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Yuan Yuan,1,* Mingyi Hou,2,* Xiaoning Song,1 Xintao Yao,1 Xuerui Wang,1 Xiangjun Chen,2 Shengnan Li1 1School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin, 300401, People’s Republic of China; 2School of Pharmacy, Shandong New Drug Loading & Release Technology and Preparation Engineering Laboratory, Binzhou Medical University, Yantai, 264003, People’s Republic of China*These authors contributed equally to this workCorrespondence: Shengnan Li; Xiaoning Song, School of Chemical Engineering and Technology, Hebei University of Technology, Xiping Road, Tianjin, 300401, People’s Republic of China, Email lisn027@hebut.edu.cn; songxn123@hebut.edu.cnBackground: With the rapid development of nanotechnology, constructing a multifunctional nanoplatform that can deliver various therapeutic agents in different departments and respond to endogenous/exogenous stimuli for multimodal synergistic cancer therapy remains a major challenge to address the inherent limitations of chemotherapy.Methods: Herein, we synthesized hollow mesoporous Prussian Blue@zinc phosphate nanoparticles to load glucose oxidase (GOx) and DOX (designed as HMPB-GOx@ZnP-DOX NPs) in the non-identical pore structures of their HMPB core and ZnP shell, respectively, for photothermally augmented chemo-starvation therapy.Results: The ZnP shell coated on the HMPB core, in addition to providing space to load DOX for chemotherapy, could also serve as a gatekeeper to protect GOx from premature leakage and inactivation before reaching the tumor site because of its degradation characteristics under mild acidic conditions. Moreover, the loaded GOx can initiate starvation therapy by catalyzing glucose oxidation while causing an upgradation of acidity and H2O2 levels, which can also be used as forceful endogenous stimuli to trigger smart delivery systems for therapeutic applications. The decrease in pH can improve the pH-sensitivity of drug release, and O2 can be supplied by decomposing H2O2 through the catalase-like activity of HMPBs, which is beneficial for relieving the adverse conditions of anti-tumor activity. In addition, the inner HMPB also acts as a photothermal agent for photothermal therapy and the generated hyperthermia upon laser irradiation can serve as an external stimulus to further promote drug release and enzymatic activities of GOx, thereby enabling a synergetic photothermally enhanced chemo-starvation therapy effect. Importantly, these results indicate that HMPB-GOx@ZnP-DOX NPs can effectively inhibit tumor growth by 80.31% and exhibit no obvious systemic toxicity in mice.Conclusion: HMPB-GOx@ZnP-DOX NPs can be employed as potential theranostic agents that incorporate multiple therapeutic modes to efficiently inhibit tumors. Keywords: Prussian Blue, glucose oxidase, co-delivery system, photothermal therapy, chemotherapy

AbstractIntegration of gold nanoparticles onto electrochemical biosensor electrodes has been widely conducted to improve the performance of biosensors. Gold nanospikes (AuNS), as one of the gold nanoparticle morphologies, can be integrated into biosensors through electrodeposition and has the potential to immobilize bioreceptor on biosensors using the self-assembled monolayer (SAM) method. This paper examines the potential of AuNS-deposited Screen-Printed Carbon Electrodes (SPCEs) on immobilizing enzymes as label-based electrochemical biosensor by evaluating the optimum parameter for glucose oxidase (GOx) enzyme immobilization on the SPCE that consists of incubation time and concentration of SAM molecule—L-cysteine—and GOx enzyme, then reviews its performances. The developed biosensor exhibits excellent performance in detecting glucose (linear range of 0.2–15 mM and limit of detection (LOD) of 116 µM), with good selectivity against uric acid, urea, ascorbic acid, dopamine, and lactic acid, and superiority towards gold nanosphere modified biosensor.

Gold nanoparticles (AuNPs) have great potential as biosensors for glucose detection due to their high sensitivity, as well as their extraordinary physical and chemical properties that improve compatibility with different biorecognition molecules, such as glucose oxidase (GOx). In this work the D-glucose quantification was determined by using the traditional technique based on biochemical reaction of GOx and AuNPs functionalized with polyvinylpirrolidone (PVP) polymer and the enzyme. The AuNPs-PVP-GOx nanocomplexes were characterized by ultraviolet-visible (UV-Visible), Infrared (FTIR), and Raman spectroscopies, as well as scanning electron microscopy (SEM), Z potential, dynamic light scattering (DLS), and thermogravimetry analysis (TGA). In general, these techniques showed significant differences after each functionalization stage with PVP and GOx, for instance it was observed: the presence of different functional groups, an increase of hydrodynamic diameter from 48.60 to 198.77 nm, a shift of the band absorption to larger wavelength, a change in the surface potential and weight loss, and in the morphology of the nanocomplex, which confirm the functionalization. In addition, the enzymatic activity of the AuNPs-PVP-GOx was confirmed through the detection of triiodide ions by UV-Visible spectrophotometry, coming from the oxidation reaction of iodide ions in the presence of H2O2. Furthermore, the nanocomplex synthesized by passive adsorption was evaluated as a possible biosensor for the quantification of D-glucose using a colorimetric assay, obtaining greater sensitivity than the traditional method. These findings indicate that PVP can be used as a linkage medium between AuNPs and GOx, which in turn can be used as a biosensor for the detection of D-glucose at low concentrations in biological fluids.

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.

Abstract Background The CRISPR/Cas9 technology is being employed as a convenient tool for genetic engineering of the industrially important filamentous fungus Trichoderma reesei. However, multiplex gene editing is still constrained by the sgRNA processing capability, hindering strain improvement of T. reesei for the production of lignocellulose-degrading enzymes and recombinant proteins. Results Here, a CRISPR/Cas9 system based on a multiple sgRNA processing platform was established for genome editing in T. reesei. The platform contains the arrayed tRNA−sgRNA architecture directed by a 5S rRNA promoter to generate multiple sgRNAs from a single transcript by the endogenous tRNA processing system. With this system, two sgRNAs targeting cre1 (encoding the carbon catabolite repressor 1) were designed and the precise deletion of cre1 was obtained, demonstrating the efficiency of sgRNAs processing in the tRNA−sgRNA architecture. Moreover, overexpression of xyr1-A824V (encoding a key activator for cellulase/xylanase expression) at the ace1 (encoding a repressor for cellulase/xylanase expression) locus was achieved by designing two sgRNAs targeting ace1 in the system, resulting in the significantly enhanced production of cellulase (up to 1- and 18-fold on the Avicel and glucose, respectively) and xylanase (up to 11- and 41-fold on the Avicel and glucose, respectively). Furthermore, heterologous expression of the glucose oxidase gene from Aspergillus niger ATCC 9029 at the cbh1 locus with the simultaneous deletion of cbh1 and cbh2 (two cellobiohydrolase coding genes) by designing four sgRNAs targeting cbh1 and cbh2 in the system was acquired, and the glucose oxidase produced by T. reesei reached 43.77 U/mL. Besides, it was found the ER-associated protein degradation (ERAD) level was decreased in the glucose oxidase-producing strain, which was likely due to the reduction of secretion pressure by deletion of the major endogenous cellulase-encoding genes. Conclusions The tRNA−gRNA array-based CRISPR-Cas9 editing system was successfully developed in T. reesei. This system would accelerate engineering of T. reesei for high-level production of enzymes including lignocellulose-degrading enzymes and other recombinant enzymes. Furthermore, it would expand the CRISPR toolbox for fungal genome editing and synthetic biology.

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 %.

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.

Abstract Enzymatic cascades are routinely used for electroanalysis of redox inactive species that can be enzymatically converted into species electroactive at moderate potentials, such as H2O2 produced by FAD‐dependent oxidases oxidising their substrates by O2. However, such cascades adaptation to micro‐biosensors is limited by enhanced mass‐transfer of produced H2O2 into solution, not to the sensing layer. Here, bi‐enzyme sensors for glucose or glutamate, produced by cross‐linking peroxidase and oxidases on carbon‐nanotube‐modified graphite macro‐electrodes (Gr), showed the from 0.1 to 10 mM glucose/glutamate linear response, while bio‐modified 5 μm carbon fibre electrodes (CFE) were mute due to fast transfer of enzymatically produced H2O2 into solution. By replacing peroxidase with peroxidase‐mimicking hemin in polyethyleneimine, the sensitivity of detection at Gr improved 3‐fold, enabling 2.8 μM glucose and 4.5 μM glutamate limits of detection, but not at CFE. Fast mass‐transfer of H2O2 from CFE to solution was restricted by the Nafion membrane facilitating glucose detection at CFE with a sensitivity of 1.67 A cm−2 M−1, at −0.6 V, escaping interference from other brain‐fluid components, redox‐inactive at this potential. Such membrane‐restricted cascade system provides the analytical access to a large group of enzymes that can be integrated in multiple enzymatic cascades for biosensing at microelectrodes.

With the advancement of scientific research, an increasing number of studies on metal nanozymes, particularly Au NPs, have been conducted. They possess glucose oxidase (GOD)-like activity and peroxidase (POD)-like activity, with GOD-like activity receiving the most attention. However, there is a lack of research and summary on future trends in Au NPs in biomedical field. Therefore, we conducted a study on the GOD-like activity of Au NPs based on 158 relevant publications downloaded from the Web of Science Core Collection between 2007 and 2023, using citation metrics, authors, nations, institutions, cited references, and keywords. We found that Au NPs were initially utilized for glucose biosensors, glucose detection in human serum, and the detection of other carbohydrates and proteins. Researchers have recently focused on its application in oncotherapy and diabetic wound treatment. In addition to being utilized to treat autoimmune illnesses, inflammation, and other diseases, Au NPs may eventually replace insulin and antibiotics. We anticipate that the use of Au NPs will increase in the future. We hope this study will serve as a guide for future researchers so that Au NPs can be applied more broadly and competently.

Purposes Combining the high selectivity of natural enzymes with the high stability of nanoenzymes in a one-pot reaction has emerged as an ideal solution to improving the diversity/complexity of biocatalytic cascades and the stability of multi-enzyme systems. Methods In this paper, we designed and synthesized an ionic magnetic Fe3O4@EB-COFs material to prepare glucose oxidase (GOx)-magnetic covalent organic framework material(GOx/Fe3O4@EB-COFs) through electrostatic interaction induction. Findings Fe3O4@EB-COFs played the role of nanoparticle enzyme and carrier material, and the obtained composite could be used for glucose concentration for colorimetric determination. Under acidic conditions, GOx/Fe3O4@EB-COFs exhibited a good cascade of catalytic glucose oxidation and 2,2′-biazo-bis-3-ethylbenzothiazoline-6-sulfonic acid oxidation. The kinetic study showed that the reaction followed the Lineweaver-Burk equation, indicating that the cascade reaction of the constructed nanoenzyme with natural enzyme still exhibited biocatalytic characteristics. GOx/Fe3O4@EB-COFs exhibited good recoverability with the addition of magnetic Fe3O4. Conclusions Therefore, the construction of a multi-enzyme catalytic system of nanoenzymes and natural enzymes is important for the realization of biomimetic catalysis.

Graphene and its variants exhibit excellent electrical properties for the construction of enzymatic interfaces. In particular, the direct electron transfer of glucose oxidase on the electrode surface is a very important issue in the development of enzyme-based bioelectrodes. However, the number of studies conducted to assess how pristine graphene forms different interfaces with other carbon materials is insufficient. Enzyme-based electrodes (formed using carbon materials) have been extensively applied because of their low manufacturing costs and easy production techniques. In this study, the characteristics of a single-walled carbon nanotube/graphene-combined enzyme interface are analyzed at the atomic level using molecular dynamics simulations. The morphology of the enzyme was visualized using an elastic network model by performing normal-mode analysis based on electrochemical and microscopic experiments. Single-carbon electrodes exhibited poorer electrical characteristics than those prepared as composites with enzymes. Furthermore, the composite interface exhibited 4.61- and 2.45-fold higher direct electron efficiencies than GOx synthesized with single-carbon nanotubes and graphene, respectively. Based on this study, we propose that pristine graphene has the potential to develop glucose oxidase interfaces and carbon-nanotube–graphene composites for easy fabrication, low cost, and efficient electrode structures for enzyme-based biofuel cells.

Nowadays, biosensors are gaining increasing interest in foods’ and beverages’ quality control, owing to their economic production, enhanced sensitivity, specificity, and faster analysis. In particular, colorimetric biosensors can be combined with color recognition applications on smartphones for the detection of analytes, rendering the whole procedure more applicable in everyday life. Herein, chitosan (CS) films were prepared with the deep eutectic solvent (DES) choline chloride/urea/glycerol (ChCl:U:Gly). Glucose oxidase (GOx), a widely utilized enzyme in quality control, was immobilized within CS films through glutaraldehyde (GA), leading to the formation of CS/GOx films. The optimized GOx concentration and DES content were determined for the films. Moreover, the effect of the pH and temperature of the glucose oxidation reaction on the enzymatic activity of GOx was studied. The structure, stability, and specificity of the CS/GOx films as well as the Km values of free and immobilized GOx were also determined. Finally, the analytical performance of the films was studied by using both a spectrophotometer and a color recognition application on a smartphone. The results demonstrated that the films were highly accurate, specific to glucose, and stable when stored at 4 °C for 4 weeks and when reused 10 times, without evident activity loss. Furthermore, the films displayed a good linear response range (0.1–0.8 mM) and a good limit of detection (LOD, 33 μM), thus being appropriate for the estimation of glucose concentration in real samples through a smartphone application.

Honeybees (Apis mellifera L.) have to face many challenges, including Varroa destructor infestation, associated with viral transmission. Oxalic acid is one of the most common treatments against Varroa. Little is known about the physiological effects of oxalic acid, especially those on honeybees’ immune systems. In this study, the short-term effects (0–96 h) of oxalic acid treatment on the immune system components (i.e., glucose oxidase, phenoloxidase, glutathione S-transferase, catalase activities, and vitellogenin contents) of house bees were preliminarily investigated. Oxalic acid contents of bee bodies and haemolymphs were also measured. The results confirm that oxalic acid is constitutively present in bee haemolymphs and its concentration is not affected by treatment. At 6 h after the treatment, a maximum peak of oxalic acid content was detected on bees’ bodies, which gradually decreased after that until physiological levels were reached at 48 h. In the immune system, the oxalic acid treatment determined a peak in glucose oxidase activity at 48 h, indicating a potential defence response and an increase in vitellogenin content at 24 h. No significant changes were recorded in phenoloxidase, glutathione S-transferase, and catalase activities. These results suggest a time-dependent response to oxalic acid, with potential immune system activation in treated bees.

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.

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.

Chemodynamic therapy (CDT), a noninvasive strategy, has emerged as a promising alternative to conventional chemotherapy for treating tumors. However, its therapeutic effect is limited by the amount of H2O2, pH value, the hypoxic environment of tumors, and it has suboptimal tumor-targeting ability. In this study, tumor cell membrane-camouflaged mesoporous Fe3O4 nanoparticles loaded with perfluoropentane (PFP) and glucose oxidase (GOx) are used as a tumor microenvironment-adaptive nanoplatform (M-mFeP@O2-G), which synergistically enhances the antitumor effect of CDT. Mesoporous Fe3O4 nanoparticles are selected as inducers for photothermal and Fenton reactions and as nanocarriers. GOx depletes glucose within tumor cells for starving the cells, while producing H2O2 for subsequent ·OH generation. Moreover, PFP, which can carry O2, relieves hypoxia in tumor cells and provides O2 for the cascade reaction. Finally, the nanoparticles are camouflaged with osteosarcoma cell membranes, endowing the nanoparticles with homologous targeting and immune escape abilities. Both in vivo and in vitro evaluations reveal high synergistic therapeutic efficacy of M-mFeP@O2-G, with a desirable tumor-inhibition rate (90.50%), which indicates the great potential of this platform for clinical treating cancer.

Abstract In recent years, glucose oxidase (GOx) has aroused great research interest in the treatment of diseases related to abnormal glucose metabolisms like cancer and diabetes. However, as a kind of endogenous oxido‐reductase, GOx suffers from poor stability and system toxicity in vivo. In order to overcome this bottleneck, GOx is encapsulated in calcium‐based biomaterials (CaXs) such as calcium phosphate (CaP) and calcium carbonate (CaCO3) by using it as a biotemplate to simulate the natural biomineralization process. The biomineralized GOx holds improved stability and reduced side effects, due to the excellent bioactivity, biocompatibitliy, and biodegradability of CaXs. In this review, the state‐of‐the‐art studies on GOx‐mineralized CaXs are introduced with an emphasis on their application in various biomedical fields including disease diagnosis, cancer treatment, and diabetes management. The current challenges and future perspectives of GOx‐mineralized CaXs are discussed, which is expected to promote further studies on these smart GOx‐mineralized CaXs biomaterials for practical applications.

Limited numbers of CYPs have been reported to work naturally as peroxygenases. The peroxide shunt pathway can be efficiently used as an alternative for the NAD(P)H and reductase systems, particularly in high hydrogen peroxide (H2O2) resistance CYPs. We reported the structural and biochemical features of CYP105D18 peroxygenase for its high H2O2 tolerance capacity. Q348 was a crucial residue for the stability of CYP105D18 during the exposure to H2O2. In addition, the role of the hydrophilic amino acid T239 from the I helix for peroxygenation and regiospecificity toward testosterone was investigated. Interestingly, T239E differs in product formation from wild type, catalyzing testosterone to androstenedione in the presence of H2O2. The other variant, T239A, worked with the Pdx/Pdr system and was unable to catalyze testosterone conversion in the presence of H2O2, suggesting the transformation of peroxygenase into monooxygenase. CYP105D18 supported the alternative method of H2O2 used for the catalysis of testosterone. The use of the same concentration of urea hydrogen peroxide adducts in place of direct H2O2 was more efficient for 2β-hydroxytestosterone conversion. Furthermore, in situ H2O2 generation using GOx/glucose system enhanced the catalytic efficiency (kcat/Km) for wild type and F184A by 1.3- and 1.9-fold, respectively, compared to direct use of H2O2 The engineering of CYP105D18, its improved peroxygenase activity, and alteration in the product oxidation facilitate CYP105D18 as a potential candidate for biotechnological applications.

Chemodynamic therapy (CDT) has been exploited as an emerging therapeutic modality for cancer treatment. However, insufficient intracellular H2O2 levels and ultrahigh glutathione (GSH) in the tumor microenvironment (TME) severely restrict CDT efficacy. To address these concerns, in this work, a self-reinforcing biodegradable nanotherapeutic was developed to modulate the TME to amplify CDT. The nanotherapeutic (GOD-FeCaP@TPZ, abbreviated GFCT) was fabricated through a mild one-step biomineralization process using the enzyme catalyst glucose oxidase (GOD) as a template to form biodegradable iron-doped calcium phosphate nanoparticles, followed by the loading of the prodrug tirapazamine (TPZ). When GFCT decomposes and releases Fe3+ in the acidic TME, the delivered GOD can effectively catalyze the oxidization of glucose to enhance the subsequent Fenton-like reaction by promoting intracellular acidity (via the production of gluconic acid) and improving the generation of H2O2. Moreover, the released iron constantly depletes GSH by self-cyclic valence alterations in Fe(III) and Fe(II) and then triggers H2O2 to produce •OH through an Fe(II)-mediated Fenton-like reaction. Moreover, the elevated level of hypoxia induced by GOD-mediated glucose oxidization can activate the prodrug TPZ for effective chemotherapy, thus achieving remarkable synergistic therapeutic outcomes. This work provides another paradigm to augment antitumor efficacy via modulation of the TME.

Abstract The food enzyme glucose oxidase (β‐d‐glucose:oxygen 1‐oxidoreductase; EC 1.1.3.4) is produced with the genetically modified Saccharomyces cerevisiae strain LALL‐GO by Lallemand Inc. The genetic modifications do not give rise to safety concerns. The food enzyme is free from viable cells of the production organism, but not from recombinant DNA. It is intended to be used in baking processes. Dietary exposure was estimated to be up to 0.233 mg total organic solids/kg body weight per day in European populations. Since the production strain meets the requirements for the Qualified Presumption of Safety approach and no issues of concern arising from the production process of the food enzyme were identified, the Panel considered that no toxicological studies were necessary. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and two matches were found. The Panel considered that, under the intended conditions of use, the risk of allergic reactions upon dietary exposure to this food enzyme cannot be excluded. The glucose oxidase under assessment shows sequence homology with an allergen from almond, which is listed in the Annex II of the Regulation (EU) No 1169/2011. Other than potential allergic reactions, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Glucose oxidase (GOx) can specifically catalyze the conversion of β-d-glucose into gluconic acid and hydrogen peroxide (H2O2) in the presence of oxygen, making it promising for tumor starvation therapy and oxidative therapy. However, GOx's immunogenicity, poor in vivo stability, short half-life, and potential systemic toxicity, limit its application in cancer therapy. Nanocarriers are capable of improving the pharmacological properties of therapeutic drugs (e.g. stability, circulating half-life, and tumor accumulation) and lower toxicity, hence resolving GOx issues and enhancing its efficacy. Although the application of targeted nanocarriers based on GOx has recently flourished, this field has not yet been reviewed and evaluated. Herein, we initially examined the mechanism of GOx-based nanocarriers for enhanced tumor therapy. Also, we present a comprehensive and up-to-date review that highlights GOx-based nanocarriers for tumor targeting therapy. This review expands on GOx-based nano-targeted combination therapies from both passive and active targeting perspectives, meanwhile, active targeting is further classified into ligand-mediated targeting and physical-mediated targeting. Furthermore, this review also emphasizes the present challenges and promising advancements.

Highlights Screen-printable functional nanocomposite inks are engineered for flexible, single-enzyme-based energy-harvesting, and self-powered biosensing devices. A BFC powered by the same biosubstrate (glucose) is developed to harvest energy in a biofluid model and act as a self-powered electrochemical glucose. Customized inks are advantageous in terms of integrating with flexible materials, which can be integrated with a wide range of wearables and soft bioelectronics.

Abstract Endometriosis is an estrogen-dependent chronic inflammatory disease. Hormonal and surgical treatments are the most commonly used clinical therapies, but they have many sides effects or are traumatic to the body. Therefore, specific drugs for endometriosis treatment are urgently needed to develop. In this study, we identified two features of endometriosis, namely the continuous recruitment of neutrophils into the ectopic lesions and the higher uptake of glucose by ectopic cells. For the above features, we designed a glucose oxidase-loaded bovine serum albumin nanoparticle (BSA-GOx-NPs) that is inexpensive and facilitates large-scale production. After injection, BSA-GOx-NPs were high specifically delivered to ectopic lesions in a neutrophil-dependent manner. Furthermore, BSA-GOx-NPs deplete glucose and induce apoptosis in the ectopic lesions. Whereupon BSA-GOx-NPs produced excellent anti-endometriosis effects when administrated in both acute and chronic inflammatory phases. These results reveal for the first time that the neutrophil hitchhiking strategy is effective in chronic inflammatory disease and provide a non-hormonal and easy-to-achieve approach for endometriosis treatment.

Abstract Trichoderma reesei (T. reesei) is well-known for its excellent ability to secret a large quantity of cellulase. However, unlike the endogenous proteins, little is known about the molecular mechanisms governing heterologous protein production. Herein, we focused on the integration loci and the secretory pathway, and investigated their combinatorial effects on heterologous gene expression in T. reesei using a glucose oxidase from Aspergillus niger as a model protein. Integration in the cel3c locus was more efficient than the cbh1 locus in expressing the AnGOx by increasing the transcription of AnGOx in the early stage. In addition, we discovered that interruption of the cel3c locus has an additional effect by increasing the expression of the secretory pathway component genes. Accordingly, overexpressing three secretory pathway component genes, that were snc1, sso2, and rho3, increased AnGOx expression in the cbh1 transformant but not in the cel3c transformant.

Honey is a natural sweet substance made from a mixture of nectar collected by worker bees and their own secretions, which has good antibacterial activity and contains a variety of natural antibacterial active substances. In recent years, a large number of studies have been reported on the progress of antimicrobial active substances in honey, including methylglyoxal, hydrogen peroxide, polyphenols, antimicrobial peptides and Major royal jelly proteins. Numerous studies have shown that hydrogen peroxide is one of the most important antibacterial substances in honey. This paper highlights the important roles by each antimicrobial effective active substance for the anti-bacterial by honey. It also further summarizes the process of glucose oxidase catalyzing the production of hydrogen peroxide from glucose. The process of glucose oxidase catalyzing the production of hydrogen peroxide from glucose is summarized using hydrogen peroxide in honey as an example. Other pathways for the production and degradation of hydrogen peroxide and the physicochemical factors affecting the production of hydrogen peroxide are also reviewed. Rational regulation of hydrogen peroxide production in honey plays an important role in its antibacterial and even other biological activities. This review would also provide a reference for the safe clinical use of honey and the development of functional foods.

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.

This paper describes the study of an amperometric glucose biosensor based on an enzymatic biofuel cell consisting of a bioanode and a biocathode modified with the same enzyme—glucose oxidase (GOx). A graphite rod electrode (GRE) was electrochemically modified with a layer of Prussian blue (PB) nanoparticles embedded in a poly(pyrrole-2-carboxylic acid) (PPCA) shell, and an additional layer of PPCA and was used as the cathode. A GRE modified with a nanocomposite composed of poly(1,10-phenanthroline-5,6-dione) (PPD) and gold nanoparticles (AuNPs) entrapped in a PPCA shell was used as an anode. Both electrodes were modified with GOx by covalently bonding the enzyme to the carboxyl groups of PPCA. The developed biosensor exhibited a wide linear range of 0.15–124.00 mM with an R2 of 0.9998 and a sensitivity of 0.16 μA/mM. The limit of detection (LOD) and quantification (LOQ) were found to be 0.07 and 0.23 mM, respectively. The biosensor demonstrated exceptional selectivity to glucose and operational stability throughout 35 days, as well as good reproducibility, repeatability, and anti-interference ability towards common interfering substances. The studies on human serum demonstrate the ability of the newly designed biosensor to determine glucose in complex real samples at clinically relevant concentrations.

Two types of low-cost reagentless electrochemical glucose biosensors based on graphite rod (GR) electrodes were developed. The electrodes modified with electrochemically synthesized platinum nanostructures (PtNS), 1,10-phenanthroline-5,6-dione (PD), glucose oxidase (GOx) without and with a polypyrrole (Ppy) layer—(i) GR/PtNS/PD/GOx and (ii) GR/PtNS/PD/GOx/Ppy, respectively, were prepared and tested. Glucose biosensors based on GR/PtNS/PD/GOx and GR/PtNS/PD/GOx/Ppy electrodes were characterized by the sensitivity of 10.1 and 5.31 μA/(mM cm2), linear range (LR) up to 16.5 and 39.0 mM, limit of detection (LOD) of 0.198 and 0.561 mM, good reproducibility, and storage stability. The developed glucose biosensors based on GR/PtNS/PD/GOx/Ppy electrodes showed exceptional resistance to interfering compounds and proved to be highly efficient for the determination of glucose levels in blood serum.

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.

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.

Lactose concentration is a key parameter for assessing the quality of raw and processed milk and identifying abnormal milk. Current methods for lactose determination are laborious, time-consuming and oftentimes require skilled lab workers, expensive equipment, and special reagents. In this study, an optical biosensor system based on nanosized titanium dioxide (TiO2) is presented for routine measurement of lactose in milk without sample preparation. TiO2 was obtained via sol-gel synthesis and characterized using dynamic light scattering, microelectrophoresis, X-ray diffraction, transmission electron microscopy, and nitrogen adsorption-desorption analysis. The system, whose colorimetric response was based on the chromogen-free TiO2-based detection of hydrogen peroxide (H2O2), used β-galactosidase and/or glucose oxidase as the biorecognition elements. The selectivity and sensitivity of the biosensors for lactose and glucose was investigated by diffuse reflectance spectroscopy using standard aqueous lactose and glucose solutions and whole milk samples. The results showed that the proposed biosensors had high optical signal reproducibility (RSD = 5–6%), high sensitivity (LOD = 0.005 wt%), and high selectivity. The linear dynamic ranges of lactose and glucose detection were from 0.005 wt% to 0.100 wt%, and the optimal response time of the biosensor was 25 min. The listed features and advantages of label-free detection make the biosensor attractive for simple, inexpensive, sensitive, and selective determination of lactose in milk.

This study aims to investigate the effects of macleaya extract and glucose oxidase combination (MGO) on growth performance, antioxidant capacity, immune function, and cecal microbiota in piglets. A total of 120 healthy 28-day-old weaned piglets were randomly divided into two treatments of six replicates. Piglets were either received a basal diet or a basal diet supplemented with 250 mg/kg MGO (2 g/kg sanguinarine, 1 g/kg chelerythrine, and 1 × 106 U/kg glucose oxidase). The results showed that MGO supplementation increased average daily gain (ADG) and decreased feed:gain ratio (F/G) (p

Since the discovery of acrylamide in heat-treated foods (crisps and biscuits) in April 2002, by a Swedish study, many efforts have been made to reduce acrylamide levels in foods. Consideration was given to reducing acrylamide levels by reducing Maillard reaction products. However, the production of potato chips creates acrylamide, a carcinogenic compound. This study aimed to use a new quantitative index and formula for l-asparaginase, glucose oxidase, their 1:1 blending enzymes, baker's yeast and green tea powder (0.5 g/kg distilled water) to reduce acrylamide production in potato chips and evaluate the products on some new indicators, such as asparagine reduction (%), acrylamide reduction (%), Asparagine / Acrylamide ratio (AAR) and Asparagine content (mg/kg). The highest acrylamide concentrations were reduced from 1346.0 ± 7.9 mg/kg in the blank sample (control) to 285.7 ± 3.2 and 325.3 ± 10.5 mg/kg in the baker's yeast sample (CT4) and green tea sample (CT5) treated sample, respectively. The potato chips treated with 0.5 g/kg l-asparaginase (CT1) reduced the acrylamide level by approximately 70.65±0.31%, while the CT4 samples showed 78.77±0.21% and asparagine contents of 116.0 ± 5.3 mg/kg and 195.0 ± 5.0 mg/kg, respectively.The results showed that some enzymes, baker's yeast and green tea powder could control the formation of acrylamide, which was formed during the processing of potato chips, allowing the food industry to produce low acrylamide foods from high starch food products such as potatoes. It has the ability to be used as a functional food, as well as to protect the human body of school-age children and adolescents from absorbing 70–80% of their daily acrylamide intake without these treatments.

We conducted this experiment to establish a consistent result of dietary glucose oxidase (GOX) supplementation in broilers’ growth performance, nutrient digestibility, gas emission, caecum bacterial count, and antoxidant status. A total of 792 broilers of 42.38 ± 0.72 g average body weight (BW) at one-day old were fractionated into four treatment groups (18 birds/pen; 11 pens/treatment) named as 0%, Basal diet; 0.01%, basal diet + 100 mg/kg GOX; 0.02%, basal diet + 200 mg/kg GOX; 0.03%, basal diet + 300 mg/kg GOX. For growth performance, this 35 days’ experimental period was divided into three phases (d 1 to 7, d 7 to 21, d 22 to 35, overall). For the final phase, nutrient digestibility, gas emission, caecum bacterial count, and blood parameters were measured. GOX supplementation (0.02%, 0.03%) showed increased body weight gain (BWG) and reduced feed conversion ratio (FCR) during days 22 to 35 and in overall period. At the same time, linear increase of BWG and linear decrease of FCR were observed. Increasing doses of GOX showed linear improvement in dry matter digestibility and a tendency for a gradual increase in energy digestibility. On day 7, GOX supplementation (0.02%, 0.03%) reduced drip loss in meat with a gradual decrease. Blood antioxidant parameters of glutathione peroxidase (GSSG) and glutathione (GSH) were linearly increased by rising doses of GOX where 0.03% GOX had the highest value. In short, GOX supplementation brought improvements in digestibility and antioxidant capacity, which helped to increase body weight gain in broilers.Highlights Glucose oxidase enzyme supplementation could benefit growth performance in broilers Dietary addition of glucose oxidase could increase apparent nutrient digestibility in broilers As a health benefit, antioxidant status of broilers were improved with glucose oxidase supplementation

Yiran Zhang,1– 4,* Hongzhi Hu,5,* Xiangtian Deng,6,* Qingcheng Song,2 Xin Xing,2,3 Weijian Liu,5 Yingze Zhang1– 3 1School of Medicine, Nankai University, Tianjin, 300071, People’s Republic of China; 2Department of Orthopaedic Surgery, Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, 050051, People’s Republic of China; 3NHC Key Laboratory of Intelligent Orthopaedic Equipment, Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, People’s Republic of China; 4HeBei Ex&Invivo Biotechnology Co. Ltd, Shijiazhuang, Hebei, 050051, People’s Republic of China; 5Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, People’s Republic of China; 6Orthopaedics Research Institute, Department of Orthopaedics, West China Hospital, Sichuan University, Chengdu, Sichuan, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yingze Zhang; Weijian Liu, Email yzling_liu@163.com; xh_liuweijian@hust.edu.cnBackground: Although chemodynamic therapy (CDT) has attracted enormous attention in anti-tumor studies for converting endogenous hydrogen peroxide (H2O2) into toxic hydroxyl radicals (•OH) by Fenton-type reaction, the treating effects of using CDT alone is still unsatisfying. Recently, glucose oxidase (GOx) was reported to be co-delivered with Fenton agent for synergistic starvation therapy (ST) and CDT. However, the overexpressed glutathione (GSH) and hypoxia in tumor microenvironment (TME) restrict the therapeutic efficacy of ST/CDT.Methods and Results: In this work, a novel nanoplatform composed of GOx plus Fenton agent (Cu2+) encapsulated core and metformin (MET)-loaded manganese dioxide nanosheets (MNSs) shell was prepared and further functionalized by arginine-glycine-aspartate (RGD). With the RGD-mediated affinity with cancer cells, the nanocomposite (GOx-CuCaP@MNSs-MET@PEG-RGD, GCMMR) could accomplish targeting delivery and TME-activated release of cargos. The intracellular GSH was depleted by MnO2/Cu2+ and abundant H2O2 was generated along with the GOx-induced glucose deprivation, which process was further enhanced by MET-mediated hypoxia relief via inhibiting mitochondria-associated respiration. Subsequently generated •OH from Cu+-mediated Fenton-like reaction exerts severe intracellular oxidative stress and cause apoptosis. Moreover, significant inhibition of tumor growth was detected in a subcutaneous xenograft model of osteosarcoma (OS) after GCMMR treatment.Conclusion: The excellent therapeutic efficacy and biosafety of the nanoplatform were confirmed both in vitro and in vivo. Collectively, this study provides an appealing strategy with catalytic cascade enhancement on targeted ST/CDT for cancer treatment, especially for hypoxic solid tumors.Graphical Abstract: Keywords: chemodynamic therapy, starvation therapy, glucose oxidase, Fenton reaction, biomineralization, metformin

Abstract Background As an emerging therapeutic modality, chemodynamic therapy (CDT), converting hydrogen peroxide (H2O2) into highly toxic reactive oxygen species (ROS), has been developed for tumor-specific therapy. However, the deficiency of endogenous H2O2 and high concentration of glutathione (GSH) in the tumor microenvironment (TME) weaken the CDT-based tumor-therapeutic efficacy. Herein, a photothermal-enhanced tumor-specific cascade catalytic nanosystem has been constructed on the basis of glucose oxidase (GOD)-functionalized molybdenum (Mo)-based polyoxometalate (POM) nanoclusters, termed as GOD@POMs. Methods GOD@POMs were synthesized by a facile one-pot procedure and covalently conjugation. Then, its structure was characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). In addition, ultraviolet-visible-near-infrared (UV-vis-NIR) absorption spectrum and infrared thermal camera were applied to evaluate the catalytic and photothermal performance, respectively. Moreover, to confirm the therapeutic effects in vitro, cell counting kit-8 (CCK-8) assay, live/dead staining and ROS staining were performed. Furthermore, the biosafety of GOD@POMs was investigated via blood routine, blood biochemistry and hematoxylin and eosin (H&E) staining in Kunming mice. Besides, the C6 glioma tumor-bearing mice were constructed to evaluate its anti-tumor effects in vivo and its photoacoustic (PA) imaging capability. Notably, RNA sequencing, H&E, TdT-mediated dUTP nick end labeling (TUNEL) and Ki-67 staining were also conducted to disclose its underlying anti-tumor mechanism. Results In this multifunctional nanosystem, GOD can effectively catalyze the oxidation of intratumoral glucose into gluconic acid and H2O2, achieving the cancer starvation therapy. Meanwhile, the generated gluconic acid decreases the pH in TME resulting in POM aggregation, which enables PA imaging-guided tumor-specific photothermal therapy (PTT), especially in the second near-infrared (NIR-II) biological window. Importantly, the Mo (VI) sites on POM can be reduced to Mo (V) active sites in accompany with GSH depletion, and then the post-produced Mo (V) transforms in situ overproduced H2O2 into singlet oxygen (1O2) via Russell mechanism, achieving self-enhanced CDT. Moreover, the PTT-triggered local tumor temperature elevation augments the synergistic nanocatalytic-therapeutic efficacy. Conclusions Consequently, the integration of GOD-induced starvation therapy, H2O2 self-supply/GSH-depletion enhanced Mo-based CDT, and POM aggregation-mediated PTT endow the GOD@POMs with remarkable synergistic anticancer outcomes with neglectable adverse effects.

ABSTRACT: In recent years, starvation-primed chemodynamic therapies (ST–CDT) have become a hot topic in the wake of many discoveries related to the aberrant metabolism of cancer cells and their resistance to traditional chemotherapies, as well as altered redox signaling within tumor cells. Nanotechnology platforms are in a unique position to exploit these interrelated phenomena to realize a therapeutic effect; few therapeutic modalities are able to deliver multiple drugs simultaneously outside of nanotechnology, a basic requirement when striving to exploit a complex, interactive system such as a cancer cell. In this review, the pertinent mechanisms of ST and CDT, as well as the important interactions between these two therapies, are discussed. We outline how these therapies may work synergistically or antagonistically, depending on both the therapeutic design and the system of reactions involved. Lastly, specific applications that nanotechnology is particularly well-suited are given, which may offer improvement over clinical state-of-the-art. Such considerations are important, as nanotechnology has historically encountered great difficulty in clinical translation.

An amino-functionalized, conjugated polymer (P(BDBT)) modified glassy carbon electrode (GCE) was employed as an immobilization platform for glucose oxidase (GOx) enzyme to assemble a novel glucose biosensor. Amino groups available on the polymer backbone served as bioconjugation sites for GOx via glutaraldehyde (GA). The biosensor response to the reduction in oxygen amount because of the enzyme reaction was monitored at –0.7 V potential versus Ag/AgCl. The biosensor displayed a broad linear range between 0.1–1.0 mM glucose with a detection limit of 0.17 mM. The values of the apparent Michaelis-Menten constant (KMapp) and sensitivity were determined as 1.74 mM, and 28.17 μA/(mM·cm2), respectively. GOx immobilized P(BDBT) film displayed high stability, selectivity, and reproducibility. Cyclic voltammetry (CV) and Scanning electron microscopy (SEM) techniques were utilized for the characterization of surface modifications. The fabricated biosensor was adept at determining the amount of glucose in a commercial beverage. The simple electrochemical method for the construction of P(BDBT)/GOx biosensors could pave the way to new perspectives in developing profitable biosensors.

Ying Du,1,2 Shujun Wang,3 Jianfeng Luan,3 Meilin Zhang,1,2 Baoan Chen,1,2,* Yanfei Shen2,* 1Department of Hematology and Oncology, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, People’s Republic of China; 2School of Medicine, Southeast University, Nanjing, Jiangsu, People’s Republic of China; 3Department of Blood Transfusion, Jinling Hospital, Nanjing University School of Medicine, Nanjing, Jiangsu, People’s Republic of China*These authors contributed equally to this workCorrespondence: Baoan Chen, Department of Hematology and Oncology, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, 210009, People’s Republic of China, Email cba8888@hotmail.com Yanfei Shen, School of Medicine, Southeast University, Nanjing, Jiangsu, 210009, People’s Republic of China, Email Yanfei.Shen@seu.edu.cnBackground: Glucose oxidase (GOx)-based starvation therapy is a new cancer treatment strategy. However, the characteristics such as limited curative effect and hypoxic tumor environment hinder its further application seriously.Methods: Herein, doxorubicin (DOX) loaded in hollow mesoporous copper sulfide (HMCuS) nanoparticles assembled with manganese dioxide (HMMD) as nanoshell was prepared. We developed a targeted enhanced cancer treatment method to camouflage HMMD by GOx-functionalized platelet (PLT) membranes (HMMD@PG).Results: GOx can be specially transported to the tumor site with PLT membrane for effective starvation treatment. Glucose and oxygen (O2) in the tumor were converted to H2O2 under the catalysis of GOx. HMMD can catalyze H2O2 to produce O2 and consume glutathione (GSH) in time, which regulates the tumor microenvironment (TME) and improves the adverse conditions of anti-tumor. In addition, DOX encapsulated in HMCuS-MnO2 release was accelerated from the nanoparticles after the “gatekeeper” MnO2 is consumed. The study of anti-tumor mechanism shows that the remarkable tumor suppressive ability of HMMD@PG comes from the three peaks synergy of starvation treatment, photothermal treatment (PTT), and chemotherapy. This nanoplatform disguised by PLT membrane has significant tumor inhibition ability, good biocompatibility and almost has no side effects in main organs.Conclusion: This work broadens the application mode of GOx and shows the new development of a multi-mode collaborative processing system of nanoplatforms based on cell membrane camouflage.Keywords: glucose oxidase, PLT membrane, nanoparticles, tumor microenvironment, tumor treatment

Accurate blood glucose determination is essential to the clinical diagnosis and management of diabetes. This work establishes an inner filter effect (IFE) strategy between upconversion nanoparticles (UCNPs) and quinone-imine complex for glucose monitoring in human serum simply and efficiently. In this system, the enzyme glucose oxidase (GOx) catalyzes the reaction of glucose into hydrogen peroxide (H2O2) and gluconic acid when compulsion by oxygen. In the presence of horseradish peroxidase (HRP), the produced H2O2 can catalytically oxidize phenol and 4-amino antipyrine (4-AAP) to generate quinone-imine products. The purple-colored quinone-imine complex effectively absorbed the fluorescence of NaYF4:Yb3+, Er3+ UCNPs, leading to the strong fluorescence quenching of UCNPs through IFE. Thus, a new approach was established for glucose monitoring by determining the fluorescence intensity. Under the optimal condition, this approach shows better linearity to glucose from 2–240 μmol/L with a low detection limit at 1.0 μmol/L. Owing to the excellent fluorescence property and background-free interference of the UCNPs, the biosensor was applied for glucose measurements in human serum and got a satisfactory result. Furthermore, this sensitive and selective biosensor revealed great potential for the quantitative analysis of blood glucose or different kinds of H2O2-involved biomolecules for the application of clinical diagnosis.

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.

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.

Ordered mesoporous carbon CMK-3 sieves with a hexagonal structure and uniform pore size have recently emerged as promising materials for applications as adsorbents and electrodes. In this study, using sucrose as the sustainable carbon source and SBA-15 as a template, CMK-3 sieves are synthesized to form bioelectrocatalytic immobilization matrices for enzymatic biofuel cell (EFC) electrodes. Their electrochemical performance, capacitive features, and the stability of enzyme immobilization are analyzed and compared to commercially available multi-walled carbon nanotubes (MWCNT) using cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The anodic reaction in the presence of glucose oxidase (GOx) and ferrocene methanol (FcMeOH) on the sustainably sourced CMK-3-based electrodes produces bioelectrocatalytic current responses at 0.5 V vs. saturated calomel electrode (SCE) that are twice as high as on the MWCNT-based electrodes under saturated glucose conditions. For the cathodic reaction, the MWCNT-based cathode performs marginally better than the CMK-3-based electrodes in the presence of bilirubin oxidase (BOD) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS2−). The CMK-3-based EFCs assembled from the GOx anode and BOD cathode results in a power output of 93 μW cm−2. In contrast, the output power of MWCNT-based EFCs is approximately 53 μW cm−2. The efficiency of CMK-3 as a support material for biofuel cell applications is effectively demonstrated.

Searching for artificial diets positively affecting the survival, immune and antioxidant systems of honey bees is one of main challenges occurring in beekeeping. Among nutrients, lipids play a significant role in insect nutrition as structural components in cell membranes, energy sources and reserves, and are involved in many physiological processes. In this context, the aim of this work was to investigate the effect of 0.5% and 1% coconut oil-enriched diet administration on newly emerged and forager bees survival rate, feed intake, immune system, antioxidant system and both fat and vitellogenin content. In newly emerged bees, supplementation with 1% coconut oil determined a decrease in feed consumption, an increase in survival rate from the 3rd to 14th day of feeding, a short-term decrease in phenoloxidase activity, an increase in body fat and no differences in vitellogenin content. Conversely, supplementation with 0.5% coconut oil determined an increase in survival rate from the 3rd to 15th day of feeding and an increase in fat content in the long term (i.e., 20 days). Regarding the forager bee diet, enrichment with 0.5% and 1% coconut oil only determined an increase in fat content. Therefore, supplementation with coconut oil in honey bee diets at low percentages (0.5 and 1%) determines fat gain. Further investigations to evaluate the use of such supplement foods to prevent the fat loss of weak families during winter are desirable.

Six phenolic acids (PAs) with related structures, i.e., gallic acid (GA), syringic acid (SA), coumaric acid (CMA), caffeic acid (CFA), ferulic acid (FA), and chlorogenic acid (CA), were compared for their effects on the gelling properties of myofibrillar protein (MP) under oxidative conditions. Of the six PAs, only the smallest GA caused significant reductions of free amine and sulfhydryl content (by 26% and 7%, respectively, P < 0.05) and SA decreased protein carbonyl formation, while CA, the largest PA with an esterified quinic group, prevented oxidative loss of amines. All PAs quenched MP fluorescence with CA showing the highest efficacy (38% suppression). During thermal gelation, the GA-modified MP displayed the strongest myosin cross-linking. The elasticity (G′) and breaking strength of MP gels were markedly enhanced by the addition of PAs, and the final G′ value ranked in the order GA > CA > FA > CMA > SA > CFA, indicating complex roles of phenolic side groups.

To obtain glucose biosensors based on glucose oxidase (GOx), the enzyme can be immobilized on the sensitive surface of a glass electrode by different techniques: deposition on membranous support (cellophane or other macromolecular material) or entrapment in a matrix. Deposition on membranous support also involves cross-linking with glutaraldehyde or entrapment in silica gel, following the sol-gel procedure. The aim of this preliminary work was to study the influence of cellophane replacement with a PVA based membranous support on the glucose biosensor performance. The data obtained at pH measurements of buffer solutions with cellophane and PVA membranous supports respectively, show that the PVA based membrane assures superior performances of the biosensor for low glucose concentrations determination (about 10-4 M). These results allow the transition to an improved immobilization technique, namely the enzyme entrapment in membranous material.