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The present work is based on developing more efficient bioanode nanocomposite materials for enzymatic biofuel cell (EBFCs) applications. The selection of useful electrode materials (EMs) is depended on their long-term stability, high current density, and low open-circuit voltage (OCV). Continuous efforts are being applied by the research communities for developing advanced efficient EMs. In the past few decades, nanomaterials and their composite have become promising materials that have been used as effective EMs in supercapacitors, solar cells (SCs) and BFCs applications. Herein, ternary nanocomposite, composed of silver nanoparticles (Ag NPs) decorated on zinc oxide nanoparticles (ZnO NPs) and graphene oxide sheets (GO), based bioanode was designed by employing Ferritin (Frt) and glucose oxidase (GO x) enzymes on the glassy carbon electrode (GCE). The formation of Ag@ZnO-NPs/GO nanocomposite was confirmed using analytical techniques such as FTIR and XRD. The structural surface morphology and in-depth investigation of Ag@ZnO-NPs/GO nanocomposite were performed using SEM and TEM. Besides these, the electrochemical behavior of as-synthesized Ag@ZnO-NPs/GO nanocomposite and the designed bioanode Ag@ZnO-NPs/GO/Frt/GO x were examined using cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). The resulting bioanode showed good catalytic activity toward glucose oxidation and splendid stability. In the presence of glucose (optimum concentration = 30 mM), the maximum current density was 7.7 mA cm−2, comparable to the other bioanode EMs. The results of this work reflected the appropriateness of Ag@ZnO-NPs/GO/Frt/GO x bioanode materials as assured EMs for the generation of EBFCs. • ZnO NPs and Ag NPs were synthesized via green route. • Ag@ZnO-NPs/GO nanocomposite was used as scaffold material. • Bioanode exhibited accomplishment of the mediated electron transfer through Frt. • Current density with bioanode was 7.7 mA cm−2 at glucose concentration of 30 mM. • High performance bioanode was achieved via wiring of enzyme. [ABSTRACT FROM AUTHOR]

The large‐pore interconnected channels in cryogels, allow convectional flow and rapid mass‐transport of solute constituents between the solution and cryogel polymer framework, as compared to slower, diffusionally‐controlled mass‐transport in small‐pore hydrogels. These features are applied to develop enzyme‐loaded polyacrylamide (pAAm) cryogels, and glucose oxidase (GOx)‐loaded pH‐responsive DNA‐based pAAm cryogels, revealing enhanced biocatalytic transformations, enhanced temporal stiffness changes, and mechanical bending functions, as compared to analog hydrogels. DNA‐based pAAm cryogel/hydrogel matrices, revealing pH‐switchable stiffness properties through reversible reconfiguration of DNA‐bridging units into i‐motif structures, are introduced. Enhanced switchable stiffness changes of DNA‐based pAAm cryogels, as compared to analog hydrogels, are demonstrated upon subjecting the cryogel/hydrogel matrices to auxiliary pH‐changes, or by integration of GOx into the frameworks, and driving pH‐changes through GOx‐catalyzed aerobic oxidation of glucose to gluconic acid. Enhanced stiffness changes of pAAm cryogels represent a major advance to control the mechanical properties of cryogels and are attributed to the convectionally‐controlled mass‐transport in the cryogel matrices. Moreover, bilayer constructs consisting of poly‐N‐isopropylacrylamide (pNIPAM) cryogels and pH‐responsive DNA‐based pAAm cryogel or hydrogel structures are constructed. Enhanced pH/glucose triggered mechanical bending rates of the pNIPAM cryogel/pAAm cryogel or pNIPAM cryogel/GOx‐loaded pAAm cryogel, as compared to analog pNIPAM cryogel/pAAm hydrogel frameworks are demonstrated. [ABSTRACT FROM AUTHOR]

Diabetes patients need to monitor blood glucose all year round. In this article, a novel scheme is proposed for blood glucose detection. The proposed sensor is based on a U-shaped microfiber prepared using hydrogen-oxygen flame-heating technology, and then 3-aminopropyltriethoxysilane (APTES) and glucose oxidase (GOD) are successively coated on the surface of the U-shaped microfiber via a coating technique. The glucose reacts with the GOD of the sensor surface to produce gluconic acid, which changes the effective refractive index and then shifts the interference wavelength. The structure and morphology of the sensor were characterized via scanning electron microscope (SEM) and confocal laser microscopy (CLM). The experimental results show that the sensitivity of the sensor is as high as 5.73 nm/(mg/mL). Compared with the glucose sensor composed of the same material, the sensitivity of the sensor increased by 329%. The proposed sensor has a broad application prospect in blood glucose detection of diabetic patients due to the advantages of miniaturization, high sensitivity, and good stability. [ABSTRACT FROM AUTHOR]

The anchoring of two-dimensional nanosheets (2D) with Prussian blue nanocubes has exhibited the advantage of high electron conductivity and better catalytic application. Herein, we reported the successful fabrication of molybdenum disulfide-supported Prussian blue nanocubes (MoS2@NiCo-PBANCs) and compared the bare MoS2 and NiCo-PBNCs for effective peroxidase, such as catalytic activity, which can catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) by the generation of H2O2, ensuring the appearance of blue colored solution. The MoS2@NiCo-PBANCs exhibited an excellent colorimetric sensing performance toward glucose in urine samples. Therefore, the present method demonstrates the high sensitivity, selectivity, simplicity, and fast colorimetric sensing ability for H2O2 and glucose detection. The synergistic effect of MoS2@NiCo-PBNCs reveals lower detection limits of 0.0075 µM and 0.01 µM for H2O2 and glucose, respectively. The exclusive structural morphology, excellent stability, large surface area, and high catalytic property have been utilized to achieve the closer interaction of glucose oxidase and TMB with MoS2@NiCo-PBANCs to oxidize glucose to gluconic acid. Overall, we utilized the MoS2@NiCo-PBNCs as a novel composite nanomaterial for the application of H2O2 and glucose peroxidase-like mimics in the urine sample. [ABSTRACT FROM AUTHOR]

Various studies have shown that the microbial proteins are often more stable than belongs to other sources like plant and animal origin. Hence, the interest in microbial enzymes has gained much attention due to many potential applications like bioenergy, biofuel production, biobleaching, bioconversion and so on. Additionally, recent trends revealed that the interest in isolating novel microbes from harsh environments have been the main focus of many scientists for various applications. Basically, industrially important enzymes can be categorized into mainly three groups: carbohydrases, proteases, and lipases. Among those, the enzymes especially carbohydrases involved in production of sugars. Carbohydrases include amylases, xylanases, pectinases, cellulases, chitinases, mannases, laccases, ligninases, lactase, glucanase, and glucose oxidase. Thus, here, an approach has been made to highlight five enzymes namely amylase, cellulase, laccase, pectinase, and xylanase from different sources with special emphasis on their properties, mechanism, applications, production optimization, purification, molecular approaches for its enhanced and stable production, and also biotechnological perspectives of its future development. Also, green and sustainable catalytic conversion strategies using nanoparticles of these enzymes have also been discussed. This review will provide insight into the carbohydrases importance and their usefulness that will help to the researchers working in this field. [ABSTRACT FROM AUTHOR]

A biocompatible BSA@Au/Pt-IR808 nanoplatform with triple-amplification of GOx/CAT/POD was constructed for PTT and enhanced PDT/catalytic therapy. [Display omitted] The weak catalytic activity of nanocatalysts and the insufficient endogenous hydrogen peroxide (H 2 O 2) in tumor microenvironment (TME) seriously restricted the efficacy of catalytic therapy, and the non-degradability of inorganic nanocarriers was also unfavorable for their clinical applications. Herein, by depositing gold nanoparticles (AuNPs) and platinum nanoparticles (PtNPs) with ultrasmall size and modifying photosensitizer (IR808), a biocompatible bovine serum albumin (BSA) nanoplatform (BSA@Au/Pt-IR808) with triple-amplification of enzyme activity was constructed to enhance photodynamic therapy (PDT) and catalytic therapy. Ultrasmall AuNPs possessed glucose oxidase (GOx)-like activity, by which the self-supplying H 2 O 2 accelerated the dual-enzyme activity of peroxidase (POD) and catalase (CAT) of ultrasmall PtNPs, promoting the generation of hydroxyl radical (·OH) and singlet oxygen (1O 2). Compared with BSA-IR808 and BSA@Pt, the yields of 1O 2 and ·OH of BSA@Au/Pt-IR808 increased by 38.2% and 18.6%. Under the combination action of photothermal therapy (PTT)/PDT/catalytic therapy of BSA@Au/Pt-IR808, the cell viability significantly reduced to 12.8%, and the tumors were completely eliminated, demonstrating the enhanced PDT and catalytic therapy against breast cancer. [ABSTRACT FROM AUTHOR]

Nanoscale metal–organic frameworks (NMOFs) with peroxidase-mimicking activity emerged as promising antibacterial agents instead of antibiotics. Therefore, here, a novel 2D bimetallic NMOF-based antibacterial agent named Al/Fe-TCPP NMOF/GOx was constructed. Compared with the Fe-TCPP NMOF, the obtained Al/Fe-TCPP NMOF exhibited significantly improved water-solubility, which favors the production and diffusion of hydroxyl radicals (˙OH). Glucose oxidase (GOx) loaded on Al/Fe-TCPP NMOF catalyze exogenous glucose to produce gluconic acid and hydrogen peroxide (H2O2), which provided an acidic environment to enhance the peroxidase-like activity of Al/Fe-TCPP NMOF and provided H2O2 for producing ˙OH to kill bacteria. Meanwhile, Fe3+ in Al/Fe-TCPP NMOF/GOx can deplete GSH, which increases the concentration of ˙OH for improving the antibacterial efficiency. The result of the antibacterial experiment in vitro demonstrated that Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were nearly completely killed in the co-incubation of Al/Fe-TCPP NMOF/GOx and glucose in vitro whereas the viabilities of E. coli and S. aureus were still higher than 50% in the presence of GOx and glucose, which illustrated that the 2D bimetallic Al/Fe-TCPP NMOF/GOx + glucose possesses excellent antibacterial action on typical E. coli and S. aureus. [ABSTRACT FROM AUTHOR]

Detection and quantification of glucose and urea are fundamental in medical analysis, real‐time monitoring, and point of care analysis. However, such analyses generally require sophisticated instrumentation and specialized personnel. Furthermore, discriminative detection of multiple analytes is often necessary for treatment and diagnosis. To address this challenge, this study describes a proof‐of‐concept for discriminative sensitive amperometric detection of both analytes. This was achieved by the fabrication of a polymer‐MWCNTs composite nanofiber matrix upon which glucose oxidase (GOD) and urease were co‐immobilized to allow detection of the corresponding substrates (glucose and urea). The (PAN(−MWCNTs)/Urease‐GOD) biosensor showed good performance in: (i) glucose biosensing with sensitivity of 31±5 μAmM−2cm−2 within an extended linear range (0.1–5.0 mM) and a limit of detection of 3.7 μM, and (ii) urea detection at very low concentration (4–30 and 30–90 μM) with sensitivity up to 350±19 μAmM−2cm−2 and very low LOD (0.1 μM). The analogous mono‐enzyme platform for urea detection (PAN(−MWCNTs)/Urease) showed very similar performance as the bi‐enzyme sensor, suggesting little to no influence of co‐immobilization on Urease activity, thus confirming that the two catalytic processes are independent of each other. The biosensors exhibited high accuracy in the detection of both analytes (at normal and pathological levels) in human serum, thus proving that the biosensor described herein can have practical applications in healthcare and remote patient monitoring. [ABSTRACT FROM AUTHOR]

Herein, we report a novel enzymatic dimerization‐induced self‐assembly (e‐DISA) procedure that converts alanine‐tyramine conjugates into highly uniform enzyme‐loaded nanoparticles (NPs) or nanocontainers by the action of horseradish peroxidase (HRP) in an aqueous medium under ambient conditions. The NP formation was possible with both enantiomers of alanine, and the average diameter could be varied from 150 nm to 250 nm (with a 5–12 % standard deviation of as‐prepared samples) depending on the precursor concentration. About 60 % of the added HRP enzyme was entrapped within the NPs and was subsequently utilized for post‐synthetic modification of the NPs with phenolic compounds such as tyramine or tannic acid. One‐pot multi‐enzyme entrapment of glucose oxidase (GOx) and peroxidase (HRP) within the NPs was also achieved. These GOx‐HRP loaded NPs allowed multimodal detection of glucose, including that present in human saliva, with a limit of detection (LoD) of 740 nM through fluorimetry. The NPs exhibited good cytocompatibility and were stable to changes in pH (acidic to basic), temperature, ultrasonication, and even the presence of organic solvent (EtOH) to a certain extent, since they are stabilized by intermolecular hydrogen bonding, π‐π, and CH‐π interactions. The proposed e‐DISA procedure can be widely expanded through the design of diverse enzyme‐responsive precursors. [ABSTRACT FROM AUTHOR]

Oxygen is crucial for converting glucose to gluconic acid catalyzed by glucose oxidase (Gox). However, industrial gluconic acid production faces oxygen supply limitations. To enhance Gox efficiency, Vitreoscilla hemoglobin (VHb) has been considered as an efficient oxygen transfer carrier. This study identified GoxA, a specific isoform of Gox in the industrial gluconic acid-producing strain of Aspergillus niger. Various forms of VHb expression in A. niger were tested to improve GoxA's catalytic efficiency. Surprisingly, the expression of free VHb, both intracellularly and extracellularly, did not promote gluconic acid production during shake flask fermentation. Then, five fusion proteins were constructed by linking Gox and VHb using various methods. Among these, VHb-GS1-GoxA, where VHb's C-terminus connected to GoxA's N-terminus via the flexible linker GS1, demonstrated a significantly higher Kcat/Km value (96% higher) than GoxA. Unfortunately, the expression of VHb-GS1-GoxA in A. niger was limited, resulting in a low gluconic acid production of 3.0 g/L. To overcome the low expression problem, single- and dual-strain systems were designed with tools of SpyCatcher/SpyTag and SnoopCatcher/SnoopTag. In these systems, Gox and VHb were separately expressed and then self-assembled into complex proteins. Impressively, the single-strain system outperformed the GoxA overexpression strain S1971, resulting in 23% and 9% higher gluconic acid production under 0.6 vvm and 1.2 vvm aeration conditions in the bioreactor fermentation, respectively. The successful construction of Gox and VHb fusion or complex proteins, as proposed in this study, presents promising approaches to enhance Gox catalytic efficiency and lower aerodynamic costs in gluconic acid production. Key points: • Overexpressing free VHb in A. niger did not improve the catalytic efficiency of Gox • The VHb-GS1-GoxA showed an increased Kcat/Km value by 96% than GoxA • The single-strain system worked better in the gluconic acid bioreactor fermentation [ABSTRACT FROM AUTHOR]

In this work the green synthesis of gold nanoparticles (Au-NPs) using the oxidoreductive enzymes Myriococcum thermophilum cellobiose dehydrogenase (Mt CDH), Glomerella cingulata glucose dehydrogenase (Gc GDH), and Aspergillus niger glucose oxidase (An GOX)) as bioreductants was investigated. The influence of reaction conditions on the synthesis of Au-NPs was examined and optimised. The reaction kinetics and the influence of Au ions on the reaction rate were determined. Based on the kinetic study, the mechanism of Au-NP synthesis was proposed. The Au-NPs were characterized by UV–Vis spectroscopy and transmission electron microscopy (TEM). The surface plasmon resonance (SPR) absorption peaks of the Au-NPs synthesised with Mt CDH and Gc GDH were observed at 535 nm, indicating an average size of around 50 nm. According to the image analysis performed on a TEM micrograph, the Au-NPs synthesized with Gc GDH have a spherical shape with an average size of 2.83 and 6.63 nm after 24 and 48 h of the reaction, respectively. Key points: • The Au NPs were synthesised by the action of enzymes CDH and GDH. • The synthesis of Au-NPs by CDH is related to the oxidation of cellobiose. • The synthesis of Au-NPs by GDH was not driven by the reaction kinetic. [ABSTRACT FROM AUTHOR]

The management of diabetic wounds poses significant challenges due to persistent bacterial infections and chronic inflammation caused by hyperglycemia. Herein, a sequential two‐phase treatment strategy involving a reactive oxygen species (ROS) burst in the first phase for anti‐infection is proposed, followed by a benign level of ROS in the second phase for wound regeneration. To this end, ultra‐small manganese oxide nanodots (BM‐NDs) are incorporated into a gelatin methacrylamide (GelMA) hydrogel via a ROS‐responsive linker to form GelMA@BM dressing. The BM‐NDs catalyze a self‐cascade reaction that decomposes glucose into hydrogen peroxide, generates hydroxyl radicals (·OH), and simultaneously depletes glutathione. Upon application on diabetic wounds, BM‐NDs are rapidly released from the hydrogel due to endogenous ROS exposure, leading to high levels of ·OH that effectively eliminate bacteria and promote macrophage polarization to M1 phenotype, thereby facilitating phagocytosis of bacteria. With the consumption of glucose and degradation of BM‐NDs, ROS in the wound area declines to a benign level, which stimulates polarization of M2 macrophages and promotes wound healing. This two‐phase treatment strategy based on GelMA@BM dressing demonstrates potent antibacterial and pro‐healing efficacy, showcasing its potential for clinical translation. [ABSTRACT FROM AUTHOR]

Fluorescent probes are essential for single‐molecule imaging. However, their application in biological systems is often limited by the short photobleaching lifetime. To overcome this, we developed a novel thiolation strategy for squaraine dyes. By introducing thiolation of the central cyclobutene of squaraine (thio‐squaraine), we observed a ≈5‐fold increase in photobleaching lifetime. Our single‐molecule data analysis attributes this improvement to improved photostability resulting from thiolation. Interestingly, bulk measurements show rapid oxidation of thio‐squaraine to its oxo‐analogue under irradiation, giving the perception of inferior photostability. This discrepancy between bulk and single‐molecule environments can be ascribed to the factors in the latter, including larger intermolecular distances and restricted mobility, which reduce the interactions between a fluorophore and reactive oxygen species produced by other fluorophores, ultimately impacting photobleaching and photoconversion rate. We demonstrate the remarkable performance of thio‐squaraine probes in various imaging buffers, such as glucose oxidase with catalase (GLOX) and GLOX+trolox. We successfully employed these photostable probes for single‐molecule tracking of CD56 membrane protein and monitoring mitochondria movements in live neurons. CD56 tracking revealed distinct motion states and the corresponding protein fractions. This investigation is expected to propel the development of single‐molecule imaging probes, particularly in scenarios where bulk measurements show suboptimal performance. [ABSTRACT FROM AUTHOR]

The article explores the concept of "Human-on-Chip" (HoC) technology, which is a miniature version of the human body within a microfluidic device. HoC allows researchers to study diseases, test drugs, and develop personalized treatments by integrating multiple organ-on-a-chip systems into a single platform. It is considered a more ethical, accurate, and reliable platform for experimentation compared to traditional methods such as cell cultures and animal testing. The article discusses the current state and future challenges of HoC technology, highlighting its potential in drug discovery, personalized medicine, reduction in animal testing, disease modeling, and safety testing. However, it also acknowledges the technical hurdles and the need for collaboration between researchers, healthcare professionals, and regulatory bodies to fully realize the potential of HoC technology. The document provides a list of references for further research on the topic, covering various scientific journals that discuss the development and applications of organs-on-chips in drug screening, disease modeling, and personalized medicine. It also highlights the potential of organs-on-chips in addressing rare diseases and the challenges and solutions in the field. [Extracted from the article]

The demand for the ubiquitous detection of gases in complex environments is driving the design of highly specific gas sensors for the development of the Internet of Things, such as indoor air quality testing, human exhaled disease detection, monitoring gas emissions, etc. The interaction between analytes and bioreceptors can described as a "lock-and-key", in which the specific catalysis between enzymes and gas molecules provides a new paradigm for the construction of high-sensitivity and -specificity gas sensors. The electrochemical method has been widely used in gas detection and in the design and construction of enzyme-based electrochemical gas sensors, in which the specificity of an enzyme to a substrate is determined by a specific functional domain or recognition interface, which is the active site of the enzyme that can specifically catalyze the gas reaction, and the electrode–solution interface, where the chemical reaction occurs, respectively. As a result, the engineering design of the enzyme electrode interface is crucial in the process of designing and constructing enzyme-based electrochemical gas sensors. In this review, we summarize the design of enzyme-based electrochemical gas sensors. We particularly focus on the main concepts of enzyme electrodes and the selection and design of materials, as well as the immobilization of enzymes and construction methods. Furthermore, we discuss the fundamental factors that affect electron transfer at the enzyme electrode interface for electrochemical gas sensors and the challenges and opportunities related to the design and construction of these sensors. [ABSTRACT FROM AUTHOR]

We propose a glucose‐powered Janus nanomotor where two faces are functionalized with glucose oxidase (GOx) and polydopamine‐Fe3+ chelates (PDF), respectively. In the glucose fuel solution, the GOx on the one side of these Janus nanomotors catalytically decomposes glucose fuels into gluconic acid and hydrogen peroxide (H2O2) to drive them at a speed of 2.67 μm/s. The underlying propulsion mechanism is the glucose‐based self‐diffusiophoresis owing to the generated local glucose concentration gradient by the enzymatic reaction. Based on the enhanced diffusion motion, such nanomotors with catalytic activity increase the uptake towards cells and subsequently exhibit excellent capabilities for Fe3+ ions delivery and H2O2 generation for enhancing ferroptosis efficiency for inducing cancer cell death. In particular, the Fe3+ ions are released from nanomotors in a slightly acidic environment, and subsequently generate toxic hydroxyl radicals via Fenton reactions, which accumulation reactive oxygen species (ROS) level (~300 %) and further lipid peroxidation (LPO) strengthened ferroptosis therapy for cancer treatment. The as‐developed glucose‐powered Janus nanomotor with efficient diffusion and Fe ions delivery capabilities show great promise as a potential in biomedical applications. [ABSTRACT FROM AUTHOR]

In this work, the β-cyclodextrins (βCD) grafted on magnetite@polynorepinephrine (Fe3O4@PNE) nanomaterial with glucose oxidase (GOx) from Aspergillus niger was presented. The electroactive nanoplatform was used to construct rapid response and long-live time biosensor for qualitative and quantitative glucose determination. The nanomaterial was deposited on the screen-printed electrode (SPE) and integrated with the potentiostat in tandem with a portable devices. The methodology may affect its relatively low unit cost, miniaturization aspect, and electrode system integrity. The potential usage is intended for advanced diabetes care with a focus on the point-of-care testing idea. The cyclic voltammetry and amperometry were used for electrochemical characterization. The presented SPE/Fe3O4@PNE@βCD-GOx biosensor enabled measurements in a wide range of concentrations (0.1–30.0 mM), an enhanced sensitivity (204.82 µA mM− 1 cm− 2), a low limit of detection (3.2 µM), and a rapid response (2.6 s). Moreover, the proposed sensor achieved long-term stability, up to 11 months. Testing on real samples (human blood, human serum, infusion fluids) showed recovery in range from 95.5 to 98.6%. The outcomes demonstrated that this biosensor has great potential for use in determining the amount of glucose in a biological fluids and commercial products. The novelty of this work would largely consist of the possibility of qualitative and quantitative measurements of glucose in real human samples with a long time stability. This portable system enables mobile diagnostics tests including point-of-care testing idea. Due to the applied β-cyclodextrins on the surface of the novel polynorepinephrine biopolymer coating, selectivity, stability, and sensitivity were improved. [ABSTRACT FROM AUTHOR]

Phototherapies induced by photoactive nanomaterials have inspired and accentuated the importance of nanomedicine in cancer therapy in recent years. During these light-activated cancer therapies, a nanoagent can produce heat and cytotoxic reactive oxygen species by absorption of light energy for photothermal therapy (PTT) and photodynamic therapy (PDT). However, PTT is limited by the self-protective nature of cells, with upregulated production of heat shock proteins (HSP) under mild hyperthermia, which also influences PDT. To reduce HSP production in cancer cells and to enhance PTT/PDT, small HSP inhibitors that can competitively bind at the ATP-binding site of an HSP could be employed. Alternatively, reducing intracellular glucose concentration can also decrease ATP production from the metabolic pathways and downregulate HSP production from glucose deprivation. Other than reversing the thermal resistance of cancer cells for mild-temperature PTT, an HSP inhibitor can also be integrated into functionalized nanomaterials to alleviate tumor hypoxia and enhance the efficacy of PDT. Furthermore, the co-delivery of a small-molecule drug for direct HSP inhibition and a chemotherapeutic drug can integrate enhanced PTT/PDT with chemotherapy (CT). On the other hand, delivering a glucose-deprivation agent like glucose oxidase (GOx) can indirectly inhibit HSP and boost the efficacy of PTT/PDT while combining these therapies with cancer starvation therapy (ST). In this review, we intend to discuss different nanomaterial-based approaches that can inhibit HSP production via ATP regulation and their uses in PTT/PDT and cancer combination therapy such as CT and ST. [ABSTRACT FROM AUTHOR]

In this work, we investigated the effect of multi-walled carbon nanotubes (MWCNTs) and bio-graphene (bG) on the structure and activity of glucose oxidase (GOx), as well as on the performance of the respective electrochemical glucose biosensors. Various spectroscopic techniques were applied to evaluate conformational changes in GOx molecules induced by the presence of MWCNTs and bG. The results showed that MWCNTs induced changes in the flavin adenine dinucleotide (FAD) prosthetic group of GOx, and the tryptophan residues were exposed to a more hydrophobic environment. Moreover, MWCNTs caused protein unfolding and conversion of α-helix to β-sheet structure, whereas bG did not affect the secondary and tertiary structure of GOx. The effect of the structural changes was mirrored by a decrease in the activity of GOx (7%) in the presence of MWCNTs, whereas the enzyme preserved its activity in the presence of bG. The beneficial properties of bG over MWCNTs on GOx activity were further supported by electrochemical data at two glucose biosensors based on GOx entrapped in chitosan gel in the presence of bG or MWCNTs. bG-based biosensors exhibited a 1.33-fold increased sensitivity and improved reproducibility for determining glucose over the sweat-relevant concentration range of glucose. [ABSTRACT FROM AUTHOR]

[Display omitted] Microgel–enzyme coatings were fabricated onto graphite substrates (highly oriented pyrolytic graphite or graphite- based screen-printed electrodes) via two-stage sequential procedure, which consists in adsorption of a pH- and temperature-sensitive copolymer microgel, followed by electrostatic immobilization of glucose oxidase into the microgel film. The microgel–enzyme coatings were examined by means of atomic force microscopy showing remarkable coverage of graphite surface by the microgels and visualizing the immobilized enzyme. Finally, amperometry was applied to reveal the effect of the polymeric (microgel) matrix on temperature behavior of glucose oxidase in the microgel– enzyme coatings. [ABSTRACT FROM AUTHOR]

Various sensors and electronic devices are recently developed to monitor human health in mechanically flexible or even stretchable forms for intimate contact with non‐flat curvilinear surfaces of the human body. For successful operation of these devices, finding a proper way to electrically power them is very important. In this work, glucose/oxygen fueled enzymatic biofuel cells (EBFCs) based on microfluidic structured elastomeric polydimethylsiloxane substrate with wrinkled gold (Au) electrodes are suggested for power supply. For doing that, firstly, bottom surface of microfluidic channel is covered with buckled Au electrodes for stretchability. By microfluidic design showing capillary imbibition through fluidic channels, loading of catalyts is promoted. Interestingly, buckled Au electrodes induce much better anodic and cathodic reaction rates than those of non‐buckled Au electrodes by 25% and 33%, respectively. This is because surface area and the amount of catalyst loading in electrodes increase by Au wrinkling. In evaluations of EBFCs using the buckled Au electrodes, maximum power density reaches 7.1 ± 0.64 µW cm−2, while they show decent performance of 5.4 ± 0.49 µW cm−2 even under external stretching. Taken together, it is corroborated that such proposed stretchable EBFCs are alternative for providing electrical power in wearable or implantable devices. [ABSTRACT FROM AUTHOR]

A novel and self referenced multi-analyte Hybrid Plasmonic Dual Grating Biosensor is proposed. The grating structure is composed of gold and corrugations are filled with dielectric ZnS. A thin layer of ZnS with slit is spread over grating thus making it dual grating structure. The influence of convexing of slit walls is modeled by parameter alpha in analytical equation. The reflectance characteristics are rigorously investigated using wavelength interrogation method for different values of parameter alpha, it is observed that wavelength varies from 722.2 to 729.6 nm for surface refractive index in the slit varying from 1.3 to 1.4 respectively at alpha equal to 0. The surface sensitivity obtained is about 74 nm/RIU. The surface sensitivity is also investigated by intensity interrogation and is equal to 0.2637 R/RIU or 26.37% R/RIU. It is observed that for higher values of alpha, the sensor is ideal for sensing gaseous analytes while at lower values of alpha can be used for liquid analytes. Refractive index range of surface analyte is correlated with the refractive index of blood by using linear refractive index model and Gladstone-Dale law for blood. It is observed that for alpha equal to 0, the grating biosensor can be used for invasive blood glucose monitoring with very high sensitivity of about 0.02641 nm/mg/dl. Linear regression model relating blood glucose and salivary glucose is used. The proposed sensor can also be used for noninvasive salivary glucose monitoring with surface sensitivity of 0.7410 nm/mg/dl. [ABSTRACT FROM AUTHOR]

Magnetic nanoparticles (MNPs) are promising in tumor treatments due to their capacity for magnetic hyperthermia therapy (MHT), chemodynamic therapy (CDT), and immuno-related therapies, but still suffer from unsatisfactory tumor inhibition in the clinic. Insufficient hydrogen peroxide supply, glutathione-induced resistance, and high-density extracellular matrix (ECM) are the barriers. Herein, we hierarchically decorated MNPs with disulfide bonds (S-S), dendritic L-arginine (R), and glucose oxidase (GOx) to form a nanosystem (MNPs-SS-R-GOx). Its outer GOx layer not only enhanced the H 2 O 2 supply to produce .OH by Fenton reaction, but also generated stronger oxidants (ONOO−) together with the interfaced R layer. The inner S-S layer consumed glutathione to interdict its reaction with oxidants, thus enhancing CDT effects. Importantly, the generated ONOO− tripled the MMP-9 expression to induce ECM degradation, enabling much deeper penetration of MNPs and benefiting CDT, MHT, and immunotherapy. Finally, the MNPs-SS-R-GOx demonstrated a remarkable 91.7% tumor inhibition in vivo. Magnetic nanoparticles (MNPs) are a promising tumor therapeutic agent but with limited effectiveness. Our hierarchical MNP design features disulfide bonds (S-S), dendritic L-arginine (R), and glucose oxidase (GOx), which boosts H 2 O 2 supply for ·OH generation in Fenton reactions, produces potent ONOO−, and enhances chemodynamic therapy via glutathione consumption. Moreover, the ONOO− facilitates the upregulation of matrix metalloprotein expression beneficial for extracellular matrix degradation, which in turn enhances the penetration of MNPs and benefits the antitumor CDT/MHT/immuno-related therapy. In vivo experiments have demonstrated an impressive 91.7% inhibition of tumor growth. This hierarchical design offers groundbreaking insights for further advancements in MNP-based tumor therapy. Its implications extend to a broader audience, encompassing those interested in material science, biology, oncology, and beyond. [Display omitted] [ABSTRACT FROM AUTHOR]

Immunotherapy is an emerging treatment modality for tumors after surgery, radiotherapy, and chemotherapy. Despite the potential for eliminating primary tumor cells and depressing cancer metastasis, immunotherapy has huge challenges including low tumor immunogenicity and undesirable immunosuppressive tumor microenvironment (TME). Herein, the two-pronged microenvironmental modulation nanoplatform is developed to overcome these limitations. Specifically, hollow mesoporous MnO 2 (HM) nanoparticles with pH responsive property are prepared and modified with glucose oxidase (GOX) by amide bond, which are further loaded with a potent glutaminase inhibitor CB839 to obtain HM-GOX/CB839. Under the low pH values in TME, HM was disintegrated, thereby releasing Mn2+, GOX and CB839. On the one hand, Mn2+ can convert H 2 O 2 that increased by GOX catalysis in tumors into highly toxic hydroxyl radicals (•OH) and further induce immunogenic cell death (ICD) through the metal-oxidase cascade catalytic reaction, enhancing immunogenicity. On the other hand, GOX and CB839 can block glycolytic and glutamine metabolism pathways, respectively, which effectively reduce the number of immunosuppressive cells and reshape TME, improving anti-tumor immune efficacy. It is demonstrated that HM-GOX/CB839 can effectively activate the body's immunity and inhibit tumor growth and metastasis, providing a potential strategy for comprehensive tumor therapy. Integrated microenvironmental modulation of metal-oxidase cascade catalysis and metabolic intervention offers a potential avenue for tumor immunotherapy. Under this premise, we constructed a two-pronged microenvironmental modulation nanoplatform (HM-GOX/CB839). On the one hand, the metal oxidase cascade could catalyze the generation of hydroxyl radicals (•OH) and induce immunogenic cell death (ICD), enhancing immunogenicity; on the other hand, metabolic intervention reprogrammed tumor microenvironment to relieve immunosuppression and thereby enhancing anti-tumor immune response. The resulting data demonstrated that HM-GOX/CB839 effectively inhibited tumor growth and metastasis, providing therapeutic potential for cancer immunotherapy. [Display omitted] [ABSTRACT FROM AUTHOR]

Methods for culturing oxygen‐sensitive cells and organisms under anaerobic conditions are vital to biotechnology research. Here, we report a biomaterial‐based platform for anaerobic culture that consists of glucose oxidase (GOX) functionalized alginate microparticles (ALG‐GOX), which are designed to deplete dissolved [O2] through enzymatic activity. ALG‐GOX microparticles were synthesized via a water‐in‐oil emulsion and had a size of 132.0 ± 51.4 µm. Despite having a low storage modulus, the microparticles remained stable under aqueous conditions due to covalent crosslinking through amide bonds. Enzyme activity was tunable based on the loaded GOX concentration, with a maximum activity of 3.6 ± 0.3 units/mg of microparticles being achieved at an initial loading concentration of 5 mg/mL of GOX in alginate precursor solution. High enzyme activity in ALG‐GOX microparticles resulted in rapid oxygen depletion, producing a suitable environment for anaerobic culture. Microparticles loaded with both GOX and catalase (ALG‐GOX‐CAT) to reduce H2O2 buildup exhibited sustained activity for potential long‐term anaerobic culture. ALG‐GOX‐CAT microparticles were highly effective for the anaerobic culture of Bacteroides thetaiotaomicron, with 10 mg/mL of ALG‐GOX‐CAT microparticles supporting the same level of growth in an aerobic environment compared to an anaerobic chamber after 16 h (8.70 ± 0.96 and 10.03 ± 1.03 million CFU, respectively; N.S. p = 0.07). These microparticles could be a valuable tool for research and development in biotechnology. [ABSTRACT FROM AUTHOR]

Electrophoretic deposition is a powerful tool for depositing materials onto a substrate by using an electric field; its application in biotechnological areas, namely, electrophoretic protein deposition (EPD), is the most promising for, e.g., fabricating novel amperometric biosensors. Unfortunately, EPD suffers from several drawbacks due to coupled parasite electrochemical processes damaging the deposit; moreover, the nature of the deposition process, the deposit, and its stability are still controversial and unknown. The present research presents a deep investigation of the EPD processes conducted by using several electroanalytical techniques and an electrochemical quartz crystal microbalance (EQCM); notably, EPD was used here as a novel tool for performing an electrophoretically assisted, classical enzyme immobilization technique like co-crosslinking, thus permitting the immobilization of the desired protein in situ, i.e., exclusively onto the deposition electrode. An electrochemical study permitted the acquisition of useful insights about electrophoresis processes as well as solvent discharge and gas evolution at the deposition electrode; further, the use of appropriate current or potential pulse sequences, as investigated and improved in this study, together with fine-tuned chemical conditions, allowed the optimization of this novel EPD approach. Moreover, an EQCM study gave useful insights into the kinetics of the process, permitting a quantitative estimate of the deposit. [ABSTRACT FROM AUTHOR]

A novel Fe2+/Tyr/H2O2 fluorescence reaction system has been established for the purpose of analyzing glucose oxidase activity. This system involves the catalysis of glucose oxidase on glucose to produce H2O2, which in turn oxidizes tyrosine to a highly fluorescent substance under the catalysis of Fe2+. The fluorescence intensity is subsequently employed to ascertain the enzymatic activity of glucose oxidase. The enzymatic oxidation reaction and tyrosine fluorescence reaction conditions were optimized based on the H2O2 standard curve equation. Direct fluorescence spectrophotometry was used to determine the activity range and detection limit of glucose oxidase, which were found to be 7.00 × 10−5–7.00 × 10−2 U/mL and 3.36 × 10−5 U/mL (Enzyme-like activity is 6.72 × 10−4 U/mL, The enzyme reaction time is 5 min), respectively, with a relative standard deviation of less than 3.2 %. This method has been successfully applied to determine the activity of glucose oxidase in food additives, with a recovery rate ranging from 96.00 % to 102.0 %.

We have designed an extended‐gate thin‐film transistor (EG‐TFT) enzyme sensor for the detection of glucose. The device is composed of a surface‐modified microneedle working electrode incorporating glucose oxidase (GOx) and Prussian blue (PB) alongside a reference electrode. The electrodes are connected to the gate and source of a transistor, respectively. The TFT structure of the device has a bottom gate and an insulating layer which protects the active layer. This system can bring higher sensitivity variation to conventional sensors, while combining with TFT to realize a more stable, integrated and flexible platform. By combining with microneedles to detect glucose in interstitial fluids for minimally invasive medical testing, the system successfully verified that there are different transistor current variations for different glucose concentrations. This platform will ultimately help to open up endless possibilities for effective healthcare and accurate clinical decision making. [ABSTRACT FROM AUTHOR]

Zhijun Zhang,1,2 Tiehong Yang,2 Jingwei Wang,2 Zhe Yu,2 Youbei Qiao,2 Chaoli Wang,2 Zhenggang Yue,1 Hong Wu2 1School of Pharmacy, Shaanxi University of Chinese Medicine, Xi’an, People’s Republic of China; 2Department of Medicine Chemistry and Pharmaceutical Analysis, School of Pharmacy, Air Force Medical University, Xi’an, People’s Republic of ChinaCorrespondence: Hong Wu, Department of Medicine Chemistry and Pharmaceutical Analysis, School of Pharmacy, Air Force Medical University, Xi’an, People’s Republic of China, Tel/Fax +86 29 84776823, Email wuhong@fmmu.edu.cn Zhenggang Yue, School of Pharmacy, Shaanxi University of Chinese Medicine, Xi’an, People’s Republic of China, Tel +86 18092086211, Email liuxingjian1981@163.comPurpose: The remarkable peroxidase-like activity of single-atom nanozymes (SAzymes) allows them to catalyze the conversion of H2O2 to •OH, rendering them highly promising for antibacterial applications. However, their practical in vivo application is hindered by the near-neutral pH and insufficient H2O2 levels present in physiological systems. This study was aimed at developing a SAzyme-based nanoreactor and investigating its in vivo antibacterial activity.Methods: We developed a hollow mesoporous molybdenum single-atom nanozyme (HMMo-SAzyme) using a controlled chemical etching approach and pyrolysis strategy. The HMMo-SAzyme not only exhibited excellent catalytic activity but also served as an effective nanocarrier. By loading glucose oxidase (GOx) with HMMo-SAzyme and encapsulating it with hyaluronic acid (HA), a nanoreactor (HMMo/GOx@HA) was constructed as glucose-triggered cascade catalyst for combating bacterial infection in vivo.Results: Hyaluronidase (HAase) at the site of infection degraded HA, allowing GOx to convert glucose into gluconic acid and H2O2. An acid environment significantly enhanced the catalytic activity of HMMo-SAzyme to promote the further catalytic conversion of H2O2 to •OH for bacterial elimination. In vitro and in vivo experiments demonstrated that the nanoreactor had excellent antibacterial activity and negligible biological toxicity.Conclusion: This study represents a significant advancement in developing a cascade catalytic system with high efficiency based on hollow mesoporous SAzyme, promising the advancement of biological applications of SAzyme. Keywords: nanozyme, nanocarrier, glucose oxidase, reactive oxygen species, bacterial infection

Guiqiang Qi,1 Guangyue Shi,1 Shengchao Wang,1 Haifeng Hu,2 Zhichen Zhang,1 Qiangqiang Yin,1 Zhongtao Li,1 Liguo Hao1,3 1Department of Molecular Imaging, School of Medical Technology, Qiqihar Medical University, Qiqihar, Heilongjiang, 161006, People’s Republic of China; 2Medical Imaging Center, The Second Affiliated Hospital of Qiqihar Medical University, Qiqihar, Heilongjiang, 161000, People’s Republic of China; 3Department of Molecular Imaging, The First Affiliated Hospital of Qiqihar Medical University, Qiqihar, Heilongjiang, 161041, People’s Republic of ChinaCorrespondence: Liguo Hao, Email haoliguo@qmu.edu.cnIntroduction: This study developed a pancreatic cancer targeted drug delivery system that responds to changes in acidity. The system was based on iron oxide core-shell magnetic mesoporous silica nanoparticles (M-MSNs) to treat pancreatic cancer through combined chemotherapy and starvation therapy.Methods: Glucose oxidase (Gox) was coupled to the cancer cell surface to reduce glucose availability for cancer cells, exacerbating the heterogeneity of the tumor microenvironment. Reduced pH accelerated the depolymerization of pH-sensitive polydopamine (PDA), thereby controlling the spatial distribution of Gox and release of doxorubicin (DOX) within tumor cells.Results: Characterization results showed the successful synthesis of DG@M-MSN-PDA-PEG-FA (DG@NPs) with a diameter of 66.02 ± 3.6 nm. In vitro data indicated DG@NPs were highly effective and stable with good cellular uptake shown by confocal laser scanning microscopy (CLSM). DG@NPs exhibited high cytotoxicity and induced apoptosis. Additionally, in vivo experiments confirmed DG@NPs effectively inhibited tumor growth in nude mice with good biosafety. The combination of starvation therapy and chemotherapy facilitated drug release, suggesting DG@NPs as a novel drug delivery system for pancreatic cancer treatment.Conclusion: This study successfully constructed a doxorubicin release system responsive to acidity changes for targeted delivery in pancreatic cancer, providing a new strategy for combination therapy.Keywords: mesoporous silica nanoparticle, drug delivery, multitherapy modality, magnetic resonance imaging, glucose oxidase

Abstract Cancer has always posed a significant threat to human health, prompting extensive research into new treatment strategies due to the limitations of traditional therapies. Starvation therapy (ST) has garnered considerable attention by targeting the primary energy source, glucose, utilized by cancer cells for proliferation. Glucose oxidase (GOx), a catalyst facilitating glucose consumption, has emerged as a critical therapeutic agent for ST. However, mono ST alone struggles to completely suppress tumor growth, necessitating the development of synergistic therapy approaches. Metal catalysts possess enzyme-like functions and can serve as carriers, capable of combining with GOx to achieve diverse tumor treatments. However, ensuring enzyme activity preservation in normal tissue and activation specifically within tumors presents a crucial challenge. Nanodelivery systems offer the potential to enhance therapy effectiveness by improving the stability of therapeutic agents and enabling controlled release. This review primarily focuses on recent advances in the mechanism of GOx combined with metal catalysts for synergistic tumor therapy. Furthermore, it discusses various nanoparticles (NPs) constructs designed for synergistic therapy in different carrier categories. Finally, this review provides a summary of GOx-metal catalyst-based NPs (G-M) and offers insights into the challenges associated with G-M therapy, delivery design, and oxygen (O2) supply.

The intricate relationships between plants and insects are essential for understanding ecological dynamics. Among these interactions, HIPVs serve as a pivotal defense mechanism. Our findings reveal the highly conserved nature of the GOX gene within the Lepidoptera order, highly expressed in the salivary glands of S. frugiperda, and its role in mediating maize’s defense responses. Notably, salivary GOX activity expression significantly decreases subsequent gene knockout. The presence of GOX in the saliva of S. frugiperda significantly modulates the emission of HIPVs during maize consumption. This research delineates that GOX selectively inhibits the emission of certain green leaf volatiles (GLVs) while concurrently enhancing the release of terpene volatiles. This study unveils a novel mechanism whereby S. frugiperda utilizes GOX proteins in OS to modulate volatile emissions from maize, offering fresh perspectives on the adaptive evolution of phytophagous insects and their interactions with their preferred host plants.

Disrupting intracellular redox homeostasis combined with immune checkpoint blockade therapy is considered as an effective way to accelerate tumor cell death. However, suppressed tumor immune microenvironment and lower cargo delivery restrict the efficiency of tumor therapy. In this study, a multifunctional tumor microenvironment (TME)‐responsive nanocomposite is constructed using manganese tetroxide (Mn3O4)‐decorated disulfide‐bond‐incorporated dendritic mesoporous organosilica nanoparticles (DMONs) to co‐deliver indoleamine 2,3‐dioxygenase (IDO) inhibitor Epacadostat (IDOi) and glucose oxidase (GOx) following modification with polyethylene glycol. Owing to the responsiveness of Mn3O4‐decorated DMONs to the mildly acidic and glutathione (GSH) overexpressed TME, the nanocomposite can rapidly decompose and release inner contents, thus substantially improving the cargo release ability. Mn3O4 can effectively catalyze hydrogen peroxide (H2O2) decomposition to generate oxygen, enhance the ability of GOx to consume glucose to produce H2O2, and further promote the generation of hydroxyl radicals (•OH) by Mn2+. Furthermore, Mn2+‐mediated GSH depletion and the production of •OH can disrupt intracellular redox homeostasis, contributing to immunogenic cell death. Simultaneously, IDOi can inhibit IDO to reverse inhibited immune response. The results show that self‐amplifying chemodynamic/starvation therapy combined IDO‐blockade immunotherapy synergistically inhibits tumor growth and metastasis in vivo. [ABSTRACT FROM AUTHOR]

Numerous studies have been done to advance the development of efficient, simple, and cheap sensors, especially for glucose, which are important in the pharmaceutical and food industries. The most common sensors and biosensors used today are based on electrochemistry. The novelty of this study is the use of dip‐pen nanolithography (DPN) in order to pattern a mixture of glucose oxidase with PMMA as nanoclusters and develop meta‐chemical surface (MCS), which leads to highly efficient working electrodes with increased detection sensitivity compared to the today‐known glucose sensors (∼1×10-9 ${\sim 1\times 1{0}^{-9}}$ M was detected in the current study). Our novel and important results support the feasibility of using DPN to develop sensors on various electrode surfaces patterned with different active species, especially in systems requiring target substance detection over large concentration ranges. [ABSTRACT FROM AUTHOR]

Laser‐inducing provides a cost‐effective, easily‐manufacturable, and environment‐friendly approach to directly transfer carbon‐rich polymers into graphene materials, which attracts attention from various fields, such as sensors, electrocatalysts, micro‐supercapacitors, etc. Laser‐induced graphene (LIG) benefits from the intrinsic properties of graphene, for example, high conductivity, high electroactivity, and high specific area. In this work the potential of laser‐induced graphene in constructing an enzymatic electrochemical biosensing interface is evaluated. Here, a laminar‐structured laser‐induced graphene material is fabricated by laser engraving with polyimide. After deposition of the electron mediator ferrocene, a conjugated enzyme complex of bovine serum albumin‐glucose oxidase (BSA‐GOx) is modified on the laser‐induced graphene by cross‐linking. The fabricated glucose oxidase/ferrocene/LIG (GOx/Fc/LIG) biosensor achieves high sensitivity of 11.3 µA mM−1 cm−2), wide linear range of 0–11 mM, and low detection of limit of 0.04 µM. The LIG electrodes exhibit high flexibility with bending angle as high as 60° without observed conductivity change. The repeatability and robustness of the developed LIG biosensor in detection of real serum samples empower it with great potential in clinical implementation in the future. [ABSTRACT FROM AUTHOR]

Designing unique nanomaterials for the selective sensing of biomolecules is of significant interest in the field of nanobiotechnology. In this work, we demonstrated the synthesis of ordered Cu nanoparticle‐functionalised mesoporous C3N5 that has unique peroxidase‐like nanozymatic activity for the ultrasensitive and selective detection of glucose and glutathione. A nano hard‐templating technique together with the in‐situ polymerisation and self‐assembly of Cu and high N‐containing CN precursor was adopted to introduce mesoporosity as well as high N and Cu content in mesoporous C3N5. Due to the ordered structure and highly dispersed Cu in the mesoporous C3N5, a large enhancement of the peroxidase mimetic activity in the oxidation of a redox dye in the presence of hydrogen peroxide could be obtained. Additionally, the optimised Cu‐functionalised mesoporous C3N5 exhibited excellent sensitivity to glutathione with a low detection limit of 2.0 ppm. The strong peroxidase activity of the Cu‐functionalised mesoporous C3N5 was also effectively used for the sensing of glucose with a detection limit of 0.4 mM through glucose oxidation with glucose oxidase. This unique Cu‐functionalised mesoporous C3N5 has the potential for detecting various molecules in the environment as well as for next‐generation glucose and glutathione diagnostic devices. [ABSTRACT FROM AUTHOR]

A sensitive glucose colorimetric detection system (Au@QCM) based on quaternized cellulose membrane (QCM) and enzyme‐mimicking Au nanoparticles (AuNPs) was successfully developed via a simple molecular self‐assembly strategy. The positively charged QCM functioned as a template to guide the negatively charged citric acid‐reduced AuNPs uniformly distributed on the surfaces along the pore walls of its porous structure, and thus gave AuNPs an ordered interconnected three‐dimensional network. This electrostatic interaction could effectively prevent the aggregation of the AuNPs and greatly increase their exposed surface area, thus endow the Au@QCM with highly active catalytic properties towards glucose oxidation with glucose oxidase (GOx). The experimental studies showed that the color change of redox indicator 3,3′,5,5′‐tetramethylbenzidine (TMB) can be clearly observed with naked eyes and the absorbance of the oxidized TMB (at 653 nm) was directly proportional to the concentration of glucose. Au@QCM could achieve a sensitive glucose detection with a limit of detection of 0.55 μM and linear response in the range of 0.01–0.5 mM. Besides, it also had good applicability in real samples detection and excellent selectivity to glucose. This novel detection system significantly improved detection performance compared to previous work based on cellulose‐based strips loaded with GOx and horseradish peroxides. [ABSTRACT FROM AUTHOR]

This research investigated the possibility of using the method of adding an additional enzyme to a monoenzyme oxidase‐based biosensor to improve the biosensor's analytical characteristics. Namely, the catalase (CAT) was used to better saturate the biomembrane with oxygen for the best glucose oxidase (GOx) performance. For this purpose, two different biosensors were created – based on one enzyme (GOx) and two (GOx and CAT). To create a bioselective membrane, the method of covalent binding in vapors of glutaraldehyde was used. The method of coimmobilization of catalase (CAT) and glucose oxidase (GOx) enzymes, as well as the concentration of enzymes in the mixture, was chosen in the work. The stability of the biosensor functioning, i. e. the repeatability during measurements and the reproducibility of the biosensors' preparation, were investigated. Analytical characteristics of the proposed biosensor were studied in comparison with a monoenzyme biosensor based on glucose oxidase only. It was shown that the addition of catalase as an auxiliary enzyme significantly improves the analytical characteristics of the biosensor, in particular, the sensitivity, the repeatability of the measurement results, and the limits of the linear and dynamic ranges of operation. The developed method can be successfully used to optimize conductometric enzyme biosensors based on oxidases. [ABSTRACT FROM AUTHOR]

A polyclonal antibody against the analog of piperine, which is a typical pungent taste substance, was produced, and its binding ability to piperine was evaluated using a surface plasmon resonance sensor. The antibody was labeled with glucose oxidase (GOx), and the hydrogen ions produced by the enzymatic reaction were measured at a lipid polymer membrane electrode for sourness in a taste sensor. The results showed that piperine could be detected by that polyclonal antibody; the response of the sourness sensor increased in dependence on the GOx‐labeled antibody concentration when the GOx of GOx‐labeled antibody was reacted with glucose. Thus, it was shown that uncharged pungent compounds can be converted into hydrogen ions. Pungent taste can be measured by the taste sensor using GOx‐labeled antibodies, and GOx‐labeled antibodies can be used as a pretreatment. [ABSTRACT FROM AUTHOR]

Schematic representation for the study of DMSN@Cu-CeO 2 @GOx in regulating the level of H 2 O 2 , glucose and oxygen. [Display omitted] Imbalances in the intracellular environment caused by high levels of glucose, H 2 O 2 , and hypoxia can greatly impact cancer development and treatment. However, there is limited research on regulating the levels of these species simultaneously in tumor cells. Here, a pH-responsive nanozyme-enzyme hybrid system was developed to regulate intracellular glucose, H 2 O 2 and O 2. The system, named DMSN@Cu-CeO 2 @GOx, consists of Cu-CeO 2 nanoparticles and glucose oxidase (GOx) immobilized in dendritic mesoporous silica (DMSN) spheres. GOx efficiently consumes glucose in tumor cells, causing a drop in pH and producing a significant amount of H 2 O 2. Cu-CeO 2 then catalyzes the conversion of H 2 O 2 to O 2 due to its high catalase-like (CAT) activity in weakly acidic conditions. The process was monitored by fluorescence probes, and the mechanism was investigated through fluorescence spectroscopy and confocal laser scanning microscopy. The cascade catalytic system with excellent biocompatibility continuously consumes glucose and elevates the level of O 2 in cells. This hybrid nanomaterial offers a means to regulate the glucose/H 2 O 2 /O 2 levels in cells and may provide insights into starvation therapy by modulating reactive species within cells. [ABSTRACT FROM AUTHOR]

We synthesize a kind of UCNPs@PVP-GOx-PpIX-Fe3+ nanoreactors with rare earth upconversion nanoparticles as the substrate, which can absorb NIR light at 980 nm and convert low-energy photons into high-energy photons, so as to cleverly generating UV radiation induction in vivo , and finally enhance ferroptosis effect through the synergistic starvation/photodynamic therapies. [Display omitted] The limitations of light source limit the clinical application of optical therapy technology. How to improve the application efficiency of radiant light has become the focus of researchers. Here, we synthesize a kind of UCNPs@PVP-GOx-PpIX-Fe3+ (UPGPF) nanoreactors with rare earth upconversion nanoparticles (UCNPs) as the substrate for the enhancement of ferroptosis effect by the synergistic starvation/photodynamic therapies. Firstly, glucose oxidase (GOx) and Fe3+ loaded in UPGPF nanoreactors are used to directly face the problems of insufficient H 2 O 2 level in tumor tissue and low Fenton reaction efficiency. Further, UCNPs can absorb NIR light at 980 nm and convert low-energy photons into high-energy photons, thereby cleverly generating ultraviolet (UV) radiation induction in vivo , which can produce a synergistic effect of enhancing iron death. The in vivo experimental results of breast cancer model mice show that the UPGPF nanoreactors have significant anticancer effect and good biosafety. With the help of the optical conversion characteristics of UCNPs, this kind of treatment idea of building a UV radiation-induced microplatform in the tumor microenvironment, which leads to the synergistic enhancement of iron death effect, provides a promising innovative design strategy for tumor research. [ABSTRACT FROM AUTHOR]

A glucose oxidase-mimicking and peroxidase-mimicking dual-nanozymes catalytic cascade system with the capabilities of reshaping the pathological microenvironments of diabetic wound via glucose consumption and acidification is constructed for antibacterial and accelerating wound healing. [Display omitted] Diabetes-related chronic wounds characterized by hyperglycemia and weak alkaline milieu provide numerous advantages for bacteria growth and biofilm formation, setting a myriad of stumbling blocks for wound healing. Therefore, reshaping the spatially and temporally pathological wound microenvironment against bacterial infection is critical to rescue stalled healing progress in diabetes-related chronic wounds. Herein, we demonstrate on the room-temperature construction of a glucose oxidase (GOx)-mimicking and peroxidase (POD)-mimicking dual-nanozymes catalytic cascade system upon the partial reduction of Fe3+ to Fe2+ and the deposition of Au nanoparticles, simultaneously. The as-prepared dual-nanozymes catalytic cascade system possesses the capabilities of reshaping the pathological microenvironments of diabetic wound via glucose consumption and acidification, leading to amplified catalytic cascade activities for sterilization. On the one hand, the GOx-mimicking enzymatic activity of the catalytic cascade system can not only deplete glucose and acidize wound milieu to inhibit bacteria growth, but also utilize the weak alkaline milieu of diabetic wound to provide sufficient H 2 O 2 and a favorable pH for subsequent OH generation. On the other hand, the POD-mimicking enzymatic activity of the catalytic cascade system can continuously produce OH for sterilization under the weak acidic milieu in the presence of abundant H 2 O 2. Benefiting from the simply and mild preparation process and the excellent dual-nanozymes catalytic cascade activities under the deliberate evolved milieus of diabetes-related chronic wounds, our catalytic cascade system exhibits the promising healing effect and clinical translation potential against diabetic wound infection. [ABSTRACT FROM AUTHOR]

[Display omitted] One of the major challenges in effective cancer therapy arises because of the hypoxic microenvironment in the tumor. This compromises the efficacy of both chemo- and radiotherapy, and thus hinders patient outcomes. To solve this problem, we constructed polydopamine (PDA)-cloaked Fe-based metal organic frameworks (MOFs) loaded with d -arginine (d -Arg), glucose oxidase (GOX), and the chemotherapeutic drug tirapazamine (TPZ). These offer simultaneous multifaceted therapy combining chemodynamic therapy (CDT)/radiotherapy (RT)/starvation therapy (ST)/gas therapy (GT) and chemotherapy. The particles further can act as contrast agents in magnetic resonance imaging. GOX catalyses the conversion of endogenous glucose and O 2 to hydrogen peroxide and gluconic acid, blocking the cells' energy supply and providing ST. With the resultant acidification of the local environment, the breakdown of the MOF releases TPZ (for chemotherapy) and Fe3+, which reacts with H 2 O 2 to produce reactive oxygen species and thus stimulates the conversion of d -Arg to NO for GT and RT sensitization. The PDA coating not only seals the pores and chelates Fe3+ to enhance the T 1 -weighted magnetic resonance imaging (MRI) properties, but also is used to graft folate bovine serum albumin (FA-BSA) and thereby target the tumor site. The combined administration of low doses of X-ray irradiation and nanoparticles reduces the side effects on healthy tissue and can prevent lung metastases in mice. This work highlights the synergistic treatment of osteosarcoma via ST/GT/CDT/RT/MRI/ chemotherapy using a PDA-cloaked MOF system. [ABSTRACT FROM AUTHOR]

Glucose oxidase (GOD) immobilized poly(o-toluidine) (POT) coated Pt electrode was designed for glucose-sensitive biosensor. Since POT film structure affects enzyme activity, parameters of enzyme immobilization and POT synthesis conditions were optimized. Optimal monomer concentration for POT film synthesis was determined as 40 mM and the scanning rate was determined as 50 mV/s. As for the immobilization process results, GOD, glutaraldehyde (GAL) and chitosan (Chi) concentrations were decided as 2 mg/ml 0.10%, and 0.5% for the Pt/POT electrode. Zinc ferrite nanoparticle (ZnFe2O4NP) was immobilized together with POT film in the presence of GOD enzyme. It was revealed that ZnFe2O4NP increased the current responses and stability of the Pt/POT electrode. [ABSTRACT FROM AUTHOR]