Glucose Oxidase Peroxidase Research Articles

Cascade Enzymes Confined in DNA Nanoanchors for Antitumor Therapy.

Cascade-enzyme reaction systems have emerged as promising tools for treating malignant tumors by efficiently converting nutrients into toxic substances. However, the challenges of poor localized retention capacity and utilization of highly active enzymes often result in extratumoral toxicity and reduced therapeutic efficacy. In this study, we introduced a cell membrane-DNA nanoanchor (DNANA) with a spatially confined cascade enzyme for in vivo tumor therapy. The DNANAs are constructed using a polyvalent cholesterol-labeled DNA triangular prism, ensuring high stability in cell membrane attachment. Glucose oxidase (GOx) and horseradish peroxidase (HRP), both modified with streptavidin, are precisely confined to biotin-labeled DNANAs. Upon intratumoral injection, DNANA enzymes efficiently colonize the tumor site through cellular membrane engineering strategies, significantly reducing off-target enzyme leakage and the associated risks of extratumoral toxicity. Furthermore, DNANA enzymes demonstrated effective cancer therapy in vitro and in vivo by depleting glucose and producing highly cytotoxic hydroxyl radicals in the vicinity of tumor cells. This membrane-engineered cascade-enzyme reaction system presents a conceptual approach to tumor treatment.

Multi-walled carbon nanotubes functionalized with a new Schiff base containing phenylboronic acid residues: applicationtothe development of a bienzymatic glucose biosensor using a response surface methodology approach.

Aninnovative supramolecular architectureis reportedfor bienzymatic glucose biosensing based on the use of a nanohybrid made of multi-walled carbon nanotubes (MWCNTs) non-covalently functionalized with a Schiff base modified with two phenylboronic acid residues (SB-dBA) as platform for the site-specific immobilization of the glycoproteins glucose oxidase (GOx) and horseradish peroxidase (HRP). The analytical signal was obtained from amperometric experiments at - 0.050V in the presence of 5.0 × 10-4M hydroquinone as redox mediator. The concentration of GOx and HRP and the interaction time between the enzymes and the nanohybrid MWCNT-SB-dBA deposited at glassy carbon electrodes (GCEs) were optimized through a central composite design (CCD)/response surface methodology (RSM). The optimal concentrations of GOx and HRP were 3.0mgmL-1 and 1.50mgmL-1, respectively, while the optimum interaction time was 3.0min. The bienzymatic biosensor presented a sensitivity of (24 ± 2) × 102 µA dL mg-1 ((44 ± 4) × 102 µA M-1), a linear range between 0.06mg dL-1 and 21.6mg dL-1 (3.1µM-1.2mM) (R2 = 0.9991),and detection and quantification limits of 0.02mg dL-1 (1.0µM) and 0.06mg dL-1 (3.1µM), respectively. The reproducibility for five sensors prepared with the same MWCNT-SB-dBA nanohybrid was 6.3%, while the reproducibility for sensors prepared with five different nanohybrids and five electrodes each was 7.9%. The GCE/MWCNT-SB-dBA/GOx-HRP was successfully used for the quantification of glucose in artificial human urine and commercial human serum samples.

Machine Learning Optimizing Enzyme/ZIF Biocomposites for Enhanced Encapsulation Efficiency and Bioactivity.

In this study, we present the first example of using a machine learning (ML)-assisted design strategy to optimize the synthesis formulation of enzyme/ZIFs (zeolitic imidazolate framework) for enhanced performance. Glucose oxidase (GOx) and horseradish peroxidase (HRP) were chosen as model enzymes, while Zn(eIM)2 (eIM = 2-ethylimidazolate) was selected as the model ZIF to test our ML-assisted workflow paradigm. Through an iterative ML-driven training-design-synthesis-measurement workflow, we efficiently discovered GOx/ZIF (G151) and HRP/ZIF (H150) with their overall performance index (OPI) values (OPI represents the product of encapsulation efficiency (E in %), retained enzymatic activity (A in %), and thermal stability (T in %)) at least 1.3 times higher than those in systematic seed data studies. Furthermore, advanced statistical methods derived from the trained random forest model qualitatively and quantitatively reveal the relationship among synthesis, structure, and performance in the enzyme/ZIF system, offering valuable guidance for future studies on enzyme/ZIFs. Overall, our proposed ML-assisted design strategy holds promise for accelerating the development of enzyme/ZIFs and other enzyme immobilization systems for biocatalysis applications and beyond, including drug delivery and sensing, among others.

Textile-Based Membraneless Microfluidic Double-Inlet Hybrid Microbial-Enzymatic Biofuel Cell.

This study reports the development of a textile-based colaminar flow hybrid microbial-enzymatic biofuel cell. Shewanella MR-1 was used as a biocatalyst on the anode, and bienzymatic system catalysts based on glucose oxidase and horseradish peroxidase were applied on an air-breathing cathode to address the overpotential loss in a body-friendly way. A single-layer Y-shaped channel configuration with a double-inlet was adopted. Microchannels of biofuel cells were patterned by silk screen printing with Ecoflex to maintain the flexibility of textile substrates without harm to the human body. The electrodes were fabricated with poly(3,4-ethylenedioxythiophene):polystyrene sulfonate and a mixture of multiwalled carbon nanotubes and single-walled carbon nanotubes by screen printing. The effects of electrode materials, catalyst type, catalyst concentration, and glucose concentration in the catholyte were investigated to optimize the fuel cell performance. The peak power density (44.9 μW cm-2) and maximum current density (388.9 μA cm-2) of the optimized hybrid biofuel cell were better than those of previously reported textile- or paper-substrate microscale single microbial fuel cells. The developed biofuel cell will be a useful platform as a microscale power source that is harmless to the environment and living organisms.

Zwitterionic Polyelectrolyte Complex Vesicles Assembled from Homopoly(2-Oxazoline)s as Enzyme Catalytic Nanoreactors for Potent Anti-Tumor Efficiency.

Enzymes are known for their remarkable catalytic efficiency across a wide range of applications. Here, we present a novel and convenient nanoreactor platform based on zwitterionic polyelectrolyte complex vesicles (PCVs), assembled from oppositely charged homopoly(2-oxazoline)s, facilitating enzyme immobilization. We show remarkable enhancements in catalytic activity and stability by encapsulation of lipase as a model enzyme. Even as the temperature rises, the performance of the lipase remains robust. Further, the structural characteristics of PCVs, including hollow architecture and semipermeable membranes, endow them with unique advantages for enzyme cascade reactions involving glucose oxidase (GOx) and horseradish peroxidase (HRP). A decline in catalytic efficiency is shown when the enzymes are individually loaded and subsequently mixed, in contrast to the coloaded GOx-HRP-PCV group. We demonstrate that the vesicle structures establish confined environments where precise enzyme-substrate interactions facilitate enhanced catalytic efficiency. In addition, the nanoreactors exhibit excellent biocompatibility and efficient anti-tumor activity, which hold significant promise for biomedical applications within enzyme-based technologies.

Assessment of fasting plasma glucose, insulin, insulin resistance and glycated haemoglobin as markers of glycemic control in apparently healthy older adults in Nnewi

: Biochemical changes in glycemic indices have been linked to aging, and many individuals have asymptomatic hyperglycemia as they get older. This leads to metabolic dysregulation, which heightens vulnerability to a number of age-related chronic conditions, such as diabetes mellitus. : This cross-sectional study assessed the levels of fasting plasma glucose, insulin, insulin resistance and glycated haemoglobin as markers of glycemic control in apparently healthy older adults in Nnewi. A total of 144 participants were involved in this study: 72 older persons and 72 control subjects. The older adults were aged 45 to 75; while the control group was composed of individuals aged 18 to 30. Six milliliters (6 ml) of fasting venous blood samples were collected from each participant for the determination of insulin (INS), glycated haemoglobin (HbA1c), and plasma glucose (FPG) levels. Enzyme-linked immunosorbent assay was used to evaluate INS, resin ion-exchange was used to estimate HbA1c, and glucose oxidase peroxidase was used to determine FPG. The Homeostasis Model Assessment Index (HOMA-IR) was used to calculate insulin resistance. : The mean FPG, HbA1c, INS and HOMA-IR were significantly higher in the older adults compared to control subjects respectively (p<0.05). Also, the mean FPG, HbA1c, INS and HOMA-IR were significantly higher in the older adult males and females compared to the control male and female subjects respectively (p<0.05). There was significant moderate positive correlation between the level of FBS Vs HbA1c (r=0.484, P-value = 0.000) and strong positive correlation between the level of Insulin Vs HOMA-IR (r=0.980, P-value = 0.000) in the control group. Also, strong significant positive correlations were observed between FPG and HbA1c (r=0.704, P-value = 0.000), FPG and HOMA-IR (r=0.778, P-value = 0.000), Insulin and HOMA-IR (r=0.778, P-value = 0.000) with a moderate significant positive correlation found between HbA1c Vs HOMA-IR (r=0.557, P-value = 0.000) in the older adults. This study showed that glycemic indices tend to become altered with advancing in age.

Confinement-Induced Biocatalytic Activity Enhancement of Light- and Thermoresponsive Polymer@Enzyme@MOF Composites.

Metal-organic frameworks (MOFs) are favorable hosting materials for fixing enzymes to construct enzyme@MOF composites and to expand the applications of biocatalysts. However, the rigid structure of MOFs without tunable hollow voids and a confinement effect often limits their catalytic activities. Taking advantage of the smart soft polymers to overcome the limitation, herein, a protection protocol to encapsulate the enzyme in zeolitic imidazolate framework-8 (ZIF-8) was developed using a glutathione-sensitive liposome (L) as a soft template. Glucose oxidase (GOx) and horseradish peroxidase (HRP) were first anchored on a light- and thermoresponsive porous poly(styrene-maleic anhydride-N,N-dimethylaminoethyl methacrylate-spiropyran) membrane (PSMDSP) to produce PSMDSP@GOx-HRP, which could provide a confinement effect by switching the UV irradiation or varying the temperature. Afterward, embedding PSMDSP@GOx-HRP in L and encapsulating PSMDSP@GOx-HRP@L into hollow ZIF-8 (HZIF-8) to form PSMDSP@GOx-HRP@HZIF-8 composites were performed, which proceeded during the crystallization of the framework following the removal of L by adding glutathione. Impressively, the biocatalytic activity of the composites was 4.45-fold higher than that of the free enzyme under UV irradiation at 47 °C, which could benefit from the confinement effect of PSMDSP and the conformational freedom of the enzyme in HZIF-8. The proposed composites contributed to the protection of the enzyme against harsh conditions and exhibited superior stability. Furthermore, a colorimetric assay based on the composites for the detection of serum glucose was established with a linearity range of 0.05-5.0 mM, and the calculated LOD value was 0.001 mM in a cascade reaction system. This work provides a universal design idea and a versatile technique to immobilize enzymes on soft polymer membranes that can be encapsulated in porous rigid MOF-hosts. It also holds potential for the development of smart polymer@enzyme@HMOFs biocatalysts with a tunable confinement effect and high catalytic performance.

Inhibitory activity against α-amylase and glucose adsorption capacity of the aqueous decoctate of Chamaecrista nigricans (Vahl) Greene

Diabetes management involves preventing its risk factors. Inhibition of glucosidases and adsorption of excess free glucose are approaches to the prevention of postprandial hyperglycemia. The objective of the present study was to evaluate the antioxidant activity, glucose adsorption capacity, and α-amylase inhibitory activity in vitro of the aqueous extract of Chamaecrista nigricans. Determination of phenolic compounds content was performed using the Folin-Ciocalteu reagent and the aluminum chloride method was used for total flavonoids one. The glucose oxidase peroxidase kit was used to determine the adsorption capacity of glucose while the 3,5-dinitrosalicylic acid method was used to assess the inhibitory activity against α-amylase. Levels ranging from 33.87 ± 2.48 mg GAE/100 mg dry extract (DE) for total phenolic compounds and 1.98 ± 0.51 mg QE/100 mg DE for total flavonoids were observed. The adsorption capacity was correlated with the glucose concentration of the solution (r = 0.95) and was up to 36.61 μmol/g DE for a glucose concentration of 30 mM. The extract from the November collection was most active against α-amylase with IC50 = 0.17 mg DE/mL. Observations confirm the traditional use of this species as a preventive measure in recipes for the treatment of diabetes. This data provides a basis for future pharmaceutical prospecting.

Bridging biochemistry and microengineering: glucose oxidation in microfluidic biofuel cells with carbon-MEMS and conductive polymers electrodes

Microfluidic biofuel cells are promising power sources for small-scale devices. Its construction is simple and requires low-cost materials. We report four glucose/O2 microfluidic enzymatic biofuel cells consisting in a double-Y-shaped microchannel and based on Carbon Micro Electro Mechanical Systems (C-MEMS) electrodes to test the composite poly(3,4-ethylene dioxythiophene)–poly(gallic acid) (PEDOT-PGAL) conducting polymer as an electroactive layer for enzyme immobilization. The following microfluidic enzymatic biofuel cells were microfabricated to compare their performances: 1) glucose/O2 using bioelectrodes, 2) glucose/O2 using glucose oxidase and Laccase, in solution, 3) glucose/hydrogen peroxide using bioelectrodes, and 4) glucose/hydrogen peroxide using glucose oxidase and horseradish peroxidase, in solution. The use of these two classes of materials, C-MEMS electrodes and conducting polymer inks, offers an advantageous interface for biomolecular electron transfer owing to the rich organic chemistry of the carbon interfaces. On the other hand, the conducting polymer PEDOT-PGAL acts as an electroactive layer for straightforward applications suitable for batch fabrication. All the studied cells presented positive electromotive forces and the discharge behavior of a fuel cell, yielding similar power densities. As expected, the cells that used enzymes in solution delivered higher power densities, but these values are dependent on the flow rate, while cells with immobilized enzymes present a more stable maximum power output. To our knowledge, this is the first report of an electrode system based on pyrolytic carbon/PEDOT-PGAL applied in a microfluidic enzymatic biofuel cell.

Accuracy of point-of-care capillary blood sugar measurements in critically ill patients: An observational study.

Accurately monitoring blood glucose levels is vital for critically ill individuals. Point-of-care (POC) glucose meters are commonly used in local intensive care units (ICUs). This study aimed to assess the precision of POC glucose meter readings in critically ill individuals with specific evaluation in patients with and without shock against the reference standard of venous blood glucose measurements. An observational study was done on adult patients admitted in the ICU at a teaching institution. Capillary blood samples were collected from the patient's fingertip using lancet device with aseptic measures. The sample was analyzed using the GlucoCare Sense Glucometer (RMD Mediaids Limited, Taiwan). At the same time, 2 ml of blood was drawn from the patient's peripheral veins and analyzed by glucose oxidase-peroxidase method as reference. POC glucose measurements averaged 140 ± 20.23 mg/dl, while laboratory values were recorded as 116.10 ± 17.13 mg/dl. The difference between the two methods was 24.34 ± 12.01 mg/dl. A strong correlation (r = 0.805) was found between capillary and laboratory blood glucose levels, indicating a significant association (P < 0.0001). Twenty-two (44%) patients were in shock during the study. The mean difference between laboratory and POC blood glucose levels was higher in patients with circulatory shock (36.82 ± 4.84 mg/dl) than those without shock (14.61 ± 4.49 mg/dl), P < 0.05. POC glucose meters may lead to underdetection of hypoglycemia in critically ill patients, as their values are higher than laboratory values. Moreover, the results showed that POC glucometers are inaccurate for monitoring glucose in hypotensive patients in shock. Standard venous glucose monitoring methods may be more appropriate for these patients.

Paper-based ligand fishing method for rapid screening and real-time capturing of α-glucosidase inhibitors from the Chinese herbs

Identifying medicinally relevant compounds from natural resources generally involves the tedious work of screening plants for the desired activity before capturing the bioactive molecules from them. In this work, we created a paper-based ligand fishing platform to vastly simplify the discovery process. This paper-based method exploits the enzymatic cascade reaction between α-glucosidase (GAA), glucose oxidase (GOx), and horseradish peroxidase (HRP), to simultaneously screen the plants and capture the GAA inhibitors from them. The designed test strip could capture ligands in tandem with screening the plants, and it features a very simply operation based on direct visual assessment. Multiple acylated flavonol glycosides from the leaves of Quercus variabilis Blume were newly found to possess GAA inhibitory activities, and they may be potential leads for new antidiabetic medications. Our study demonstrates the prospect of the newly discovered GAA ligands as potential bioactive ingredients as well as the utility of the paper-based ligand fishing method.

Smartphone-based portable electrochemical-colorimetric dual-mode biosensor for glucose detection in a co-reaction system

Regular monitoring of blood sugar levels is essential for diabetics, both for adjusting medication or insulin doses and for preventing complications like blindness, nerve damage, heart disease, and kidney failure. This paper presents a novel smartphone-based electrochemical-colorimetric dual-mode detecting system for detecting glucose at low concentrations. This system utilizes a smartphone as a mobile terminal to control the electrochemical circuit board and enable data analysis. The circuit board integrates cyclic voltammetry and differential pulse voltammetry, providing a low-cost and palm-sized solution for glucose detection. Additionally, digital image colorimetry is employed to enable efficient and accurate colorimetric detection. The use of glucose oxidase and horseradish peroxidase (GOx/HRP) in combination with 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) ABTS substrates facilitates glucose dual-mode quantitative analysis in a-coreaction system. The electrochemical and colorimetric methods exhibit limits of detection of 0.467 µM and 10 µM, respectively. This system shows a point-of-care testing (POCT) potential for reliable and convenient monitoring of blood glucose levels, particularly for individuals with diabetes.

Anti-RAGE (Receptor Advanced Glycation End products) Antibody Improves Diabetic Retinopathy in Rats via Hypoglycemic and Anti-inflammatory Mechanism

Background: Receptor advanced glycation end products (RAGE) activation plays an essential role in diabetic retinopathy (DR) progression. This study was aimed to explore the role of anti-RAGE antibodies (RAGE antagonists) in inhibiting DR progression through their hypoglycemic and anti- inflammatory mechanism in diabetic retinopathy induced rats.&#x0D; Methods: A total of 30 male Wistar rats were randomly divided into five group. The group was consisted of normal control group, DR group without treatment, DR group with anti-RAGE 1 g/kg BW, 10 g/kg BW, and 100 g/kg BW. To assess the diabetic retinopathy, fundus photographs were taken every week using a camera with 16x magnification placed in front of the rat's eyes. Blood glucose was checked by the glucose oxidase-peroxidase method. Retinal TNF-? levels and VEGF were examined using an enzyme-linked immunosorbent assay (ELISA) kit.&#x0D; Results: The finding of this study showed that anti-RAGE treatment at dose of 10 and 100 g/kg BW, HbA1c levels were significantly higher (p&lt; 0.05) compared to the normal control group but significantly lower (p&lt; 0.05) than in the diabetes group. The mean blood vessel diameter in the DR+anti-RAGE 10 and 100 g/kg BW groups was significantly lower than in the diabetic retinopathy group (p&lt; 0.05). The administration of anti-RAGE 10 and 100 g/kg BW showed the ability to significantly reduce VEGF levels compared to the DR group (p&lt; 0.05).&#x0D; Conclusions: This study revealed at doses of 10 and 100 g/kg BW, anti-RAGE antibodies improved diabetic retinopathy in Wistar rats through hypoglycemic effects and anti-inflammatory mechanisms.

Highly sensitive SERS sensors for glucose detection based on enzyme@MOFs and ratiometric Raman

Diabetes is a common chronic metabolic disease. The frequent fluctuation of glucose is the main cause of most diabetes complications, which in turn causes harm to the health of patients. Surface-enhanced Raman scattering (SERS) spectroscopy has attracted much attention in the rapid detection of glucose due to its unique molecular fingerprinting ability, ultra-high sensitivity and fast response. However, due to the low affinity between glucose and SERS substrate, poor signal, susceptibility to complex environmental interference, and poor stability of SERS detection, it is still a challenge for SERS to accurately and sensitively determine glucose in complex environments. In this work, we encapsulated 4-mercaptobutyronitrile (4-MBN) as an internal standard (IS) in Au@Ag NRs inside and then Au@4-MBN@Ag NRs, Leucomalachite Green (LMG), glucose oxidase (GOx) and horseradish peroxidase (HPR) were encapsulated in ZIF-8 to prepare a tandem enzyme catalytic ratiometric SERS sensor Au@4-MBN@Ag@LMG@ZIF-8(GOx, HPR) for the detection of glucose in saliva. Because ZIF-8 enhanced the catalytic activity of the enzyme, the ability of glucose enrichment, and weakens the aggregation of Ag NRs. The internal standard signal molecule improves the accuracy and sensitivity of detection. The ratiometric Raman signal I412/I2233 of glucose has a good linear relationship with the concentration in the range of 0.1–100 μM, and the limit of detection (LOD) could be down to 0.03 μM. At the same time, it has excellent selectivity, repeatability and accuracy. The recovery rate of glucose in saliva is 96.50%–105.56 %, which proves the feasibility of the method. The Au@4-MBN@Ag@LMG@ZIF-8(GOx, HPR) sensor prepared in this study showed excellent SERS performance, which was able to detect glucose quickly, sensitively and accurately. This work provides a new strategy for the design of enzyme-catalyzed SERS sensors.

Accuracy of a Non-Invasive Home Glucose Monitor for Measurement of Blood Glucose.

Patients with diabetes mellitus monitor their blood glucose at home with monitors that require a drop of blood or use a continuous glucose monitoring device that implants a small needle in the body. However, both cause discomfort to the patients which may inhibit them for regular blood glucose checks. Photoplethysmogram (PPG) sensing technology is an approach for non-invasive blood glucose measurement and PPG sensors can be used to predict hypoglycaemic episodes. InChcek is a PPG-based non-invasive glucose monitor. However, its accuracy has not been checked yet. Hence, this study aimed to evaluate the accuracy of InCheck, a non-invasive glucose monitor for the estimation of blood glucose. In a tertiary care hospital, patients who came for blood glucose estimation were tested for blood glucose non-invasively on the InCheck device and then by the laboratory method (glucose oxidase-peroxidase). These two readings were compared. We used International Organization for Standardization (ISO) 15197:2013 (95% of values should be within ± 15 mg/dL of reference reading if reference glucose <100 mg/dL or within ± 15% of reference reading if reference glucose ≥100 mg/dL and 99% of the values should be within zones A and B in consensus error grid), and Surveillance Error Grid for analyzing the accuracy. A total of 1223 samples were analyzed. There was a significant difference between the reference method glucose level (135 [Q1-Q3: 97 - 179] mg/dL) and monitor-measured glucose level (188.33 [Q1-Q3: 167.33-209.33] mg/dL) (P < 0.0001). A total of 18.5% of readings were following ISO 15197:2013 criteria and 67.25% of coordinates were within zone A and zone B of the consensus error grid. In the surveillance error grid analysis, about 29.4% of values were in the no-risk zone, 51.8% in slight risk, 18.6% in moderate risk, and 0.2% were in the severe risk zone. The accuracy of the InCheck device for the estimation of blood glucose by PPG signal is not following the recommended guidelines. Hence, further research is necessary for programming or redesigning the hardware and software for a better result from this optical sensor-based non-invasive home glucose monitor.

Correlation of serum uric acid levels with certain anthropometric parameters in prediabetic and drug-naive diabetic subjects.

Uric acid is produced during the metabolism of nucleotide and adenosine triphosphate and contains the final product of human purine metabolism. It acts both as an antioxidant and pro-inflammatory marker and has a positive association with visceral fat in overweight subjects. The aim of the present study is to find an association of uric acid level with certain anthropometric parameters in subjects having type 2 diabetes. The study included 124 urban drug-naive diabetic Indian subjects above 18 years of age from the general population of the city of North India. Uric acid concentrations were estimated by the uricase method. Fasting plasma glucose (FPG) concentrations were estimated by the glucose oxidase-peroxidase method. Anthropometric measurements and information on lifestyle factors and disease history were collected through in-person meeting. All participants of the study subjects had a body mass index (BMI) of more than 23.5. BMI, waist-to-hip ratio (WHR), waist-to-height ratio, waist circumference, neck circumference, weight, age, sagittal abdominal diameter (SAD), skinfold thickness, and body roundness index were positively correlated with the serum uric acid level. The correlation of weight, BMI, SAD, and WHR was statistically significant. We found that serum uric acid level increases as body fat content increases. Statistical data show remarkable results for a significant correlation of uric acid level with BMI, WHR, SAD, and FPG. Hypertrophy occurs as a result of inflammatory processes and oxidative stress when the supply of energy starts to exceed the storage capacity of adipocytes, as a result, adipokines such as interleukin (IL)-1, IL-6, and tumor-necrosis factor-alpha are released more frequently which lead to low-grade chronic inflammation. Uric acid levels are much lean toward visceral obesity than overall body fat content.

Study of age, sex and body mass index wise variation in C-peptide level among urban population of Northern part of Bihar

Background: Different factors regulate the insulin level in blood. Earlier C-peptide was considered as by product of insulin biosynthesis and its role in body seems to be negligible. C-peptide at low physiological concentrations mimics the effects of insulin. However, in the presence of elevated level of insulin concentrations concomitant raised level of C-peptide may blunt peripheral effects of insulin age. This study was carried out to verify the age, sex, and BMI wise variation in level of C-peptide among apparently healthy individual and its contribution in fine-tuning of the tissue’s metabolism under different physiological conditions. Methods: This is a prospective cross-sectional observational study. Estimation of serum c-peptide level was done by solid phase direct sandwich enzyme linked immunosorbent assay (ELISA) kit method. Glucose is estimated by Glucose oxidase peroxidase (GOD-POD) end point colorimetric method and HbA1C was estimated by ion exchange resin method (kit method). Result: Serum C-peptide level is significantly high in advance age and males in compared to younger age and females respectively. The mean level of serum C-peptide is higher in higher body mass index (BMI) group compared to lower, but this difference is statistically insignificant. Conclusions: In normal subjects, the level of C-peptide shows positive correlation with age and BMI. Males have higher level of C-peptide in comparison to females. Apart from these variation C-peptide contributes to different biological effects.

Patterning of Protein-Sequestered Liquid-Crystal Droplets Using Acoustic Wave Trapping.

Development of spatially organized structures and understanding their role in controlling kinetics of multistep chemical reactions are essential for the successful design of efficient systems and devices. While studies that showcase different types of methodologies for the spatial organization of various colloidal systems are known, design and development of well-defined hierarchical assemblies of liquid-crystal (LC) droplets and subsequent demonstration of biological reactions using such assemblies still remain elusive. Here, we show reversible and reconfigurable one-dimensional (1D) assemblies of protein-bioconjugate-sequestered monodisperse LC droplets by combining microfluidics with noninvasive acoustic wave trapping technology. Tunable spatial geometries and lattice dimensions can be achieved in an aqueous medium comprising ≈19 or 62 μm LC droplets. Different assemblies of a mixed population of larger and smaller droplets sequestered with glucose oxidase (GOx) and horseradish peroxidase (HRP), respectively, exhibit spatially localized enzyme kinetics with higher initial rates of reaction compared with GOx/HRP cascades implemented in the absence of an acoustic field. This can be attributed to the direct substrate transfer/channeling between the two complementary enzymes in close proximity. Therefore, our study provides an initial step toward the fabrication of LC-based devices for biosensing applications.

Dual enzymes proteinosome with cascade activity for ultrasensitive glucose biosensing

Catalytic cascades derived from the combination of multiple enzymes with efficient catalytic activity and high selectivity have attracted widespread attention in biosensing and biomedical applications. A key consideration in the development of cascade reaction systems is the combination of multiple enzymes to improve overall catalytic performance. Inspired by natural protein self-assembly, herein, proteinosomes formed by enzyme-surfactant complexes based on an interfacial assembly strategy are developed and they exhibit significant enhanced activity via cascade reaction of glucose oxidase (GOX) and horseradish peroxidase (HRP) that are located in proximity. The proteinosomes not only exhibit significantly elevated stability and reusability, but also possess enhanced cascade catalytic performance. These enhanced activities can be explained on the basis of the proximity effect of multiple enzymes within proteinosomes. Moreover, we employed highly efficient and reusability dual-enzyme-based proteinosomes to demonstrate the ultrasensitive detection of glucose, achieving a detection limit as low as 1.08 µM. Finally, the proteinosomes can be immobilized in a test strip for easy and fast glucose detection. Due to their ultra-sensitive detection limit, they can be used for non-invasive glucose detection. They can accurately assess glucose levels in saliva, yielding results highly congruent with those from commercially available assay kits. We further indicate the rapid capability of our system to detect glucose, as compared to commercial glucose kit. These finds demonstrate the potential of the test strip as a promising tool for daily glucose monitoring, and the facile approach presents an inventive solution for test strip development.

Spatially confined enzymatic tandem system with GOx and HRP compartmentalized in ultrafiltration membrane

The precise control of timely and spatially defined enzymatic reactions is of considerable interest in biology, biomedical engineering, and bio-catalysis. In this study, we report a robust multi-enzymatic cascade system with glucose oxidase (GOx) and horseradish peroxidase (HRP) spatially compartmentalized in a polyether sulfone ultrafiltration (UF) membrane by co-deposition of polydopamine (PDA) and polyethyleneimine (PEI). The PDA/PEI nanolayers reduce enzyme leakage, retaining ∼98 and ∼70 % of GOx and HRP, respectively, and facilitate substrates and intermediates passage and enrichment near the enzyme's active sites. The membrane serves as a porous scaffold facilitating enzyme immobilization and recyclability, improving stability and catalytic efficiency. The spatially defined cascade system exhibits superior catalytic activity, leading to a 1.48-fold and 3-fold increase compared to free GOx and HRP, respectively. This improvement is likely due to substrate channeling, substrate diffusion and product convection. Furthermore, the dynamics of the GOx and HRP tandem catalysis was investigated in a closed system which demonstrated the crucial roles of dissolved oxygen in both the oxidoreductase and peroxidase reactions. The concept of tandem enzyme reactions in UF membranes can be generalized to create efficient and stable enzyme systems for applications in biosensing and industrial processes.