Carbon Nanozymes Research Articles

SOD1 Is an Integral Yet Insufficient Oxidizer of Hydrogen Sulfide in Trisomy 21 B Lymphocytes and Can Be Augmented by a Pleiotropic Carbon Nanozyme

SOD1 Is an Integral Yet Insufficient Oxidizer of Hydrogen Sulfide in Trisomy 21 B Lymphocytes and Can Be Augmented by a Pleiotropic Carbon Nanozyme

Self-adaptive carbon nanozyme regulation of ROS balance for bacteria-infected wound therapy

Nanozymes sterilizing drug-resistant (DR) bacteria by generating reactive oxygen species (ROS) have emerged as a promising approach for treating infected wounds. However, designing biocompatible adaptive ROS balance therapeutic platform for DR bacteria-infected wounds remains a great challenge. Herein, biocompatible lignin-based carbon dot nanomaterials (LCDs-OA) with more CO and COOH functional groups on the surface were prepared by hydrothermal organic acid co-processing and used as a dual enzyme-like active nanozyme for the therapy of wounds infected by DR bacteria. Experimental and theoretical calculations demonstrated that the CO and COOH functional groups in LCDs-OA have site-switching roles in the dual enzyme-like activity, which can balance reactive oxygen species (ROS) according to the changes in microenvironmental pH at the wound site, and realize the adaptive regulation of ROS generation for bactericidal and ROS scavenging for healing. Furthermore, the performance differences between different organic acid treatments were investigated and an adaptive ROS balance therapeutic platform (LCDs-OA@CaO2) was constructed to overcome the major limitation in treating DR bacterial infected wounds. The system achieved >99.6 % in vitro antimicrobial efficiency against DR bacteria and was highly biocompatible while effectively reducing oxidative damage to normal tissues, resulting in satisfactory therapeutic results in repairing wounds infected with DR bacteria.

Vanadium doped ZIF-L derived V-NC peroxidase-like nanozymes for tannic acid sensing

Transition metal-based nitrogen doping carbon nanozyme has attracted great attention owning to their high potential to replace natural enzymes. In this study, we prepared novel vanadium doped ZIF-L derived N-doped carbon nanozyme (V-NC) via facilely pyrolysis strategy. The cross-shaped morphology endows V-NC with unique V-Nx active sites, hierarchical pore character and large specific surface area, leading to its good peroxidase-mimetic activity. The steady-state kinetics trials revealed the low Km values of V-NC for TMB and H2O2, demonstrating its good affinity to TMB and H2O2. Mechanism research revealed that the excellent peroxidase-like activity of V-NC resulted from co-participation of •OH and O2•−, which were confirmed by reactive oxygen species (ROS) scavenging experiments and EPR trials. Under optimized operational conditions, and by virtue of the antioxidant properties of tannic acid (TA), a colorimetric sensing assay based on the peroxidase-like activity of V-NC was developed for sensitive detection of TA in the 0.1–2.5 µM linear range with low detection limit of 19.8 nM and the relative standard deviation (RSD, n = 3) of below 5%. This work renders a new idea for designing and developing high activity N-doped carbon nanozyme, and provides an accurate and feasible assay for the analysis of TA in real samples.

Molecularly imprinted electrochemiluminescence-colorimetric dual-mode sensor based on Mn@NC nanozyme amplification for the detection of phoxim

The common detection methods of phoxim mostly rely on the output mode of single signal, which is easily disturbed by complex environmental media and causes errors. Herein, in order to improve the reliability of detection, we developed a dual-mode detection strategy based on nanozyme for the detection of phoxim. Firstly, manganese-nitrogen co-doped carbon nanozyme (Mn@NC) with peroxidase-like activity was synthesized by one-step pyrolysis, which was used to construct in the luminol-H2O2 electrochemiluminescence (ECL) system with molecularly imprinted polymer (MIP) technology. Among them, Mn@NC can act as a co-reaction promoter to catalyze H2O2 to produce large amounts of hydroxyl radicals (•OH), thereby significantly amplifying the cathode signal of luminol and improving the stability of the signal. Benefiting from the specific selection of phoxim by MIP, this molecularly imprinted electrochemiluminescence (MIECL) mode has considerable sensitivity and selectivity, with a low limit of detection (LOD) of 0.011 ng/mL (S/N = 3). Moreover, the •OH produced by Mn@NC-catalyzed H2O2 oxidized the colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to blue oxidized TMB (oxTMB). Taking advantage of the fact that the simultaneous presence of acetylcholinesterase (AChE) and acetylthiocholine (ATCh) inhibited the activity of Mn@NC. A sensitive and simple colorimetric pesticide sensing platform was constructed by combining the nanozyme with the TMB-H2O2 system to achieve the colorimetric detection of phoxim, with the LOD as low as 1.27 ng/mL. The dual-mode sensor was successfully applied to the determination of phoxim in agricultural products with satisfactory results, showing its great potential in the monitoring of food hazards.

Oxidized Carbon Nanoparticles Enhance Cellular Energetics With Application to Injured Brain.

Pro-energetic effects of functionalized, oxidized carbon nanozymes (OCNs) are reported. OCNs, derived from harsh acid oxidation of single-wall carbon nanotubes or activated charcoal are previously shown to possess multiple nanozymatic activities including mimicking superoxide dismutase and catalyzing the oxidation of reduced nicotinamide adenine dinucleotide (NADH) to NAD+. These actions are predicted to generate a glycolytic shift and enhance mitochondrial energetics under impaired conditions. Impaired mitochondrial energy metabolism is increasingly recognized as an important facet of traumatic brain injury (TBI) pathophysiology and decreases the efficiency of electron transport chain (ETC)-coupled adenosine triphosphate (ATP) and NAD+ regeneration. In vitro, OCNs promote a pro-aerobic shift in energy metabolism that persists through ETC inhibition and enhances glycolytic flux, glycolytic ATP production, and cellular generation of lactate, a crucial auxiliary substrate for energy metabolism. To address specific mechanisms of iron injury from hemorrhage, OCNs with the iron chelator, deferoxamine (DEF), covalently-linked were synthesized. DEF-linked OCNs induce a glycolytic shiftin-vitroandin-vivoin tissue sections from a rat model of TBI complicated by hemorrhagic contusion. OCNs further reduced hemorrhage volumes 3 days following TBI. These results suggest OCNs are promising as pleiotropic mediators of cell and tissue resilience to injury.

A Novel Colorimetric Biosensor for the Detection of Catalase-Positive Staphylococcus aureus Based on an Onion-like Carbon Nanozyme

Staphylococcus aureus is one of the leading causes of skin and soft tissue infections, and it is even life-threatening if it enters the bloodstream, lung or heart. In the present work, we proposed a novel colorimetric biosensor for the detection of S. aureus through hydrogen peroxide consumption. An onion-like carbon nanozyme with high peroxidase-like activity was prepared, which competed with the endogenous catalase of S. aureus in consuming hydrogen peroxide. This reaction was further characterized by the colorimetric reaction of 3,3′,5,5′-tetramethylbenzidine. The results showed that our approach allowed for the simple and rapid determination of S. aureus, with a linear range of 2 × 104 to 2 × 107 CFU/mL. Moreover, our method displayed good selectivity, with Bacillus subtilis and Escherichia coli showing negligible responses at the concentration of 2 × 105 CFU/mL. The application of the as-prepared biosensor to analyze S. aureus in real water samples yielded recovery rates ranging from 95% to 112%, with relative standard deviations less than 7%. The method demonstrated good accuracy and specificity, which offers a novel approach for the simple and selective detection of S. aureus.

Electronic structure engineering of N-doped carbon nanozyme via incorporating Cl and sp3-hybridized defected carbon for organophosphorus pesticides assay

Metal-free carbon-based nanozymes often exhibit superior chemical stability and detection reliability compared to their metal-doped counterparts. However, their catalytic activity remains an area ripe for further enhancement. Herein, we successfully prepared a chlorine (Cl)-modified, metal-free, and porous N-doped carbon nanozyme (Clx-pNC) via NaCl molten etching. The incorporation of Cl induced an increase in the intrinsic defects of sp3-hybridized carbon within Clx-pNC and optimized the electronic structure of the N-connected carbon atoms. Remarkably, the peroxidase (POD)-like activity of Clx-pNC was enhanced twelvefold compared to porous N-doped carbon (pNC). Theoretical simulations highlighted that the introduction of Cl not only promoted H2O2 adsorption but also lowered the energy barrier for its decomposition, facilitating the generation of active intermediates and thus boosting POD-like activity. Based on the POD mimic activity of Clx-pNC, we developed a colorimetric platform for OPs detection utilizing a cascade amplification strategy. This work provides insights into the rational design of carbon-based nanozymes and the development of nanozyme-based colorimetric biosensors.

Innovative Colorimetric NQO1 Detection Strategy via Substrate Competitive and Biomimetic Cascade Reactions with a Highly Active NADH Oxidase Mimic.

NAD(P)H: quinone oxidoreductase-1 (NQO1) plays critical roles in antioxidation and abnormally overexpresses in tumors. Developing a fast and sensitive method of monitoring NQO1 will greatly promote cancer diagnosis in clinical practice. This study introduces a transformative colorimetric detection strategy for NQO1, harnessing an innovative competitive substrate mechanism between NQO1 and a new NADH oxidase (NOX) mimic, cobalt-nitrogen-doped carbon nanozyme (CoNC). This method ingeniously exploits the differential consumption of NADH in the presence of NQO1 to modulate the generation of H2O2 from CoNC catalysis, which is then quantified through a secondary, peroxidase-mimetic cascade reaction involving Prussian blue (PB) nanoparticles. This dual-stage reaction framework not only enhances the sensitivity of NQO1 detection, achieving a limit of detection as low as 0.67 μg mL-1, but also enables the differentiation between cancerous and noncancerous cells by their enzymatic activity profiles. Moreover, CoNC exhibits exceptional catalytic efficiency, with a specific activity reaching 5.2 U mg-1, significantly outperforming existing NOX mimics. Beyond mere detection, CoNC serves a dual role, acting as both a robust mimic of cytochrome c reductase (Cyt c) and a cornerstone for enzymatic regeneration, thereby broadening the scope of its biological applications. This study not only marks a significant step forward in the bioanalytical application of nanozymes but also sets the stage for their expanded use in clinical diagnostics and therapeutic monitoring.

Pt-Cluster-Embedded Metal-Organic Frameworks-Derived Fe@C as Dual-Enzyme Mimics for NADH Detection in Serum.

Dihydro-nicotinamide adenine dinucleotide (NADH) detection is crucial since it is a vital coenzyme in organism metabolism. Compared to the traditional method based on natural NADH oxidase (NOX), nanozymes with multienzyme-like activity can catalyze multistage reactions in a singular setup, simplifying detection processes and enhancing sensitivity. In this study, an innovative NADH detection method was developed using iron-doped carbon (Fe@C) nanozyme synthesized from metal-organic frameworks with in situ reduced Pt clusters. This nanozyme composite (Pt/Fe@C) demonstrated dual NOX and peroxidase-like characteristics, significantly enhancing the catalytic efficiency and enabling NADH conversion to NAD+ and H2O2 with subsequent detection. The collaborative research involving both experimental and theoretical simulations has uncovered the catalytic process and the cooperative effect of Fe and Pt atoms, leading to enhanced oxygen adsorption and activation, as well as a decrease in the energy barrier of the key step in the H2O2 decomposition process. These findings indicate that the catalytic performance of Pt/Fe@C in NOX-like and POD-like reactions can be significantly improved. The colorimetric sensor detects NADH with a limit of detection as low as 0.4 nM, signifying a breakthrough in enzyme-mimicking nanozyme technology for precise NADH measurement.

Self-assembling gelatin based delivery of multienzyme activity nanozyme and photosensitizer for ROS storm based cancer therapy

Nanozymes with multienzyme activity for reactive oxygen species (ROS) generation and intracellular redox imbalance are attractive strategy for cancer therapy. However, it is severely limited by low biocompatibility and catalytic efficiency, hypoxic and high levels of GSH in the tumor microenvironment. To address these issues, a copper doping carbon nanozyme (CC) with multienzyme activity was designed and integrated with photosensitizer Ce6 and gelatin to fabricate ROS amplifier (CCC). Gelatin endowed CCC with good biocompatibility, low hemolysis, and enzyme responsive degradation. CCC with high CAT-like, POD-like, OXD-like, and GSHox-like activities can induce the intracellular ROS storm formation to eliminate the cancer cells. The OXD-like activity and PDT performance mediated 1O2 generation was markedly potentiated by the CAT-like activity of CCC via catalyzing high expression of H2O2 to generate O2. At the same time, a large amount of ·OH were produced through POD-like activity of CCC and GSH was depleted by the GSHox-like activities of CCC, resulting in a destructive ROS storm formation and cellular redox homeostasis disruption. Both in vivo and in vitro experiments showed that CCC displayed satisfactory anti-tumor activity and biocompatibility. Our work provides a novel strategy for the development of nanozyne enhanced photodynamic therapy of cancer.

Oxidation of Hydrogen Sulfide to Polysulfide and Thiosulfate by a Carbon Nanozyme: Therapeutic Implications with an Emphasis on Down Syndrome (Adv. Mater. 10/2024)

Oxidation of Hydrogen Sulfide to Polysulfide and Thiosulfate by a Carbon Nanozyme: Therapeutic Implications with an Emphasis on Down Syndrome (Adv. Mater. 10/2024)

Rational Biomimetic Construction of Lignin-based Carbon Nanozyme for Identification of Uric Acid in Human Urine

Nanozymes have made remarkable progress in the field of sensing assays by replacing native enzyme functions. However, it is still a challenge to rationally design active centers from molecular structure to enhance the catalytic performance and develop low-cost nanozymes. In this work, guided by the catalytic site of horseradish peroxidase (HRP), iron source and histidine were coupled to the main chain of aminated sodium lignosulfonate (SL) through the self-assembly biomimetic strategy to construct His-SL-Fe with peroxidase activity. The inherent functional groups and basic framework of aminated SL provide a robust environment and promote the formation of active sites. His-SL-Fe shows excellent robustness over multiple test cycles and has a strong affinity for the substrate compared to HRP. His-SL-Fe had been effectively integrated in the sensing system for catalytic detection of uric acid (UA) to achieve accurate recognition of UA in the range of 0.5–100 μM with the limit of detection as low as 0.18 μM. The recovery of human urine samples is in the range of 96.8%–106.1 % and the error is within 4 %. This work not only provides a new approach for the directed design of high-performance nanozymes, but also demonstrates promising ideas for the refined application of biomass resources.

Biotemplated fabrication of N/O co-doped porous carbon confined spinel NiFe2O4 heterostructured mimetics for triple-mode sensing of antioxidants and ameliorating packaging properties

In this work, shrimp shell-derived magnetic NiFe2O4/N, O co-doped porous carbon nanozyme with superior oxidase (OXD)-like activity was prepared and used for colorimetric/photothermal/smartphone dual-signal triple-mode detection of antioxidants in fruits and beverages. The magnetic NiFe2O4/N, O co-doped porous carbon (MNPC) material was triumphantly fabricated using a combined in-situ surface chelation and pyrolysis method. The resultant MNPC composite exhibits a superior OXD-like activity, which can effectively oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) for yielding colorimetric/temperature dual-signal (CTDS) in absence of H2O2. This CTDS output sensor was successfully used for the determination of ascorbic acid and tannic acid. The proposed CTDS sensor with good specificity and high sensitivity can satisfy different on-site analysis requirements. Interestingly, the MNPC as a sustainable filler was further used for improving packaging properties of polyvinyl alcohol film. In short, this work offers a large-scale and cheap method to fabricate magnetic carbon-based nanozyme for monitoring antioxidants and ameliorating packaging properties.

Cascade selective recognition of H2O2 and ascorbic acid in living cells using carbon-based nanozymes with peroxidase-like activity

The design of optical nanosensors based on carbon nanozymes has gained considerable interest in analyte detection. In this study, a simple and rapid fluorescence/colorimetry probe, NH2GQDs/o-phenylenediamine (OPD), was constructed by combining amino-functionalized graphene quantum dots (NH2GQDs) and o-phenylenediamine. In the presence of NH2GQDs/H2O2, OPD was oxidized to 2,3-diaminophenazine (DAP), giving fluorescent and colorimetric signals, which can be used to quantitatively measure H2O2. Furthermore, NH2GQDs/OPD/ H2O2 exhibited high selectivity and sensitivity for detecting ascorbic acid (AA) with a detection limit of 0.062 μM using the fluorescent method. Its selectivity for AA was ascribed to the formation of the condensation compound of DAP with dehydroascorbic acid rather than the quinoxaline path for dopamine and glucose. The colorimetric sensing system NH2GQDs/OPD displayed yellow in the presence of H2O2, while it changed to green upon adding AA. This sensing system was successfully applied for imaging H2O2 and AA in human cervical cancer cells and onion tissues. Additionally, the flexible sensing system can be used to fabricate the logic gate “AND.” The results provide a valuable method for its potential application in the biosensing, clinical medicine, and food industries.

N, P, S Codoped Carbon Nanozymes with Enhanced Peroxidase-like Activity and Binding Affinity for Total Antioxidant Capacity Assay

N, P, S Codoped Carbon Nanozymes with Enhanced Peroxidase-like Activity and Binding Affinity for Total Antioxidant Capacity Assay

A Mild Hyperthermia Hollow Carbon Nanozyme as Pyroptosis Inducer for Boosted Antitumor Immunity.

The immune checkpoint blockade (ICB) antibody immunotherapy has demonstrated clinical benefits for multiple cancers. However, the efficacy of immunotherapy in tumors is suppressed by deficient tumor immunogenicity and immunosuppressive tumor microenvironments. Pyroptosis, a form of programmed cell death, can release tumor antigens, activate effective tumor immunogenicity, and improve the efficiency of ICB, but efficient pyroptosis for tumor treatment is currently limited. Herein, we show a mild hyperthermia-enhanced pyroptosis-mediated immunotherapy based on hollow carbon nanozyme, which can specifically amplify oxidative stress-triggered pyroptosis and synchronously magnify pyroptosis-mediated anticancer responses in the tumor microenvironment. The hollow carbon sphere modified with iron and copper atoms (HCS-FeCu) with multiple enzyme-mimicking activities has been engineered to induce cell pyroptosis via the radical oxygen species (ROS)-Tom20-Bax-Caspase 3-gasdermin E (GSDME) signaling pathway under light activation. Both in vitro and in vivo antineoplastic results confirm the superiority of HCS-FeCu nanozyme-induced pyroptosis. Moreover, the mild photothermal-activated pyroptosis combining anti-PD-1 can enhance antitumor immunotherapy. Theoretical calculations further indicate that the mild photothermal stimulation generates high-energy electrons and enhances the interaction between the HCS-FeCu surface and adsorbed oxygen, facilitating molecular oxygen activation, which improves the ROS production efficiency. This work presents an approach that effectively transforms immunologically "cold" tumors into "hot" ones, with significant implications for clinical immunotherapy.

A metal–organic framework-derived ruthenium–nitrogen–carbon nanozyme for versatile hydrogen sulfide and cystathionine γ-lyase activity assay

In this study, a novel approach exploiting the interactions between hydrogen sulfide (H2S) and ruthenium-nitrogen-carbon (Ru–N–C) nanozymes is presented, advancing H2S and cystathionine γ-lyase (CSE) biosensing techniques. Utilizing the intrinsic peroxidase-like activity of Ru–N–C nanozymes and the noticeable inhibition effect caused by H2S, an efficient, simple, and economical assay has been developed. This innovative method allows for the versatile real-time monitoring of H2S from various sources, including specialized donors and native bacterial production. Furthermore, the assay has been applied to reveal the interactions within tumor cells and tissues ex vivo, providing a clearer and simpler view of CSE expression levels through an improved colorimetric method. This contribution enhances our understanding of the complex roles of H2S metabolism and represents a significant advancement in the versatile application of nanozymes in biomedical research.

Enhanced mimic peroxidase activity of carbon nanozyme by simultaneous phosphorus, oxygen dual-heteroatom doping and nanosheet structure construction

The carbon-based nanomaterials with peroxidase-like property show huge potential as candidates for natural enzymes. The design of carbon nanozymes with high activity can expand their potential application. Herein, the carbon nanozymes with enhanced catalytic property by simultaneous phosphorus, oxygen dual-doping and nanosheet structure construction are fabricated through one-step pyrolysis process. The dual-doped phosphorus and oxygen element is conducive to accelerate electron transfer and form active site with moderate free energy for activation of H2O2 to ·OH. Besides, the nanosheet structure with enlarged surface area is beneficial to expose more catalytic sites. Benefiting from its great peroxides-like activity, the phosphorus, oxygen dual-doped carbon nanosheet materials (POCNS) are used in colorimetric determination of H2O2 and glucose with cascade reaction of glucose oxidase and POCNS. And the sensitive colorimetric detection assay for organophosphorus pesticide of chlorpyrifos was constructed with regulation of peroxidase-like activity by aptamer. The system of POCNS and H2O2 further displays great antibacterial property in inactivation of Escherichia coli. This work provides an avenue to construct high-efficient carbon nanozymes and develop their potential application in environmental and biological field.

Hydrolysis enabled specific colorimetric assay of carbosulfan with sensitivity manipulation via metal-doped or metal-free carbon nanozyme

Precise determination of the carbamate pesticide carbosulfan is crucial for assessing the associated risks in food and environment. Due to the strong interaction between carbosulfan and target enzyme, current methods primarily depend on the acetylcholinesterase (AChE) inhibition strategy, which generally lacks selectivity. In this study, we propose a nanozyme colorimetric sensor for the specific carbosulfan detection, based on its distinctive hydrolysis property. In contrast to other pesticides, carbosulfan can be hydrolyzed to produce the reductive sulfide compound by the cleavage of N–S bond under acidic condition, thereby significantly hindering the nanozyme-mediated chromogenic reaction. Consequently, the absorbance is significantly correlated with carbosulfan concentration. Furthermore, the influence of nanozyme type is disclosed, and two oxidase-like carbon nanozymes were formulated, namely metal-free NC and metal-based CeO2@NC. However, the distinct active sites significantly impact the proposed sensor. For CeO2@NC-based sensor, the produced sulfide compounds not only poison Ce active site, but also consume the reactive oxygen species, thereby, exhibiting high sensitivity with low detection limit of 3.3 nM. By contrast, the metal-free nature of NC allows the assay to remain unaffected by coordination effects, exhibiting superior anti-interference capability. This work not only offers an efficient alternative to the conventional method for detecting carbosulfan specifically, but also shed light on the role of metal-based or metal-free nanozyme among analytical applications.

A Covalent Organic Framework Derived N-doped Carbon Nanozyme as the All-rounder for Targeted Catalytic Therapy and NIR-II Photothermal Therapy of Cancer.

Nanomaterials with intrinsic enzyme-like activities (nanozymes) have gained significant attention in cancer catalytic therapy; however, developing metal-free nanozymes with multivariant enzyme-like activity as the "all-rounder" for cancer therapy remains challenging. Herein, a covalent organic framework (COF) derived carbon-based nanozyme is rationally devised to achieve synergistic catalytic therapy and second near-infrared (NIR-II) photothermal therapy of cancer. The developed nanozyme possesses multivariant enzyme-like activities, including oxidase (OXD)-like, catalase (CAT)-like, and peroxidase (POD)-like catalytic activities, which enables the nanozyme to produce adequate reactive oxygen species (ROS) for cancer cell killing. Furthermore, the nanozyme showed excellent photothermal converting activity that could kill cancer cells upon NIR-II laser irradiation, owing to the strong NIR-II absorption capacity of carbon-based materials. It is also worth noting that the nanozyme exhibited cytotoxicity specifically in tumor tissue profiting from the discrepant H2O2 level between tumor and normal tissue and the spatiotemporal controllability of laser irradiation. This work may inspire further development of intelligent nanozymes in biological applications across broad therapeutic and biomedical fields.