Encapsulating Glucose Oxidase Research Articles

Synergetic Enzyme-Incorporated Metal-Organic Framework and Polyoxometalate Nanozyme: Achieving Stable Tandem Catalysis for Organic Photoelectrochemical Transistor Bioanalysis.

Organic photoelectrochemical transistor (OPECT) has emerged as a promising technique for biomolecule detection, yet its operational rationale remains limited due to its short development time. This study introduces a stable tandem catalysis protocol by synergizing the enzyme-incorporated metal-organic frameworks (E-MOFs) with polyoxometalate (POM) nanozyme for sensitive OPECT bioanalysis. The zeolitic imidazolate framework-8 (ZIF-8) acts as the skeleton to protect the encapsulated glucose oxidase (GOx), allowing the stable catalytic generation of H2O2. With peroxidase-like activity, a phosphotungstic acid hydrate (PW12) is then able to utilize the H2O2 to induce the biomimetic precipitation on the photogate, ultimately resulting in the altered device characteristics for quantitative detection. This work reveals the potential and versatility of an engineered enzymatic system as a key enabler to achieve novel OPECT bioanalysis, which is believed to offer a feasible framework to explore new operational rationale in optoelectronic and bioelectronic detection.

Enzyme-delivery Metal-organic Framework Composite Coatings for Restoration of Hyperglycemia-damaged Osteoblast Differentiation

There is a significant clinical need to develop effective treatments for bone defects in patients with diabetes mellitus (DM), as they are at higher risk of fractures and impaired healing. Guided bone tissue engineering using biocompatible and biodegradable polymers is a promising approach. However, current diabetic bone regenerative therapies often fail due to the accumulation of advanced glycation products, which can affect the integration of traditional tissue engineering scaffolds with native bone. Therefore, novel approaches are needed to improve the efficacy of diabetic bone regeneration. This study presents a proof-of-concept development of a multifunctional polymer composite coating tailored towards restoring diabetes-related damage in osteoblast differentiation. Our composite system involves 3D-printed poly(caprolactone fumarate) (PCLF) and poly(caprolactone) (PCL) blend scaffolds coated with multifunctional chitosan methacrylate (chiMA). The chiMA coating is embedded with a sustained-release formulation of glucose oxidase (GOx) from MIL-127 metal-organic frameworks making the coating a stimuli-responsive biomolecule delivery system. The multifunctional coating is designed for the sustained release of GOx and sodium pyruvate for in vitro glucose modulation and oxidative stress reduction, respectively. We propose that sustained release of GOx from MIL-127 embedded chiMA coatings can modulate the high glucose (HG) cellular milieu towards normal glucose (NG), enhancing osteoblast (OB) differentiation via downstream effects. Our results show successful synthesis of MIL-127, encapsulation of GOx, and fabrication of composite coating on the PCLF/PCL scaffolds with effective enzyme activity measured as a function of lowering glucose concentration in HG media for 144 h to normal levels. In vitro evaluation of OB viability, attachment, proliferation, and differentiation showed an overall decrease in cellular activity in HG conditions, which was restored through the glucose-modulating functionality of the GOx-releasing MIL-127 coatings. Our results also presented preliminary evidence of a statistical correlation between DM-related gene markers and osteogenic markers in vitro that requires further exploration. Although this proof-of-concept study holds promise for advancing precision biomaterials development for diabetic tissue engineering and meeting the unmet clinical need for effective treatments and warrants future in vivo evaluation of the composite coating and molecular biology understanding of correlations between DM and osteogenic markers.

Enhancing Substrate Channeling with Multi-Enzyme Architectures in Hydrogen-Bonded Organic Frameworks.

Hydrogen-bonded organic frameworks (HOF) represent an emerging category of organic structures with high crystallinity and metal-free, which are not commonly observed in alternative porous organic frameworks. These needle-like porous structure can help in stabilizing enzymes and allow transfer of molecules between enzymes participating in cascade reactions for enhanced substrate channelling. Herein, we systematically synthesized and investigated the stability of HOF at extreme conditions followed by one-pot encapsulation of single and bi-enzyme systems. Firstly, we observed HOF to be stable at pH 1 to 14 and at high temperatures (up to 115 °C). Secondly, the encapsulated glucose oxidase enzyme (GOX) showed 80 % and 90 % of its original activity at 70 °C and pH 11, respectively. Thirdly, transient time close to 0 seconds was observed for HOF encapsulated bi-enzyme cascade reaction system demonstrating a 4.25-fold improvement in catalytic activity when compared to free enzymes with enhanced substrate channelling. Our findings showcase a facile system synthesized under ambient conditions to encapsulate and stabilize enzymes at extreme conditions.

Prussian Blue-Derived Nanocomposite Synergized with Calcium Overload for Three-Mode ROS Outbreak Generation to Enhance Oncotherapy.

Calcium overload can lead to tumor cell death. However, because of the powerful calcium channel excretory system within tumor cells, simplistic calcium overloads do not allow for an effective antitumor therapy. Hence, the nanoparticles are created with polyethylene glycol (PEG) donor-modified calcium phosphate (CaP)-coated, manganese-doped hollow mesopores Prussian blue (MMPB) encapsulating glucose oxidase (GOx), called GOx@MMPB@CaP-PEG (GMCP). GMCP with a three-mode enhancement of intratumor reactive oxygen species (ROS) levels is designed to increase the efficiency of the intracellular calcium overload in tumor cells to enhance its anticancer efficacy. The released exogenous Ca2+ and the production of cytotoxic ROS resulting from the perfect circulation of the three-mode ROS outbreak generation that Fenton/Fenton-like reaction and consumption of glutathione from Fe2+/Fe3+and Mn2+/Mn3+ circle, and amelioration of hypoxia from MMPB-guided and GOx-mediated starvation therapy. Photothermal efficacy-induced heat generation owing to MMPB accelerates the above reactions. Furthermore, abundantROS contribute to damage to mitochondria, and the calcium channels of efflux Ca2+ are inhibited, resulting in a calcium overload. Calcium overload further increases ROS levels and promotes apoptosis of tumor cells to achieve excellent therapy.

Encapsulation of Glucose Oxidase on Zeolitic Imidazolate Framework-67 Collaborates with Carbon Nanotubes to Enhance the Electrochemical Performance of the Enzymatic Electrode

Encapsulation of Glucose Oxidase on Zeolitic Imidazolate Framework-67 Collaborates with Carbon Nanotubes to Enhance the Electrochemical Performance of the Enzymatic Electrode

A Potentially Versatile Enzyme Sensor Platform: Enzyme-Loaded, Tagged, Porous Polymeric Nanocapsules.

Enzymes are essential to life and indispensable in a wide range of industries (food, pharmaceutical, medical, biosensing, etc.); however, a significant shortcoming of these fragile biological catalysts is their poor stability. To address this challenge, a variety of immobilization methods have been described to enhance the enzyme's stability. These immobilization methods generally are specific to an individual enzyme or optimal for a particular application. The aim of this study is to explore the utility of porous, indicator moiety-tagged, polymeric nanocapsules (NCs) for the encapsulation of enzymes and measurement of the enzyme's substrate. As a model enzyme, glucose oxidase (GOx) is used. The GOx enzyme-loaded, fluorophore-tagged NCs were synthesized by using self-assembled surfactant vesicle templates. To show that the biological activity of GOx is preserved during entrapment, the rate of the GOx enzyme catalyzed reaction was measured. To evaluate the protective features of the porous NCs, the encapsulated GOx enzyme activity was followed in the presence of hydrolytic enzymes. During the encapsulation of GOx and the purification of the GOx-loaded NCs, the GOx activity decayed less than 10%, and up to 30% of the encapsulated GOx activity could be retained for 3-5 days in the presence of hydrolytic enzymes. In support of the potentially unique advantages of the enzyme-loaded NCs, as a proof-of-concept example, the fluorophore-tagged, GOx-loaded NCs were used for the determination of glucose in the concentration range between 18 and 162 mg/dL and for imaging the distribution of glucose concentration in imaging experiments.

Targeting and Microenvironment-Activated Nanoreactor for Diabetic Chronic Wound Healing via Multienzyme Cascade Reactions.

The development of cell-like nanoreactors with the ability to initiate biocatalytic cascades under special conditions holds tremendous potential for therapeutic applications. Herein, conformationally gated nanoreactors that respond to the acidic microenvironment of infected diabetic wounds were developed by cucur[8]bituril (CB[8])-based supramolecular assembly. The bioinspired nanoreactors exhibit not only self-regulated permeability and selectivity to control internal enzyme activities by substance exchange but also distinct binding specificities toward Gram-positive and Gram-negative bacteria via noncovalent modification with different ligands. The encapsulation of glucose oxidase (GOx), Fe3O4 nanozyme, and l-arginine (l-Arg) into the nanocarriers enables intelligent activation of multienzyme cascade reactions upon glucose (Glu) uptake to produce gluconic acid (GA) and hydrogen peroxide (H2O2), which is further converted into highly toxic hydroxyl radicals (·OH) for selective antibacterial activity. Moreover, acidic H2O2 promotes the oxidization of l-Arg, leading to the release of nitric oxide (NO). Consequently, this nanoreactor provides a multifunctional and synergistic platform for diabetic chronic wound healing by combining enzyme dynamic therapy with NO gas therapy to combat bacterial infections and inflammation under high blood Glu levels.

Designing Tough Hydrogel Shells for Glucose Sensing.

Conventional hydrogel microcapsules often suffer from inadequate mechanical stability, hindering their use. Here, water-cored double-network (DN) hydrogel shells are designed, formed by polyacrylamide and calcium alginate networks using triple-emulsion templates. These DN hydrogel shells offer robust mechanical stability, optical transparency, and a precisely-defined cut-off threshold. The feasibility of this platform is demonstrated through the development of a fluorometric glucose sensor. Glucose oxidase is enclosed within the water core, while a pH-responsive fluorescent dye is incorporated into the DN shells. Glucose diffuses into the core through the DN shells, where the glucose oxidase converts glucose into gluconic acid, leading to pH reduction and a subsequent decrease in fluorescence intensity of DN shells. Additionally, the pH-sensitive colorant dissolved in the medium enables visual pH assessment. Thus, glucose levels can be determined using both fluorometric and colorimetric methods. Notably, the DN shells exhibit exceptional stability, enduring intense mechanical stress and cycles of drying and rehydration without leakage. Moreover, the DN shells act as effective barriers, safeguarding glucose oxidase against proteolysis by large disruptive proteins, like pancreatin. This versatile DN shell platform extends beyond glucose oxidase encapsulation, serving as a foundation for various capsule sensors utilizing enzymes and heterogeneous catalysts.

ZIF-8 encapsulated-enzymes integrated nanozyme cascade biocatalysis platform for the colorimetric sensing of glucose and lactose in milk

Cascade biocatalytic reactions have a wide range of applications, especially in the filed of food analysis. Herein, a multi-enzyme composite (ZGGPC) was prepared by in-situ synthesis of Zeolite imidazole framework-8 (ZIF-8) on Prussian blue (PB) modified carbon cloth (CC). The composite encapsulated both glucose oxidase and β-galactosidase simultaneously during the synthesis process. CC and ZIF-8 showed high loading capacity for PB and natural enzymes, respectively. And ZIF-8 also displayed excellent tolerance in protecting enzyme activity under extreme conditions. Based on the cascade biocatalysis, ZGGPC was used to detect glucose and lactose by colorimetric method with detection limits of 1.2 μM and 1.7 mM, respectively. Benefiting from the merits of low cost, easy preparation, and good stability, the sensing system was used to successfully determine glucose and lactose in different milk samples. The present cascade biocatalysis system is hopeful to develop simple and efficient sensing platforms for food analysis.

Glucose-driven transformable complex eliminates biofilm and alleviates inflamm-aging for diabetic periodontitis therapy

Diabetic periodontitis is a major complication of diabetes, which has a deep involvement in teeth loss and more serious systematic diseases, including Alzheimer's disease, atherosclerosis and cancers. Diabetic periodontitis is difficult to treat because of recalcitrant infection and hyperglycemia-induced tissue dysfunction. Current treatments fail to completely eliminate infection due to the diffusion-reaction inhibition of biofilm, and ignore the tissue dysfunction. Here, we design a glucose-driven transformable complex, composed of calcium alginate (CaAlg) hydrogel shell and Zeolitic imidazolate framework-8 (ZIF-8) core encapsulating Glucose oxidase (GOx)/Catalase (CAT) and Minocycline (MINO), named as CaAlg@MINO/GOx/CAT/ZIF-8 (CMGCZ). The reaction product of glucose-scavenging, gluconic acid, could dissolve ZIF-8 core and transform CMGCZ from inflexible to flexible, facilitating the complex to overcome the diffusion-reaction inhibition of biofilm. Meanwhile, reduced glucose concentration could ameliorate the pyroptosis of macrophages to decrease the secretion of pro-inflammatory factors, thereby reducing inflamm-aging to alleviate periodontal dysfunction.

Self-Propelled Enzymatic Nanomotors from Prodrug-Skeletal Zeolitic Imidazolate Frameworks for Boosting Multimodel Cancer Therapy Efficiency.

Self-propelled nanomotors, which can autonomous propelled by harnessing others type of energy, have shown tremendous potential as drug delivery systems for cancer therapy. However, it remains challenging for nanomotors in tumor theranostics because of their structural complexity and deficient therapeutic model. Herein, glucose-fueled enzymatic nanomotors (GC6@cPt ZIFs) are developed through encapsulation of glucose oxidase (GOx), catalase (CAT), and chlorin e6 (Ce6) using cisplatin-skeletal zeolitic imidazolate frameworks (cPt ZIFs) for synergetic photochemotherapy. The GC6@cPt ZIFs nanomotors can produce O2 through enzymatic cascade reactions for propelling the self-propulsion. Trans-well chamber and multicellular tumor spheroids experiments demonstrate the deep penetration and high accumulation of GC6@cPt nanomotors. Importantly, the glucose-fueled nanomotor can release the chemotherapeutic cPt and generate reactive oxygen species under laser irradiation, and simultaneously consume intratumoral over-expressed glutathione. Mechanistically, such processes can inhibit cancer cell energy and destroy intratumoral redox balance to synergistically damage DNA and induce tumor cell apoptosis. Collectively, this work demonstrates that the self-propelled prodrug-skeleton nanomotors with oxidative stress activation can highlight a robust therapeutic capability of oxidants amplification and glutathione depletion to boost the synergetic cancer therapy efficiency.

Biomimetic nanoplatform with H2O2 homeostasis disruption and oxidative stress amplification for enhanced chemodynamic therapy.

Chemodynamic therapy (CDT) is a powerful cancer treatment strategy by producing excessive amount of reactive oxygen species (ROS) to kill cancer cells. However, the inadequate hydrogen peroxide (H2O2) supply and antioxidant defense systems in tumor tissue significantly impair the therapeutic effect of CDT, hindering its further applications. Herein, we present an intelligent nanoplatform with H2O2 homeostasis disruption and oxidative stress amplification properties for enhanced CDT. This nanoplatform is obtained by encapsulating glucose oxidase (GOx) in a pH- and glutathione (GSH)-responsive degradable copper doped-zeolitic imidazolate framework (Cu-ZIF8), followed by loading of 3-amino-1,2,4-triazole (3AT) and modification of hyaluronic acid (HA) for tumor targeting delivery. The GOx@Cu-ZIF8-3AT@HA not only reduces energy supply and increases H2O2 level by exhausting intratumoral glucose, but also disturbs tumor antioxidant defense systems by inhibiting the activity of catalase (CAT) and depleting intracellular GSH, resulting in disrupted H2O2 homeostasis in tumor. Moreover, the elevated H2O2 will transform into highly toxic hydroxyl radical (·OH) by Cu+ that generated from redox reaction between Cu2+ and GSH, amplifying the oxidative stress to enhance the CDT efficacy. Consequently, GOx@Cu-ZIF8-3AT@HA has significantly inhibited the 4T1 xenograft tumor growth without discernible side effects, which provides a promising strategy for cancer management. STATEMENT OF SIGNIFICANCE: The inadequate H2O2 level and antioxidant defense system in tumor tissues significantly impair the therapeutic effect of CDT. Herein, we developed an intelligent nanoplatform with H2O2 homeostasis disruption and oxidative stress amplification properties for enhanced CDT. In this nanoplatform, GOx could exhaust intratumoral glucose to reduce energy supply accompanied with production of H2O2, while the suppression of CAT activity by 3AT and depletion of GSH by Cu2+ would weaken the antioxidant defense system of tumors. Ultimately, the raised H2O2 level would convert to highly toxic •OH by Fenton-like reaction, amplifying the CDT efficacy. This work provides a promising strategy for cancer management.

Development of an intelligent heterojunction fenton catalyst for chemodynamic/starvation synergistic cancer therapy

Chemodynamic therapy (CDT) as an emerging modality in cancer treatment, its implementation remains a daunting challenge by the lack of smart Fenton catalyst under acidic tumor microenvironments. Herein, we have successfully constructed a Fe3O4@MIL-100 heterojunction by growing Fe-based metal-organic framework (MIL-100) onto the surface of Fe3O4 nanoparticles. The as-made heterojunction after encapsulating glucose oxidase (termed FMG) is demonstrated as a pH-responsive intelligent Fenton nanosystem with the synergistic effect of starvation therapy (ST). Density functional theory (DFT) calculations reveal that such heterojunction could greatly reduce the energy barrier of the Fenton reaction, which better explains the mechanism of Fenton performance improvement. Moreover, the encapsulated glucose oxidase has successfully activated the ST process, in which its generated H2O2 and gluconic acid further improve the CDT efficiency. More O2 from the enhanced CDT in turn promotes the enzymatic reaction of glucose oxidase. The Fenton/cascade enzymatic reaction operates in a self-feedback manner as proposed. In vitro and in vivo experiments demonstrate that such intelligent Fenton nanoreactors provide a powerful anticancer mechanism for effective tumor ablation with enough safety. This work provides insights into the developments of MOF-based heterojunctions as powerful anticancer treatment nanoreactors.

Prussian Blue-Derived Nanoplatform for In Situ Amplified Photothermal/Chemodynamic/Starvation Therapy

Chemodynamic therapy (CDT) is an emerging tumor treatment; however, it is hindered by insufficient endogenous hydrogen peroxide (H2O2) and high glutathione (GSH) concentrations in the tumor microenvironment (TME). Furthermore, CDT has limited therapeutic efficacy as a monotherapy. To overcome these limitations, in this study, a nanoplatform is designed and constructed from Cu-doped mesoporous Prussian blue (CMPB)-encapsulated glucose oxidase (GOx) with a coating of hyaluronic acid (HA) modified with a nitric oxide donor (HN). In the proposed GOx@CMPB-HN nanoparticles, the dopant Cu2+ ions are crucial to combining and mutually promoting multiple therapeutic approaches, namely, CDT, photothermal therapy (PTT), and starvation therapy. The dopant Cu2+ ions in CMPB protect against reactive oxygen species to deplete the intracellular GSH in the TME. Additionally, the byproduct Cu+ ions act as a substrate for a Fenton-like reaction that activates CDT. Moreover, H2O2, which is another important substrate, is produced in large quantities through intracellular glucose depletion caused by the nanoparticle-loaded GOx, and the gluconic acid produced in this reaction further enhances the TME acidity and creates a better catalytic environment for CDT. In addition, Cu2+ doping greatly improves the mesoporous Prussian blue (MPB) photothermal conversion performance, and the resultant increase in temperature accelerates CDT catalysis. Finally, the HN coating enables the nanoparticles to actively target CD44 receptors in cancer cells and also enhances vascular permeability. Therefore, this coating has multiple effects, such as facilitating enhanced permeability and retention and deep laser penetration. In vitro and in vivo experiments demonstrate that the proposed GOx@CMPB-HN nanoplatform significantly inhibits tumor growth with the help of in situ enhanced synergistic therapies based on the properties of the TME. The developed nanoplatform has the potential to be applied to cancer treatment and introduces new avenues for tumor treatment research.

Portable dual-mode biosensor based on smartphone and glucometer for on-site sensitive detection of Listeria monocytogenes

Contamination of Listeria monocytogenes (L. monocytogenes) in the environment and food can pose a serious threat to human health, and there is an urgent need to establish sensitive on-situ detection methods to mitigate its hazards. In this study, we have developed a field assay that combines magnetic separation technology with antibody-labeled ZIF-8 encapsulating glucose oxidase (GOD@ZIF-8@Ab) to capture and specifically identify L. monocytogenes while GOD catalyzes glucose catabolism to produce signal changes in glucometers. On the other side, horseradish peroxidase (HRP) and 3,3′,5,5′-tetramethylbenzidine (TMB) were added to recombined with the H2O2 generated by the catalyst to form a colorimetric reaction system that changes from colorless to blue. The smartphone software was used for RGB analysis to complete the on-site colorimetric detection of L. monocytogenes. This dual-mode biosensor showed good detection performance for the on-site application of L. monocytogenes in lake water and juice samples, both with a limit of detection up to 101 CFU/mL and a good linear range of 101–106 CFU/mL. Therefore, this dual-mode on-site detection biosensor has a promising application for the early screening of L. monocytogenes in environmental and food samples.

Freezing-assisted reverse microemulsion synthesis of hollow mesoporous silica encapsulated glucose oxidase

Bio-activity conservation of biomolecules after immobilizing in nanomaterials has been a tough challenge, especially in biomedical applications.

Critical Parameters in an Enzymatic Way to Obtain the Unsweet Lactose-Free Milk Using Catalase and Glucose Oxidase Co-Encapsulated into Hydrogel with Chemical Cross-Linking.

The presented work involves obtaining and characterising a two-enzymatic one-pot bioreactor, including encapsulated (co-immobilised) glucose oxidase and catalase. The enzymatic capsules were applied to produce unsweet, lactose-free milk during low-temperature catalysis. Furthermore, operational conditions, like pH and aeration, were selected in the paper, which sorts out discrepancies in literature reports. All experiments were carried out at 12 °C, corresponding to milk storage and transportation temperature. Preliminary studies (for reasons of analytical accuracy) were carried out in a buffer (pH, concentration of sugars mimicking conditions in the lactose-free milk, the initial glucose concentration 27.5 g/L) verified by processes carried out in milk in the final stage of the study. The presented results showed the need for regulating pH and the aeration of the reaction mixture in the continuous mode during the process. The procedure of co-immobilisation was performed in an alginate matrix with the cross-linking of glutaraldehyde or carbodiimide while carbodiimide showed better enzymes retention inside alginate capsules. Co-encapsulated enzymes could be used for nine cycles, preserving finally about 40% of the initial activity.

Glucose oxidase-amplified CO generation for synergistic anticancer therapy via manganese carbonyl-caged MOFs

Carbon monoxide (CO) as one of the therapeutic gaseous molecules has been widely applied for treating various diseases, especially in cancer therapy. However, the in situ-triggered and efficient transport of CO to tumors are the primary obstacles that limit its clinical applicability. To address this obstacle, herein, a H2O2-triggered CO gas releasing nanoplatform has been designed by embedding manganese carbonyl (MnCO) into Zr (IV)-based metal-organic frameworks (MOFs). The porous structures of MOFs provide encapsulation capacity for glucose oxidase (GOx) loading, thereby catalyzing the endogenous glucose into gluconic acid and H2O2 to accelerate CO release and energy depletion. In the meantime, the Mn2+ produced by MnCO can react with intracellular H2O2 via the Fenton reaction to form cytotoxic •OH. Therefore, the synthesized gas nanogenerator demonstrated a synergistic efficacy of CO gas therapy, reactive oxygen species (ROS)-mediated therapy, and energy starvation to prevent tumor growth. Both in vitro and in vivo studies indicated that this multifunctional nanoplatform not only successfully inhibited tumors through a synergistic effect, but also provided a new technique for the creation of starvation/gas/chemodynamic combination therapy in a single material. Statement of significanceIn this study, we developed a H2O2 responsive CO gas nanogenerator to augment the in-situ generation of CO gas for combined modality therapy of tumors. The nanogenerator was constructed by encapsulating glucose oxidase (GOx) and manganese carbonyl (MnCO) into UiO-67-bpy, which can catalyze the conversion of intracellular glucose to H2O2 for cutting off energy supply of cancer cells. Meanwhile, the cumulated H2O2 can trigger the release of CO for gas therapy and generation of •OH for chemodynamic therapy (CDT) via the Fenton-like reaction, thereby resulting in apoptosis of the cancer cells. Collectively, our designed nanotherapeutic agent not only displays the synergistic therapy efficacy of starvation-enhanced CO gas therapy and CDT, but also provides an efficient strategy for developing the intelligent nanocarrier for CO gas delivery and release.

Dual-enzyme cascade amplification electrochemical biosensor for human papillomavirus based on DNA nanoflower structure

The lack of large-scale human papillomavirus (HPV) DNA screening is a major contributor to the high incidence and mortality of cervical cancer in economically undeveloped areas. The development of sensitive, rapid, and low-cost screening techniques is urgently needed. Here, DNA nanoflowers encapsulating glucose oxidase and horseradish peroxidase (GHDFs) were synthesized by one-pot rolling circle amplification, and then the GHDFs were used as the cargo of DNA hydrogel and applied for HPV DNA detection. When target DNA was present, the DNA hydrogel cross-linking structure was disrupted, releasing GHDFs, which then catalysed the oxidation of glucose and tetramethylbenzidine in a cascade, generating a significant electrical signal. Signal intensity had a linear relationship with the logarithm of target DNA concentration in the range of 10 fM-1 nM with a detection limit of 3.76 fM. The detection time of the proposed biosensor was 25 min, which was suitable for large-scale HPV DNA screening in economically underdeveloped areas and provides a blueprint for the detection of other DNA of interest.

Antimicrobial nanozyme-enzyme complex catalyzing cascade reaction of glucose to hydroxyl radical to combat bacterial infection

Bacterial infection is a serious threat to patients and cytotoxic agents that can kill bacterial cells in the high-glucose environment will be a potential therapy. In this work, we load hollow mesoporous Prussian blue nanoparticle (HMPBNP) with glucose oxidase (GOx) to devise a nanozyme-enzyme complex HMPBNP@GOx to achieve the generation of the cytotoxic hydroxyl radical (OH) in situ at the infected wounds. The HMPBNP with peroxidase-like activity can catalyze the conversion of the non-natural, toxic substrate, hydrogen peroxide (H2O2) to OH. Here, encapsulation of GOx in HMPBNP couples GOx-catalyzed conversion of glucose to H2O2 with HMPBNP-catalyzed reaction of H2O2 to OH, which exerts a short-range bacterial killing effect. One of the challenges of the nanozyme-enzyme cascade systems is the incompatibility of the reaction conditions of the two catalysts. In our design, GOx catalyzed oxidation also produces glucuronic acid, which increases the acidity of the microenvironment to increase the activity of HMPBNP. This synergy drives efficient cascade flow towards the production of OH. The HMPBNP@GOx complex effectively inhibits the growth of Staphylococcus aureus and Escherichia coli and their infectivity to mammalian cells, reduces bacterial infection in vivo, and promotes wound healing in the animal model of Staphylococcus infected wounds.