensitivity, selectivity, and accuracy. However, issues like calibration requirements, motion artifacts, and skin irritation persist. Transdermal glucose sensors show promise for non-invasive, convenient diabetes monitoring but require further enhancements to address limitations in accuracy, reliability, and biocompatibility. Continued research and innovation focusing on sensor materials, designs, and surface chemistry is needed to optimize biosensor performance and utility. The study offers a comprehensive analysis of the present status of technological advancement and highlights areas that need more research.

High-sensitive glucose sensor based on tilted fiber Bragg gratings

In this paper, we proposed a high-sensitive glucose sensor using the tilted fiber Bragg gratings (TFBGs). The TFBGs with different tilt angle has been fabricated by phase mask scanning method with an argon ion double-frequency 244 nm laser. As tilt angle increases, the bandwidth of the cladding mode excited by TFBGs gradually expands and cladding mode region shifts towards shorter wavelengths. The higher-order cladding modes appeared at the shorter wavelength side demonstrate a larger separation in the spectrum. TFBGs with different tilt angles for glucose concentration measurement have been investigated experimentally. When the concentration of glucose solution increases, the surrounding refractive index changing make the cut-off mode resonance shift to a longer wavelength. In addition, the tilt angle of TFBGs does affect the glucose sensitivity, that the larger tilt angle is, the higher sensitivity could achieve. In this work, a maximum glucose sensitivity of 80.91 pm/(mg/ml) could be obtained for TFBGs with tilt angle of 10°. The proposed TFBGs with superiorities of high glucose sensitivity and wider detection range, makes it potential for glucose detection in the field of chemical and biomedical sensing.

Nanostructured metallic enzymes mimic for electrochemical biosensing of glucose

In many domains, the creation of nonenzymatic glucose sensors with robust electrocatalytic activity and chemical stability is indispensable. However, the design of nanoarchitecture transition metals and their nanocomposites as sensing interfaces for nonenzymatic recognition groups remains a formidable challenge. This review discusses the engineered nanoarchitecture transition metals used as non-enzymatic glucose sensors, with a particular focus on their applications characterized by low cost, high sensitivity, and long-term durability. Central to our discussion is the imperative of crafting nanostructured transition materials with expansive specific surface areas and well-defined active sites to serve as electrochemical sensing platforms. Our objective is to shed light on the enhanced electrochemical behavior toward glucose without reliance on mediators or templates. Leveraging advancements in nanotechnology, this review seeks to elucidate strategies for refining conventional nanostructures to optimize enzyme-free glucose sensing applications. Additionally, we delve into the inherent challenges and potential applications of these sensors for detecting glucose and outline ways to develop better non-enzymatic electrochemical glucose sensors.

A Glycemic Status Classification Model Using a Radiofrequency Noninvasive Blood Glucose Monitor.

Despite significant efforts in the development of noninvasive blood glucose (BG) monitoring solutions, delivering an accurate, real-time BG measurement remains challenging. We sought to address this by using a novel radiofrequency (RF) glucose sensor to noninvasively classify glycemic status. The study included 31 participants aged 18-65 with prediabetes or type 2 diabetes and no other significant medical history. During control sessions and oral glucose tolerance test sessions, data were collected from both a RF sensor that rapidly scans thousands of frequencies and concurrently from a venous blood draw measured with an US Food and Drug Administration (FDA)-cleared glucose hospital meter system to create paired observations. We trained a time series forest machine learning model on 80% of the paired observations and reported results from applying the model to the remaining 20%. Our findings show that the model correctly classified glycemic status 93.37% of the time as high, normal, or low.

Chemosensitive Properties of Electrochemically Synthesized Poly-3-Thienylboronic Acid: Conductometric Detection of Glucose and Other Diol-Containing Compounds under Electrical Affinity Control.

Due to the presence of the boronic acid moieties, poly-3-thienylboronic acid has an affinity for saccharides and other diol-containing compounds. Thin films of this novel chemosensitive polymer were synthesized electrochemically on the gold surface. The adhesion of the polymer was enhanced by the deposition of a monomolecular layer of thiophenol. The technology was used to fabricate conductometric sensors for glucose and other diol-containing compounds. Simultaneous two- and four-electrode conductivity measurements were performed. The chemical sensitivity to sorbitol, fructose, glucose, and ethylene glycol was studied at different pH and electrode potentials, and the corresponding binding constants were obtained. Depending on the electrode potential, the reciprocal values of the binding constants of glucose to poly-3-thienylboronic acid at neutral pH are in the range of 0.2 mM-1.0 mM. The affinity for glucose has been studied in buffer solutions and in solutions containing the major components of human blood. It was shown that the presence of human serum albumin increases the affinity of poly-3-thienylboronic acid for diol-containing compounds.

CuxO decorated Ti3C2Tx MXene composites for non-enzymatic glucose sensing with large linear ranges.

Ti3C2Tx MXene/CuxO composites were prepared by acid etching combined with electrochemical technique. The abundant active sites on the surface of MXene greatly increase the loading of CuxO nanoparticles, and the synergistic effect between the different components of the composite can accelerate the oxidation reaction of glucose. The results indicate that at the working potential of 0.55V (vs. Ag/AgCl), the glucose sensor based on Ti3C2Tx MXene/CuxO composite presents large linear concentration ranges from 1 µM to 4.655 mM (sensitivity of 361 µA mM-1 cm-2) and from 5.155 mM to 16.155 mM (sensitivity of 133 µA mM-1 cm-2). The limit of detection is 0.065 µM. In addition, the sensor effectively avoids the oxidative interference of common interfering species such as ascorbic acid, dopamine and uric acid. Thesensor has good reproducibility, stability and acceptable recoveries for the detection of glucose in human sweat sample (97.5-103.3%) with RSD values less than 4%. Based on these excellent properties it has great potential for the detection of glucose in real samples.

Advancements in enzyme-free electrochemical glucose sensor materials

ABSTRACT Increased health awareness has called for better health monitoring devices, resulting in continuous research and advancement in glucose sensors. Innovations in both enzymatic and enzyme-free sensors (or non-enzymatic) are revolutionising diabetes control. While enzymatic sensors offer superior sensitivity and selectivity, enzyme-free sensors are preferred for stability and affordability, advancing the quest for rapid and accurate glucose tests. Progress in the development of enzyme-free glucose sensors is being achieved by improvements in electrode materials as well as sensor design. The selection of electrode materials is crucial in these sensors for attaining optimum values of sensing time as well as accuracy. Numerous electrode materials, including graphene, carbon nanotubes, metal oxides (such as platinum and gold), and conductive polymers, have been developed and studied by researchers to be employed in glucose sensors. Among the most critical factors being considered for developing glucose sensor materials is the selectivity for glucose molecules without interference due to the presence of another molecule. This article focuses on tracing recent developments in enzyme-free glucose sensor research, highlighting efforts to overcome limitations and drive innovation in glucose monitoring technology.

Technology in the management of diabetes in hospitalised adults.

Suboptimal glycaemic management in hospitals has been associated with adverse clinical outcomes and increased financial costs to healthcare systems. Despite the availability of guidelines for inpatient glycaemic management, implementation remains challenging because of the increasing workload of clinical staff and rising prevalence of diabetes. The development of novel and innovative technologies that support the clinical workflow and address the unmet need for effective and safe inpatient diabetes care delivery is still needed. There is robust evidence that the use of diabetes technology such as continuous glucose monitoring and closed-loop insulin delivery can improve glycaemic management in outpatient settings; however, relatively little is known of its potential benefits and application in inpatient diabetes management. Emerging data from clinical studies show that diabetes technologies such as integrated clinical decision support systems can potentially mediate safer and more efficient inpatient diabetes care, while continuous glucose sensors and closed-loop systems show early promise in improving inpatient glycaemic management. This review aims to provide an overview of current evidence related to diabetes technology use in non-critical care adult inpatient settings. We highlight existing barriers that may hinder or delay implementation, as well as strategies and opportunities to facilitate the clinical readiness of inpatient diabetes technology in the future.

Enhanced sensing performance of flexible non-enzymatic electrochemical glucose sensors using hollow Fe3O4 nanospheres of controllable morphologies

Rapid and accurate monitoring of glucose concentration is of great significance in clinical diagnosis and treatment of diabetes and hence, it is necessary to develop glucose sensors of superior electro-catalytic capacity. Most literature utilize synergistic effect of nanocomposites to enhance glucose sensing performance, whereas it suffers from crucial restriction in physical and chemical characteristics of each constituents. Morphology of nanostructures significantly affects the electro-catalytic capacity, thus it is a novel route to improve glucose sensing performance to adjust morphology of nanostructures. Herein, we presented highly sensitive non-enzymatic electrochemical sensors for rapid and accurate glucose analysis with hollow Fe3O4 nanospheres (Fe3O4NSs) of controllable morphologies decorated on flexible fibers. The morphologies of the Fe3O4NSs were evaluated with quantitative parameters like diameter, roundness, roughness, skewness, and kurtosis acquired from SEM images and image processing algorithms, and their effect on the interfacial characteristics and the electro-catalytic capacity of the glucose sensors was investigated. Owing to the unique spherical nanostructures and superior catalysis, the Fe3O4NSs exhibit desirable solid/liquid interface for mass diffusion and abundant active sites for sufficient oxidation of glucose. Moreover, much rounder and rougher Fe3O4NSs of near Gaussian surface are readily produced at a higher Fe3+ concentration and result in favorable sensing performance. Accordingly, the optimal glucose sensor shows sensitivities of 96.1 ± 5.4 μA mM−1 cm−2 and 38.2 ± 2.2 μA mM−1 cm−2 over a preferable range of 0–18.0 mM, and a lower detection limit of 19.2 μM. Besides, the glucose sensors remain acceptable response after continuous testing for 20 times and repetitive bending for 50 times, and display superior selectivity to glucose and accurate analysis to practical samples. It is a facile and effective methodology to regulate the morphologies of the Fe3O4NSs for enhanced electro-catalytic capacity of glucose sensors.

Development of Highly Sensitive and Selective Electrochemical Glucose Sensors Based on the Modification of the Surface, Structural, and Morphological Properties of ZnO Using Vitamin-B Complexes

Non-enzymatic electrochemical glucose sensors are particularly advantageous because of their simplicity, low cost, efficiency, and long storage life. ZnO structures were modified with water-soluble vitamin B12, B9, and B6 complexes in alkaline 0.1 M NaOH solutions to enhance glucose sensing. ZnO samples were hydrothermally synthesized using 5 mg fixed masses of B12, B9, and B6 complexes. X-ray diffraction, scanning electron microscopy, UV-visible spectrometry, and Fourier transform infrared spectroscopy were used to determine crystalline properties, morphology, and optical band gap. Zinc oxide obtained from vitamin B complexes had a hexagonal structure similar to wurtzite, modified nanorods on its surface, and a reduced optical band gap. The molecular weight, size, and number of functional groups vitamins also influenced surface and structural characteristics of ZnO. Zinc oxide from the B12 complex proved excellent for non-enzymatic glucose sensing in alkaline conditions. B12-derived ZnO glucose sensors have a linear range of 0.1 to 10 mM with a detection limit of 0.005 mM. In the glucose sensing process, a satisfactory level of stability, reproducibility, and selectivity was observed. Furthermore, it was found that ZnO derived from B12 had a high electrical conductivity, which facilitated electron transfer during glucose oxidation.

A wearable non-enzymatic sensor for continuous monitoring of glucose in human sweat

To enhance personalized diabetes management, there is a critical need for non-invasive wearable electrochemical sensors made from flexible materials to enable continuous monitoring of sweat glucose levels. The main challenge lies in developing glucose sensors with superior electrochemical characteristics and high adaptability. Herein, we present a wearable sensor for non-enzymatic electrochemical glucose analysis. The sensor was synthesized using hydrothermal and one-pot preparation methods, incorporating gold nanoparticles (AuNPs) functionalized onto aminated multi-walled carbon nanotubes (AMWCNTs) as an efficient catalyst, and crosslinked with carboxylated styrene butadiene rubber (XSBR) and PEDOT:PSS. The sensors were then integrated onto screen-printed electrodes (SPEs) to create flexible glucose sensors (XSBR-PEDOT:PSS-AMWCNTs/AuNPs/SPE). Operating under neutral conditions, the sensor exhibits a linear range of 50 μmol/L to 600 μmol/L, with a limit of detection limit of 3.2 μmol/L (S/N = 3), enabling the detection of minute glucose concentrations. The flexible glucose sensor maintains functionality after 500 repetitions of bending at a 180° angle, without significant degradation in performance. Furthermore, the sensor exhibits exceptional stability, repeatability, and resistance to interference. Importantly, we successfully monitored changes in sweat glucose levels by applying screen-printed electrodes to human skin, with results consistent with normal physiological blood glucose fluctuations. This study details the fabrication of a wearable sensor characterized by ease of manufacture, remarkable flexibility, high sensitivity, and adaptability for non-invasive blood glucose monitoring through non-enzymatic electrochemical analysis. Thus, this streamlined fabrication process presents a novel approach for non-invasive, real-time blood glucose level monitoring.

Honeycomb-shaped vertically aligned carbon nanotubes decorated with molybdenum trioxide as an electrochemical sensor for glucose

In this study, an electrode based on transition metal oxide molybdenum trioxide (MoO3) was fabricated and applied to electrochemical biosensing for glucose. In the process of making electrodes with relatively larger specific surface areas, an array of carbon nanotubes (CNTs) was deposited on a silicon substrate, and then, MoO3 was coated on the array of CNTs by chemical vapor deposition to produce a MoO3/CNTs/Si structure of three-dimensional electrochemical biosensing electrodes. Biosensing measurement was carried out in the concentration region from 20 μM to 7 mM of sodium hydroxide (NaOH). The highest sensitivity of 17.4 μA/μM cm2 was measured in the concentration range of 20–100 μM. The correlation coefficient of linear response (R2) was 0.9929, thus showing that MoO3/CNTs/Si is an excellent nonenzymatic glucose electrochemical sensor.