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Background andAims: Guidelines now recommend inpatient continuous glucose monitor (CGM) use with confirmatory blood glucose measurements. However, the Food and Drug Administration has not yet officially approved CGM for inpatient use in large part because its accuracy has not been established in this setting. We tested the accuracy of the Dexcom G6 (G6) in 28 adults on an insulin infusion in a medical–surgical intensive care unit with 1064 matched CGM and arterial point-of-care pairs. Methods: The participants were on average 57.29 (SD 2.39) years, of whom 13 had a prior diagnosis of diabetes and 14 were admitted for a surgical diagnosis. The first 19 participants received the G6 without calibration and had a mean absolute relative difference (MARD) of 13.19% (IQR 5.11, 19.03) across 659 matched pairs, which just meets the critical care expert recommendation of MARD <14%. We then aimed to improve accuracy for the subsequent 9 participants using a calibration protocol. Results: The MARD for calibrated participants was 9.65% (3.03, 13.33), significantly lower than for uncalibrated participants (P < 0.001). Calibration also demonstrated excellent safety with 100% of values within the Clarke Error Grid zones A and B compared with 99.07% without calibration. Our protocol achieved the lowest MARD and safest CEG profile in the critical care setting and well exceeds the critical care expert recommendations. Our large sample of heterogenous critically ill patients also reached comparable accuracy to the MARD of 9% for G6 in outpatients. We believe our calibration protocol will allow G6 to be used with sufficient accuracy in inpatients. [ABSTRACT FROM AUTHOR]

Measurements of the refractive index of liquids are in high demand in numerous fields such as agriculture, food and beverages, and medicine. However, conventional ellipsometric refractive index measurements are too expensive and labor‐intensive for consumer devices, while Abbe refractometry is limited to the measurement at a single wavelength. Here, a new approach is proposed using machine learning to unlock the potential of colorimetric metasurfaces for the real‐time measurement of the dispersive refractive index of liquids over the entire visible spectrum. The platform with a proof‐of‐concept experiment for measuring the concentration of glucose is further demonstrated, which holds a profound impact in non‐invasive medical sensing. High‐index‐dielectric metasurfaces are designed and fabricated, while their experimentally measured reflectance and reflected colors, through microscopy and a standard smartphone, are used to train deep‐learning models to provide measurements of the dispersive background refractive index with a resolution of ≈10−4, which is comparable to the known index as measured with ellipsometry. These results show the potential of enabling the unique optical properties of metasurfaces with machine learning to create a platform for the quick, simple, and high‐resolution measurement of the dispersive refractive index of liquids, without the need for highly specialized experts and optical procedures. [ABSTRACT FROM AUTHOR]

Elevated blood glucose levels, known as hyperglycemia, play a significant role in sudden cardiac arrest, often resulting in sudden cardiac death, particularly among those with diabetes. Understanding the internal mechanisms has been a challenge for healthcare professionals, leading many research groups to investigate the relationship between blood glucose levels and cardiac electrical activity. Our hypothesis suggests that glucose-sensing biophysics mechanisms in cardiac tissue could clarify this connection. To explore this, we adapted a single-compartment computational model of the human pacemaker action potential. We incorporated glucose-sensing mechanisms with voltage-gated sodium ion channels using ordinary differential equations. Parameters for the model were based on existing experimental studies to mimic the impact of glucose levels on pacemaker action potential firing. Simulations using voltage clamp and current clamp techniques showed that elevated glucose levels decreased sodium ion channel currents, leading to a reduction in the pacemaker action potential frequency. In summary, our mathematical model provides a cellular-level understanding of how high glucose levels can lead to bradycardia and sudden cardiac death. [ABSTRACT FROM AUTHOR]

Hypothalamic gliosis associated with high-fat diet (HFD) feeding increases susceptibility to hyperphagia and weight gain. However, the body-weight-independent contribution of microglia to glucose regulation has not been determined. Here, we show that reducing microglial nuclear factor κB (NF-κB) signaling via cell-specific IKKβ deletion exacerbates HFD-induced glucose intolerance despite reducing body weight and adiposity. Conversely, two genetic approaches to increase microglial pro-inflammatory signaling (deletion of an NF-κB pathway inhibitor and chemogenetic activation through a modified Gq-coupled muscarinic receptor) improved glucose tolerance independently of diet in both lean and obese rodents. Microglial regulation of glucose homeostasis involves a tumor necrosis factor alpha (TNF-α)-dependent mechanism that increases activation of pro-opiomelanocortin (POMC) and other hypothalamic glucose-sensing neurons, ultimately leading to a marked amplification of first-phase insulin secretion via a parasympathetic pathway. Overall, these data indicate that microglia regulate glucose homeostasis in a body-weight-independent manner, an unexpected mechanism that limits the deterioration of glucose tolerance associated with obesity.

Printing techniques hold great potential in the manufacture of electronics such as sensors, micro-supercapacitors, and flexible electronics. However, developing large-scale functional conductive inks with appropriate rheological properties and active components still remains a challenge. Herein, through optimizing the formulations of ink, iron single sites supported N-doped carbon black (Fe1-NC) inks can serve as both conductive electrodes and high-reactive catalysts to realize convenient glucose detection, which pronouncedly reduces the dosage of enzyme and simplifies the sensors preparation. In detail, utilizing in-situ pyrolysis method, Fe1-NC single-atom catalysts (SACs) are prepared in bulk (dekagram-level). The batched Fe1-NC SACs materials can be uniformly mixed with modulated ink to realize the screen printing with high resolution and uniformity. Also, the whole scalable preparation and ink-functional process can be extended to various metals (including Co, Ni, Cu, and Mn). The introduction of highly active Fe1-NC sites reduces the amount of enzyme used in glucose detection by at least 50%, contributing to the cost reduction of sensors. The strategy in harnessing the SACs onto the carbon inks thus provides a broad prospect for the low-cost and large-scale printing of sensitive sensing devices. [ABSTRACT FROM AUTHOR]

Tailoring a material's surface with hierarchical structures from the micro‐ to the nanoscale is key for fabricating highly sensitive detection platforms. To achieve this, the fabrication method should be simple, inexpensive, and yield materials with a high density of surface features. Here, using benchtop fabrication techniques, gold surfaces with hierarchically structured roughness are generated for sensing applications. Hierarchical gold electrodes are prepared on pre‐stressed polystyrene substrates via electroless deposition and amperometric pulsing. Electrodes fabricated using 1 mm H[AuCl₄] and roughened with 80 pulses revealed the highest electroactive surface area. These electrodes are used for enzyme‐free detection of glucose in the presence of bovine serum albumin and achieved a limit of detection of 0.36 mm, below glucose concentrations in human blood. The surfaces nanoroughened with 100 pulses also showed excellent surface‐enhanced Raman scattering (SERS) response for the detection of rhodamine 6G, with an enhancement factor of ≈2 × 106 compared to detection in solution, and for the detection of a self‐assembled monolayer of thiophenol, with an enhancement factor of ≈30 compared to the response from microstructured gold surfaces. It is envisioned that the simplicity and low fabrication cost of these gold‐roughened structures will expedite the development of electrochemical and SERS sensing devices. [ABSTRACT FROM AUTHOR]

Glucose mainly serves as an energy source, highly crucial for development and respiration. Dysregulation can result in diabetes mellitus and related complications. In the current study, Erythrina suberosa sawdust-deposited manganese dioxide nanoparticles (MnO2 NPs) were used for colorimetric glucose detection. Sawdust-deposited MnO2 NPs were synthesized using Dalbergia sissoo extract and characterized with different analytical techniques such as XRD, FTIR, EDX, SEM, and UV–Vis spectrophotometer. Various functional groups in FTIR spectrum of MnO2 were reported such as –OH, Mn–O, and –OH coupled with Mn. XRD spectrum showed that the particles were in orthorhombic phase with a particle size of 38 nm. SEM analysis showed that the particles are dispersed homogenously on the surface of sawdust. EDX analysis showed the presence of various elements in the synthesized platform at different ratios. Color change from colorless to blue–green was noticed by the addition of glucose with the naked eye and analyzed confirmed by a UV–Vis spectrophotometer. To achieve optimum results, various parameters were optimized, such as nanoparticles loading, TMB concentration, pH, and incubation time. The proposed sensor's limit of detection and limit of quantification were calculated to be 1.8 × 10–8 M and 6.25 × 10–8 M, respectively, with a linear range of 1 × 10–9–3.6 × 10–7 M and an R2 value of 0.9992. The reaction time of the suggested sensor for glucose sensing was just 150 s. The proposed sensor has also been used for the detection of glucose in the urine samples of diabetic patients. [ABSTRACT FROM AUTHOR]

Abstract Measurements of the refractive index of liquids are in high demand in numerous fields such as agriculture, food and beverages, and medicine. However, conventional ellipsometric refractive index measurements are too expensive and labor‐intensive for consumer devices, while Abbe refractometry is limited to the measurement at a single wavelength. Here, a new approach is proposed using machine learning to unlock the potential of colorimetric metasurfaces for the real‐time measurement of the dispersive refractive index of liquids over the entire visible spectrum. The platform with a proof‐of‐concept experiment for measuring the concentration of glucose is further demonstrated, which holds a profound impact in non‐invasive medical sensing. High‐index‐dielectric metasurfaces are designed and fabricated, while their experimentally measured reflectance and reflected colors, through microscopy and a standard smartphone, are used to train deep‐learning models to provide measurements of the dispersive background refractive index with a resolution of ≈10−4, which is comparable to the known index as measured with ellipsometry. These results show the potential of enabling the unique optical properties of metasurfaces with machine learning to create a platform for the quick, simple, and high‐resolution measurement of the dispersive refractive index of liquids, without the need for highly specialized experts and optical procedures.

Highlights A novel photoelectrochemical (PEC) photosensor composed of GaN nanowire-on-Si platform demonstrates record-high responsivity of 247.8 mA W−1 with ultra-stable operation characteristics. Strategic internal and external band structure engineering of semiconductor nanowires promotes efficient PEC reaction via controlling carrier dynamics while preserving nanowires from material degradation. The glucose sensing system is constructed to successfully analyze blood glucose levels in real human serum samples, featuring a high sensitivity of 0.173 µA µM−1 cm−2 and a low detection limit of 0.07 µM.

Managing diabetes mellitus (DM) includes achieving acceptable blood glucose levels and minimizing the risk of complications from DM. The appropriate glucose sensing method is continuous glucose monitoring (CGM). Effective evaluation metrics that reflect glucose fluctuations can be realized. However, compared with self-monitoring of blood glucose (SMBG), CGM data are not easy to obtain. Therefore, this article studies a fusion model to achieve this objective, including Gaussian process regression (GPR) and long short-term memory (LSTM). Compared with the three commonly used LSTM, GPR, and support vector machine, the proposed model can construct accurate results. By using the constructed CGM data, the conventional metrics, such as the mean amplitude of glycemic excursion (MAGE), mean blood glucose (MBG), standard deviation (SD), and time in range (TIR), are calculated. These metrics and other variables are input into statistical methods to realize diabetic retinopathy risk assessment. In this way, the relationship between the glycemic variability of the constructed CGM data by the mathematical model and DR could be achieved. The utilized statistical methods include single-factor analysis and binary multivariate logistic regression analysis. Results show that fasting blood glucose, disease course, history of hypertension, MAGE and TIR are independent risk factors for DR.

Highlights: A novel photoelectrochemical (PEC) photosensor composed of GaN nanowire-on-Si platform demonstrates record-high responsivity of 247.8 mA W−1 with ultra-stable operation characteristics. Strategic internal and external band structure engineering of semiconductor nanowires promotes efficient PEC reaction via controlling carrier dynamics while preserving nanowires from material degradation. The glucose sensing system is constructed to successfully analyze blood glucose levels in real human serum samples, featuring a high sensitivity of 0.173 µA µM−1 cm−2 and a low detection limit of 0.07 µM. Photosensors with versatile functionalities have emerged as a cornerstone for breakthroughs in the future optoelectronic systems across a wide range of applications. In particular, emerging photoelectrochemical (PEC)-type devices have recently attracted extensive interest in liquid-based biosensing applications due to their natural electrolyte-assisted operating characteristics. Herein, a PEC-type photosensor was carefully designed and constructed by employing gallium nitride (GaN) p–n homojunction semiconductor nanowires on silicon, with the p-GaN segment strategically doped and then decorated with cobalt–nickel oxide (CoNiOx). Essentially, the p–n homojunction configuration with facile p-doping engineering improves carrier separation efficiency and facilitates carrier transfer to the nanowire surface, while CoNiOx decoration further boosts PEC reaction activity and carrier dynamics at the nanowire/electrolyte interface. Consequently, the constructed photosensor achieves a high responsivity of 247.8 mA W−1 while simultaneously exhibiting excellent operating stability. Strikingly, based on the remarkable stability and high responsivity of the device, a glucose sensing system was established with a demonstration of glucose level determination in real human serum. This work offers a feasible and universal approach in the pursuit of high-performance bio-related sensing applications via a rational design of PEC devices in the form of nanostructured architecture with strategic doping engineering. [ABSTRACT FROM AUTHOR]

[Display omitted] Herein, we present a novel microwave-assisted method for the synthesis of palladium nanoparticles (PdNPs) supported by Limonia acidissima Groff tree extract gum. The synthesized PdNPs were characterized using various analytical techniques, including FTIR, SEM, TEM, UV–visible, and powder XRD analyses. TEM and XRD analysis confirmed that the synthesized LAG-PdNPs are highly crystalline nature spherical shapes with an average size diameter of 7–9 nm. We employed these gum-capped PdNPs to investigate their peroxidase-like activity for colorimetric detection of hydrogen peroxide (H 2 O 2) and glucose. The oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) by H 2 O 2 , catalyzed by PdNPs, produces oxidation products quantified at 652 nm using spectrophotometry. The catalytic activity of PdNPs was optimized with respect to temperature and pH. The developed method exhibited a linear range of detection from 1 to 50 µm, with detection limits of 0.35 µm for H 2 O 2 and 0.60 µm for glucose. [ABSTRACT FROM AUTHOR]

Ni3(HITP)2 (HITP: 2,3,6,7,10,11-hexaiminotriphenylene) is a very typical 2D electrically conductive metal–organic framework (EC-MOF) material with great promising as active materials in electronic devices. Gas–liquid interface self-assembly is a common method of processing free-standing thin films for this EC-MOF. Owing to the different contact environment during growth process, Ni3(HITP)2 film prepared by gas–liquid interface method has different morphology for up-side surface exposed to air and down-side surface infiltrated in solution. However, the asymmetrical morphology of Ni3(HITP)2 film and its influence on sensing performance have never been implemented. In this work, gas–liquid interface self-assembly method is used to obtain an asymmetrical Ni3(HITP)2 nanofilm in surface morphology with a flat up-side surface and an island-like down-side surface. The surface morphology of as-prepared film has a remarkable influence on the glucose sensing property. The island-like structure for down-side surface film exhibits more excellent glucose sensing performance because of its abundant crystal defect which play an important role in enhancing glucose catalytic oxidation capacity. [ABSTRACT FROM AUTHOR]

Nanosecond laser patterning of Copper Metal–Organic Framework (Cu‐MOF) coated substrates is performed to fabricate non‐enzymatic glucose sensing electrodes. The Cu‐MOF coated glass substrate with a cover glass is subjected to a laser patterning process; the amount of MOF, laser fluence, and scan speeds mainly influenced the patterning process. The electrodes are fabricated on coated and covered glass with varying electrical conductivity due to the high laser energy absorptivity. The patterned electrodes consist of graphitic carbon incorporated with nano‐Cu and show a stable electrical conductivity on the coated substrates. The electrodes are chemically active in the Fe2+/Fe3+ redox system; however, their activity varies with patterning conditions. The electrochemical studies in alkaline electrolytes reveal that the as‐fabricated electrodes can sense the glucose molecule in the linear concentration range of 0.025–1.0 and 1.0–10.0 mm, with a maximum sensitivity of 3260.3 µA mM−1 cm−2 and a response time of no more than 5 s, and a limit of detection (LOD) of 0.25 µm. The current recovery rate is higher (> 80%) when adding glucose molecules than when adding other interference molecules, confirming that the electrode is selective toward glucose sensing. The results reveal that the fabricated electrodes act as stable, reusable, non‐enzymatic glucose‐sensing electrodes. [ABSTRACT FROM AUTHOR]

Bipyridyl Ruthenium-decorated Ni-MOFs on multi-walled carbon nanotubes (MWCNT-RuBpy@Ni-MOF) were synthesized. In an alkaline solution, the glucose was electrocatalytically oxidized at +0.5 V vs. Ag/AgCl at the composite interface of MWCNT-RuBpy@Ni-MOF on a glassy carbon electrode. The Ni3+/Ni2+ redox couples in Ni-MOFs played a key role as the active center for the catalytic oxidation of glucose at the electrode, where both RuBpy and MWCNTs enhanced the current responses to glucose. The resulting enzymeless glucose sensor from MWCNT-RuBpy@Ni-MOF exhibited a wide range of linear responses, high sensitivity and selectivity for the determination of glucose. [ABSTRACT FROM AUTHOR]

Abstract Cost‐effective miniaturized electrodes that maintain a high electroactive surface area (ESA) are needed for the widespread deployment of point‐of‐care sensors. Cost‐effective methods are recently developed to fabricate nanoroughened microstructured gold electrodes (NR‐MSEs) with ultrahigh ESA. In this work, the effectiveness of NR‐MSEs for bioelectrochemical enzymatic sensors is evaluated. A glucose sensor is constructed by first casting onto NR‐MSEs a solution containing reduced graphene oxide decorated with gold nanoparticles, glucose oxidase, and glutaraldehyde, followed by a solution containing ferrocene, and a layer of chitosan to prevent the leakage of sensor components. A urea biosensor is also fabricated using Nafion as a cationic exchanger for the electropolymerization of polyaniline, followed by the deposition of a composite containing urease, bovine serum albumin, and glutaraldehyde. The limit of quantification for both biosensors is below clinically relevant concentrations of the analytes in biofluids, 0.67 mm for glucose and 1.70 mm for urea. The sensors exhibit excellent performance in complex matrixes (human blood serum and wine for glucose and human blood serum and urine for urea), with recovery for spiked analytes in the range of 92–108%. It is anticipated that NR‐MSEs will expedite the development of highly sensitive bioelectrochemical sensors for use in resource‐limited settings.

Elevated blood glucose levels, known as hyperglycemia, play a significant role in sudden cardiac arrest, often resulting in sudden cardiac death, particularly among those with diabetes. Understanding the internal mechanisms has been a challenge for healthcare professionals, leading many research groups to investigate the relationship between blood glucose levels and cardiac electrical activity. Our hypothesis suggests that glucose-sensing biophysics mechanisms in cardiac tissue could clarify this connection. To explore this, we adapted a single-compartment computational model of the human pacemaker action potential. We incorporated glucose-sensing mechanisms with voltage-gated sodium ion channels using ordinary differential equations. Parameters for the model were based on existing experimental studies to mimic the impact of glucose levels on pacemaker action potential firing. Simulations using voltage clamp and current clamp techniques showed that elevated glucose levels decreased sodium ion channel currents, leading to a reduction in the pacemaker action potential frequency. In summary, our mathematical model provides a cellular-level understanding of how high glucose levels can lead to bradycardia and sudden cardiac death.

In this article, we demonstrate an improved efficient fibre sensor with a high sensitivity to measure glucose concentrations in the physiological range of human beings, operating in a broad spectral bandwidth from the near- to mid-infrared. The sensor consists of a dual-peak long period grating (DPLPG) with a period of 150 μm inscribed in an optical fibre with a diameter of 80 μm. The investigation of sensing for refractive index results in a sensitivity of ~−885.7 nm/refractive index unit (RIU) and ~2008.6 nm/RIU in the range of 1.30–1.44. The glucose measurement is achieved by the immobilisation of a layer of enzyme of glucose oxidase (GOD) onto the fibre surface for the selective enhancement of sensitivity for glucose. The sensor can measure glucose concentrations with a maximum sensitivity of −36.25 nm/(mg/mL) in the range of 0.1–3.0 mg/mL. To the best of our knowledge, this is the highest sensitivity ever achieved for a measurement of glucose with a long period grating-based sensor, indicating its potential for many applications including pharmaceutical, biomedical and food industries. [ABSTRACT FROM AUTHOR]

[Display omitted] Manipulating metal valence states and porosity in the metal–organic framework (MOF) by alloying has been a unique tool for creating high-valent metal sites and pore environments in a structure that are inaccessible by other methods, favorable for accelerating the catalytic activity towards sensing applications. Herein, we report Fe3+-driven formation of catalytic active Ni3+ species in the amine-crafted benzene-dicarboxylate (BDC-NH 2)-based MOF as a high-performance electrocatalyst for glucose sensing. This work took the benefit of different bonding stability between BDC-NH 2 ligand, and Fe3+ and Ni2+ metal precursor ions in the heterometallic Ni x Fe (1- x) -BDC-NH 2 MOF. The FeCl 3 that interacts weakly with ligand, oxidizes the Ni2+ precursor to Ni3+-based MOF owing to its Lewis acidic behavior and was subsequently removed from the structure supported by Ni atoms, during solvothermal synthesis. This enables to create mesopores within a highly stable Ni-MOF structure with optimal feed composition of Ni 0.7 Fe 0.3 -BDC-NH 2. The Ni3+-based Ni 0.7 Fe 0.3 -BDC-NH 2 demonstrates superior catalytic properties towards glucose sensing with a high sensitivity of 13,435 µA mM−1 cm−2 compared to the parent Ni2+-based Ni-BDC-NH 2 (10897 μA mM−1 cm−2), along with low detection limit (0.9 μM), short response time (≤5 s), excellent selectivity, and higher stability. This presented approach for fabricating high-valent nickel species, with a controlled quantity of Fe3+ integrated into the structure allowing pore engineering of MOFs, opens new avenues for designing high-performing MOF catalysts with porous framework for sensing applications. [ABSTRACT FROM AUTHOR]

A series of non‐enzymatic electrochemical glucose sensors were prepared by template‐assisted electrodeposition of nickel to produce nickel nanowire arrays (NiNWAs) of varying lengths. These electrodes were analyzed for their performance as non‐enzymatic glucose sensors, in order to explore the relationship between nanowire structure and electrochemical sensor performance. All of the NiNWAs, regardless of length, had linear responses to glucose in the 0.05–10 mM range. However, an inverse relationship between wire length and sensitivity was observed: the shortest of the NiNWAs had a sensitivity of 160 μA mM−1 cm−2, while the longest NiNWA had a sensitivity of only 100 μA mM−1 cm−2. This indicates that, with no other change to material parameters, choosing an optimum length of nanowire provides significant improvement in performance. No change in electrochemical mechanism was observed by cyclic voltammetry, and no significant loss of selectivity was observed with varying nanowire length. This study demonstrates that the structural optimization of an electrode can provide significant performance enhancement for nickel‐based electrochemical sensors. [ABSTRACT FROM AUTHOR]

Diabetes mellitus (DM) presents a substantial global health concern due to elevated blood glucose levels, necessitating an affordable, rapid, and reliable continuous glucose monitoring (CGM) solution. In this pursuit, a pioneering approach is introduced utilizing optical fiber (OF) sensors based on nanocomposite photonic hydrogel functionalized with phenylboronic acid (PBA) for precise CGM. The fabrication of OF sensors involves a streamlined process, involving one‐step polymerization of PBA‐based hydrogel onto a commercial fiber tip and the integration of gold nanoparticles (AuNPs) via a simple dipping process. These sensors offer robust performance within the physiological glucose range (0–20 mm), exhibiting a remarkable 25% increase in transmission intensity and a 4 nm blue shift in the surface plasmon resonance with increasing glucose concentration. Additionally, there is a noticeable elevation in reflection intensity, affirming the sensor's suitability for remote sensing applications. These results are further validated using a green laser, underlining the method's reliability. The sensors exhibit a swift 30 s response time, followed by a 5 min saturation period, for all measurements. Practicality is demonstrated through smartphone readouts, utilizing the phone's photodiode to measure optical power changes concerning various glucose concentrations. These OF sensors hold great promise for CGM integration, enhancing diabetic management. [ABSTRACT FROM AUTHOR]

AbstractIntroduction: Insulin secretion is a highly regulated process critical for maintaining glucose homeostasis. This abstract explores the intricate interplay between three essential pathways: The Triggering Pathway, The Metabolic Amplifying Pathway, and Cellular Transduction, in orchestrating glucose-dependent biphasic insulin secretion.Mechanism: During the triggering pathway, glucose metabolism in pancreatic beta-cells leads to ATP production, closing ATP-sensitive potassium channels and initiating insulin exocytosis. The metabolic amplifying pathway enhances insulin secretion via key metabolites like NADH and glutamate, enhancing calcium influx and insulin granule exocytosis. Additionally, the cellular transduction pathway involves G-protein coupled receptors and cyclic AMP, modulating insulin secretion.Result and Conclusion: These interconnected pathways ensure a dynamic insulin response to fluctuating glucose levels, with the initial rapid phase and the subsequent sustained phase. Understanding these pathways’ complexities provides crucial insights into insulin dysregulation in diabetes and highlights potential therapeutic targets to restore glucose-dependent insulin secretion. [ABSTRACT FROM AUTHOR]

Glucose sensing devices have experienced significant progress in the last years in response to the demand for cost-effective monitoring. Thus, research efforts have been focused on achieving reliable, selective, and sensitive sensors able to monitor the glucose level in different biofluids. The development of enzyme-based devices is challenged by poor stability, time-consuming, and complex purification procedures, facts that have given rise to the synthesis of enzyme-free sensors. Recent advances focus on the use of different components: metal-organic frameworks (MOFs), carbon nanomaterials, or metal oxides. Motivated by this topic, several reviews have been published addressing the sensor materials and synthesis methods, gathering relevant information for the development of new nanostructures. However, the abundant information has not concluded yet in commercial devices and is not useful from an engineering point of view. The dependence of the electrode response on its physico-chemical nature, which would determine the selection and optimization of the materials and synthesis method, remains an open question. Thus, this review aims to critically analyze from an engineering vision the existing information on non-enzymatic glucose electrodes; the analysis is performed linking the response in terms of sensitivity when interferences are present, stability, and response under physiological conditions to the electrode characteristics. [ABSTRACT FROM AUTHOR]

Non-enzymatic detection of glucose is important and is found useful not only in clinical settings but also for quality analysis in food and beverages industry. The fabrication of a good electrocatalyst demands for excellent activity, stability, and easy synthesis methods. Herein, a non-enzymatic glucose sensor has been constructed using Au nanoparticles decorated over Cu2O cubes (Cu2O/nAu) synthesized via a simple cost-effective microwave-assisted technique. The preliminary characterizations including UV–Vis spectroscopy (UV–Vis), Scanning electron microscopy, and Elemental mapping confirmed the formation of Au-decorated over the Cu2O cubes and proved gold nanoparticles were decorated over the cubic structure of the Cu2O. Furthermore, the fabricated Cu2O/nAu was applied for non-enzymatic glucose detection in 0.1 M KOH. The modified glassy carbon electrode of Cu2O/nAu (Cu2O/nAu/GCE) exhibited a linear range from 10 µM to 1 mM for glucose with a limit of detection of 1 µM. The as-developed glucose sensor demonstrates outstanding electrocatalytic activity for the oxidation of glucose with strong stability and high reproducibility. The practical applicability of the developed sensor for non-enzymatic glucose detection was demonstrated by studying artificial sweetener, and commercially available glucose drink. Thus, the as-developed Cu2O/nAu/GCE have the potential for the development of a sensor for analyzing glucose in food and beverages. A simple and non-enzymatic glucose sensor with Nano Au Decorated Hybrid Cu2O cubes is demonstrated. The sensor exhibited a linear range from 10 µM to 1 mM for glucose with a limit of detection of 1 µM. The practical applicability was demonstrated with commercially available glucose drink and artificial sweetener [ABSTRACT FROM AUTHOR]

The efficient hydrolysis of lignocellulosic biomass into fermentable sugars is key for viable economic production of biofuels and biorenewable chemicals from second‐generation feedstocks. Consolidated bioprocessing (CBP) combines lignocellulose saccharification and chemical production in a single step. To avoid wasting valuable resources during CBP, the selective secretion of enzymes (independent or attached to the surface) based on the carbon source available is advantageous. To enable enzyme expression and secretion based on extracellular glucose levels, we implemented a G‐protein‐coupled receptor (GPCR)‐based extracellular glucose sensor; this allows the secretion and display of cellulases in the presence of the cellulosic fraction of lignocellulose by leveraging cellobiose‐dependent signal amplification. We focused on the glucose‐responsiveness of the HXT1 promoter and engineered PHXT1 by changing its core to that of the strong promoter PTHD3, increasing extracellular enzyme activity by 81%. We then demonstrated glucose‐mediated expression and cell‐surface display of the β‐glucosidase BglI on the surface of Saccharomyces cerevisiae. The display system was further optimized by re‐directing fatty acid pools from lipid droplet synthesis toward formation of membrane precursors via knock‐out of PAH1. This resulted in an up to 4.2‐fold improvement with respect to the baseline strain. Finally, we observed cellobiose‐dependent signal amplification of the system with an increase in enzymatic activity of up to 3.1‐fold when cellobiose was added. [ABSTRACT FROM AUTHOR]

Aims/hypothesis: The brain is a major consumer of glucose as an energy source and regulates systemic glucose as well as energy balance. Although glucose transporters such as GLUT2 and sodium−glucose cotransporter 2 (SGLT2) are known to regulate glucose homeostasis and metabolism, the identity of a receptor that binds glucose to activate glucose signalling pathways in the brain is unknown. In this study, we aimed to discover a glucose receptor in the mouse hypothalamus. Methods: Here we used a high molecular mass glucose–biotin polymer to enrich glucose-bound mouse hypothalamic neurons through cell-based affinity chromatography. We then subjected the enriched neurons to proteomic analyses and identified adhesion G-protein coupled receptor 1 (ADGRL1) as a top candidate for a glucose receptor. We validated glucose–ADGRL1 interactions using CHO cells stably expressing human ADGRL1 and ligand–receptor binding assays. We generated and determined the phenotype of global Adgrl1-knockout mice and hypothalamus-specific Adgrl1-deficient mice. We measured the variables related to glucose and energy homeostasis in these mice. We also generated an Adgrl1Cre mouse model to investigate the role of ADGRL1 in sensing glucose using electrophysiology. Results: Adgrl1 is highly expressed in the ventromedial nucleus of the hypothalamus (VMH) in mice. Lack of Adgrl1 in the VMH in mice caused fasting hyperinsulinaemia, enhanced glucose-stimulated insulin secretion and insulin resistance. In addition, the Adgrl1-deficient mice had impaired feeding responses to glucose and fasting coupled with abnormal glucose sensing and decreased physical activity before development of obesity and hyperglycaemia. In female mice, ovariectomy was necessary to reveal the contribution of ADGRL1 to energy and glucose homeostasis. Conclusions/interpretation: Altogether, our findings demonstrate that ADGRL1 binds glucose and is involved in energy as well as glucose homeostasis in a sex-dependent manner. Targeting ADGRL1 may introduce a new class of drugs for the treatment of type 2 diabetes and obesity. [ABSTRACT FROM AUTHOR]

This paper focuses on designing a simple photonic crystal fiber (PCF) biosensor. The proposed glucose sensor is modelled by Lumerical software using the finite element method. To evaluate the efficiency of this model, different sensing properties such as birefringence, coupling length, and relative sensitivity are calculated at different air-filling fractions. The principle of this PCF is to detect the variations in the refractive index of the different concentration glucose solutions. The analyte will be injected into an elliptical channel surrounded by two rings of air holes in a hexagonal shape. Numerical simulations show that increasing the air-filling fraction yields high performance and more light confinement. At the air-filling fraction of 0.45, the maximum birefringence and relative sensitivity were 4.01 × 10−3 and 91%, respectively. Also, the coupling length reaches a minimum of 162.09 μm. [ABSTRACT FROM AUTHOR]

The possibility of establishing a novel technique for reliably accessing glycemic information in a non-invasive, easy to implement method at THz frequencies via the fingernail bed is investigated. The nail bed’s major content is blood at its various glucose levels and is also partially protected from environmental conditions by the nail plate, making it a desirable platform for non-invasive glucose sensing. The study is based on a 2D computational electromagnetics (EM) model of the layered fingernail in COMSOL Multiphysics, where the required dielectric function (i.e. permittivity and conductivity) of the fingernail plate is measured using THz-Time-Domain- Spectroscopy (THz-TDS), and the glucose-dependend dielectric functions of the fingernail bed are taken from available experimental data in the literature. From this data a material model using a multipole Cole-Cole model is established for both, the nail plate and the nail bed, where the glucose content in the latter is varied from 3.0-19.0 mmol/l. A numerical analysis of the THz reflectometry at the fingernail in the frequency range of 0.1-2.0 THz revealed that the reflectance spectra are sensitive to the glucose content in the nail bed proving that accurate glucose sensing via the fingernail bed may become feasible around 0.2-0.4 THz.

This article discusses the challenges faced by college students with Type 1 diabetes mellitus (T1DM) and the need for research to improve diabetes management in this population. The article highlights the importance of creating treatment options, clinical services, and social support for college-going patients with T1DM. It explores themes such as treatment options, diet and weight management, education and social support, and the role of mental health in T1DM management. The article emphasizes the need for easy and reliable treatment options, education and counseling, access to health monitoring, and support for a healthy lifestyle to facilitate the transition of young adults with T1DM to college life. [Extracted from the article]

This article reports a microstrip spurline sensor for glucose concentration monitoring. The microstrip spurline sensor is a low-cost and easy-to-fabricate device that uses printed circuit board (PCB) technology. It consists of a combination of four spurlines and transmission lines. The four spurlines are used to reject unwanted frequencies, while the transmission lines allow the desired frequencies to pass through. The resonance frequency (Fr) and reflection coefficient (S11) were recorded through meticulous simulations and experiments over a frequency range from 1.5 GHz to 4 GHz. In addition, the sensor was used to detect changes in glucose concentration, ranging from 0 mg/dL to 150 mg/dL. The findings of this study show that the antenna-based sensor proposed in this research can effectively measure glucose levels across the diabetes range, from hypoglycemia to normoglycemia to hyperglycemia, with a high degree of sensitivity of 7.82 x 10−3 dB/(mg/dL) and 233.33 kHz/(mg/dL).

Diabetes mellitus (DM) presents a substantial global health concern due to elevated blood glucose levels, necessitating an affordable, rapid, and reliable continuous glucose monitoring (CGM) solution. In this pursuit, a pioneering approach is introduced utilizing optical fiber (OF) sensors based on nanocomposite photonic hydrogel functionalized with phenylboronic acid (PBA) for precise CGM. The fabrication of OF sensors involves a streamlined process, involving one‐step polymerization of PBA‐based hydrogel onto a commercial fiber tip and the integration of gold nanoparticles (AuNPs) via a simple dipping process. These sensors offer robust performance within the physiological glucose range (0–20 mm), exhibiting a remarkable 25% increase in transmission intensity and a 4 nm blue shift in the surface plasmon resonance with increasing glucose concentration. Additionally, there is a noticeable elevation in reflection intensity, affirming the sensor's suitability for remote sensing applications. These results are further validated using a green laser, underlining the method's reliability. The sensors exhibit a swift 30 s response time, followed by a 5 min saturation period, for all measurements. Practicality is demonstrated through smartphone readouts, utilizing the phone's photodiode to measure optical power changes concerning various glucose concentrations. These OF sensors hold great promise for CGM integration, enhancing diabetic management.

Diabetes Mellitus incidence and its negative outcomes have dramatically increased worldwide and are expected to further increase in the future due to a combination of environmental and social factors. Several methods of measuring glucose concentration in various body compartments have been described in the literature over the years. Continuous advances in technology open the road to novel measuring methods and innovative measurement sites. The aim of this comprehensive review is to report all the methods and products for non-invasive glucose measurement described in the literature over the past five years that have been tested on both human subjects/samples and tissue models. A literature review was performed in the MDPI database, with 243 articles reviewed and 124 included in a narrative summary. Different comparisons of techniques focused on the mechanism of action, measurement site, and machine learning application, outlining the main advantages and disadvantages described/expected so far. This review represents a comprehensive guide for clinicians and industrial designers to sum the most recent results in non-invasive glucose sensing techniques' research and production to aid the progress in this promising field. [ABSTRACT FROM AUTHOR]

Terahertz metamaterials have shown promises in biomolecules detection, however, aqueous solvents such as blood serum strongly absorb the terahertz waves, interfering with the detection. To avoid such interference, an ultrathin, flexible, biogel‐based metamaterial that can specifically detect the transmission of terahertz waves through biomolecules in aqueous solution is proposed and demonstrated. The glucose in water can be detected with a sensitivity of 0.0446 dL mg−1 and a detection limit of 1.64 mg dL−1, as well as glucose in human serum. The metamaterial that detects glucose in human sweat is part of a wearable device. The biosensor functions well for more than 100 detection cycles. The results suggest a strategy for real‐time detection of glucose and potentially other biomolecules. [ABSTRACT FROM AUTHOR]

The development of sensor electrode materials for the detection of metabolites will enable point‐of‐care diagnostic devices for the monitoring and treatment of metabolic diseases such as diabetes. Current state‐of‐the‐art glucose sensing electrodes employ the organic salt tetrathiafulvene tetracyanoquinodimethane (TTF TCNQ) to receive electrons directly from enzymatic reactions of glucose. However, TTF TCNQ is insoluble in most solvents, making it challenging to deposit high‐quality electrodes. Furthermore, its hydrophobicity hinders its interface with aqueous solutions in physiological environments. To overcome these issues, TCNQ derivatives are introduced into an electron‐rich and hydrophilic conjugated polymer. Thus, a polymeric electrode is demonstrated that is easily solution processible and can undergo volumetric direct electron transfer with glucose reactions throughout its bulk. This study further elucidates the electron transfer mechanism during chemical doping and metabolite sensing reactions to inform general design rules for this new class of glucose sensing materials. [ABSTRACT FROM AUTHOR]

Recent advances in wearable devices have enabled noninvasive monitoring for healthcare applications. Smart contact lenses have gained substantial attention for medical diagnosis through the analysis of vital signs in tear fluids. However, previous studies have mostly focused on designs embedded with electronic devices or antennas for wireless transmission, which are power‐intensive and require external receivers around the ocular system. Here, the study reports a power‐free smart contact lens for noninvasive glucose sensing according to the color changes of multiple electrochromic electrodes to achieve direct data transmission without the external wireless system. The device detects various glucose concentrations, from the ordinary range (0.16–0.5 mm) to abnormally high concentrations (0.9 mm). The multi‐electrode design exhibits acceptable accuracy, with a correlation coefficient r = 0.99543 to the controlled sample and allowed low‐glucose detections with concentrations down to 0.05 mm. The device shows good reproducibility, with standard deviations of determined glucose levels of 0.0462 and 0.025 for four continuous cycles and for an interval of several days, respectively. It is believed that the reported smart contact lens has the potential for daily health monitoring by ordinary users without a power supply and external devices. Its simple electronics‐free structure will allow for immediate application to the market with cost‐effective manufacturing. [ABSTRACT FROM AUTHOR]

Diabetes is a major worldwide health issue, impacting millions of people around the globe and putting pressure on healthcare systems. Accurate detection of glucose is critical for efficient diabetes care, because it allows for prompt action to control blood sugar levels and avoid problems. Reliable glucose-sensing devices provide individuals with real-time information, allowing them to make more educated food, medicine, and lifestyle decisions. The progress of glucose sensing holds the key to increasing the quality of life for diabetics and lowering the burden of this prevalent condition. The present investigation addresses the synthesis of a CuO@lemon-extract nanoporous material using the sol–gel process. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to analyze the morphological properties of the composite, which revealed a homogeneous integration of CuO nanoparticles (NPs) on the surface of the matrix. The existence of primarily oxidized copper species, especially CuO, was confirmed by X-ray diffraction spectroscopy (XRD) investigation in combination with energy-dispersive X-ray (EDX) spectroscopy. The CuO@lemon-extract-modified glassy carbon electrode (CuO@lemon-extract GCE) performed well in non-enzymatic electrochemical sensing applications such as differential pulse voltammetry (DPV) and amperometric glucose detection. The electrode achieved a notable sensitivity of 3293 µA mM−1 cm−2 after careful adjustment, with a noticeable detection limit of 0.01 µM (signal-to-noise ratio of 3). The operational range of the electrode was 0.01 µM to 0.2 µM, with potential applied of 0.53 V vs. Ag/AgCl. These findings underscore the CuO@lemon-extract GCE's promise as a robust and reliable platform for electrochemical glucose sensing, promising advances in non-enzymatic glucose sensing (NEGS) techniques. [ABSTRACT FROM AUTHOR]

Gold nanomaterials possess leading interest in the field of nanomaterials due to their vast applications both in advanced chemical and medicinal industries. Gold nanorods (AuNRs) were synthesized via a seed-mediated growth approach for catalytic and electrocatalytic applications. UV–vis absorption spectroscopy and scanning electron microscopy were employed to characterize AuNRs. The focus was to achieve AuNRs of high aspect ratios and good yield. For anisotropic AuNRs, two plasmon peaks are observed; transverse and longitudinal peaks. In the synthesis process, morphology of the gold nanorods was tuned varying the pH of the solution ranges from 3.45 to 1.6. By varying the pH, gold nanorods of different aspect ratios were obtained. Gold nanorods with the aspect ratio of 7.5 containing maximum amount of nitric acid and a pH value of 1.6 revealed the most stability. Catalytic applications were monitored by degradation of an organic pollutant. The degradation percentages of 98% were achieved at 12 min duration. Non-enzymatic electrochemical glucose sensor was fabricated via glassy carbon electrode modification with gold nanorods and studied using cyclic voltammetry. All samples showed good electrochemical response. Among all samples, the one with maximum amount of nitric acid and a pH value of 1.6 revealed the most stability and high sensitivity for glucose sensing. [ABSTRACT FROM AUTHOR]

Bipyridyl Ruthenium-decorated Ni-MOFs on multi-walled carbon nanotubes (MWCNT-RuBpy@Ni-MOF) were synthesized. In an alkaline solution, the glucose was electrocatalytically oxidized at +0.5 V vs. Ag/AgCl at the composite interface of MWCNT-RuBpy@Ni-MOF on a glassy carbon electrode. The Ni3+/Ni2+ redox couples in Ni-MOFs played a key role as the active center for the catalytic oxidation of glucose at the electrode, where both RuBpy and MWCNTs enhanced the current responses to glucose. The resulting enzymeless glucose sensor from MWCNT-RuBpy@Ni-MOF exhibited a wide range of linear responses, high sensitivity and selectivity for the determination of glucose.

To address the urgent need for glucose level detection in the human body, several affordable, lightweight, and skin-mounted glucose sensors have been developed. Enzymatic sensors are frequently utilized, but they have challenges of enzyme degradation and indirect charge transfer through a redox mediator, which affect their reusability and shelf life. Here, enzyme-free nickel oxide thin film electrode in an alkaline medium is used to enable direct charge transfer with glucose. A chemical reaction between glucose and the electrode surface occurs, leading to an additional oxidation (Ni+2/Ni+3) of the electrode under external bias. Additionally, the colorimetric analysis further validated this reaction through the transformation of a dark-colored NiO (Ni+3) electrode into a bleached color state (reduced from Ni+3 to Ni+2) through the oxidation of glucose. As the glucose concentrations increase to 5 mM, the color of the electrode is no longer optically readable (ΔT% ∼ 66%). The corresponding amperometric response is determined with a detection limit of 2 μM and a 3579 μA mM−1 cm−2 sensitivity, and it also recognizes a passive response to other interfering species and facilitates its one-month shelf life. Additionally, a two-electrode electrochemical colorimetric liquid cell-type glucose sensor has been designed to pave the way for future applications.

Constructing high-performance glucose sensors is of great significance for the prevention and diagnosis of diabetes, and the key is to develop new sensitive materials. In this paper, a series of Ni2Co1-L MOFs (L = H2BPDC: 4,4′-biphenyldicarboxylic acid; H2NDC: 2,6-naphthalenedicarboxylic acid; H2BDC: 1,4-benzenedicarboxylic acid) were synthesized by a room temperature stirring method. The effects of metal centers and ligands on the structure, compositions, electrochemical properties of the obtained Ni2Co1-L MOFs were characterized, indicating the successful preparation of layered MOFs with different sizes, stacking degrees, electrochemical active areas, numbers of exposed active sites, and glucose catalytic activity. Among them, Ni2Co1-BDC exhibits a relatively thin and homogeneous plate-like morphology, and the Ni2Co1-BDC modified glassy carbon electrode (Ni2Co1-BDC/GCE) has the highest electrochemical performance. Furthermore, the mechanism of the enhanced glucose oxidation signal was investigated. It was shown that glucose has a higher electron transfer capacity and a larger apparent catalytic rate constant on the Ni2Co1-BDC/GCE surface. Therefore, tunable non-enzymatic glucose electrochemical sensing was carried out by regulating the metal centers and ligands. As a result, a high-sensitivity enzyme-free glucose sensing platform was successfully constructed based on the Ni2Co1-BDC/GCE, which has a wide linear range of 0.5–2899.5 μM, a low detection limit of 0.29 μM (S/N = 3), and a high sensitivity of 3925.3 μA mM−1 cm−2. Much more importantly, it was also successfully applied to the determination of glucose in human serum with satisfactory results, demonstrating its potential for glucose detection in real samples. [ABSTRACT FROM AUTHOR]

Diabetes has become a chronic disease that necessitates timely and accurate detection. Among various detection methods, electrochemical glucose sensors have attracted much attention because of low cost, real-time detection, and simple and easy operation. Nonenzymatic biomimetic nanomaterials are the vital part in electrochemical glucose sensors. This review article summarizes the methods to enhance the glucose sensing performance of noble metal, transition metal oxides, and carbon-based materials and introduces biomimetic nanomaterials used in noninvasive glucose detection in sweat, tear, urine, and saliva. Based on these, this review provides the foundation for noninvasive determination of trace glucose for diabetic patients in the future. [ABSTRACT FROM AUTHOR]

A phenylboronic acid-based, hydrogel-interlayer Radio-Frequency (RF) resonator is demonstrated as a highly-responsive, passive and wireless sensor for glucose monitoring. Constructs are composed of unanchored, capacitively-coupled split rings interceded by glucose-responsive hydrogels. Phenylboronic acid-hydrogels exhibit volumetric and dielectric variations in response to environmental glucose concentrations-these are efficiently converted to large shifts in the resonant response of interlayer-RF sensors. These tiny, stretchable and scalable sensors (5 mm × 5 mm x 250 μm) require no microelectronics or power at the sensing node and can be read-out remotely via near-field coupling. Sensors exhibit high sensitivities (~10% shift in resonant frequency-corresponding to 50 MHz-per 150 mg/dL of glucose), possess a limit of detection of 10 mg/dL, and a step response time of approximately 1 h to abrupt shifts in carbohydrate concentration. Notably, these sensors exhibited no signal drift or hysteresis over the time periods characterized herein (45 days at room temperature). We transform sensors into bioelectronic RF reporter-tags via the attachment of a single LED-these remotely report on glucose concentration via emitted light. We anticipate the non-degradative, long-term nature of both RF read-out and phenylboronic acid-based hydrogels will enable biosensors capable of long-term, remote read-out of glucose.