Measurement Of Glucose Concentration Research Articles

Impacts of transient exposure of human T cells to low oxygen, temperature, pH and nutrient levels relevant to bioprocessing for cell therapy applications.

T-cell therapy advances have stimulated the development of bioprocesses to address the specialized needs of cell therapy manufacturing. During concentrated cell washing, the cells are frequently exposed to transiently reduced oxygen, temperature, pH, and nutrient levels. Longer durations of these conditions can be caused by process deviations or, if they are not harmful, be used to ease the scheduling of process stages during experiments as well as manufacturing. To avoid unpredictable impacts on T-cell quality during bioprocessing, we measured the influences of such environmental exposures generated by settling 250 million activated human T cells per mL, for up to 6 h at temperatures from 4 to 37°C. The measured glucose concentration decreased to as low as 0.5 mM and the pH to 6, while lactate increased up to 55 mM. The concentrated cell conditions at 37°C resulted in by far the greatest losses in viable cell numbers with, on average, only 58% and 41% of the cells recovered after 3 and 6 h, respectively. Likewise, their subsequent cell expansion cultures were substantially reduced even after only 3 h of exposure, and with decreased percentages of central memory T cells and increased percentages of effector memory and effector T cells. Although under similar environmental conditions at room temperatures, the negative impacts of high cell concentrations were greatly diminished for up to 3 h. At 4°C the transient conditions were less extreme, and the cells well maintained for 6 h. Overall, when developing processes and devices for T-cell therapy manufacturing that involve concentrated cells, the results of this study indicate that more practically feasible room temperatures can be used for up to 3 h to obtain high viable cell recoveries whereas lower temperatures such as 4°C should be used if there is a need for more prolonged concentrated T-cell conditions.

The influence of intestinal microbiota on the development of type 1 diabetes

Introduction and purpose Type 1 diabetes (T1D) is an autoimmune disease that results in the destruction of pancreatic β cells, which leads to insulin deficiency and hyperglycemia. One significant factor that may influence the development of type 1 diabetes is a change in the intestinal microbiota. This study aim is to present the significance and role of intestinal microbiota in the pathogenesis of T1D. This subject is important, as it offers prospects for new therapeutic solutions, especially given the significant social impact of T1D. Description Type 1 diabetes (T1D) causes a number of symptoms and complications, including an increased risk of developing cardiovascular diseases. Diagnosis includes measurements of glucose concentration, glycated hemoglobin, and specific antibodies in the blood. The basic therapy for T1D is insulin replacement therapy. Numerous studies have shown that both the composition and function of the intestinal microbiota are impaired in patients with T1D. It has been observed that an increase in the number of Bacterioides and a decrease in the number of Firmicutes, which are the main microorganisms of the intestinal microbiome, are correlated with a high risk of developing T1D. Summary Type 1 Diabetes (T1D) is a serious health problem that affects many people worldwide and the incidence of the disease is constantly increasing. There is a growing number of studies that emphasize the influence of the intestinal microbiota on the development of T1D. It is important to enlarge our knowledge about this disease. Further studies are needed to determine the importance and the role of the intestinal microbiota in the pathogenesis of T1D.

Electrical Tissue Adhesives for Strain‐Insensitive In‐situ Biosensing

In‐situ biosensing, a rapidly evolving field that focuses on the development of biosensors capable of on‐site detection of biomolecules directly from local tissue regions, holds the potential to revolutionize medicine through real‐time monitoring, personalized diagnosis, and targeted therapies. However, interfacing rigid, nonstretchable biosensors with soft, deformable tissues presents significant challenges due to their fundamentally contradictory properties. Herein, an electrical tissue adhesive featuring an entangled adhesive polymer network interpenetrated with a sacrificial dissipative polymer network is developed, which can rapidly and robustly adhere electrochemical biosensors with biological tissues, enabling strain‐insensitive physiological monitoring. The electrical tissue adhesive achieves a high fracture toughness of up to 3000 J m−2, a low Young's modulus of around 20 kPa, superior stretchability up to 15 times its initial length, and an overall biosensor‐tissue interfacial toughness of up to 500 J m−2. Using an electrochemical glucose sensor as one example, it is demonstrated that the electrical tissue adhesive can maintain resilient glucose sensing under various stress states and stretch levels. Additionally, the application of the electrical tissue adhesive for in‐situ monitoring of exercise and diet in subjects with various BMIs is demonstrated by measuring glucose concentration in sweat.

Characterizing the Impact of Physical Activity on Patients with Type 1 Diabetes Using Statistical and Machine Learning Models

Continuous glucose monitoring (CGM) represents a significant advancement in diabetes management, playing an important role in glycemic control for patients with type 1 diabetes (T1D). Despite their benefits, their performance is affected by numerous factors such as the carbohydrate intake, alcohol consumption, and physical activity (PA). Among these, PA could cause hypoglycemic episodes, which might happen after exercising. In this work, two main contributions are presented. First, we extend the performance evaluation of two glucose monitoring devices, Eversense and Free Style Libre (FSL), for measuring glucose concentrations during high-intensity PA and normal daily activity (NDA). The impact of PA is investigated considering (1) different glucose ranges (hypoglycemia, euglycemia, and hyperglycemia); and (2) four time periods throughout the day (morning, afternoon, evening, and night). Second, we evaluate the effectiveness of machine learning (ML) models, including logistic regression, K-nearest neighbors, and support vector machine, to automatically detect PA in T1D individuals using glucose measurements. The performance analysis showed significant differences between glucose levels obtained in the PA and NDA period for Eversense and FSL devices, specially in the hyperglycemic range and two time intervals (morning and afternoon). Both Eversense and FSL devices present measurements with large variability during strenuous PA, indicating that their users should be cautious. However, glucose recordings provided by monitoring devices are accurate for NDA, reaching similar values to capillary glucose device. Lastly, ML-based models yielded promising results to determine when an individual has performed PA, reaching an accuracy value of 0.93. The results can be used to develop an individualized data-driven classifier for each patient that categorizes glucose profiles based on the time interval during the day and according to if a patient performs PA. Our work contributes to the analysis of PA on the performance of CGM devices.

Quantitative analysis of human blood glucose by dynamic optical rotation angle of multiple wavelengths based on the polarization camera

Measurement of blood glucose concentration is important in the prevention and treatment of diabetes. To improve the measurement signal-to-noise ratio and accuracy, using a polarization camera as the sensor, this paper proposes a multi-wavelength dynamic optical rotation angle method to quantitatively analyze human blood glucose. First, this paper utilizes a split-time approach to drive nine different wavelengths of light sources to work separately to achieve the collection of multiple different wavelengths of data and increase the amount of information. Second, to capture images with an array sensor such as a camera, using space-for-accuracy, this paper uses the cumulative value of the gray values of all pixel points in the image at each angle as the light intensity value to improve the amplitude (light intensity) resolution. Third, the extraction method of the dynamic optical rotation angle in this paper is to extract the difference between the maximum and minimum values of the optical rotation angle from each cycle of the signal of the continuous cyclic change of the length of the optical path, and the accumulated value of the difference of multiple cycles is recorded as the dynamic optical rotation angle, which not only reduces the errors caused by the individual differences, the external environment and the measuring instrument, but also has the effect of averaging and improves the signal-to-noise ratio of the optical rotation angle. To prove the effectiveness of the proposed methods, human finger real and simulation experiments are carried out, respectively. Firstly, the polarization camera is used to collect the image data of elliptically polarized light of nine different wavelengths of linearly polarized light after passing through the human body’s finger, and obtains the optical rotation angle under each wavelength that changes with the photoplethysmography (PPG) through data processing, and extracts the dynamic optical rotation angles of the nine wavelengths by the extraction method, and the human body’s blood glucose can be quantitatively analyzed. Secondly, this paper builds a simulation model to simulate the blood volume conversion of the human finger, and uses the simulation experimental system to collect the dynamic optical rotation angles of nine wavelengths of a total of 137 human serum samples, and uses partial least squares regression to establish a model between the dynamic optical rotation angles and blood glucose concentration. In the results of predicting all samples using the model, the correlation coefficient and root mean square error were 0.7960 and 2.16 mmol/L, respectively, both of which improved by 137.26 % and decreased by 35.33 %, respectively, compared to the existing method. The experimental results show that the method in this paper has high accuracy in detecting the blood glucose concentration in human beings, which is of great significance in realizing the noninvasive quantitative analysis of human blood glucose components by the polarized light method.

Glucose inhibitor tubes in Croatian laboratories: are we doing well?

Reliable and accurate measurement of blood glucose concentration is of crucial importance for making clinical decisions in diagnosis diabetes, gestational diabetes and impaired fasting glucose tolerance. Survey was performed in form of questionnaire. Questionnaire was sent to all Croatian laboratories (N = 204) in electronic form using SurveyMonkey cloud-based software (SurveyMonkey, Inc., San Mateo, USA) as an extra-analytical module of the Croatian EQA (External Quality Assessment) provider Croatian center for external quality assessment (CROQALM) in June 2023. In total 148 (73%) of laboratories responded to the survey. Large proportion of laboratories never use glucose inhibitor tubes for random glucose measurement (more than half) or for glucose function tests (one quarter). Only three laboratories use recommended glycolysis inhibitor citrate. Many other inhibitors are also used, even if some of them are not recommended for plasma glucose measurement. Glucose is almost never (93%) sampled on ice when glucose inhibitor tube is not available. Laboratories in Croatia do not follow the recommended procedures regarding glycolysis inhibitors for glucose determination.

Physiological and metabolic effects of short-term dopamine reduction in healthy horses using a tyrosine hydroxylase inhibitor (alpha-methyl-para-tyrosine)

Alpha-methyl-para-tyrosine (AMPT) is a reversible inhibitor of tyrosine hydroxylase, the rate-limiting enzyme in catecholamine synthesis. This study aimed to determine whether AMPT could reduce dopamine concentrations in horses. Six healthy adult Standardbred geldings were administered AMPT (40 mg/kg BW, orally) or placebo in a randomised crossover study design. Clinical examination findings were recorded, and blood samples were collected for up to 6 h after administration of AMPT or placebo, for measurement of blood glucose, plasma ACTH and cortisol concentrations, and plasma metabolomic analysis. Plasma prolactin concentration was determined as a proxy index of central dopamine reduction. No adverse clinical effects were detected after oral administration of AMPT, with heart rate, mean arterial pressure and blood glucose concentration not differing between AMPT treatment or placebo. Plasma prolactin concentration peaked 1 h after AMPT administration before returning to baseline at 2 h (for five horses) or 6 h (for one horse). Metabolomic analysis demonstrated a reduction in plasma dopamine (0.72-fold change; P=0.016) 1 h after AMPT treatment. Plasma ACTH and cortisol concentrations were not different between AMPT and placebo over time. A few metabolites associated with ketogenesis were increased, and certain amino acids decreased, at 1 h compared with baseline, for both AMPT treatment and placebo. Therefore, AMPT was effective in reducing both central and circulating dopamine concentrations in healthy horses following a single oral dose. Further pharmacokinetic and pharmacodynamic studies are warranted to optimise the dose and duration of AMPT treatment to achieve longer-term dopamine reduction. Plasma metabolomic findings suggested an interruption to energy flux at the time of sample collection, which may be relevant to nutritional studies in horses and warrants further investigation.

Arterial to jugular-bulb lactate difference in patients undergoing elective brain tumor craniotomy.

Hyperlactatemia is common during tumor craniotomy, but the underlying pathophysiology is unclear. This study measured simultaneous arterial and jugular-bulb lactate concentrations in patients undergoing brain tumor craniotomy to investigate the hypothesis that hyperlactatemia was associated with a net cerebrovascular lactate input. In 20 patients, arterial and jugular-bulb blood was collected hourly from the start of surgery to 6 h postoperatively for measurement of lactate, glucose, and oxygen concentration. For each marker, data were analyzed using a linear mixed-effects model with jugular-bulb concentration as dependent variable, arterial concentration as fixed effect, and patient as random effect. Furthermore, we generated regression lines between arterial and jugular-bulb concentrations. The slope of the regression line between arterial and jugular-bulb lactate was 0.95 (95% CI 0.93-0.97, R2 = 0.98), indicating that increasing arterial lactate levels were associated with an increasingly positive net cerebrovascular balance (net input). The line crossed the identity line at 2.86 (95% CI 0.57-5.16) mmol/L, indicating that lower levels of lactate were associated with a negative net cerebrovascular balance (net output). This suggests a switch from net lactate output during normolactatemia towards net input during hyperlactatemia. Hyperlactatemia in tumor-craniotomy patients probably does not originate from the brain.

Comparison between a Flash Glucose Monitoring System and a Portable Blood Glucose Meter for Monitoring of Cats with Diabetic Ketosis or Ketoacidosis.

Cats with diabetic ketosis or ketoacidosis DK(A) require intensive glucose monitoring. The aim of this study was to assess the agreement between a portable blood glucose meter (PBGM) and a flash glucose monitoring system (FGMS; FreeStyle Libre 2.0 Abbott®) measuring interstitial glucose in cats with DK(A). Ten client-owned cats with naturally occurring DK(A) were prospectively enrolled. Glucose concentrations were assessed with both methods every 1-3 h until resolution of DK(A), and every 4-8 h thereafter. While the median FGMS measured glucose concentration (14.3 mmol/L) was significantly lower than the median PBGM measured glucose concentration (19 mmol/L) (p < 0.001), the overall correlation between the FGMS and PBGM was high (r = 0.88; p < 0.001). In the Parkes error grid analysis, 98.3% of measurements fell in zones A and B. Bland-Altman plot analysis demonstrated that in the low glycaemic range (BG < 5.5 mmol/L), 50% of FGMS measurements deviated more than ±0.83 mmol/L, and in the high glycaemic range (BG > 5.5 mmol/L), 81% of results deviated >15% from the PBGM measurements. There was significant inter-individual variation in the difference between glucose concentrations measured by the FGMS and PBGM (p < 0.001). In spite of being more easily tolerated and easier to use, currently this method cannot be recommended for routine monitoring of cats with DK(A).

Flexible surface plasmon based coupled triple band UHF-microwave sensor for glucose sensing application

Although the correlation between a glucose concentration and its permittivity is somewhat weak to be measured, the glucose concentration is a strong function of the dispersion. In terahertz or microwave frequencies, dispersion can be observed or measured along the interface between an object under test and a metamaterial or surface plasmonic surface, which is basically a metal structure characterized by periodically arrayed holes, grooves, or metal grating. In this work, we have focused on the method for improving the accuracy of a glucose measurement by proposing a new triple-band microwave sensor design and by measuring the resonant frequency shift associated with a glucose concentration at three frequencies simultaneously. A new triple-band glucose sensor of dimension (30 mm x 10 mm) was designed with the main sensing region as compact as 14 mm with two conducting microstrip lines on both ends of the sensor. The sensor design has been realized on a thin flexible substrate of 0.15 mm thickness. The proposed sensor has been designed to measure glucose concentration through the measurement of a resonant frequency shift at 650 MHz, 4.45 GHz, and 10.35 GHz. Overall, the glucose concentration has been found to be correlated positively and linearly with the resonant frequency shift at these frequencies.

Comparison of Glucose and Immunoglobulin a Levels in Serum and Saliva of Patients with Type 1 and Type 2 Diabetes

Introduction: The monitoring and management of blood glucose levels are of significant importance in individuals diagnosed with diabetes mellitus. Accordingly, the objective of this study was to examine the potential of a non-invasive approach for the diagnosis and management of diabetes, through the measurement of glucose concentration and salivary IgA, and a comparison with fasting glucose and serum IgA levels in individuals with type 1 and 2 diabetes, in relation to a control group of healthy individuals. Methods: This case-control study was conducted on 76 individuals with diabetes (31 with type 1 diabetes and 45 with type 2 diabetes) and 24 healthy individuals. After obtaining the code of ethics and informed consent, serum and salivary IgA levels as well as fasting glucose, were measured for each participant. The data were analyzed using SPSS version 16 statistical software and the Spearman, Kruskal-Wallis, and Mann-Whitney tests. Results: The results showed a significant difference among the three groups (type 1 diabetes, type 2 diabetes, and healthy group) based on Fasting Blood Glucose, Hemoglobin A1c, Immunoglobulin A, salivary sugar, and salivary IgA (p&lt;0.001). Additionally, in the case group, parameters such as FBS, HbA1c, and salivary IgA showed a significant correlation with salivary sugar. Conversely, in the control group, only the salivary sugar level demonstrated a significant relationship with serum glucose level. The study's findings indicated that serum and salivary IgA levels were lower and higher, respectively, in the control subjects compared to the diabetic group (p&lt;0.001). Conclusion: In healthy individuals, salivary sugar can serve as an indicator to determine fasting blood sugar levels. In diabetic patients, salivary sugar can predict of FBS, HbA1c, and salivary IgA levels.

Advancement in glucose concentration measurement in human blood: a surface plasmon resonance-based optical sensing approach

Advancement in glucose concentration measurement in human blood: a surface plasmon resonance-based optical sensing approach

The Self-Powered Thermoelectric System Driving an Electric Field for Raman-Spectrum Glucose Quantitative Analysis

For a long time, blood glucose monitoring has been a challenging issue in the field of medicine. Although it is possible to visit a hospital for regular blood tests to track blood sugar concentration, the physiological reactions triggered by blood collection might lead to feeling weak, dizzy, or even vomiting. Therefore, especially for diabetic patients, they need to frequently monitor their blood sugar concentration in their daily lives to ensure their health. Currently, the primary methods for blood glucose testing still rely on invasive techniques, such as using fingertip glucose meters and other methods which require skin puncture to obtain blood samples. Although these methods provide a quick assessment of current blood glucose concentration, they come with the pain and discomfort of blood collection process and the potential risk of infection. As a result, in recent years, many researchers have been dedicated to developing non-invasive blood glucose monitoring methods. However, accurately measuring glucose concentration inside the human body remains a challenging task. One of the primary issues is the presence of strong noise and background noise. To avoid this challenge, we have developed an innovative detection platform that is combines surface-enhanced Raman spectroscopy (SERS) and external electric field sensing technology. With the electromagnetic effect, we add external electric field in our platform to excite more the surface plasmon resonance. By using this method, we can achieve signal amplification to detect lower concentrations of glucose. Now, we can detect down to 0.001mM of glucose. We also exhibit self-powered electric field system, using the flexible themoelctric device to combine our platform. By the property of self-powered, we success to create a self-powered electric field system. We focus on driving themoelectric through the temperature different between body temperature and environment. The approach is aimed at generating power from the human body, providing a self-powered thermoelectric system for Raman-spectrum glucose sensors. This innovative approach holds promise for advancing non-invasive blood glucose monitoring and benefiting a larger population of diabetes patients in the future.

The sodium correction factor for dogs undergoing treatment for a hyperglycemic crisis is a 1.6-mEq/L decrease in sodium per 100-mg/dL increase in glucose.

To determine the sodium correction factor for clinical use in hyperglycemic diabetic dogs. Retrospective analysis of 76 hospitalization episodes from 67 different dogs presenting to the University of Georgia Veterinary Teaching Hospital between January 1, 2015, and January 1, 2023. For each hospitalization episode, paired blood sodium and glucose concentration measurements were recorded from the time of presentation until glucose concentration was ≤ 201 mg/dL. Therapies administered, primary diagnosis, and concurrent diseases were also recorded for each episode. A linear mixed model was used to determine the sodium correction factor per 100-mg/dL increase in glucose. Piecewise linear mixed models were also constructed for blood glucose measurements ≤ 400 mg/dL and > 400 mg/dL to explore potential correction factor differences between low and high glucose concentrations. A sodium correction factor of a 1.6-mEq/L (95% CI, 1.3 to 1.9 mEq/L) decrease in sodium concentration per 100-mg/dL increase in blood glucose concentration was calculated. Differences in the correction factor between conditions of low and high glucose concentrations could not be determined due to a small sample size of blood glucose values > 400 mg/dL. Most dogs received similar treatments throughout the study period, including balanced isotonic crystalloids (97% [74/76]), electrolyte supplementation (84% [64/76]), and regular insulin (97% [74/76]). Almost all patients (93% [71/76]) had 1 or more concurrent diseases. A sodium correction factor of 1.6 mEq/L (decrease in sodium per 100-mg/dL increase in glucose) is recommended for clinical use in hyperglycemic diabetic dogs.

Non-Invasive Analysis of the Bioelectrical Impedance of a Human Forearm

Abstract This study explores the practical application and impact of bioimpedance analysis in mobile devices for monitoring human health. The objective of the study is to propose a feasible application of non-invasive bioimpedance analysis by using the tetrapolar electrode connection method and the Cole–Cole model. Bioimpedance measurements and the calculation of electrical parameters are performed using ANSYS HFSS software for theoretical calculations and digital signal processing technology for real-time measurements using hardware devices. The study focuses on a model of the front arm, including tissues such as bone, fat, muscles, arteries and skin, with glucose concentrations as test cases. The simulated characteristic impedance with the ANSYS HFSS software package at 125 kHz varied from 315.8 Ω to 312.6 Ω, and the measured forearm characteristic impedance with hardware varied from 150.1 Ω to 151.3 Ω. The measured characteristic impedance when the heart is in systole and diastole also differed, with a difference of about 0.85% of the maximum impedance measured. The study demonstrates the potential of non-invasive bioimpedance analysis to address health issues such as obesity and heart disease. It also highlights its usefulness as a non-invasive alternative for measuring glucose concentration in diabetic patients to reduce the risk of infection. The findings indicate the feasibility of using bioimpedance analysis in mobile devices for health monitoring purposes.

Paper-Based Microfluidic Analytical Device Patterned by Label Printer for Point-of-Care Blood Glucose and Hematocrit Detection Using 3D-Printed Smartphone Cassette.

This study presents a portable, low-cost, point-of-care (POC) system for the simultaneous detection of blood glucose and hematocrit. The system consists of a disposable origami microfluidic paper-based analytical device (μPAD) for plasma separation, filtration, and reaction functions and a 3D-printed cassette for hematocrit and blood glucose detection using a smartphone. The origami μPAD is patterned using a cost-effective label printing technique instead of the conventional wax printing method. The 3D-printed cassette incorporates an array of LED lights, which mitigates the effects of intensity variations in the ambient light and hence improves the accuracy of the blood glucose and hematocrit concentration measurements. The hematocrit concentration is determined quantitatively by measuring the distance of plasma wicking along the upper layer of the origami μPAD, which is pretreated with sodium chloride and Tween 20 to induce dehydration and aggregation of the red blood cells. The filtered plasma also penetrates to the lower layer of the origami μPAD, where it reacts with embedded colorimetric assay reagents to produce a yellowish-brown complex. A color image of the reaction complex is captured using a smartphone inserted into the 3D-printed cassette. The image is analyzed using self-written RGB software to quantify the blood glucose concentration. The calibration results indicate that the proposed detection platform provides an accurate assessment of the blood glucose level over the range of 45-630 mg/dL (R2 = 0.9958). The practical feasibility of the proposed platform is demonstrated by measuring the blood glucose and hematocrit concentrations in 13 human whole blood samples. Taking the measurements obtained from commercial glucose and hematocrit meters as a benchmark, the proposed system has a differential of no more than 6.4% for blood glucose detection and 9.1% for hematocrit detection. Overall, the results confirm that the proposed μPAD is a promising solution for cost-effective and reliable POC health monitoring.

Advancing Glucose Monitoring: A Near-Infrared Device for Continuous Invasive Assessment

Diabetes is a chronic disease that affects millions of people worldwide, with the number of newly diagnosed cases continuing to rise at an alarming rate. Patients diagnosed with diabetes require routine monitoring of their blood glucose levels, which is commonly done through invasive and minimally invasive techniques. However, these methods are often painful, prone to infection, and costly in the long run. Therefore, it is necessary to develop non-invasive, pain-free, affordable glucose monitoring techniques. Near-infrared spectroscopy has emerged as a promising technique among the non-invasive techniques for glucose monitoring, with several studies reporting its efficacy in detecting glucose concentration. This study designed and developed a near-infrared system based on an 1150nm wavelength for continuous non-invasive glucose monitoring. The system gave the output voltages that vary with increased glucose concentrations. It was ascertained from the Clark error grid analysis that the glucose concentration falls within region A and region B. This implies that the device is suitable for measuring glucose concentration non-invasively. As per Bland Altman's analysis, the majority of the data points were within both limits of agreement except one data point that was outside the upper limit of agreement, indicating 93% degree of accuracy, and the residual plot indicates that the regression model for the system is appropriate for predicting non-invasive glucose measurements.

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.

Transcending antibiotic resistance: The potential of mass Galla chinensis et camelliae Fermentata to Dismantle Helicobacter pylori biofilms and enhance anti-biotic activity

Ethnopharmacological relevanceHelicobacter pylori (H. pylori) infections are on the rise, presenting a significant global health challenge. Mass Galla chinesis et camelliae Fermentata (Chinese gall leaven, CGL), a traditional Chinese medicinal product made from the fermentation of Rhus chinensis Mill., is frequently employed to address digestive system ailments. Contemporary pharmacological research reveals that CGL exhibits anti-inflammatory, anti-diarrheal, and enzyme-inhibitory activities and holds potential as a treatment for H. pylori infections. However, the precise mechanisms underlying CGL's efficacy against H. pylori remain to be fully elucidated. AimThe objective of the study is to evaluate CGL's ability to disrupt the H. pylori biofilm and to explore its synergistic potential with antibiotics in targeting the biofilm-efflux pump system, a mechanism implicated in bacterial resistance. MethordsThe study determined the Minimum Inhibitory Concentration (MIC) of CGL and metronidazole against H. pylori and evaluated their effects on H. pylori biofilms using an in vitro model. Structural changes induced by drug interventions were compared to those in untreated and antibiotic-treated models through scanning electron microscopy and laser confocal microscopy. The accumulation of H33342 dye in planktonic and biofilm H. pylori before and after drug treatment was assessed to evaluate cell viability and biofilm disruption. The study also involved adding experimental drugs to a biofilm H. pylori medium containing D-glucose, measuring glucose concentrations post-intervention using the glucose oxidase method, and calculating changes in glucose uptake. Finally, the relative expression levels of several genes in planktonic and biofilm H. pylori treated with CGL alone or in combination with antibiotics were measured to understand the impact on the biofilm-efflux pump system. ResultsBoth CGL alone and in combination with metronidazole demonstrated effective disruption of H. pylori biofilms. The combination therapy was particularly effective in reducing the biofilm transfer-enhancing effect of metronidazole and decreasing SpoT expression in the 'SpoT-(p)ppGpp' pathway, especially in biofilms. It showed a greater inhibition of the 'σ54-gluP-sugar uptake' pathway, with significant reductions in rpoN and gluP expression under biofilm conditions compared to CGL or metronidazole alone. The treatment also suppressed H. pylori proliferation and may have altered glucose uptake mechanisms. Moreover, it significantly inhibited the 'hp0939/hp0497/hp0471-RND efflux pump' pathway, with a notable reduction in gene expression compared to the 1/2 MIC metronidazole treatment. ConclusionThis study demonstrates that CGL effectively hinders the development of drug resistance in H. pylori by targeting biofilm formation and critical molecular pathways associated with antibiotic resistance. The synergistic effect of combining CGL with metronidazole notably enhances biofilm disruption and inhibits the bacterium's metabolic and reparative mechanisms. Further in vivo studies are needed to confirm these results and to investigate additional mechanisms of CGL's action.

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.