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Glucose oxidase (GOD) has been investigated as a potential additive for enhancing intestinal health and growth performance in poultry. However, limited research exists on the effects of ultra-high doses of GOD in practical poultry production. This study aimed to investigate the impact of high dietary GOD levels on broiler growth performance, antioxidant capacity, and intestinal microbiota. A total of 400 healthy, 1-day-old, slow-growing broiler chickens were randomly assigned to four treatment groups. The control group was fed a standard basal diet, while the other groups (G1, G2, and G3) were fed the basal diet supplemented with 4 U/g, 20 U/g, and 100 U/g of VTR GOD, respectively. The results showed that a dose of 100 U/g GOD significantly improved the final body weight and average daily feed intake (ADFI) (p

Abstract Enzymatic fuel cells (EFCs) offer renewable energy conversion via highly selective electrode reactions using enzymes as natural catalysts even under mild conditions. Electrochemical impedance spectroscopy (EIS) is a valuable tool for evaluating EFC performance, providing insights into substrate mass transport, enzyme kinetics, and electrode stability. Despite its acknowledged importance, the use of EIS coupled with distribution of relaxation times (DRT) analysis in EFCs research is limited. Our study addresses this gap by employing EIS and DRT analysis to investigate enzyme‐based anodic processes, focusing on the bioelectrocatalytic oxidation of glucose catalyzed by glucose oxidase (GOx). Through careful variation of multiple parameters, it was possible to identify three distinct regions in the DRT plot. Each region has been subsequently associated with a key anodic process. The first region (R1) is associated with high‐frequency phenomena occurring at the electrodes, primarily due to ionic conduction in the electrolyte. Intermediate‐frequency processes are associated to charge transfer kinetics in region 2 (R2). Region 3 (R3) is linked to diffusion processes occurring at low frequencies. This thorough examination offers an insight into the functioning of enzymatic bioelectrodes, which in turn drives improvements in the design and components of biofuel cells to increase their power output.

Despite decades of laboratory and clinical trials, breast cancer remains the main cause of cancer-related disease burden in women. Considering the metabolism destruction effect of metformin (Met) and cancer cell starvation induced by glucose oxidase (GOx), after their efficient delivery to tumor sites, GOx and Met may consume a large amount of glucose and produce sufficient hydrogen peroxide in situ. Herein, a pH-responsive epigallocatechin gallate (EGCG)-conjugated low-molecular-weight chitosan (LC-EGCG, LE) nanoparticle (Met–GOx/Fe@LE NPs) was constructed. The coordination between iron ions (Fe3+) and EGCG in this nanoplatform can enhance the efficacy of chemodynamic therapy via the Fenton reaction. Met–GOx/Fe@LE NPs allow GOx to retain its enzymatic activity while simultaneously improving its stability. Moreover, this pH-responsive nanoplatform presents controllable drug release behavior. An in vivo biodistribution study showed that the intracranial accumulation of GOx delivered by this nanoplatform was 3.6-fold higher than that of the free drug. The in vivo anticancer results indicated that this metabolism destruction/starvation/chemodynamic triple-combination therapy could induce increased apoptosis/death of tumor cells and reduce their proliferation. This triple-combination therapy approach is promising for efficient and targeted cancer treatment.

Abstract Background Aspergillus niger ATCC 20611 is an industrially important fructooligosaccharides (FOS) producer since it produces the β-fructofuranosidase with superior transglycosylation activity, which is responsible for the conversion of sucrose to FOS accompanied by the by-product (glucose) generation. This study aims to consume glucose to enhance the content of FOS by heterologously expressing glucose oxidase and peroxidase in engineered A. niger. Results Glucose oxidase was successfully expressed and co-localized with β-fructofuranosidase in mycelia. These mycelia were applied to synthesis of FOS, which possessed an increased purity of 60.63% from 52.07%. Furthermore, peroxidase was expressed in A. niger and reached 7.70 U/g, which could remove the potential inhibitor of glucose oxidase to facilitate the FOS synthesis. Finally, the glucose oxidase-expressing strain and the peroxidase-expressing strain were jointly used to synthesize FOS, which content achieved 71.00%. Conclusions This strategy allows for obtaining high-content FOS by the multiple enzymes expressed in the industrial fungus, avoiding additional purification processes used in the production of oligosaccharides. This study not only facilitated the high-purity FOS synthesis, but also demonstrated the potential of A. niger ATCC 20611 as an enzyme-producing cell factory.

Photothermal therapy (PTT) has a great prospect in further improving tumor therapeutic outcomes, whereas its efficiency is restrained by low light penetration, excessive heat damage to normal tissues, up‐regulated heat shock proteins (HSPs), and limited effect of single treatment. Herein, an enzyme‐engineered coppery nanozyme based on dendritic mesoporous coppery carbon nanosphere as the cornerstone to load with glucose oxidase (GOx) followed by modification with hyaluronic acid is constructed. Density functional theory calculations indicate that the obtained coppery nanozyme exhibits peroxidase and glutathione oxidase mimicking activities to improve hydroxyl radicals (•OH) production. Furthermore, both the generation of •OH production and GOx‐induced energy supply blockade can reduce HSPs expression to enhance the mild PTT (η = 34.9 %) of coppery nanozyme upon the irradiation of 1064 nm laser, and in turn, accelerate the catalytic processes of coppery nanozyme for more generation of •OH. Last but not least, the introduction of copper can induce lipoylated protein dihydrolipoamide S‐acetyltransferase aggregation to cause cellular cuproptosis. Due to the synergy of multiple therapies, the tumor inhibition rate can reach 93.4%. Overall, this work provides an effective strategy for potential tumor treatment on the basis of synergistic therapies. [ABSTRACT FROM AUTHOR]

CO gas therapy has attracted enormous attention in tumor therapy due to the abilities of mitochondrial damage and inhibition of cellular respiration. However, the inefficient and random release of CO greatly limit its application. Taking this into account, the study constructs an acid‐unlocked nanostructure based on MPDA‐MnCO‐GOx@DSNPs, designated as MMGD. The nanostructure enables tumor microenvironment (TME) specific enzyme and CO prodrug (manganese carbonyl, MnCO) cascade reaction, thus facilitating CO release in situ. Mesoporous polydopamine (MPDA) can provide the space for MnCO and glucose oxidase (GOx) loading. Especially, lanthanide (Ln3+)‐doped down‐shifting luminescent nanoparticles (DSNPs) can not only serve as the near‐infrared II (NIR‐II) fluorescence imaging probe, but also act as the acid‐unlocked gating switch. The slightly acidic TME can render the dissociation of DSNPs, thus exposing GOx and releasing MnCO. The catalytic reaction of GOx can produce H2O2 and create a more acidic environment, which facilitates the CO generation in situ, leading to mitochondrial damage by reducing cytochrome c oxidase activity and adenosine triphosphate (ATP) levels. Meanwhile, MPDA has the NIR light absorption capability for photothermal therapy (PTT). This study provides an ingenious strategy for efficient and controllable CO gas, starvation, and PTT of tumor guided by NIR‐II fluorescence imaging. [ABSTRACT FROM AUTHOR]

Nanomedicine has reshaped the landscape of cancer treatment. However, its efficacy is still hampered by innate tumor defense systems that rely on adenosine triphosphate (ATP) for fuel, including damage repair, apoptosis resistance, and immune evasion. Inspired by the naturally enzymatic reaction of glucose oxidase (GOx) with glucose, here a novel "two birds with one stone" technique for amplifying enzyme‐mediated tumor apoptosis and enzyme‐promoted metabolic clearance is proposed and achieved using GOx‐functionalized rhenium nanoclusters‐doped polypyrrole (Re@ReP‐G). Re@ReP‐G reduces ATP production while increasing H2O2 concentrations in the tumor microenvironment through GOx‐induced enzymatic oxidation, which in turn results in the downregulation of defense (HSP70 and HSP90) and anti‐apoptotic Bcl‐2 proteins, the upregulation of pro‐apoptotic Bax, and the release of cytochrome c. These processes are further facilitated by laser‐induced hyperthermia effect, ultimately leading to severe tumor apoptosis. As an enzymatic byproduct, H2O2 catalyzes the conversion of rhenium nanoclusters in Re@ReP‐G nanostructures into rhenate from the outside in, which accelerates their metabolic clearance in vivo. This Re@ReP‐G‐based "two birds with one stone" therapeutic strategy provides an effective tool for amplifying tumor apoptosis and safe metabolic mechanisms. [ABSTRACT FROM AUTHOR]

In this study we examine effect of the solvent ratio on TiO 2 physical and photoelectrochemical properties utilizing economical hydrothermal process. Sample properties were examined using XRD, SEM, Raman, UV–vis, PL, photocurrent, Mott–Schottky, and EIS measurements. XRD patterns revealed that TiO 2 samples represent a polycrystalline nature with a Tetragonal structure. Peaks at 609, 144, and 443 cm−1 were observed in Raman spectra indicating the production of the TiO 2 rutile phase. SEM images showed that TiO 2 nanorods formed evenly with square top facets and a tetragonal form. UV–vis results displayed an optical absorption edge between 386 and 405 nm which is associated with the band gap of TiO 2 NRs films. The generated TiO 2 NRs films exhibit n-type semiconductor behavior according to the photocurrent measurements. Mott-Schottky experiments indicated that the donor density and flat band potential varied with decreased acid ratio from 1.55 × 1018 to 3.33 × 1018 cm−3 and-0.47 to-0.72 V, respectively. As observed by EIS, the resistivity to charge transfer declined, reaching its lowest level at 5:11 ml, indicating improvement of electrochemical activity and structural properties with decreasing the HCl concentration. Additionally, the fabricated TiO2 NRs films was employed as biosensor for glucose where a fast amperometric response and good operating stability were detected. [ABSTRACT FROM AUTHOR]

The study aims to address the need for accurate and real-time monitoring of glucose levels in college athletes during physical activities. This work reports on the development of an electrochemical sensor that uses glucose oxidase (GOx) immobilized on PdO nanoparticles to reduce graphene oxide (rGO) nanocomposite printed on a cellulose substrate (GO x /PdO-rGO/C-PE). The successful reduction of GO to rGO, the production of the PdO-rGO nanocomposite, and the electropolymerization of GOx on the PdO-rGO nanocomposite were all validated by the material characterization. The biosensor's electrochemical response investigation showed that its detection limit was 0.046 μM and its sensitivity was 0.03239 μA/μM. Excellent stability, reproducibility, and glucose selectivity were shown by the GOx/PdO-rGO/C-PE, which makes it a viable option for consistent and dependable glucose sensing in real-world applications. The real sample analysis assessed how well the combination of GOx/PdO-rGO/C-PE could identify glucose in human serum. Furthermore, under a variety of real-world conditions, such as during various physical activities and at different times of the day, the sensor demonstrated outstanding performance in real-time glucose monitoring. These findings imply that the GOx/PdO-rGO/C-PE offers accurate and dependable readings in the field of non-invasive glucose monitoring, which will be especially helpful for college and professional athletes. [ABSTRACT FROM AUTHOR]

The inorganic content and the catalytic performance pose metal‐loaded enzyme nanoflowers as promising candidates for developing bioelectrodes capable of functioning without the external addition of a redox mediator. However, these protein‐inorganic hybrids have yet to be successfully applied in combination with electrode materials. Herein, the synthesis procedure of these bionanomaterials is reproposed to precisely control the morphology, composition, and performance of this particular protein‐mineral hybrid, formed by glucose oxidase and cobalt phosphate. This approach aims to enhance the adherence and electron mobility between the enzyme and a carbon electrode. The strategy relies on dressing the protein in a tailored thin nanogel with multivalent chemical motifs. The functional groups of the polymer facilitate the fast protein sequence‐independent biomineralization. Furthermore, the engineered enzymes enable the fabrication of robust cobalt‐loaded enzyme inorganic hybrids with exceptional protein loads, exceeding 90% immobilization yields. Notably, these engineered biohybrids can be readily deposited onto flat electrode surfaces without requiring chemical pre‐treatment. The resulting bioelectrodes are robust and exhibit electrochemical responses even without the addition of a redox mediator, suggesting that cobalt complexes promote electron wiring between the active site of the enzyme and the electrode. [ABSTRACT FROM AUTHOR]

Radiotherapy-induced immune activation holds great promise for optimizing cancer treatment efficacy. Here, we describe a clinically used radiosensitizer hafnium oxide (HfO2) that was core coated with a MnO2 shell followed by a glucose oxidase (GOx) doping nanoplatform (HfO2@MnO2@GOx, HMG) to trigger ferroptosis adjuvant effects by glutathione depletion and reactive oxygen species production. This ferroptosis cascade potentiation further sensitized radiotherapy by enhancing DNA damage in 4T1 breast cancer tumor cells. The combination of HMG nanoparticles and radiotherapy effectively activated the damaged DNA and Mn2+-mediated cGAS-STING immune pathway in vitro and in vivo. This process had significant inhibitory effects on cancer progression and initiating an anticancer systemic immune response to prevent distant tumor recurrence and achieve long-lasting tumor suppression of both primary and distant tumors. Furthermore, the as-prepared HMG nanoparticles "turned on" spectral computed tomography (CT)/magnetic resonance dual-modality imaging signals, and demonstrated favorable contrast enhancement capabilities activated by under the GSH tumor microenvironment. This result highlighted the potential of nanoparticles as a theranostic nanoplatform for achieving molecular imaging guided tumor radiotherapy sensitization induced by synergistic immunotherapy. [ABSTRACT FROM AUTHOR]

Safe, accurate, and reliable analysis of urinary biomarkers is clinically important for early detection and monitoring of the progression of chronic kidney disease (CKD), as it has become one of the world's most prevalent non-communicable diseases. However, current technologies for measuring urinary biomarkers are either time-consuming and limited to well-equipped hospitals or lack the necessary sensitivity for quantitative analysis and post a health risk to frontline practitioners. Here we report a robust paper-based dual functional biosensor, which is integrated with the clinical urine sampling vial, for the simultaneous and quantitative analysis of pH and glucose in urine. The pH sensor was fabricated by electrochemically depositing IrOx onto a paper substrate using optimised parameters, which enabled an ultrahigh sensitivity of 71.58 mV pH-1. Glucose oxidase (GOx) was used in combination with an electrochemically deposited Prussian blue layer for the detection of glucose, and its performance was enhanced by gold nanoparticles (AuNPs), chitosan, and graphite composites, achieving a sensitivity of 1.5 μA mM-1. This dual function biosensor was validated using clinical urine samples, where a correlation coefficient of 0.96 for pH and 0.98 for glucose detection was achieved with commercial methods as references. More importantly, the urine sampling vial was kept sealed throughout the sample-to-result process, which minimised the health risk to frontline practitioners and simplified the diagnostic procedures. This diagnostic platform, therefore, holds high promise as a rapid, accurate, safe, and user-friendly point-of-care (POC) technology for the analysis of urinary biomarkers in frontline clinical settings. [ABSTRACT FROM AUTHOR]

17β-Estradiol (E2) is an important endogenous estrogen, which disturbs the endocrine system and poses a threat to human health because of its accumulation in the human body. Herein, a biofuel cell (BFC)-based self-powered electrochemical aptasensor was developed for E2 detection. Porous carbon nanocage/gold nanoparticle composite modified indium tin oxide (CNC/AuNP/ITO) and glucose oxidase modified CNC/AuNP/ITO were used as the biocathode and bioanode of BFCs, respectively. [Fe(CN)6]3− was selected as an electroactive probe, which was entrapped in the pores of positively charged magnetic Fe3O4 nanoparticles (PMNPs) and then capped with a negatively charged E2 aptamer to form a DNA bioconjugate. The presence of the target E2 triggered the entrapped [Fe(CN)6]3− probe release due to the removal of the aptamer via specific recognition, which resulted in the transfer of electrons produced by glucose oxidation at the bioanode to the biocathode and produced a high open-circuit voltage (EOCV). Consequently, a "signal-on" homogeneous self-powered aptasensor for E2 assay was realized. Promisingly, the BFC-based self-powered aptasensor has particularly high sensitivity for E2 detection in the concentration range of 0.5 pg mL−1 to 15 ng mL−1 with a detection limit of 0.16 pg mL−1 (S/N = 3). Therefore, the proposed BFC-based self-powered electrochemical aptasensor has great promise to be applied as a successful prototype of a portable and on-site bioassay in the field of environment monitoring and food safety. [ABSTRACT FROM AUTHOR]

Background: The pre-analytical (PA) phase is the most vulnerable phase of the laboratory testing procedure, with critical procedures-collection, handling, sample transport, and time and temperature of sample storage. This study aimed to examine the stability of basic biochemical parameters depending on the samples' storage conditions and the number of freeze-thaw cycles (FTCs). In parallel, the presence of sample bacterial contamination during routine laboratory work was examined. Methods: Two plasma pools (ethylenediaminetetraacetic acid (EDTA), and sodium-fluoride/potassium oxalate plasma (NaF)) were stored at +4 °C/-20 °C. Total chole - sterol (TC), glucose, triglycerides (TG), urea, and albumin concentrations were measured using BioSystems reagents (cholesterol oxidase/peroxidase, glucose oxidase/per - oxidase, glycerol phosphate oxidase/peroxidase, urease/salicylate, and bromcresol green method, respectively) on Ilab 300+. Sample bacterial contamination was determined by 16S rRNA sequence analysis. The expe - riment encompassed a 5 day-period: Day 1-fresh sample, Day 2-1st FTC, Day 3-2nd FTC, Day 4-3rd FTC, Day 5-4th FTC. The appearance of bacteria in two consecutive samples was the experiment's endpoint. Results: During 4 FTCs, there were no changes in plasma urea concentrations. Glucose was stable in EDTA +4 °C and NaF -20 °C until the 3rd FTC (P=0.008, P=0.042, respectively). TG concentrations changed significantly in the EDTA -20 °C sample after 1st and 4th FTCs (P=0.022, P=0.010, respectively). In NaF samples, no bacterial contamination was observed during 4 FTCs. Conclusion: Urea and glucose concentrations were robust. Changes in lipid concentrations after FTCs follow complex patterns. Bacterial growth was not observed in NaF plasma samples. This can promote NaF use in analytical procedures in which bacterial contamination affects the quality of analysis. [ABSTRACT FROM AUTHOR]

An enzymatic fluorescent probe is developed for the selective detection of glucose. In this work, a Bovine Serum Albumin stabilized gold nanocluster (BSA‐AuNCs) was synthesized by microwave assisted method, and it is modified with glucose oxidase, thereby a fluorescent enzymatic sensor (BSA‐AuNCs@GoX) was designed for the sensitive detection of glucose with a limit of detection of 0.03 mM. The red fluorescence exhibited by the probe is quenched by the production of H2O2 on addition of glucose via. a static quenching mechanism from UV visible absorption and Fluorescence lifetime results. The developed probe exhibits good selectivity and sensitivity with other coexisting molecular species such as glycine, creatinine, methionine, histidine, uric acid, albumin, and ions such as sodium, potassium, calcium, magnesium, zinc etc. that appear in the body fluid. The practical applicability was studied in paper strip and extended its reproducibility in biological matrixes such as human serum and urine and found a good recovery percentage of 94–101 %. By this way, we have fabricated an effective fluorescent enzymatic "turn‐off" sensing probe for the detection of glucose. [ABSTRACT FROM AUTHOR]

The development of nanozymes, artificial enzymes made from inorganic nanoparticles, is widely studied due to their affordability, durability, and strength. Gold nanoparticles (AuNPs) are employed to imitate peroxidase, glucose oxidase, lactate oxidase, superoxide dismutase, and catalase. The last one transforms intracellular hydrogen peroxide into molecular oxygen, whose deficiency is characteristic of the hypoxic tumor microenvironment. Thus, gold nanoparticles are thought to enhance the overall effectiveness of photodynamic therapy. However, the enzyme‐like activity of nanoparticles rapidly decreases in biological media, due to the aggregation and formation of the so‐called "protein corona". In this study, polymeric submicrocapsules loaded with AuNPs and a photodynamic dye are fabricated via Layer‐by‐Layer (LbL) assembly. The enhancement of photodynamic treatment efficacy by in situ production of oxygen by the catalase‐like effect of AuNPs is investigated. Polymeric capsules are thoroughly characterized in terms of physicochemical and catalytic properties, and as a proof of concept, their therapeutic potential is evaluated in vitro. Furthermore, encapsulated AuNPs shows significantly lower aggregation both upon storage and during the reaction course. The results shows that the polymer capsules, containing AuNPs and photodynamic dye, show significantly higher light‐induced cytotoxicity in comparison to the individual photodynamic dye, suggesting a synergistic effect between the formation of molecular oxygen by catalase‐like gold nanozymes and photodynamic action. [ABSTRACT FROM AUTHOR]

Honey is a natural sweetener made by bees that exhibits antimicrobial activity, mainly related to its H2O2 content. The aim of this work was to research the H2O2 concentration of 24 Spanish honeys from different botanical origins, studying their possible correlation with glucose oxidase (GOx), catalase (CAT), and anti-Staphylococcus aureus activities (minimal inhibition concentration (MIC), minimal bactericidal concentration (MBC), and percentage of inhibition at 5% (w/v) honey against Staphylococcus aureus), as well as possible correlations among all the analyzed parameters. The results showed that the H2O2 concentration did not depend on the botanical origin of the honeys. There were neither correlations between the H2O2 concentration and the activities of GOx and CAT, nor between GOx and antimicrobial activity. However, CAT and antimicrobial activities were positively correlated. Therefore, CAT could be successfully used as a possible marker of the antimicrobial activity of honeys against Staphylococcus aureus. Furthermore, a linear regression model has been fitted to explain the antimicrobial activity from CAT and GOx activity and H2O2 concentration. Although H2O2 is one of the compounds involved in honey's antibacterial activity, this capacity also strongly depends on other honey components (such as low water activity, acidity, osmolarity, and phenolic compounds). The very high anti-Staphylococcus aureus activity exhibited by all samples could be interesting for commercial honey-based formulations also helping to promote local beekeeping. [ABSTRACT FROM AUTHOR]

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This document provides a summary of various research articles on the development of sensors and biosensors for different applications. The articles cover a range of topics, including the sensing of urea and creatinine, the detection of the CagA antigen in gastric cancer, the electrochemical sensing of methotrexate, the measurement of antibodies and antioxidant activity in saliva, the detection of genetic signatures of viruses, the investigation of the sensing properties of VSe2 monolayers, and the determination of ochratoxin A. The articles present different fabrication methods and techniques, as well as the optimization of detection limits and sensitivities. The research findings suggest the potential for these biosensors to be used in practical applications for monitoring health and detecting diseases. [Extracted from the article]

Real-time monitoring of physiological indicators inside the body is pivotal for contemporary diagnostics and treatments. Implantable electrodes can not only track specific biomarkers but also facilitate therapeutic interventions. By modifying biometric components, implantable electrodes enable in situ metabolite detection in living tissues, notably beneficial in invasive glucose monitoring, which effectively alleviates the self-blood-glucose-managing burden for patients. However, the development of implantable electrochemical electrodes, especially multi-channel sensing devices, still faces challenges: (1) The complexity of direct preparation hinders functionalized or multi-parameter sensing on a small scale. (2) The fine structure of individual electrodes results in low spatial resolution for sensor functionalization. (3) There is limited conductivity due to simple device structures and weakly conductive electrode materials (such as silicon or polymers). To address these challenges, we developed multiple-channel electrochemical microneedle electrode arrays (MCEMEAs) via a separated functionalization and assembly process. Two-dimensional microneedle (2dMN)-based and one-dimensional microneedle (1dMN)-based electrodes were prepared by laser patterning, which were then modified as sensing electrodes by electrochemical deposition and glucose oxidase decoration to achieve separated functionalization and reduce mutual interference. The electrodes were then assembled into 2dMN- and 1dMN-based multi-channel electrochemical arrays (MCEAs), respectively, to avoid damaging functionalized coatings. In vitro and in vivo results demonstrated that the as-prepared MCEAs exhibit excellent transdermal capability, detection sensitivity, selectivity, and reproducibility, which was capable of real-time, in situ glucose concentration monitoring. [ABSTRACT FROM AUTHOR]

Directed toward the limitations of natural enzymes in diabetes management, it is possible to design nano-enzymatic structures and modulate the activity as needed to obtain superior materials that are more suitable for the specific application environment. In this work, noble metal–semiconductor composite nanozymes [Te–Au nanowires (NWs)] were designed and their enzyme-like activities were systematically investigated for diabetes management. The results indicated that Te–Au NWs exhibited pH-switching multi-enzyme-like activities and adapted to a wider range of reaction conditions than natural enzymes. The kinetics of their enzyme-catalyzed reactions followed the Michaelis–Menten model, showing their substrate affinity similar to that of natural enzymes. Actually, the nanozymes showed reliable application stability, maintaining more than 80% of various enzyme activities under prolonged or extreme storage conditions. Furthermore, the nanozymes can be flexibly applied to various paths of glucose detection. For example, we constructed three different colorimetric detection methods to achieve the detection of glucose in saliva and blood. All three detection methods showed a wider linear range and lower limit of detection (LOD), among which the most optimal method was the combination of Te–Au NWs and glucose oxidase (GOx), with a linear range of 0.05–4 mM and a LOD of 2.11 μM. In summary, nanozymes with multiple enzyme-like activities have significant advantages and effectively address the limitations of natural enzymes in the application of diabetes management. [ABSTRACT FROM AUTHOR]

Oxidative stress from excess H2O2 activates transcription factors that restore redox balance and repair oxidative damage. Although many transcription factors are activated by H2O2, it is unclear whether they are activated at the same H2O2 concentration, or time. Dose-dependent activation is likely as oxidative stress is not a singular state and exhibits dose-dependent outcomes including cell-cycle arrest and cell death. Here, we show that transcription factor activation is both dose-dependent and coordinated over time. Low levels of H2O2 activate p53, NRF2 and JUN. Yet under high H2O2, these transcription factors are repressed, and FOXO1, NF-κB, and NFAT1 are activated. Time-lapse imaging revealed that the order in which these two groups of transcription factors are activated depends on whether H2O2 is administered acutely by bolus addition, or continuously through the glucose oxidase enzyme. Finally, we provide evidence that 2-Cys peroxiredoxins control which group of transcription factors are activated. H2O2 stress is known to activate a slew of transcription factors that restore redox balance. Here, the authors use live-cell imaging and single-cell analysis to reveal that the transcription factors that are activated and their timing of activation is dose dependent. [ABSTRACT FROM AUTHOR]

Glucose oxidase (GOx) catalyzes the oxidation of D -glucose to D -glucono-1,5-lactone and has a wide range of applications in various industries. However, the strict substrate specificity of GOx hampers its application in the conversion of other abundant sugars such as D -xylose. In this study, the substrate preference of GOx from Aspergillus niger (AnGOx) was engineered using a semi-rational design approach. The mutant T110V/F414L exhibited a 5.7-fold increase in D -xylose oxidation activity compared to that of the wild-type enzyme, which was attributed to its enhanced affinity for the substrate. Molecular dynamics simulations indicated that the T110V and F414L mutations may mitigate the non-productive binding of D -xylose at the entrance of the substrate-binding pocket, and therefore, are beneficial for providing access of its C1 hydroxyl group to the catalytic residues. Moreover, the mutant simultaneously oxidized D -xylose and D -glucose in the corncob hydrolysate to the corresponding aldonic acids when coupled with catalase. These findings provide new insights into substrate recognition by GOx and offer a new method for the utilization of D -xylose from lignocellulosic feedstocks. [ABSTRACT FROM AUTHOR]

Considering the application prospects of a cascade catalytic system in biomedical analysis, it remains significant to develop a cascade catalytic system for one-step rapid colorimetric detection. Herein, PVP/NH2-MIL-101(Fe) possessing enhanced peroxidase (POD)-like activity was successfully synthesized by microwave-assisted and polyvinylpyrrolidone (PVP) modification strategies. Then, PVP/NH2-MIL-101(Fe) and glucose oxidase (GOx) were covalently coupled via the bifunctional cross-linker glutaraldehyde, the GOx@PVP/NH2-MIL-101(Fe) with dual enzymatic functional activities (POD-like and GOx activities) was subsequently synthesized. GOx@PVP/NH2-MIL-101(Fe) had strong affinities for the substrates glucose, 3,3',5,5'-tetramethylbenzidine, and hydrogen peroxide. Based on this specific nanozyme GOx@PVP/NH2-MIL-101(Fe), a one-step colorimetric assay for rapid glucose determination was built. This detection method not only took 20 min to analyze but also possessed a linear range of 10–250 µM with a detection limit of 1.05 µM. Furthermore, the cascade catalytic system was applied to determine glucose concentrations in human serum samples. Compared with commercial blood glucose meters, the proposed method was also accurate and effective, making it a candidate method for determining blood glucose. [ABSTRACT FROM AUTHOR]

Here, we developed magnetically recoverable biocatalysts based on magnetite nanoparticles coated with an ultra-thin layer (about 0.9 nm) of chitosan (CS) ionically cross-linked by sodium tripolyphosphate (TPP). Excessive CS amounts were removed by multiple washings combined with magnetic separation. Glucose oxidase (GOx) was attached to the magnetic support via the interaction with N-hydroxysuccinimide (NHS) in the presence of carbodiimide (EDC) leading to a covalent amide bond. These steps result in the formation of the biocatalyst for D-glucose oxidation to D-gluconic acid to be used in the preparation of pharmaceuticals due to the benign character of the biocatalyst components. To choose the catalyst with the best catalytic performance, the amounts of CS, TPP, NHS, EDC, and GOx were varied. The optimal biocatalyst allowed for 100% relative catalytic activity. The immobilization of GOx and the magnetic character of the support prevents GOx and biocatalyst loss and allows for repeated use. [ABSTRACT FROM AUTHOR]

Starvation therapy mediated by glucose oxidase is a widely used therapeutic approach for tumor treatment, but it is limited by the simultaneous drawbacks of weak therapeutic efficacy, nonspecificity, and systemic toxicity. Thus, combination therapy was used to complement the widely used therapeutic strategy for anticancer therapy. On the basis of starvation therapy, we designed a catalytic model of nanosheets with biological cascade enzymes synergizing with anticancer drugs. In short, two cascade enzymes (glucose oxidase and horseradish peroxidase) are covalently immobilized on Ti3C2 MXene nanosheet and a cascade enzyme nanoreactor is formed by electrostatically adsorbing positive charged DOX. Finally, the outer layer is coated with hyaluronic acid. By combining glucose oxidase-mediated starvation therapy, photothermal therapy, and chemotherapy, we have achieved the therapeutic effect of "killing three birds with one stone" by combining the dual stimulation response of endogenous and exogenous sources to the tumor site. This method not only achieves the targeting of cancer cells but also improves the systemic toxicity and reduced efficacy of biological enzymes and realizes synergistic cancer therapy with enhanced cascade reactions. It opens up a new path for the research of nanomedicine. [ABSTRACT FROM AUTHOR]

Recently protein binders have emerged as a promising substitute for antibodies due to their high specificity and low cost. Herein, we demonstrate an electrochemical biosensor chip through the electronic labelling strategy using lead sulfide (PbS) colloidal quantum dots (CQDs) and the unnatural SARS-CoV-2 spike miniprotein receptor LCB. The unnatural receptor can be utilized as a molecular probe for the construction of CQD-based electrochemical biosensor chips, through which the specific binding of LCB and the spike protein is transduced to sensor electrical signals. The biosensor exhibits a good linear response in the concentration range of 10 pg mL−1 to 1 μg mL−1 (13.94 fM to 1.394 nM) with the limit of detection (LOD) being 3.31 pg mL−1 (4.607 fM for the three-electrode system) and 9.58 fg mL−1 (0.013 fM for the HEMT device). Due to the high sensitivity of the electrochemical biosensor, it was also used to study the binding kinetics between the unnatural receptor LCB and spike protein, which has achieved comparable results as those obtained with commercial equipment. To the best of our knowledge, this is the first example of using a computationally designed miniprotein receptor based on electrochemical methods, and it is the first kinetic assay performed with an electrochemical assay alone. The miniprotein receptor electrochemical biosensor based on QDs is desirable for fabricating high-throughput, large-area, wafer-scale biochips. [ABSTRACT FROM AUTHOR]

Ethyl (S)-4-chloro-3-hydroxybutyrate ((S)-CHBE) is an important chiral intermediate in the synthesis of the cholesterol-lowering drug atorvastatin. Studying the use of SpyTag/SpyCatcher and SnoopTag/SnoopCatcher systems for the asymmetric reduction reaction and directed coupling coenzyme regeneration is practical for efficiently synthesizing (S)-CHBE. In this study, Spy and Snoop systems were used to construct a double-enzyme directed fixation system of carbonyl reductase (BsCR) and glucose dehydrogenase (BsGDH) for converting 4-chloroacetoacetate (COBE) to (S)-CHBE and achieving coenzyme regeneration. We discussed the enzymatic properties of the immobilized enzyme and the optimal catalytic conditions and reusability of the double-enzyme immobilization system. Compared to the free enzyme, the immobilized enzyme showed an improved optimal pH and temperature, maintaining higher relative activity across a wider range. The double-enzyme immobilization system was applied to catalyze the asymmetric reduction reaction of COBE, and the yield of (S)-CHBE reached 60.1% at 30 °C and pH 8.0. In addition, the double-enzyme immobilization system possessed better operational stability than the free enzyme, and maintained about 50% of the initial yield after six cycles. In summary, we show a simple and effective strategy for self-assembling SpyCatcher/SnoopCatcher and SpyTag/SnoopTag fusion proteins, which inspires building more cascade systems at the interface. It provides a new method for facilitating the rapid construction of in vitro immobilized multi-enzyme complexes from crude cell lysate. [ABSTRACT FROM AUTHOR]

This work aims to develop new H2O2-sensing elements and nanozyme-oxidase-based sensors for the detection of hydrogen peroxide, glucose, and galactose. Methods. Chemical synthesis. Assay of enzymatic activity. Scanning electron microscope. Results. Hexacyanoferrates of several transient metals were synthesized and tested for their nanozymes (HCF NZs) (certificial peroxidase) activity in solution. The best representative nanozymes (NZs) were used for the construction of H2O2-sensitive sensors and nanozyme-oxidase-based biosensors. The NZs-based sensors: nAuHCF/GE and nPtHCF/GE demonstrated higher sensitivity (7.5 and 9.4-fold) than the biosensor with natural peroxidase. The developed biosensors GOX/nPtHCF/GE and GaOx/nPtHCF/GE for the detection of glucose and galactose showed enhanced sensitivity: 900 and 540 A·M-1·m-2, respectively, broad linear range (0.02-0.2 mM). Along with a broad linear range of detection these biosensors possess low limits of detection -- 4.0 μM for glucose and 6.0 μM for galactose. Additionally, these biosensors exhibited improved stability when compared to the control. Conclusions. The novelty of the presented work is related to the synthesis of new peroxidase-like NZs and the evaluation of their functionality as the chemosensors on H2O2 and as the sensing components in the oxidase-based-biosensors for assay of glucose and galactose. The nPtHCF and nAuHCF NZs exhibit high sensitivity for the target analytes, a broad linear range, and satisfactory storage stability. The main advantages of the proposed nanozyme-oxidase-based biosensors are the simple architecture of the sensing layer and the ability to operate at low working electrode potentials. [ABSTRACT FROM AUTHOR]

Fish gelatin (FG)-based wound dressings exhibit superior water absorption capacity, thermal stability, and gelation properties, which enhance the performance of these dressings. In this study, our objective was to investigate the conditions underlying the enzymatic hydrolysis of FG and subsequent cross-linking to prepare high-performance gels. A two-step enzymatic method of protease-catalyzed hydrolysis followed by glutamine transglutaminase (TGase)-catalyzed cross-linking was used to prepare novel high-performance fish gelatin derivatives with more stable dispersion characteristics than those of natural gelatin derivatives. Compared with conventional TGase cross-linked derivatives, the novel derivatives were characterized by an average pore size of 150 μm and increased water solubility (423.06% to 915.55%), water retention (by 3.6-fold to 43.89%), thermal stability (from 313 °C to 323 °C), and water vapor transmission rate, which reached 486.72 g·m−2·24 h−1. In addition, loading glucose oxidase onto the fish gelatin derivatives increased their antibacterial efficacy to >99% against Escherichia coli and Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

Aimed to improve the tensile properties, color, and sensory quality of bran-fortified stewing noodles using bran extrusion and improvers. A single-factor experiment and Box–Behnken design response surface experiment were designed, and the multi-index comprehensive weighted scoring method was applied. The single-factor experiment indicated high-quality bran-fortified stewing noodles when wheat gluten, glucose oxidase, and guar gum contents were 10%, 40 mg/kg, and 0.3%, respectively. The response surface experiment showed that the comprehensive weighted score in the response surface optimal group was maximum (86.33 points) when wheat gluten, glucose oxidase, and guar gum contents were 5%, 40 mg/kg, and 0.2%, respectively. The verified model experiment showed that the average comprehensive weighted score was 89.31±0.49 points, indicating that the model was feasible to improve the quality of bran-fortified stewing noodles. The optimal formula involved wheat gluten, glucose oxidase, and guar gum contents of 6.67%, 28 mg/kg, and 0.22%, respectively. Bran extrusion and improvers can improve the quality of bran-fortified stewing noodles. The findings may serve as a reference for the quality improvement and industrial production of fiber-rich stewing noodles. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Herein, the hybrid nanozyme MnOx NPs/Co3O4 NPs on indium tin oxide coated glass substrate (ITO) was manufactured by imparting the porous morphology with its distinct merits: its surface valence states, oxygen vacancies, large surface area, and abundant active sites. The oxidase-like activity was investigated via the catalytic oxidation of chromogenic substrate in the presence of glucose visualized by the eyes. MnOx NPs containing Mn2+ and Mn3+ have a superior ability to oxidize glucose by reducing dissolved oxygen and producing H2O2. Co3O4 NPs, in turn, reduce H2O2 with concomitant 3,3′,5,5′-tetramethylbenzidine (TMB) oxidization. Thus, the nanozyme mimics the dual roles of glucose oxidase and peroxidase. The oxidaselike activity of hybrid nanozyme for glucose was found to be higher than those of single components. The nanozyme responded to glucose with a linear range from 60 µM to 1200 μM. The acceptable performance is probably due to the facilitated access of glucose to the proximity of the sensor surface. Good reproducibility was accomplished by virtue of the meticulous construction of NPs. Without functionalization and enzyme utilization, the fabricated nanozyme holds promise as a substitute for peroxidase and oxidase for detecting glucose. [ABSTRACT FROM AUTHOR]

Ferroptosis, a unique iron-dependent mode of cell death characterized by lipid peroxide accumulation, holds significant potential for the treatment of glioblastoma (GBM). However, the effectiveness of ferroptosis is hindered by the limited intracellular ferrous ions (Fe2+) and hydrogen peroxide (H 2 O 2). In this study, a novel near-infrared (NIR)-light-responsive nanoplatform (ApoE-UMSNs-GOx/SRF) based on upconversion nanoparticles (UCNPs) was developed. A layer of mesoporous silica and a lipid bilayer were coated on UCNPs sequentially and loaded with glucose oxidase (GOx) and sorafenib, respectively. Further attachment of the ApoE peptide endowed the nanoplatform with BBB penetration and GBM targeting capabilities. Our results revealed that ApoE-UMSNs-GOx/SRF could efficiently accumulated in the orthotopic GBM and induce amplified ferroptosis when combining with NIR irradiation. The UCNPs mediated the photoreduction of Fe3+ to Fe2+ by converting NIR to UV light, and excess H 2 O 2 was produced by the reaction of glucose with the loaded GOx. These processes greatly promoted the production of ROS, which together with inhibition of system Xc− by the loaded sorafenib, leading to enhanced accumulation of lipid peroxides and significantly improved the antiglioma effect both in vitro and in vivo. Our strategy has the potential to enhance the effectiveness of ferroptosis as a therapeutic approach for GBM. A novel nanoplatform (ApoE-UMSNs-GOx/SRF) for the efficient treatment of glioblastoma through NIR-promoted enhanced ferroptosis. [Display omitted] [ABSTRACT FROM AUTHOR]

Microneedle array systems loaded with responsive nanoparticles have received increasing attention due to the advantages of good drug stability, targeting ability, controlled release of drugs, high bioavailability, painlessness, and good patient compliance. Compared with oral drug delivery, microneedle transdermal drug delivery eliminates the need to pass through the gastrointestinal tract and liver, reducing the metabolic consumption of drugs by first‐pass effect. While compared with intravenous drug delivery, microneedle transdermal drug delivery reduces patient discomfort and does not require professional administration. However, there are few review articles on microneedles loaded with responsive nanoparticles. Herein, the current researches on microneedles loaded with specific responsive nanoparticles such as glucose‐responsive, pH‐responsive, enzyme‐responsive, light‐responsive, magnetic‐responsive, ultrasound‐responsive, and multiresponsive, and the biomedical application of these microneedle array systems are summarized. In addition, the challenges and prospects of microneedle strategies loaded with responsive nanoparticles are briefly discussed, which will facilitate the development of such versatile drug‐delivery strategy. [ABSTRACT FROM AUTHOR]

Continuous spring cropping of Qingke (Hordeum viilgare L. var. nudum Hook. f.) results in a reduction in grain yield in the Xizang autonomous region. However, knowledge on the influence of continuous cropping on grain yield caused by reactive oxygen species (ROS)-induced stress remains scarce. A systematic comparison of the antioxidant defensive profile at seedling, tillering, jointing, flowering, and filling stages (T1 to T5) of Qingke was conducted based on a field experiment including 23-year continuous cropping (23y-CC) and control (the first year planted) treatments. The results reveal that the grain yield and superoxide anion (SOA) level under 23y-CC were significantly decreased (by 38.67% and 36.47%), when compared to the control. The hydrogen peroxide content under 23y-CC was 8.69% higher on average than under the control in the early growth stages. The higher ROS level under 23y-CC resulted in membrane lipid peroxidation (LPO) and accumulation of malondialdehyde (MDA) at later stages, with an average increment of 29.67% and 3.77 times higher than that in control plants. Qingke plants accumulated more hydrogen peroxide at early developmental stages due to the partial conversion of SOA by glutathione (GSH) and superoxide dismutase (SOD) and other production pathways, such as the glucose oxidase (GOD) and polyamine oxidase (PAO) pathways. The reduced regeneration ability due to the high oxidized glutathione (GSSG) to GSH ratio resulted in GSH deficiency while the reduction in L-galactono-1,4-lactone dehydrogenase (GalLDH) activity in the AsA biosynthesis pathway, higher enzymatic activities (including ascorbate peroxidase, APX; and ascorbate oxidase, AAO), and lower activities of monodehydroascorbate reductase (MDHAR) all led to a lower AsA content under continuous cropping. The lower antioxidant capacity due to lower contents of antioxidants such as flavonoids and tannins, detected through both physiological measurement and metabolomics analysis, further deteriorated the growth of Qingke through ROS stress under continuous cropping. Our results provide new insights into the manner in which ROS stress regulates grain yield in the context of continuous Qingke cropping. [ABSTRACT FROM AUTHOR]

Electrochemical method is used for glycated hemoglobin (HbA1c) detection using a new configuration of working electrodes coated by ZnO nanorods. HbA1c reflects the average plasma glucose over two months. In this work, HbA1c is directly detected electrochemically without any proteolytic digestion for the first time. ZnO nanorods modify the working electrode to increase the surface of sensing, leading to amplifying the electrochemical signal and providing a stable enzyme bed for GOx immobilization. The limit of detection (LOD) is 0.32 μg/μl which can be achieved in 40 seconds as the sensor's response time. The range of detection is 0.32 μg/μl (0.21% of HbA1c)-22.4 μg/μl (14.93% of HbA1c) that covers the standard diagnosis range. Due to embedded nanostructures, a small amount of about 2 μl GOx solution and 50 nl of blood is required for detection. The low response time makes this sensor suitable for fast tests such as diabetic population enumeration and screening. [ABSTRACT FROM AUTHOR]

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In recent years, the synthesis of nanofibers using plant extracts and bioactive materials has been extensively studied and recognized as a suitable and efficient method applicable in the food packaging field. In this research, an antimicrobial material was introduced by the immobilization of glucose oxidase (GOx) in Nylon–Ag masterbatch/chitosan/Rosmarinus officinalis extract nanofiber via electrospinning technology. Nylon–Ag masterbatch/chitosan/Rosmarinus officinalis composite nanofibrous membranes with an average diameter of 207 ± 18 nm were successfully prepared using the electrospinning technique. The chemical properties of membranes were analyzed by Fourier transform infrared spectroscopy (FTIR) and the morphological characterization of nanofibers was evaluated with field emission scanning electron microscopy (FE-SEM). Moreover, enzymatic activity of GOx was determined by the Carmine method. FTIR results showed the successful incorporation of glucose oxidase and Rosmarinus officinalis into the nanofiber composite. Immobilized GOx showed high (79.5%) enzymatic activity in the optimum sample. The Rosmarinus officinalis, glucose oxidase-incorporated Nylon–Ag masterbatch/chitosan nanofibrous exhibited excellent antimicrobial activity on both gram-negative bacterium Escherichia coli (97.5%) and gram-positive bacterium Staphylococcus aureus (99.5%). The antibacterial and antioxidant Nylon–Ag masterbatch/chitosan/Rosmarinus officinalis/GOx nanofibrous membrane showed higher potential, compared to the control sample, to be used as food packaging by improving the shelf life and maintaining the quality of food stuffs. Therefore, this research recommends it as a promising candidate for food preservation applications. [ABSTRACT FROM AUTHOR]

Background: Oxidative enzymes targeting lignocellulosic substrates are presently classified into various auxiliary activity (AA) families within the carbohydrate-active enzyme (CAZy) database. Among these, the fungal AA3 glucose–methanol–choline (GMC) oxidoreductases with varying auxiliary activities are attractive sustainable biocatalysts and important for biological function. CAZy AA3 enzymes are further subdivided into four subfamilies, with the large AA3_2 subfamily displaying diverse substrate specificities. However, limited numbers of enzymes in the AA3_2 subfamily are currently biochemically characterized, which limits the homology-based mining of new AA3_2 oxidoreductases. Importantly, novel enzyme activities may be discovered from the uncharacterized parts of this large subfamily. Results: In this study, phylogenetic analyses employing a sequence similarity network (SSN) and maximum likelihood trees were used to cluster AA3_2 sequences. A total of 27 AA3_2 proteins representing different clusters were selected for recombinant production. Among them, seven new AA3_2 oxidoreductases were successfully produced, purified, and characterized. These enzymes included two glucose dehydrogenases (TaGdhA and McGdhA), one glucose oxidase (ApGoxA), one aryl alcohol oxidase (PsAaoA), two aryl alcohol dehydrogenases (AsAadhA and AsAadhB), and one novel oligosaccharide (gentiobiose) dehydrogenase (KiOdhA). Notably, two dehydrogenases (TaGdhA and KiOdhA) were found with the ability to utilize phenoxy radicals as an electron acceptor. Interestingly, phenoxy radicals were found to compete with molecular oxygen in aerobic environments when serving as an electron acceptor for two oxidases (ApGoxA and PsAaoA), which sheds light on their versatility. Furthermore, the molecular determinants governing their diverse enzymatic functions were discussed based on the homology model generated by AlphaFold. Conclusions: The phylogenetic analyses and biochemical characterization of AA3_2s provide valuable guidance for future investigation of AA3_2 sequences and proteins. A clear correlation between enzymatic function and SSN clustering was observed. The discovery and biochemical characterization of these new AA3_2 oxidoreductases brings exciting prospects for biotechnological applications and broadens our understanding of their biological functions. [ABSTRACT FROM AUTHOR]

Nanozymes, as artificial enzymes, overcome the low catalytic efficiency, poor stability, and cost-effectiveness of previous artificial enzymes. In this work, vanadium carbide@vanadium oxide (V2C@VOx) nanosheets were synthesized by a one-pot hydrothermal method using V2C as a precursor and H2O2 as an oxidant. The prepared V2C@VOx nanosheets exhibited excellent multi-enzyme activity such as peroxidase-like activity, superoxide dismutase-like activity, and oxidase-like activity. The entire synthetic process of V2C@VOx nanosheets does not need any additional intercalation agent, strong acid, or base. Meanwhile, the synthesized method of nanozymes was simple, time-saving, and environmentally friendly. In particular, based on the multi-enzyme activity of V2C@VOx nanosheets, the nanozymes catalyzed H2O2 and dissolved O2 to oxidize 3′,3,5,5′-tetramethylbenzidine (TMB). Additionally, glucose reacted with glucose oxidase (GOx) to form H2O2 under water bath conditions. Therefore, the colorimetric sensing strategy of glucose was constructed based on the multi-enzyme activity of V2C@VOx nanosheets and the enzymatic reaction of glucose. The detection limit of the sensor was as low as 0.08 μM. Furthermore, the colorimetric method was successfully used to detect glucose in human serum. The sensor exhibited low cost, high stability, and easy construction. Overall, this work proposed a promising strategy based on novel vanadium-based nanozymes with excellent multi-enzyme activity for biomedical detection. [ABSTRACT FROM AUTHOR]

Wearable glucose biosensors enable noninvasive glucose monitoring, thereby enhancing blood glucose management. In this work, we present a wearable biosensor based on carbon black nanoparticles (CBNPs) for glucose detection in human sweat. The biosensor consists of CBNPs, Prussian blue (PB), glucose oxidase, chitosan, and Nafion. The fabricated biosensor has a linear range of 5 µM to 1250 µM, sensitivity of 14.64 µA mM−1 cm−2, and a low detection potential (−0.05 V, vs. Ag/AgCl). The detection limit for glucose was calculated as 4.83 µM. This reusable biosensor has good selectivity and stability and exhibits a good response to glucose in real sweat. These results demonstrate the potential of our CBNP-based biosensor for monitoring blood glucose in human sweat. [ABSTRACT FROM AUTHOR]

We describe the creation of a conductive microcavity based on the assembly of two pieces of carbon nanotube buckypaper for the entrapment of two enzymes, horseradish peroxidase (HRP) and glucose oxidase (GOx), as well as a redox mediator: 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid diammonium salt (ABTS). The hollow electrode, employing GOx, HRP, and the mediator, as an electrochemical enzyme cascade model, is utilized for glucose sensing at a potential of 50 mV vs. Ag/AgCl. This bienzyme electrode demonstrates the ability to oxidize glucose by GOx and subsequently convert H2O2 to water via the electrical wiring of HRP by ABTS. Different redox mediators (ABTS, potassium hexacyanoferrate (III), and hydroquinone) are tested for HRP wiring, with ABTS being the best candidate for the electroenzymatic reduction of H2O2. To demonstrate the possibility to optimize the enzyme cascade configuration, the enzyme ratio is studied with 1 mg HRP combined with variable amounts of GOx (1–4 mg) and 2 mg GOx combined with variable amounts of HRP (0.5–2 mg). The bienzyme electrode shows continuous operational stability for over a week and an excellent storage stability in phosphate buffer, with a decay of catalytic current by only 29% for 1 mM glucose after 100 days. [ABSTRACT FROM AUTHOR]

The noble metal NPs that are currently applied to photothermal therapy (PTT) have their photoexcitation location mainly in the NIR-I range, and the low tissue penetration limits their therapeutic effect. The complexity of the tumor microenvironment (TME) makes it difficult to inhibit tumor growth completely with a single therapy. Although TME has a high level of H 2 O 2 , the intratumor H 2 O 2 content is still insufficient to catalyze the generation of sufficient hydroxide radicals (‧OH) to achieve satisfactory therapeutic effects. The AuPd-GOx-HA (APGH) was obtained from AuPd bimetallic nanodumbbells modified by glucose oxidase (GOx) and hyaluronic acid (HA) for photothermal enhancement of tumor starvation and cascade catalytic therapy in the NIR-II region. The CAT-like activity of AuPd alleviates tumor hypoxia by catalyzing the decomposition of H 2 O 2 into O 2. The GOx-mediated intratumoral glucose oxidation on the one hand can block the supply of energy and nutrients essential for tumor growth, leading to tumor starvation. On the other hand, the generated H 2 O 2 can continuously supply local O 2 , which also exacerbates glucose depletion. The peroxidase-like activity of bimetallic AuPd can catalyze the production of toxic ‧OH radicals from H 2 O 2 , enabling cascade catalytic therapy. In addition, the high photothermal conversion efficiency (η = 50.7 %) of APGH nanosystems offers the possibility of photothermal imaging-guided photothermal therapy. The results of cell and animal experiments verified that APGH has good biosafety, tumor targeting, and anticancer effects, and is a precious metal nanotherapeutic system integrating glucose starvation therapy, nano enzyme cascade catalytic therapy, and PTT therapy. This study provides a strategy for photothermal-cascade catalytic synergistic therapy combining both exogenous and endogenous processes. AuPd-GOx-HA cascade nanoenzymes were prepared as a potent cascade catalytic therapeutic agent, which enhanced glucose depletion, exacerbated tumor starvation and promoted cancer cell apoptosis by increasing ROS production through APGH-like POD activity. The designed system has promising photothermal conversion ability in the NIR-II region, simultaneously realizing photothermal-enhanced catalysis, PTT, and catalysis/PTT synergistic therapy both in vitro and in vivo. The present work provides an approach for designing and developing catalytic-photothermal therapies based on bimetallic nanoenzymatic cascades. [Display omitted] [ABSTRACT FROM AUTHOR]

Background: Aspergillus niger ATCC 20611 is an industrially important fructooligosaccharides (FOS) producer since it produces the β-fructofuranosidase with superior transglycosylation activity, which is responsible for the conversion of sucrose to FOS accompanied by the by-product (glucose) generation. This study aims to consume glucose to enhance the content of FOS by heterologously expressing glucose oxidase and peroxidase in engineered A. niger. Results: Glucose oxidase was successfully expressed and co-localized with β-fructofuranosidase in mycelia. These mycelia were applied to synthesis of FOS, which possessed an increased purity of 60.63% from 52.07%. Furthermore, peroxidase was expressed in A. niger and reached 7.70 U/g, which could remove the potential inhibitor of glucose oxidase to facilitate the FOS synthesis. Finally, the glucose oxidase-expressing strain and the peroxidase-expressing strain were jointly used to synthesize FOS, which content achieved 71.00%. Conclusions: This strategy allows for obtaining high-content FOS by the multiple enzymes expressed in the industrial fungus, avoiding additional purification processes used in the production of oligosaccharides. This study not only facilitated the high-purity FOS synthesis, but also demonstrated the potential of A. niger ATCC 20611 as an enzyme-producing cell factory. [ABSTRACT FROM AUTHOR]