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Schematic illustration of the mechanism by which universal NR promotes Fenton/Fenton-like reactions. [Display omitted] Fenton/Fenton-like reaction induced chemical dynamic therapy (CDT) has been widely recognized in tumor therapy. Due to the low efficiency of conversion from high-valent metal ions (M(n+1)+) to low-valent ions (M n+) in the Fenton/Fenton-like catalytic process, enhancing the conversion efficiency safely and effectively would create a great opportunity for the clinical application of CDT. In the study, a universal nanoreactor (NR) consisting of liposome (Lip), tumor cell membrane (CM), and bis(2,4,5-trichloro-6-carboxyphenyl) oxalate (CPPO) is developed to tackle this challenge. The CPPO was first discovered to decompose under weak acidity and H 2 O 2 conditions to generate carboxylic acids (R′COOH) and alcohols (R′OH) with reducibility, which will reduce M(n+1)+ to M n+ and magnify the effect of CDT. Furthermore, glucose oxidase (GOx) was introduced to decompose glucose in tumor and generate H 2 O 2 and glucose acid, which promote the degradation of CPPO, further strengthening the efficiency of CDT, leading to a butterfly effect. This demonstrated that the butterfly effect triggered by NR and GOx encourages Fenton/Fenton-like reactions of Fe 3 O 4 and MoS 2 , thereby enhancing the tumor inhibition effect. The strategy of combining GOx and CPPO to strengthen the Fenton/Fenton-like reaction is a universal strategy, which provides a new and interesting perspective for CPPO in the application of CDT, reflecting the exquisite integration of Fenton chemistry and catalytic medicine. [ABSTRACT FROM AUTHOR]

[Display omitted] Starvation therapy has shown promise as a cancer treatment, but its efficacy is often limited when used alone. In this work, a multifunctional nanoscale cascade enzyme system, named CaCO 3 @MnO 2 -NH 2 @GOx@PVP (CMGP), was fabricated for enhanced starvation/chemodynamic combination cancer therapy. CMGP is composed of CaCO 3 nanoparticles wrapped in a MnO 2 shell, with glucose oxidase (GOx) adsorbed and modified with polyvinylpyrrolidone (PVP). MnO 2 decomposes H 2 O 2 in cancer cells into O 2 , which enhances the efficiency of GOx-mediated starvation therapy. CaCO 3 can be decomposed in the acidic cancer cell environment, causing Ca2+ overload in cancer cells and inhibiting mitochondrial metabolism. This synergizes with GOx to achieve more efficient starvation therapy. Additionally, the H 2 O 2 and gluconic acid produced during glucose consumption by GOx are utilized by MnO 2 with catalase-like activity to enhance O 2 production and Mn2+ release. This process accelerates glucose consumption, reactive oxygen species (ROS) generation, and CaCO 3 decomposition, promoting the Ca2+ release. CMGP can alleviate tumor hypoxia by cycling the enzymatic cascade reaction, which increases enzyme activity and combines with Ca2+ overload to achieve enhanced combined starvation/chemodynamic therapy. In vitro and in vivo studies demonstrate that CMGP has effective anticancer abilities and good biosafety. It represents a new strategy with great potential for combined cancer therapy. [ABSTRACT FROM AUTHOR]

[Display omitted] Reactive oxygen species (ROS)-centered chemodynamic therapy (CDT) holds significant potential for tumor-specific treatment. However, insufficient endogenous H 2 O 2 and extra glutathione within tumor microenvironment (TME) severely deteriorate the CDT's effectiveness. Herein, rich-Zn-Co 3 O 4 / N -doped porous carbon (Zn-Co 3 O 4 /NC) was fabricated by two-step pyrolysis, and applied to build high-efficiency nano-platform for synergistic cancer therapy upon combination with glucose oxidase (GOx), labeled Zn-Co 3 O 4 /NC-GOx for clarity. Specifically, the multiple enzyme-like activities of the Zn-Co 3 O 4 /NC were scrutinously investigated, including peroxidase-like activity to convert H 2 O 2 to O 2 ∙−, catalase-like activity to decompose H 2 O 2 into O 2 , and oxidase-like activity to transform O 2 to O 2 ∙−, which achieved the CDT through the catalytic cascade reaction. Simultaneously, GOx reacted with intracellular glucose to produce gluconic acid and H 2 O 2 , realizing starvation therapy. In the acidic TME, the Zn-Co 3 O 4 /NC-GOx rapidly caused intracellular Zn2+ pool overload and disrupted cellular homeostasis for ion-intervention therapy. Additionally, the Zn-Co 3 O 4 /NC exhibited glutathione peroxidase-like activity, which consumed glutathione in tumor cells and reduced the ROS consumption for ferroptosis. The tumor treatments offer some constructive insights into the nanozyme-mediated catalytic medicine, coupled by avoiding the TME limitations. [ABSTRACT FROM AUTHOR]

[Display omitted] The cancer therapeutic efficacy of the peroxidase (POD)-mimicking nanozyme-based monotherapy is significantly hindered due to insufficient intratumoral hydrogen peroxide (H 2 O 2) and glutathione (GSH) consumption effect on reactive oxygen species (ROS). In this study, we present the development of poly (o -phenylenediamine)@gold nanoparticles (AuNPs) (PoPD@Au) nanocomposites for multifunctional catalytic-photothermal therapy. These nanocomposites exhibit triple distinct nanozymatic activities, i.e. , POD-like activity that catalyzes H 2 O 2 to ROS, glucose oxidase (GOx)-like activity that supplements endogenous H 2 O 2 , and GSH depleting activity that decreases the ROS consumption efficiency. This open source and reduce expenditure strategy for ROS generation allows for the amplification of tumor oxidative stress, thereby enhancing anti-tumor efficiency. Additionally, the PoPD@Au nanocomposites demonstrate outstanding photothermal conversion efficiency, contributing to the synergistic effect between PoPD and AuNPs. Moreover, we reveal the improved photothermal performance of PoPD@Au triggered by the tumor microenvironment pH, which provides additional benefits for targeted catalytic-photothermal therapy. This "four-in-one" design of PoPD@Au enables efficient anti-tumor effects both in vitro and in vivo , making it a universal strategy for engineering catalytic-photothermal therapeutic nanoagents. [ABSTRACT FROM AUTHOR]

AuPt@MnO 2 nanoplatform with CAT/POD/Gox-like activities was constructed for NIR-II photothermal-promoted catalytic therapy. [Display omitted] Bimetallic nanozymes exhibited multi-enzyme activities, but glutathione (GSH) overexpression and weak catalytic capability restricted their catalytic therapeutic performance. Thus, this study developed a smart nanozyme (AuPt@MnO 2) with a core–shell structure by coating manganese dioxide (MnO 2) on the gold-platinum (AuPt) nanozyme (AuPt@MnO 2) surface to enhance catalytic therapy. In this nanozyme, AuPt possessed triple-enzyme activities, i.e., catalase, peroxidase, and glucose oxidase, which greatly improved oxygen, hydroxyl radicals (·OH), and hydrogen peroxide generation, due to cyclic reactions. Moreover, GSH consumption degraded the MnO 2 shell, which then enhanced ·OH generation of Mn2+. More importantly, the near-infrared-II (NIR-II) photothermal performance of AuPt@MnO 2 with a high conversion efficiency of 38.7 % further promoted multi-enzyme activities and enhanced catalytic therapy. Moreover, combining NIR-II photothermal therapy and enhancing catalytic therapy decreased the cell viability to 10.8 %, and thereby, the tumors were cleared. Thus, the AuPt@MnO 2 smart nanoplatform developed in this study exhibited NIR-II photothermal-promoted multi-enzyme activities and excellent antitumor efficacy, which will be promising for enhancing catalytic therapy. [ABSTRACT FROM AUTHOR]

[Display omitted] As different monosaccharides exhibit different redox characteristics, this paper presented a novel colorimetric sensor array based on the glucose oxidase-like (GOx-like) activity of Au nanoparticles (NPs) for monosaccharides identification. AuNPs can use O 2 , ABTS+•, or [Ag(NH 3) 2 ]+ as an electron acceptor to catalyze the oxidation of monosaccharides in different velocity, resulting in cross-responsive signals. The current sensor array can distinguish between different monosaccharides or their mixtures through linear discriminant analysis (LDA) and hierarchical clustering analysis (HCA). Moreover, the glucose and fructose concentrations can be estimated simultaneously using a neural network regression model based on the sensor array. This method shows potential for monosaccharide detection in industrial, medical, and biological applications. [ABSTRACT FROM AUTHOR]

[Display omitted] Multidrug-resistant (MDR) bacteria-infected wound healing remains greatly challenging, especially in diabetic patients. Herein, a novel nano-drug delivery based on endogenous glucose-driven cascade reaction is proposed for boosting MDR bacteria-infected diabetic wound healing with high efficacy by improving wound microenvironment and enhancing photodynamic antibacterial activity. The composite nanoagent is first self-assembled by integrating berberine (B BR) and epigallocatechin gallate (E GCG) from natural plant extracts, named as BE NPs , which is successively coated with manganese dioxide nanoshells (M nO 2 NSs) and glucose oxidase (G OX) to form the final BEMG NPs. The cascade reaction is triggered by glucose at the wound site of diabetes which is specifically catalyzed by GOX in the BEMG NPs to produce gluconic acid and hydrogen peroxide (H 2 O 2). That is subsequently to decompose MnO 2 NSs in the BEMG NPs to generate oxygen (O 2). The BEMG NPs as photosensitizers effectively produce reactive oxygen species (ROS) to enhance the eradication of bacteria with the assistance of O 2. Under the synergistic function of the cascaded reaction, the BEMG NPs present excellent antibacterial efficacy even for MDR bacteria. The in vivo experiments explicitly validate that the constructed nano-drug delivery can augment the MDR bacteria-infected diabetic wound healing with excellent biosafety. The as-proposed strategy provides an instructive way to combat ever-threatening MDR bacteria, which particularly is beneficial for diabetic patients. [ABSTRACT FROM AUTHOR]

[Display omitted] Here, we report the preparation of a novel Janus nanoparticle with opposite Ir and mesoporous silica nanoparticles through a partial surface masking with toposelective modification method. This nanomaterial was employed to construct an enzyme-powered nanomachine with self-propulsion properties for on-command delivery. The cargo-loaded nanoparticle was provided with a pH-sensitive gate and unit control at the mesoporous face by first attaching boronic acid residues and further immobilization of glucose oxidase through reversible boronic acid esters with the carbohydrate residues of the glycoenzyme. Addition of glucose leads to the enzymatic production of H 2 O 2 and gluconic acid, being the first compound catalytically decomposed at the Ir nanoparticle face producing O 2 and causing the nanomachine propulsion. Gluconic acid leads to a pH reduction at the nanomachine microenvironment causing the disruption of the gating mechanism with the subsequent cargo release. This work demonstrates that enzyme-mediated self-propulsion improved release efficiency being this nanomotor successfully employed for the smart release of Doxorubicin in HeLa cancer cells. [ABSTRACT FROM AUTHOR]

[Display omitted] The lack of selective release ability in the tumor microenvironment and the limited efficacy of monotherapy are important factors that limit the current use of carbon monoxide (CO) donors for tumor therapy. Herein, inspired by endogenous biochemical reactions in vivo , one kind of CO-releasing nanomotor was designed for the multimodal synergistic treatment of tumor. Specifically, glucose oxidase (GOx) and 5-aminolevulinic acid (5-ALA) were co-modified onto metal–organic framework material (MIL-101) to obtain MIL-GOx-ALA nanomotors (M-G-A NMs), which exhibit excellent biocompatibility and degradation ability in tumor microenvironment. Subsequently, the released 5-ALA generates CO in the tumor microenvironment through an endogenous reaction and further acts on mitochondria to release large amounts of reactive oxygen species (ROS), which directly kill tumor cells. Furthermore, the produced ROS and the degradation products of M-G-A NMs can also provide the reaction substrate for the Fenton reaction, thereby enhancing chemodynamic therapy (CDT) and inducing apoptosis of tumor cells. Both in vitro and in vivo experimental data confirm the successful occurrence of the above process, and the combination of CO gas therapy/enhanced CDT can effectively inhibit tumor growth. This CDT-enhancing agent designed based on endogenous biochemical reactions has good prospects for tumor treatment application. [ABSTRACT FROM AUTHOR]

A biodegradable hollow mesoporous Fe/HMnO 2 @DOX-GOD@HA nanoreactor was constructed for GSH-responsive MR imaging, chemotherapy and enhanced bimetallic CDT by self-supplying O 2 /H 2 O 2. [Display omitted] As an endogenous catalytic treatment, chemodynamic therapy (CDT) was attracting considerable attention, but the weak catalytic efficiency of Fenton agents and the non-degradation of nanocarriers severely limited its development. In this work, a biodegradable bimetallic nanoreactor was developed for boosting CDT, in which Fe-doped hollow mesoporous manganese dioxide (HMnO 2) was selected as nanocarrier, and the Fe/HMnO 2 @DOX-GOD@HA nanoprobe was constructed by loading doxorubicin (DOX) and modifying glucose oxidase (GOD) and hyaluronic acid (HA). The glutathione (GSH) responsive degradation of HMnO 2 promoted the release of DOX, by which the release rate significantly increased to 96.6%. Moreover, by the GSH depletion, the reduction of Mn2+/Fe2+ achieved strong bimetallic Fenton efficiency, and the hydroxyl radicals (·OH) generation was further enhanced using the self-supplying H 2 O 2 of GOD. Through the active targeting recognition of HA, the bimetallic nanoreactor significantly enriched the tumor accumulation, by which the enhanced antitumor efficacy was realized. Thus, this work developed biodegradable bimetallic nanoreactor by consuming GSH and self-supplying H 2 O 2 , and provided a new paradigm for enhancing CDT. [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]

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]

[Display omitted] Inspired by the way many living organisms utilize chemical/biological reactions to regulate their skin and respond to stimuli in the external environment, we have developed a self-regulating hydrogel design by incorporating chemical reaction networks (CRNs) into biomimetic photonic crystal hydrogels. In this hydrogel system, we used host–guest supramolecular non-covalent bonds between beta-cyclodextrin (β-CD) and ferrocene (Fc) as partial crosslinkers and designed a CRN involving enzyme-fuel couples of horseradish peroxidase (HRP)/H 2 O 2 and glucose oxidase (GOD)/ d -glucose, by which the responsive hydrogel was transformed into a glucose-driven self-regulating hydrogel. Due to the biomimetic structural color in the hydrogel, the progress of the chemical reaction was accompanied by a change in the color of the hydrogel. Based on this principle, the designed supramolecular photonic hydrogel (SPH) can not only achieve naked-eye detection of H 2 O 2 and glucose concentrations with the assistance of a smartphone but also monitor the reactions of HRP and GOD enzymes and determine their activity parameters. The sensitivity and stability of the sensor have been proven. In addition, due to the reversibility of the chemical reaction network, the sensor can be reused, thus having the potential to serve as a low-cost point-of-care sensor. The SPH was ultimately used to detect glucose in human plasma and H 2 O 2 in liver tumor tissue. The results are comparable with commercial assay kits. By redesigning the chemical reaction network in the hydrogel, it is expected to be used for detecting other enzymes or fuels. [ABSTRACT FROM AUTHOR]

[Display omitted] • Tumor microenvironment (TME)-activatable metal–organic frameworks (MOF) were developed for targeted tumor therapy. • pH-responsive breakdown of the framework gradually released glucose oxidase/Prussian Blue nanozyme, boosting tumor specificity. • Starvation therapy mediated by glucose oxidase was used to enhance chemodynamic therapy as well as to starve tumor cells. • Cascade catalytic reactions promoted ROS-induced DNA cleavage, growth inhibition, and finally tumor cell apoptosis. • The antitumor nanocomposites enabled chemodynamic/starvation synergism, high therapeutic efficiency, and minimal side effects. Targeted tumor therapy through tumor microenvironment (TME)-responsive nanoplatforms is an emerging treatment strategy used to enhance tumor-specificity to selectively kill cancer cells. Here, we introduce a nanosized zeolitic imidazolate framework-8 (ZIF-8) that simultaneously contains natural glucose oxidase (GOx) and Prussian blue nanoparticles (PBNPs) to construct multi-component metal-organic framework nanocomposites (denoted as ZIF@GOx@PBNPs), which possess cascade catalytic activity selectively within the TME. Once reaching a tumor site, GOx and PBNPs inside the nanocomposites are sequentially released and participate in the cascade catalytic reaction. In weak acidic TME, GOx, which effectively catalyzes the oxidation of intratumoral glucose to hydrogen peroxide (H 2 O 2) and gluconic acid, not only initiates starvation therapy by cutting off the nutrition source for cancer cells but also produces the reactant for sequential Fenton reaction for chemodynamic therapy. Meanwhile, PBNPs, which are released from the ZIF-8 framework dissociated by acidified pH due to the produced gluconic acid, convert the generated H 2 O 2 into harmful radicals to melanomas. In this way, the cascade catalytic reactions of ZIF@GOx@PBNPs enhance reactive oxygen species production and cause oxidative damage to DNA in cancer cells, resulting in remarkable inhibition of tumor growth. The tumor specificity is endowed by using the biomolecules overexpressed in TME as a "switch" to initiate the first catalytic reaction by GOx. Given the significant antitumor efficiency both in vitro and in vivo, ZIF@GOx@PBNPs could be applied as a promising therapeutic platform enabling starvation/chemodynamic synergism, high therapeutic efficiency, and minimal side effects. [ABSTRACT FROM AUTHOR]

[Display omitted] • We have developed a novel multifunctional theranostic nanoplatform (denoted as MBIG NCs) through surface modification of manganese oxide nanosheets (MnOx NSs) with bovine serum albumin (BSA) followed by subsequent anchoring of photo-responsive IR780 and glucose oxidase (GOx). • This nanocomposite formulation is advantageous to improve the therapeutic functions of MnOx through self-activation in the tumor microenvironment. • The as-synthesized MBIG NCs are biocompatible in non-stimulus conditions, and demonstrated high cancer cell killing efficacy in presence of glucose and light due to the win–win cooperative effect between starvation therapy, chemodynamic therapy and phototherapy. • The fluorescence and magnetic resonance imaging properties of MBIG NSs are helpful for cancer diagnosis. • We present a simple and practical strategy for developing pathological stimuli responsive combination therapy, which has the potential of advancing precision cancer medicine. Development of tumor microenvironment (TME) modifying nanomedicine with cooperative effect between multiple stimuli responsive therapeutic modalities is necessary to achieve lower dosage induced tumor specific therapy. Accordingly, herein, a multifunctional MnOx NSs@BSA-IR780-GOx nanocomposite (MBIG NCs) is developed to modulate the oxidative stress in TME, and thus attain higher therapeutic efficacy. In the presence of glucose, the as-synthesized MBIG NCs are served as a chemodynamic agents and generated reactive oxygen species (ROS) by self-activation through a cascade of reactions from glucose oxidase (GOx) and manganese oxide nanosheets (MnOx NSs). Also, the MBIG NCs demonstrated excellent photodynamic properties upon irradiation with 808 nm laser owing to the presence of IR780. The combination of glucose-mediated chemodynamic and light-mediated photodynamic properties generated higher ROS than that obtained with individual stimuli. Further, the MBIG NCs exhibited photothermal effect with conversion efficiency of 33.8 %, which helped to enhance the enzymatic activities. In in vitro studies, the MBIG NCs exhibited good biocompatibility to cancerous and non-cancerous cells under non-stimulus conditions. Nevertheless, in the presence of glucose and light stimuli, they triggered more than 90 % cell toxicity at 200 ppm concentration via the cooperative effect between starvation therapy, chemodynamic therapy, and phototherapy. Furthermore, the MBIG NCs demonstrated magnetic resonance and fluorescence imaging properties. These results are suggesting that MBIG NCs would be potential theranostic agents to for cancer diagnosis and target specific therapy. More importantly, the fabrication process is paving a way to improve the aqueous dispersibility, stability, and bio-applicability of MnOx NSs and IR780. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nanocomposites of ZIF-8, carbon nanodots and silver nanoparticles are prepared. • A novel fluorescent sensing strategy is developed for the detection of H 2 O 2 and glucose based on AgNP-CD-ZIF-8. • Excellent analytical performances are achieved, which might inspire future studies on MOF assembly. In this study, a novel fluorescent biosensor is developed for the detection of H 2 O 2 and glucose based on Zeolitic Imidazolate Framework-8 (ZIF-8) nanocomposites. ZIF-8 encapsulating carbon nanodot (CD) exhibits bright fluorescence emission. After further loading of AgNP, the fluorescence is quenched, which is mainly based on the excited electron transfer from CD to AgNP. Besides, the excitation wavelength of CD falls within the adsorption range of AgNP, which leads to efficient inhibition of the excitation energy. The as-prepared AgNP-CD-ZIF-8 nanocomposites can be utilized as a highly sensitive platform for the analysis of H 2 O 2 and glucose. In the presence of glucose, H 2 O 2 can be generated by the catalysis of glucose oxidase (GOD), which induces the etching of AgNP and subsequent recovery of CD-ZIF-8 fluorescence. This "turn on" biosensor can be applied for facile and convenient quantification of H 2 O 2. It can also be further extended to detect glucose in real samples after combining specific catalytic effect of GOD. The analytical performances are excellent, which demonstrates great potential for practical utility. [ABSTRACT FROM AUTHOR]

This work reports a universal strategy that functionalizes various metal–organic frameworks by endogenous bioenzyme of glucose oxidase, which achieves monodispersity and water-stability. We further integrate it as a highly efficient nanoplatform for cancer synergistic therapy. Generation of large amounts of reactive oxygen species induces cell apoptosis, and further guarantees good therapeutic effect and anti-migration performance. [Display omitted] The agglomeration of metal–organic frameworks (MOFs) has long been a problem, and achieving stable monodispersity in water remains a great challenge. This paper reports a universal strategy that functionalizes MOFs by using an endogenous bioenzyme namely glucose oxidase (GOx), to achieve stable water monodispersity, and integrates it as a highly efficient nanoplatform for cancer synergistic therapy. Phenolic hydroxyl groups in GOx chain confers robust coordination interactions with MOFs, which not only endows stable monodispersion in water, but also provides many reactive sites for further modification. Silver nanoparticles are uniformly deposited onto MOFs@GOx to achieve high conversion efficiency from near-infrared light to heat, resulting in an effective starvation and photothermal synergistic therapy model. In vitro and in vivo experiments confirm excellent therapeutic effect at very low doses without using any chemotherapeutics. In addition, the nanoplatform generates large amounts of reactive oxygen species, induces heavy cell apoptosis, and demonstrates the first experimental example to effectively inhibit cancer migration. Our universal strategy enables stable monodispersity of various MOFs via GOx functionalization and establishes a non-invasive platform for efficient cancer synergistic therapy. [ABSTRACT FROM AUTHOR]

[Display omitted] Glutathione (GSH) is a crucial factor in limiting the effects of chemodynamic therapy (CDT) and ferroptosis, an iron-based cell death pathway. Based on this, we constructed iron-rich mesoporous dopamine (MPDA@Fe) nanovehicles with a dual-GSH depletion function by combining MPDA and Fe. Poly (ethylene glycol) (PEG) was further modified to provide desirable stability (PM@Fe) and glucose oxidase (GOx) was grafted onto PM@Fe (GPM@Fe) to address the limitation of hydrogen peroxide (H 2 O 2). After the nanoparticles reached the tumor site, the weakly acidic microenvironment promoted the release of Fe. Then FeII reacted with H 2 O 2 to generate hydroxyl radical (OH) and FeIII. The generated FeIII was reduced to FeII by GSH, which circularly participated in the Fenton reaction and continuously produced tumor inhibitory free radicals. Meanwhile, GOx consumed glucose to provide H 2 O 2 for the reaction. MPDA had also been reported to deplete GSH. Therefore, dual consumption of GSH led to the destruction of intracellular redox balance and inhibition of glutathione-dependent peroxidase 4 (GPX4) expression, resulting in an increase in lipid peroxides (LPO) and further induction of ferroptosis. Additionally, MPDA-mediated photothermal therapy (PTT) raised the temperature of tumor area and produced photothermal-enhanced cascade effects. Hence, the synergistic strategy that combined dual-GSH depletion-induced ferroptosis, enhanced CDT and photothermal cascade enhancement based on MPDA@Fe could provide more directions for designing nanomedicines for cancer treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] The design of enzymatic droplet-sized reactors constitutes an important challenge with many potential applications such as medical diagnostics, water purification, bioengineering, or food industry. Coacervates, which are all-aqueous droplets, afford a simple model for the investigation of enzymatic cascade reaction since the reactions occur in all-aqueous media, which preserve the enzymes integrity. However, the question relative to how the sequestration and the proximity of enzymes within the coacervates might affect their activity remains open. Herein, we report the construction of enzymatic reactors exploiting the simple coacervation of ampholyte polymer chains, stabilized with agar. We demonstrate that these coacervates have the ability to sequester enzymes such as glucose oxidase and catalase and preserve their catalytic activity. The study is carried out by analyzing the color variation induced by the reduction of resazurin. Usually, phenoxazine molecules acting as electron acceptors are used to characterize glucose oxidase activity. Resazurin (pink) undergoes a first reduction to resorufin (salmon) and then to dihydroresorufin (transparent) in presence of glucose oxidase and glucose. We have observed that resorufin is partially regenerated in the presence of catalase, which demonstrates the enzymatic cascade reaction. Studying this enzymatic cascade reaction within coacervates as reactors provide new insights into the role of the proximity, confinement towards enzymatic activity. [ABSTRACT FROM AUTHOR]

[Display omitted] Ferroptosis is a newly found cell death mechanism, which could bypass apoptosis and reverse multidrug resistance of tumors. However, efficient induction of tumor ferroptosis remains a challenge. In this study, multifunctional "ball-rod" Janus nanoparticles (FTG/L&SMD) were constructed for non-small cell lung cancer (NSCLC) ferroptosis treatment. Protected by tannic acid (TA), FTG/L&SMD maintains long-term function in blood circulation, while modification by 2, 3-dimethylmaleic anhydride (DMMA) confers the FTG/L&SMD with pH-responsive charge reversal. Glucose oxidase (GOD) on FTG/L&SMD catalyzes glucose to produce H 2 O 2. Then, iron ion converts H 2 O 2 to highly active hydroxyl radicals (OH•) via Fenton reaction, leading to lethal lipid peroxidation (LPO) accumulation. Meanwhile, TA reduces Fe3+ to Fe2+ to boost Fenton reaction cycle. Sor down-regulated glutathione peroxidase 4 (GPX4) expression in another pathway to induce ferroptosis synergistically. In vitro studies have shown that compared with sorafenib (Sor), FTG/L&SMD not only has more efficient tumor targeting and higher cytotoxicity, but also inhibits tumor migration. In vivo antitumor therapy experiments demonstrate that FTG/L&SMD inhibits tumor growth efficiently, and its toxicity is negligible. In general, FTG/L&SMD can initiate Fenton reaction cycle and reinforced ferroptosis to kill tumor cells, which is a promising anti-tumor nano-drug for NSCLC. [ABSTRACT FROM AUTHOR]

[Display omitted] Life is fueled by multi-enzymatic tandem processes that display unmatched catalytic efficiencies owing to certain features of the biological reactors such as compartmentalization, nano-confinement, and out-of-equilibrium dynamics. With an attempt to match such natural catalytic systems, herein, we present a chemoenzymatic pH clock mediated transient assembly of a vesicular nanozyme. Distinct confinement of two catalytically discrete units, Histidine groups on the periphery and hemin in the lipid bilayer, results in an efficient hydrolase-peroxidase tandem catalysis in a temporally controlled fashion. The pH clock, constituted by alkaline TRIS (Tris(hydroxymethyl)aminomethane hydrochloride) buffer (promoter) and glucose oxidase (GOx) catalyzed oxidation of glucose, steers the transience in an asymmetric fashion. Alkaline TRIS buffer enhances the pH of the system and triggers the formation of imine linked Supramolecular Peptide Amphiphiles (SPAs) that further assemble into vesicles. On the other hand, oxidation of glucose produces gluconolactone and H 2 O 2. Gluconolactone hydrolyzes to gluconic acid (deactivator) which dissipates the nanozyme while H 2 O 2 is used in the peroxidase catalysis. Thus, the bi-directional feedback from the fuel not only regulates the existence of the transient state but also controls the activity of the assembly. The transiently assembled nanozyme protected the activity of the catalytic units, displayed substrate specificity and catalytic reproducibility over multiple fueling cycles. [ABSTRACT FROM AUTHOR]

The high-level of glucose in daily nutrition causes diabetes (Diabetes mellitus) and obesity. It is also important to determine glucose levels in food production processes for quality control methods. Biosensors are bio analytical devices that provides cheap, simple, analyses and have a fast response time. Silver nanoparticles are used to modify electrodes in bio-sensing glucose. The nanoparticles could be synthesized via the green synthesis technique. In this technique, plants could be used both reducing and stabilizing agents. Agricultural waste, an environmental problem, is increasing with the population. These wastes are a good natural source and have the potential for green synthesis of silver nanoparticles to use in biosensor applications. In this study, a new amperometric glucose biosensor was designed. For this purpose, carbon paste electrode (CPE) was modified by green synthesized waste tea based silver nanoparticles (WT-AgNPs) and the glucose oxidase enzyme was immobilized on MCPE by the cross-linking. Glucose determination was performed based on the reduction of hydrogen peroxide at +0.4 V versus Ag/AgCl. The linear working range was determined as 0.10–1.0 µM. In addition, the designed biosensor was applied to detect the amount of glucose in a commercial fruit juice. The results showed that the designed biosensor has low detection limit, very good reproducibility, selectivity, and almost long shelf life. • Food glucose levels must be determined cheaply and rapidly. • Biosensors provides cheap, simple, analyses and have a fast response time. • Agricultural wastes with their bio compounds could be used in silver nanoparticle synthesize. • In this study, waste black tea leaves based silver nanoparticles were synthesized. • The nanoparticles were used to prepare a new amperometric glucose biosensor. [ABSTRACT FROM AUTHOR]

This study introduces the UV/glucose-oxidase@Kaolin (GOD@Kaolin) coupled organic green rust (OGR) system (UV/OGR/GOD@Kaolin) to investigate the promotion of glucose oxidase activity by UV light and its synergistic degradation mechanism for photosensitive pollutants, specifically targeting the efficient degradation of 4-chlorophenol (4-CP). The enzyme system demonstrates its ability to overcome drawbacks associated with traditional Fenton systems, including a narrow pH range and high localized concentration of H 2 O 2 , by gradually releasing hydrogen peroxide in situ within a neutral environment. In the presence of UV radiation under specific conditions, enhanced enzyme activity is observed, resulting in increased efficiency in pollutant removal. The gradual release of hydrogen peroxide plays a crucial role in preventing unwanted reactions among active substances. These unique features facilitate the generation of highly reactive species, such as Fe(IV) O, •OH, and •O 2 −, tailored to efficiently target the organic components of interest. Additionally, the system establishes a positive iron cycle, ensuring a sustained reactive capability throughout the degradation process. The results highlight the UV/OGR/GOD@Kaolin system as an effective and environmentally friendly approach for the degradation of 4-CP, and the resilience of the enzyme extends the system's applicability to a broader range of scenarios. [Display omitted] • UV irradiation enhances the enzymatic activity through irritating GOD photosensitivity. • UV irradiation reduces Fe3+ to Fe2+, promoting the iron cycle. • The in-situ release of hydrogen peroxide improves its utilization efficiency. • The in-situ release of hydrogen peroxide improves its utilization efficiency. • GOD loading on kaolin enhances enzyme structure and activity and can also be recycled. [ABSTRACT FROM AUTHOR]

[Display omitted] Altering the glucose supply and the metabolic pathways would be an intriguing strategy in starvation therapy toward cancers. Nevertheless, starvation therapy alone could be inadequate to eliminate tumor cells completely. Herein, a multifunctional bioreactor was fabricated for synergistic starvation-chemotherapy through embedding glucose oxidase (GOx) and doxorubicin (DOX) in the tumor targeting ligands (RGD) modified red blood cell membrane camouflaged metal-organic framework (MOF) nanoparticle (denoted as RGD-mGZD). Owing to the remarkable biointerfacing property, the designed RGD-mGZD could not only possess enhanced blood retention time inherited from red blood cells, but also preferentially target the tumor site after the modification with RGD peptide. Once the bioreactor reached the desired region, GOx promptly consumed the intratumoral glucose and oxygen to starve cancer cells for robust starvation therapy. More importantly, the aggravated acidic microenvironment at the tumor region was found to induce the decomposition of the MOF structure, thus triggering the release of DOX for reinforced chemotherapy. This bioreactor would further prompt the development of synergistic patterns toward cancer treatment in a spatiotemporally controlled manner. [ABSTRACT FROM AUTHOR]

[Display omitted] In this research, to mimic the structures and the functionalities of the organelles in living cells multienzyme proteinosomes with β-galactosidase (β-gal), glucose oxidase (GOx) and horseradish peroxidase (HRP) on the surfaces are fabricated by hydrophobic-interaction induced self-assembly approach. To investigate the mechanism of the formation of proteinosomes, poly(di(ethylene glycol) methyl ether methacrylate) (PDEGMA) and bovine serum albumin are employed in a model system and the study demonstrates that the hydrophobic interaction between the dehydrated polymer chains and the hydrophobic patches on the proteins plays a key role in the fabrication of the proteinosomes. Based on the model system, multienzyme proteinosomes with β-gal, GOx and HRP on the surfaces are fabricated through hydrophobic interaction between PDEGMA and enzyme molecules. Enzyme-catalyzed cascade reactions are performed on the surfaces of the proteinosomes, and the immobilized enzymes show higher bioactivities than the "free" enzymes, due to the direct transfer of the product as a substrate from one enzyme molecule to another. This research provides a unique method for the synthesis of multienzyme proteinosomes with improved bioactivities, and the biofunctional structures will find promising applications in medical and biological science. [ABSTRACT FROM AUTHOR]

I-motif DNA structure functionalized UIO-66-NH 2 can responsively release the locked methylene blue to indicate the content of tumor marker when it was placed in an acidic environment. The acidic condition was generated by the aerobic oxidation of glucose that was catalyzed with ZIF-8@GOx immunoprobe. [Display omitted] • A proton responsive annunciator based on UIO-66-NH 2 was fabricated. • UIO-66-NH 2 encapsulated methylene blue was functionalized with i-motif DNA. • Reformative UIO-66-NH 2 can release methylene blue in an acidic solution. Reformative exploitation for metal organic frameworks (MOFs) has been a topic subject in electrochemical sensing, in which the loading of electroactive species is always introduced to enable them to generate electrochemical signal. However, insulation shielding of MOFs and flimsy combination method interfere with the signal readout of electroactive dyes when they are co-immobilized on electrode surface, indicating that an amelioration is imperatively proposed to solve these issues. Herein, a proton-activated annunciator for responsive release of methylene blue (MB) based on i-motif DNA structure modified UIO-66-NH 2 was presented to design electrochemical immunosensor (Squamous cell carcinoma antigen was used as the model analyte). With the catalysis of a ZIF-8 immunoprobe contained glucose oxidase (GOx) to glucose in test tube, protons are produced in ambient solution and then they can be used as the key to unlock the i-motif functionalized UIO-66-NH 2 , releasing the loaded MB molecules to be readout on an improved electrode. This stimuli-responsive mode not merely eliminates the insulation effect of MOFs but also provides a firm loading method for electroactive dyes. Under the optimal conditions, the proposed immunoassay for SCCA had displayed excellent performance with a wide linear range from 1 µg mL−1 to 1 pg mL−1 and an ultralow detection limit of 1.504 fg mL−1 (S/N = 3) under the optimal conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] Photodynamic therapy (PDT) of tumor has achieved good results, but the treatment efficiency is not high due to the lack of effective photosensitizers and tumor hypoxia. In this study, iridium dioxide nanoparticles (IrO 2 NPs) with excellent photothermal/photodynamic effects and catalase like activity were synthesized by a simple method. The combination of glucose oxidase (GOx) and IrO 2 NPs is formed by hyaluronic acid (HA), which have the activities of glucose oxidase and catalase, can target tumor sites and form in situ amplifiers in tumor microenvironment (IrO 2 -GOx@HA NPs). Firstly, GOx convert the high levels of glucose in the tumor to hydrogen peroxide (H 2 O 2), and then IrO 2 NPs convert H 2 O 2 to oxygen (O 2), which can enhance the type II of PDT. IrO 2 NPs also can be used as a thermosensitive agent for photothermal therapy (PTT). In cancer cells, IrO 2 -GOx@HA NPs-mediated amplifier enhances the effect of type II of PDT, aggravating the apoptosis of breast cancer (4T1) cells and cooperating with its own PTT to further improve the overall treatment effect. Under simulated hypoxic conditions of tumor tissue, it was found that IrO 2 -GOx@HA NPs treatment can effectively relieve hypoxia inside tumor tissue. In addition, the results in vivo further proved that, IrO 2 -GOx@HA NPs can enhance the role of II PDT and cooperate with PTT to treat breast cancer effectively. The results highlight the prospect of IrO 2 -GOx@HA NPs in controlling and regulating tumor hypoxia to overcome the limitations of current cancer therapy. [ABSTRACT FROM AUTHOR]

Experiment-based guidelines for analysis of metal surface effect to overall catalytic process was suggested. [Display omitted] • Catalytic input of nanoparticle surface in enzyme-gold nanoparticle catalysts was investigated. • Kinetic behavior of catalysts with four coating scenarios was analyzed. • No actual enzymatic acceleration on gold nanoparticles was observed. In recent years, many papers have reported a catalytic "acceleration" of enzymes when immobilized on gold nanoparticles. Concordantly, gold nanoparticles are often considered as an inert and safe nanomaterial, and are widely used for various purposes, e.g., experiments with humans are being conducted in vivo. In this work we have carried out an in-detail study of catalytic properties of citrate-capped gold nanoparticles and gold nanoparticle-protein conjugates using three model proteins – enzymes glucose oxidase and catalase, and catalytically inactive protein bovine serum albumin. Catalytic properties were studied at different protein-nanoparticle ratios. UV–Vis, DLS, AFM and ζ potential measurements confirmed protein-nanoparticle conjugate formation. Catalytic activity measurements were conducted using oxygen electrode and the data were analyzed by modeling the activity of conjugates. The designed experiments demonstrated that gold nanoparticles form stable conjugates with all the investigated proteins, yet they do not increase catalytic activity of the investigated enzymes – in certain conditions gold nanoparticles mimic enzymatic reactions, which may be misattributed to accelerated enzymatic catalysis. Additionally, we present specific key points demonstrating why it may be difficult to differentiate between enzyme- and gold nanoparticle-catalyzed reactions, as well as suggest specific measurements enabling better differentiation. We do not claim that enzymes cannot be accelerated on nanoparticles in general, but rather emphasize, that experimental results demonstrating atypical catalytic performance of enzymes on nanoparticles should be interpreted with additional care, and a widely propagated view of "inert gold nanoparticles" should probably be reconsidered. [ABSTRACT FROM AUTHOR]

A metastable aqueous interface method is developed for biomimetic synthesis of a novel chrysanthemum-like smart nanosystem with multi-functions. Well-designed surface and micro-structure allow ultrahigh loading capacity for glucose oxidase and l -arginine, special selectivity for cancer cells, and responsive degradation to regenerate large amounts of oxygen, which effectively overcomes hypoxia limitation and achieves excellent starvation/gas synergistic therapy and unprecedented anti-migration performance. [Display omitted] • A metastable aqueous interface strategy is developed for biomimetic synthesis of a smart nanosystem. • The nanosystem has ultrahigh loading capacity for glucose oxidase and l -arginine, and special selectivity for cancer cells. • Effective in vivo and in vitro starvation/gas therapy is achieved by overcoming the intracellular hypoxia limitations. • The first experimental anti-migration example for synergistic starvation/gas therapy is reported. Glucose oxidase (GOx)-mediated starvation therapy holds great promise in cancer treatment. However, the worse hypoxia conditions result into low therapeutic efficiency, and undegradability of carriers poses potential threats to living bodies. To address this, herein a bioinspired MnO 2 nanosystem with controllable surface was developed for highly efficient starvation/gas synergistic enhanced therapy. Biomimetic design and further surface modification unprecedentedly endowed the nanosystem with ultrahigh loading capacity for GOx and l -Arginine (l -Arg) and special selectivity toward cancer cells. Especially, the dissipative O 2 during starvation therapy was well replenished by a positive cycle formed by the nanosystem, which continuously reproduced O 2 and accelerated glucose consumption. The abundant H 2 O 2 was further used to oxidize l -Arg into nitric oxide to realize gas therapy. In vitro and in vivo testing confirmed that this new treatment effectively blocked the nutrition and energy sources of cells to obtain excellent therapeutic effect. We reported the first experimental item of this nanosystem for inhibiting cancer cell migration. Considering the novel design concept with facile biomimetic methods, effective co-loading of endogenous substances, and good anti-tumor and anti-migration effects, this work provided new theoretical and experimental basis for starvation therapy and inspired people to design more delicate platform for cancer treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] The combination of photodynamic therapy (PDT) and chemodynamic therapy (CDT) have attracted a great deal of interest, but tumor hypoxia and glutathione (GSH) overproduction still limit their further applications. Herein, an intelligent reactive oxygen species (ROS) nanogenerator Ce6/GOx@ZIF-8/PDA@MnO 2 (denoted as CGZPM; Ce6, GOx, ZIF-8, PDA, MnO 2 are chlorin e6, glucose oxidase, zeolitic imidazolate framework-8, polydopamine and manganese dioxide respectively) with O 2 -generating and GSH-/glucose-depleting abilities was constructed by a facile and green one-pot method. After intake by tumor cells, the outer MnO 2 was rapidly degraded by the acidic pH, and the overexpression of hydrogen peroxide (H 2 O 2) and GSH with abundant Mn2+ and O 2 produced would eventually achieve multifunctionality. The Mn2+ acted as an ideal Fenton-like agent and magnetic resonance (MR) imaging contrast agent, while the O 2 promoted the PDT via hypoxia relief and facilitated the intratumoral glucose oxidation by GOx for starvation therapy (ST). Benefiting from the GOx-based glycolysis process, sufficient H 2 O 2 was generated to improve the CDT efficacy through Mn2+-mediated Fenton-like reaction. Notably, MnO 2 and PDA could decrease the tumor antioxidant activity by consuming GSH, resulting in remarkably enhanced PDT/CDT. Such a novel cascade bioreactor with tumor microenvironment (TME)-modulating capability opens new opportunities for ROS-based and combinational treatment paradigms. [ABSTRACT FROM AUTHOR]

A polymer-templated raspberry assembly method is developed to generally co-assemble proteins and inorganic clusters on the surface of P4VP. The representative GOX-{Mo 72 Fe 30 }@P4VP co-assemblies can efficiently catalyze the oxidation of o-dianisidine with the presence of glucose, where the color change points out their potential in rapid detection of glucose and biomass conversion. [Display omitted] The hybridization of enzymes and inorganics in controlled manner is challenging, however, critical for the development of chemo-enzymatic cascade catalyst with high efficiency and selectivity. Here, proteins and metal oxide clusters can be facilely co-assembled on the surface of colloid of poly(4-vinylpyridine) (P4VP) via hydrogen bonding, due to their enriched surface hydrogen bonding donors. The co-assembly method can be generally applied for preparing chemo-enzymatic catalyst within the selected database of various proteins and metal oxide clusters while the assembly units retain their structures and activities. Typically, a 2.5 nm metal oxide cluster {Mo 72 Fe 30 }, with peroxidase-like activity, are complexed with glucose oxidase (GOX) on P4VP for the catalysis against the oxidization of o-dianisidine (ODA) with the existence of glucose. Due to the synergistic effects of chemical and enzymatic catalysis, the co-assemblies show even higher ODA oxidation activity compared to GOX/catalase bi-enzymatic system, confirming the effectiveness of the co-assembly protocol for cascade catalysis and enabling its applications in rapid glucose detection and biomass conversion. [ABSTRACT FROM AUTHOR]

This study investigates the co-catalytic capabilities of MoO 3 nanosheets in enhancing the enzyme-like catalytic activity of a two-dimensional ultrathin Fe(III)-modified covalent triazine framework (Fe-CTF) under neutral pH conditions. The unique physicochemical surface properties and two-dimensional structures of Fe-CTF enable the direct immobilization of native enzymes (glucose oxidase (GOD) and xanthine oxidase (XOD)) through adsorption, eliminating the need for chemical processes. Efficient immobilization of the native enzymes within the Fe-CTF/GOD(XOD) hybrid is achieved through multipoint attachment involving various interactions. The Fe-CTF/MoO 3 co-catalytic system exhibits enzyme-mimicking activity at neutral pH and, when combined with the high catalytic activity of the immobilized native enzymes, enables the development of a colorimetric method for glucose detection. This method demonstrates excellent facilitation, rapidity, sensitivity, and selectivity, with a linear detection range of 50–1000 μM and a limit of detection of 8.8 μM for glucose. Furthermore, a straightforward one-pot colorimetric method is established for screening XOD inhibitors. The inhibitory potential of a crude extract derived from Chinese water chestnut peel on XOD activity is evaluated using this method. The findings of this study pave the way for the utilization of nanozyme/native enzyme hybrids in pH-neutral conditions for one-pot colorimetric sensing. This work contributes to the advancement of enzyme-based sensing technologies and holds promise for various applications in biosensing and biomedical research. [Display omitted] • MoO 3 boost the enzyme-like activity of Fe-CTF under neutral pH conditions. • Fe-CTF achieves direct immobilization of native enzymes by adsorption. • Fe-CTF/MoO 3 is utilized for colorimetric sensing of glucose and screening of inhibitors. [ABSTRACT FROM AUTHOR]

• Immobilization of GOx on Ti 3 C 2 MXene for cascade glucose oxidation reaction. • PLL modification provides the Ti 3 C 2 with a bio biocompactible surface for GOx loading. • Superior enzymatic activity and stability are obtained in the Ti 3 C 2 -PLL-GOx. • The Ti 3 C 2 -PLL-GOx nanosheet can be used to build a high-performance glucose sensor. Two-dimensional (2D) nanoreactors with cascade catalytic activity for glucose oxidation and hydrogen peroxide decomposition are prepared via immobilizing glucose oxidase (GOx) on Ti 3 C 2 MXene nanosheets. Amino-rich polypeptide, poly- l -lysine (PLL), is applied to modify the ultra-thin Ti 3 C 2 MXene nanosheets with a compatible surface for GOx immobilization. The PLL-modified Ti 3 C 2 nanosheets possess a positively charged surface and show an excellent GOx loading capacity as high as 50 wt% of the Ti 3 C 2 nanosheets. The physically adsorbed enzymes are then cross-linked with the amine groups in the PLL chains to form a robust GOx-PLL network covered on the MXene nanosheets. The GOx-conjugated Ti 3 C 2 -PLL (Ti 3 C 2 -PLL-GOx) nanosheets showed superior enzymatic activities than the activities of GOx immobilized on an inert porous silica substrate, largely because that the Ti 3 C 2 nanosheets can catalyze the decomposition of the toxic intermediate H 2 O 2 generated from the glucose oxidation. Given the excellent electrical conductivity of Ti 3 C 2 MXene, the Ti 3 C 2 -PLL-GOx nanosheets are further deposited on glassy carbon electrode to construct a high-performance biosensor with a glucose detection limit of 2.6 μM. [ABSTRACT FROM AUTHOR]

• A photoelectrochemical electrode was fabricated based on a graphene honeycomb film. • A fluorescent probe (AFP-PFBT-GOD) was synthesized for the detection current promotion. • This photoelectrochemical biosensor can sensitively detect alpha-fetoprotein by competitive immunoassay. • The photoelectrochemical biosensor has high detection sensitivity and good reliability. • The detection limit of alpha-fetoprotein is lower than 0.05 ng/mL. Alpha-fetoprotein (AFP) in adult serum often appears in early liver cancer. Therefore, early detection of an abnormal elevation of AFP concentration is important for the early diagnosis and treatment of primary liver cancer. In this work, a photoelectrochemical (PEC) electrode was fabricated for AFP-sensitive detection based on a reduced graphene oxide (rGO) honeycomb structure. After layer-by-layer bioconjugation, the immunoassay graphene electrode was modified with anti-AFP antibodies (Ab). Meanwhile, polymer nanoparticles (PFBT dots) were prepared via a nanoprecipitation method. In addition, the AFP was modified by using the PFBT dots and glucose oxidase (GOD), which formed a fluorescent probe (AFP-PFBT-GOD). By the competitive linkage of AFP and AFP-PFBT-GOD onto the anti-AFP modified honeycomb structure electrode, an immunosensor for AFP detection was obtained. During the PEC test, the electrons produced by the catalytic reaction of glucose and GOD can scavenge the photogenerated holes on the PFBT dots, which can reduce the recombination of photogenerated holes and electrons on the PFBT dots. The PEC immunosensor based on a rGO honeycomb structure exhibited a linear detection range of 0.05–100 ng/mL with a detection limit of 0.05 ng/mL. The excellent detection performance of the graphene PEC biosensor provides an opportunity for the early diagnosis of primary liver cancer. [ABSTRACT FROM AUTHOR]

The one-pot cascade reaction of naturally occurring enzymes is exciting for highly selective complex reaction and biodegradable approaches. Tamoxifen is the main drug against breast cancer for decades and induces an anticancerous effect upon metabolic activation by cytochrome P450 (CYP450). Herein, bi-enzymatic nanoreactors (NRs) are developed as a multimodality platform for smart action against breast tumors. CYP BM3 of Bacillus magaterium (CYP) is co-confined with glucose oxidase (GOx) where GOx produces H 2 O 2 in the presence of glucose that elicits the CYP-mediated transformation of tamoxifen. The scintillating and mesoporous LaF 3 :Tb as nanocarrier showed advantages like a wide range of pore size and positive surface charge for efficient loading of enzyme couple, while the smallest pores were available for substrate/product diffusion. The obtained NRs were camouflaged with human serum albumin (HSA) to overcome premature enzyme leaching and provide active stealth properties. The nanocomposite was characterized for physicochemical properties and glucose-mediated sequential catalysis. The in vitro studies demonstrated the cell internalization of NRs in both ER+ and triple-negative breast cancer cell lines and showed significant cytotoxicity. The developed NRs not only improve the outcomes of endocrine therapy in ER+ cells but also synergistically act with oxidation therapy for enhanced therapeutic effect. Importantly, inhibition of triple-negative cells was also achieved. Thus, the development of the new multimodal nanomedicine of the present work should afford new tools towards the theranosis of breast cancer with minimized adverse effects. [ABSTRACT FROM AUTHOR]

Nanotechnology's rapid development of nanostructured materials with disruptive material properties has inspired research for their use as electrocatalysts to potentially substitute enzymes. Herein, a novel electrocatalytic nanomaterial was constructed by growing gold nanograss (AuNG) on 2D nanoassemblies of gold nanocubes (AuNC). The resulting structure (NG@NC) was used for the detection of H 2 O 2 via its electrochemical reduction. The NG@NC electrode displayed a large active surface area, resulting in improved electron transfer efficiency. On the nanoscale, AuNG maintained its structure, providing high stability and reproducibility of the sensing platform. Our nanostructured electrode showed excellent catalytic activity towards H 2 O 2 at an applied potential of −0.5 V vs Ag/AgCl. This facilitated H 2 O 2 detection with excellent selectivity in an environment like human urine, and a linear response from 50 µM to 30 mM, with a sensitivity of 100.66 ± 4.0 μA mM−1 cm−2. The NG@NC-based sensor hence shows great potential in nonenzymatic electrochemical sensing. [ABSTRACT FROM AUTHOR]

Hybrid Pt/EMT nanomaterials in size of about 15–20 nm were synthesized by highly dispersing Pt nanoparticles (5–8 nm) on the support of ultrasmall EMT zeolite, which were utilized as peroxidase mimics for accurate detection of H 2 O 2 and glucose with a sensitive and reliable colorimetric assay, based on the catalytic oxidation of colorless TMB into blue ox-TMB using uniformly loaded Pt nanoparticles as active sites on microporous EMT zeolite with large surface area and pore volume. In past decade, Pt-based nanomaterials as peroxidase mimics have attracted much attention for H 2 O 2 and glucose detection. However, easy aggregation of Pt nanoparticles (Pt NPs) greatly decreases their peroxidase-like activity. In this work, novel Pt/EMT nanocomposites were prepared by uniformly loading Pt NPs (5–8 nm) onto the support of ultrasmall EMT zeolite (15–20 nm), a kind of low-silica microporous aluminosilicate material. The hybrid Pt/EMT nanomaterials could be well dispersed in water to form a homogeneous suspension, and were then utilized as a superior peroxidase-like catalyst for oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H 2 O 2). The optimal catalyst of 2.6Pt/EMT nanocomposite exhibited excellent catalytic performance toward H 2 O 2 and TMB than natural enzyme of horseradish peroxidase (HRP) by using a steady-state kinetic analysis based on the typical Michaelis-Menten kinetics theory. The peroxidase-like catalyst showed a promising activity in a wide pH and temperature range as well as the long-term stability. A facile and reliable colorimetric assay based on the peroxidase mimic of Pt/EMT nanocomposite was constructed for precise detection of H 2 O 2 and glucose in a wide linear range, with low limits of detection of 1.1 μM and 13.2 μM, respectively. Due to high selectivity to glucose against other sugars on the catalyst, the method was demonstrated to accurately measure the concentration of glucose in real samples including human blood serum and fruit juices, indicating a potential application of the Pt/EMT nanocomposites as a robust peroxidase mimic and a reliable biosensor in the fields of clinical diagnosis, pharmaceutical, food research and so on. [ABSTRACT FROM AUTHOR]

Various fungi are significant threats to vegetable yield via causing destructive diseases. Rhizoctonia solani is a soilborne fungal pathogen affecting tomato with considerable damage in crop production, worldwide. Understanding plant defense mechanisms against different Rhizoctonia spp. isolates can be useful in designing novel and effective disease control approaches. Therefore, we performed cellular, molecular and biochemical assays to investigate the interaction of various taxonomic groups of multinucleate R. solani and a binucleate isolate of Rhizoctonia sp. (BNR) with tomato as a susceptible host. Histochemical and enzymatic experiments showed that the highest levels of O 2 −, H 2 O 2 , callose accumulation and superoxide dismutase activity were observed for the isolate of R. solani AG 3, which caused lower disease severity compared to the highly pathogenic R. solani isolates belonging to AG 4 HG-I and AG 4 HG-II. Gene expression investigations via quantitative reverse transcription-polymerase chain reaction revealed the highest levels of the SOD gene upregulation in the plants with R. solani AG 3 and the BNR inoculations, which showed the lowest levels of pathogenicity on tomato plants. Whereas, the highest upregulation of the POX expression was detected in tomato plant infected with the highly pathogenic R. solani isolates belonging to AG 4 HG-I and AG 4 HG-II at most of the time points investigated. Xanthine/xanthine oxidase treatment, which induced O 2 − production, increased the disease symptoms. But, glucose/glucose oxidase, which increased H 2 O 2 , decreased the disease symptoms. Ascorbate, as an inhibitor of H 2 O 2 accumulation, reduced callose deposition and increased the disease severity. In overall, upregulation of the SOD gene expression and activation of the corresponding enzyme, which are linked to H 2 O 2 and callose accumulation, might be related to lower level of the disease progress on the plants inoculated with R. solani AG 3 and the BNR isolates. So, priming these defense mechanisms via different environmentally safe treatments could be helpful in disease management, which needs further investigations in future. • Rhizoctonia solani AG 3 caused lower disease severity om tomato compared to R. solani isolates of AG 4 HG-I and AG 4 HG-II. • The highest levels of O 2 −, H 2 O 2 , callose and superoxide dismutase activity were observed for the isolate of R. solani AG 3. • Xanthine/xanthine oxidase treatment, which induced O 2 − production, increased the disease symptoms. • Ascorbate, as an inhibitor of H 2 O 2 accumulation, reduced callose and increased the disease progress. • Higher activity of cellulase as a cell wall degrading enzyme was observed for the fungal isolates with higher pathogenicity. [ABSTRACT FROM AUTHOR]

Honey possesses health-promoting properties; however, industrial processing and manipulation of raw honey can harm on its biological activities, including antibacterial activity. Therefore, this study aimed to compare the honey's antibacterial activity, its total protein content, and the abundance of the most dominant bee-derived proteins in honey between raw (n = 92) and supermarket (n = 17) samples. We showed that tested raw honey samples were much more effective in inhibiting the growth of Staphylococcus aureus , a model bacterium, at a median minimal inhibitory concentration (MIC) value of 4.5 % compared to supermarket honey samples ceasing bacterial growth at median MIC value of 36 %. Moreover, raw honey samples, tested in this study, contained significantly higher amounts of total protein as well as the content of particular bee-derived proteins (major royal jelly protein 1 (MRJP1), glucose oxidase (GOX), and α-glucosidase) in contrast to supermarket honey samples. These data hint that some supermarket honey samples exhibited strikingly low protein content. Furthermore, α-amylase (diastase) from Aspergillus oryzae was found in the supermarket sample characterised with the lowest protein content. Our findings highlight the burning need to refine and monitor the specific quality parameters, ensuring the authenticity of honey and maintaining its reputation as a functional food. • Nectar-originated proteins/peptides are negligible in comparison to bee-derived proteins. • Raw honeys contained significantly higher amounts of total proteins. • The antibacterial activity of raw and supermarket honeys was significantly different. [ABSTRACT FROM AUTHOR]

Samples of Spanish unifloral avocado (Persea americana Mill.) honey (n = 30) have been characterized by composition criteria, sensory attributes and mineral content in order to fully describe this type of honey. Due to the significant gaps concerning the characterization of unifloral avocado honeys, this work aimed to contribute to its characterization based on different routine laboratory analysis which included: pollen content (qualitative), water content, sugar content, water activity; electrical conductivity, diastase activity; glucose oxidase activity; specific optical rotation; hydroxymethylfurfural; pH; colour of honey and acidity (free, lactonic and total). To define its sensory profile thirty-one sensorial attributes were evaluated: three descriptors for appearance, eight for olfactory characteristics, three of texture in the mouth, four basic tastes, eight of aroma, three trigeminal sensations (piquancy, freshness and astringency), persistence and after taste. A mineral content analysis was also carried out and the elements studied were Fe, Zn, Cu, Ca, Mg and Na. The obtaining results revealed that, it was possible to define and authenticate Spanish unifloral avocado honey based on a combination of common routine laboratory analysis. Image 1 • Electrical conductivity as an important parameter characterizing unifloral avocado honeys. • Sensory profile was obtained for the authentication of Spanish avocado unifloral honeys. • Spanish avocado honey was well-distinguished as unifloral honey based on its mineral content. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H 2 O 2) is a by-product of some biochemical processes which is catalyzed by enzymes such as glucose oxidase (GOx), cholesterol oxidase (ChoOx), etc and its overproduction in living cells can trigger cancer growth and various diseases. Therefore, H 2 O 2 sensing is of great importance in the determination of diseases as well as industries and environmental health plans. We produced ZnO-CuO nanofibers by electrospinning method for non-enzymatic electrochemical H 2 O 2 sensing. The sensing properties of the carbon paste electrode (CPE) modified with ZnO (0.3 wt%)/CuO (0.7 wt%) nanofibers (named as ZnO3-CuO7) for detection of H 2 O 2 were explored in phosphate-buffered saline (PBS) at pH ∼ 7.4 solution. The ZnO3-CuO7 nanofiber exhibited the lowest charge transfer resistance and the highest electrocatalytic performance among other modified electrodes for detection of H 2 O 2 and considered as an optimized sample. The effect of scan rate and H 2 O 2 concentration in the reduction process were also investigated by cyclic voltammetry (CV) and the mechanism for the electrochemical reaction of H 2 O 2 at the surface of the optimized electrode was studied. The diffusion coefficient of H 2 O 2 and the catalytic rate constant were evaluated by chronoamperometry as 1.65 × 10−5 cm2 s−1 and 6 × 103 cm3 mol−1 s−1, respectively. Furthermore, amperometric detection of H 2 O 2 with a low detection limit of 2.4 µM and a wide linear range of 3 to 530 µM were obtained. Meanwhile, the optimized electrode displayed no recognizable response towards some biomolecules such as ascorbic acid, uric acid, dopamine and glucose. The obtained results confirmed that the modified electrode shows high sensitivity and selectivity as a H 2 O 2 biosensor with improved reproducibility and stability. [ABSTRACT FROM AUTHOR]

Graphical abstract We develop a covalent biofunctionalization strategy of MoS 2 NSs with high conjugation efficiency of peptides for intracellular caspase-3 activity detection. Abstract Intracellular detection of caspase-3 activity is crucial for the study of cell apoptosis and caspase-3 related diseases. Although various nanomaterials-based biosensors have been constructed for this purpose, they often suffer from poor stability or complicated construction due to the lack of a facile and efficient biofunctionalization method, which decreases their sensing performance and limits their use in the complex physiological environments. As novel two-dimentional (2D) nanomaterials, MoS 2 nanosheets (NSs) have shown great potential for biosensing due to their unique properties. Herein, we develop a versatile yet facile covalent biofucntionalization strategy of MoS 2 NSs by utilizing polydopamine (PDA) as nano-bio interface, and construct an intracellular fluorescent biosensor (MoS 2 @PDA-PEG-Peptide, MPPP) for the determination of caspase-3 activity. This covalent biofunctionalization of MoS 2 NSs can significantly improve the conjugation efficiency of biomolecules and enhance their stability in complicated environments, which is much better than conventional biofunctionalization by using thiol-metal coordination. Furthermore, this novel caspase-3 biosensor based on peptides biofunctionalized MoS 2 NSs shows high sensitivity and selectivity for the detection of caspase-3 with a limit of detection (LOD) of 0.33 ng/mL, and can be used for high-contrast fluorescent imaging of cell apoptosis. [ABSTRACT FROM AUTHOR]

Abstract Glucose oxidase (GOx) based biosensor is an effective method to determine glucose level. However, the biosensors embedded with high electroactive species suffered from high background signal levels, which leading to relative low sensitivity for glucose sensing. In this work, a novel 3D network materials based glucose biosensor with low background signal was constructed, which demonstrated high sensitivity and selectivity towards glucose assay. Here, the combination of ionic liquid modified graphene sheets (GS-IL) and Au nanorods (Au NRs) acted as high electroactive catalyst, and thiol-containing silica sol-gel served as a nonconductive matrix to self-assembly of GS-IL and Au NRs to form the three-dimensional (3D) network materials. Meanwhile, the doping amount of the sol-gel had significant influences on electrochemical performance of the 3D network materials based biosensor. As a result, optimized 3.75% doping 3D network materials were selected to construct the glucose biosensor, which exhibited low background signal and high sensitivity. This biosensor was successfully applied in monitoring the glucose levels of serum and brain microdialysate samples. Highlights • The novel 3D network materials based glucose biosensor exhibiting high sensitivity with low background signal was designed. [ABSTRACT FROM AUTHOR]

Oxidative stress plays a central role in cataract formation suggesting that antioxidants might slow cataract progression. The anticataract activity of N-acetylcysteine amide (NACA) and (2 R, 2 Rʼ)-3,3ʼ-disulfanediyl bis(2-acetamidopropanamide) (diNACA) and/or N-acetylcysteine (NAC), were evaluated in porcine and rat lens models. Cataractogenesis via oxidation was induced with H 2 O 2 and/or glucose oxidase (GO). Porcine lenses were incubated in 0.1 mM, 1 mM, or 10 mM NAC, NACA or diNACA for 24 h. Lenses were then transferred to media containing 0.75 mM H 2 O 2 and 4.63U of GO in order to maintain a constant H 2 O 2 level for an additional 8 h. At the end of incubation, lenses were imaged under darkfield microscopy. Separately, rat lenses were extracted from 3-week-old Wistar rats and incubated with either 10 mM NACA or 10 mM diNACA for 24 h prior to treatment with 0.2U GO to generate a steady source of ∼0.6 mM H 2 O 2. Rat lenses were analyzed by LC-MS/MS to quantify changes in cysteine, cystine, glutathione (GSH) or oxidised glutathione (GSSG) levels in the lens epithelium, cortex or core. Pre-treatment with NACA or diNACA followed by oxidation with H 2 O 2 and/or GO to stimulate cataract formation afforded rapid assessment in ex vivo porcine (32 h) and rat (48 h) lens models. Pre-treatment of isolated porcine lenses with 0.1 mM, 1 mM or 10 mM of either NAC, NACA or diNACA followed by H 2 O 2 /GO treatment resulted in reduced lens opacity relative to the lenses exposed to H 2 O 2 /GO, with NACA and diNACA reducing opacities to a greater extent than NAC. Rat lenses incubated with 10 mM NACA or 10 mM diNACA without exposure to H 2 O 2 showed no signs of opacities. Pre-treatment of rat lenses with 10 mM NACA or 10 mM diNACA, followed by GO cataract induction resulted in reduced opacities compared to control (GO alone). LC-MS/MS analyses revealed that NACA, but not diNACA, increased cysteine, cystine and GSH levels in rat lens epithelium and cortex regions. Taken together, both NACA and diNACA inhibited cataract formation to a greater extent than NAC (all at 1–10 mM) in an ex vivo porcine lens model. Both NACA and diNACA (both at 10 mM) reduced cataract formation in rat lenses. Based on LC-MS/MS analyses, NACA-induced reduction in opacity observed in rat lenses was attributed to enhanced cysteine and GSH levels while the diNACA-induced reduction in opacity induced did not consistently increase cysteine, cystine and GSH levels and, therefore, appears to involve a different antioxidant mechanism. These screening studies warrant further testing of NACA and diNACA as anticataract agents. • NACA and diNACA were tested for their anti-cataract activity. • NACA and diNACA reduced opacities induced by H 2 O 2 in porcine and rat lenses. • NACA reduced opacities by enhancing cysteine and glutathione in the rat lens. • DiNACA reduced opacities by a pathway which may involve mixed disulphide formation. • Further work is warranted to further test NACA and diNACA as anticataract agents. [ABSTRACT FROM AUTHOR]

As a type of nanomaterials with enzyme-mimetic catalytic properties, nanozymes have attracted wide concern in biological detection. H 2 O 2 was the characteristic product of diverse biological reactions, and the quantitative analysis for H 2 O 2 was an important way to detect disease biomarkers, such as acetylcholine, cholesterol, uric acid and glucose. Therefore, there is of great significance for developing a simple and sensitive nanozyme to detect H 2 O 2 and disease biomarkers by combining with corresponding enzyme. In this work, Fe-TCPP MOFs were successfully prepared by the coordination between iron ions and porphyrin ligands (TCPP). In addition, the peroxidase (POD) activity of Fe-TCPP was proved, in detail, Fe-TCPP could catalyze H 2 O 2 to produce ·OH. Herein, glucose oxidase (GOx) was chosen as the model to build cascade reaction by combining Fe-TCPP to detect glucose. The results indicated glucose could be detected by this cascade system selectively and sensitively, and the limit of detection of glucose was achieved to 0.12 μM. Furthermore, a portable hydrogel (Fe-TCPP@GEL) was further established, which encapsulated Fe-TCPP MOFs, GOx and TMB in one system. This functional hydrogel could be applied for colorimetric detection of glucose by coupling with a smartphone easily. Nanozyme of Fe-TCPP and corresponding hydrogel were constructed, and they were further developed to detect glucose. [Display omitted] • A simple and efficient nanozyme for the detection of glucose is reported. • A universal hydrogel system containing both natural enzymes and nanozymes is developed. • Fe-TCPP@GEL could carry out the quantitative analysis of glucose by coupling with a smartphone easily. [ABSTRACT FROM AUTHOR]

Climate change is modifying the composition of the grapes, increasing sugar and pH levels, which produces unbalanced wines with high alcohol degree, low acidity and poor aromatic notes. In this study, glucose oxidase (GOX) and catalase (CAT) were applied in white must with high sugar content and pH (>3.8) to simultaneously decrease glucose concentration and pH. The effect of enzyme treatment on volatile composition of wine was investigated. A concentration of 0.17 mkat/L for both GOX and CAT was sufficient to produce a remarkable reduction of glucose concentration in the must (61.5 g/L), achieving similar results within the pH range of 3–4. The musts subjected to enzymatic treatment yielded more balanced wines, lowering their alcohol content by 10–27 mL/L and pH by 0.3–0.5, while leaving their chromatic characteristics unchanged compared to the control wines. As positive effects, enzyme treatment reduced the concentrations of C6-alcohols with green-herbaceous notes and high-chain ethyl esters with soapy notes in wines, and did not modify the concentrations of short-chain ethyl esters, acids and higher alcohols. However, the concentrations of heptyl acetate and 2-phenylethanol with floral notes, and some ketones with floral and fruit notes, were lower in wines from treated musts. • Glucose oxidase (GOX) yielded wines with low alcohol degree and pH. • GOX had no effect on short-chain ethyl esters, acids, or higher alcohols levels. • GOX decreased C6-alcohols (herbaceous notes) and high ethyl esters (soapy notes). • Enzyme reduced the levels of acetates, alcohols and ketones (floral-fruit notes). [ABSTRACT FROM AUTHOR]

In this study, an adaptable HRP/GOX-Glu system was established due to the trait, efficient degradation of pollutants in the catalytic process of HRP named the ping-pong bibi mechanism and a sustained release of H 2 O 2 in-situ under the catalysis of glucose oxidase (GOX). Compared with the traditional HRP/H 2 O 2 system, the HRP was more stable in the HRP/GOX-Glu system based on the feature of persistent releasing H 2 O 2 in-situ. Simultaneously, the high valent iron was found out to give a greater contribution to Alizarin Green (AG) removal through ping-pong mechanism, whereas the hydroxyl radical and superoxide free radical generated by Bio-Fenton were also the main active substances for AG degradation. Furthermore, on the basis of effect evaluation of the co-existence of two different degradation mechanisms in the HRP/GOX-Glu system, the degradation pathways of AG were proposed. Moreover, the optimum reaction conditions preferentially triggering ping-pong bibi mechanism instead of Bio-Fenton were determined by single factor analysis and degradation mechanism elaboration. This study would provide a reference for how to give full play to the advantages of ping-pong bibi mechanism in the dual-enzyme system based on HRP to degrade pollutants with high efficiency. • A dual-enzyme system of glucose oxidase and horseradish peroxidase was established. • Sustainable release of H 2 O 2 and its promoting effect on the ping-pong bibi degradation mechanism. • The advantages of the ping-pong bibi mechanism compared with the degradation of bio-Fenton were reflected. • The optimal conditions to promote the ping-pong bibi degradation mechanism were explored. [ABSTRACT FROM AUTHOR]