Biodegradable and Peroxidase-Mimetic Boron Oxynitride Nanozyme for Breast Cancer Therapy

Metal nanozymes modulation of reactive oxygen species as promising strategies for cancer therapy

Nanozymes, nanostructured materials emulating natural enzyme activities, exhibit potential in catalyzing reactive oxygen species (ROS) production for cancer treatment. By facilitating oxidative reactions, elevating ROS levels, and influencing the tumor microenvironment (TME), nanozymes foster the eradication of cancer cells. Noteworthy are their superior stability, ease of preservation, and cost-effectiveness compared to natural enzymes, rendering them invaluable for medical applications. This comprehensive review intricately explores the interplay between ROS and tumor therapy, with a focused examination of metal-based nanozyme strategies mitigating tumor hypoxia. It provides nuanced insights into diverse catalytic processes, mechanisms, and surface modifications of various metal nanozymes, shedding light on their role in intra-tumoral ROS generation and applications in antioxidant therapy. The review concludes by delineating specific potential prospects and challenges associated with the burgeoning use of metal nanozymes in future tumor therapies.

Thermoresponsive and Substrate Self-Cycling Nanoenzyme System for Efficient Tumor Therapy

Cerium oxide (CeO2-x) performs well in photothermal and catalytic properties due to its abundance of oxygen vacancies. Based on this, we designed a thermosensitive therapeutic nanoplatform to achieve continuous circular drug release in tumor. It can solve the limitation caused by insufficient substrate in the process of tumor treatment. Briefly, CeO2-x and camptothecin (CPT) were wrapped in an agarose hydrogel, which could be melted by the photothermal effect of CeO2-x. At the same time, the local temperature increase provided photothermal treatment, which could induce the apoptosis of tumor cell. After that, CPT was released to damage the DNA in tumor cells to realize chemical treatment. In addition, CPT could active nicotinamide adenine dinucleotide oxidase to react with O2 to increase the intracellular H2O2. After that, the exposed CeO2-x could catalyze H2O2 to generate cytotoxic reactive oxygen species for chemodynamic therapy. More importantly, CeO2-x could catalyze H2O2 to produce O2, which could combine with the catalytic action of CPT to construct a substrate self-cycling nanoenzyme system. Overall, this self-cycling nanoplatform released hypoxia in the tumor microenvironment and built a multimode tumor treatment, which achieved an ideal antitumor affect.

Nanoenzymes: A Radiant Hope for the Early Diagnosis and Effective Treatment of Breast and Ovarian Cancers

Breast and ovarian cancers, despite having chemotherapy and surgical treatment, still have the lowest survival rate. Experimental stages using nanoenzymes/nanozymes for ovarian cancer diagnosis and treatment are being carried out, and correspondingly the current treatment approaches to treat breast cancer have a lot of adverse side effects, which is the reason why researchers and scientists are looking for new strategies with less side effects. Nanoenzymes have intrinsic enzyme-like activities and can reduce the shortcomings of naturally occurring enzymes due to the ease of storage, high stability, less expensive, and enhanced efficiency. In this review, we have discussed various ways in which nanoenzymes are being used to diagnose and treat breast and ovarian cancer. For breast cancer, nanoenzymes and their multi-enzymatic properties can control the level of reactive oxygen species (ROS) in cells or tissues, for example, oxidase (OXD) and peroxidase (POD) activity can be used to generate ROS, while catalase (CAT) or superoxide dismutase (SOD) activity can scavenge ROS. In the case of ovarian cancer, most commonly nanoceria is being investigated, and also when folic acid is combined with nanoceria there are additional advantages like inhibition of beta galactosidase. Nanocarriers are also used to deliver small interfering RNA that are effective in cancer treatment. Studies have shown that iron oxide nanoparticles are actively being used for drug delivery, similarly ferritin carriers are used for the delivery of nanozymes. Hypoxia is a major factor in ovarian cancer, therefore MnO2-based nanozymes are being used as a therapy. For cancer diagnosis and screening, nanozymes are being used in sonodynamic cancer therapy for cancer diagnosis and screening, whereas biomedical imaging and folic acid gold particles are also being used for image guided treatments. Nanozyme biosensors have been developed to detect ovarian cancer. This review article summarizes a detailed insight into breast and ovarian cancers in light of nanozymes-based diagnostic and therapeutic approaches.

Cu-BTC Derived Mesoporous CuS Nanomaterial as Nanozyme for Colorimetric Detection of Glutathione

In this paper, Cu-BTC derived mesoporous CuS nanomaterial (m-CuS) was synthesized via a two-step process involving carbonization and sulfidation of Cu-BTC for colorimetric glutathione detection. The Cu-BTC was constructed by 1,3,5-benzenetri-carboxylic acid (H3BTC) and Cu2+ ions. The obtained m-CuS showed a large specific surface area (55.751 m2/g), pore volume (0.153 cm3/g), and pore diameter (15.380 nm). In addition, the synthesized m-CuS exhibited high peroxidase-like activity and could catalyze oxidation of the colorless substrate 3,3',5,5'-tetramethylbenzidine to a blue product. Peroxidase-like activity mechanism studies using terephthalic acid as a fluorescent probe proved that m-CuS assists H2O2 decomposition to reactive oxygen species, which are responsible for TMB oxidation. However, the catalytic activity of m-CuS for the oxidation of TMB by H2O2 could be potently inhibited in the presence of glutathione. Based on this phenomenon, the colorimetric detection of glutathione was demonstrated with good selectivity and high sensitivity. The linear range was 1-20 μM and 20-300 μM with a detection limit of 0.1 μM. The m-CuS showing good stability and robust peroxidase catalytic activity was applied for the detection of glutathione in human urine samples.

Micronutrient Status and Breast Cancer: A Narrative Review

Breast cancer is one of the most common cancers worldwide, at the same time being one of the most prevalent causes of women's death. Many factors such as alcohol, weight fluctuations, or hormonal replacement therapy can potentially contribute to breast cancer development and progression. Another important factor in breast cancer onset includes micronutrient status. In this narrative review, we analyzed 23 micronutrients and their possible influence on breast cancer onset and progression. Further, the aim of this study was to investigate the impact of micronutrient status on the prevention of breast cancer and its possible influence on various therapeutic pathways. We researched meta-analyses, systemic and narrative reviews, retrospective studies, as well as original studies on human and animal models. The results of these studies indicate a possible correlation between the different levels of micronutrients and a decreased risk of breast cancer as well as a better survival rate. However, further studies are necessary to establish adequate doses of supplementation of the chosen micronutrients and the exact mechanisms of micronutrient impact on breast cancer therapy.

Nanozymes with biomimetically designed properties for cancer treatment

Nanozymes, as a type of nanomaterials with enzymatic catalytic activity, have demonstrated tremendous potential in cancer treatment owing to their unique biomedical properties. However, the heterogeneity of tumors and the complex tumor microenvironment pose significant challenges to the in vivo catalytic efficacy of traditional nanozymes. Drawing inspiration from natural enzymes, scientists are now using biomimetic design to build nanozymes from the ground up. This approach aims to replicate the key characteristics of natural enzymes, including active structures, catalytic processes, and the ability to adapt to the tumor environment. This achieves selective optimization of nanozyme catalytic performance and therapeutic effects. This review takes a deep dive into the use of these biomimetically designed nanozymes in cancer treatment. It explores a range of biomimetic design strategies, from structural and process mimicry to advanced functional biomimicry. A significant focus is on tweaking the nanozyme structures to boost their catalytic performance, integrating them into complex enzyme networks similar to those in biological systems, and adjusting functions like altering tumor metabolism, reshaping the tumor environment, and enhancing drug delivery. The review also covers the applications of specially designed nanozymes in pan-cancer treatment, from catalytic therapy to improved traditional methods like chemotherapy, radiotherapy, and sonodynamic therapy, specifically analyzing the anti-tumor mechanisms of different therapeutic combination systems. Through rational design, these biomimetically designed nanozymes not only deepen the understanding of the regulatory mechanisms of nanozyme structure and performance but also adapt profoundly to tumor physiology, optimizing therapeutic effects and paving new pathways for innovative cancer treatment.

Nanocatalysts for modulating antitumor immunity: fabrication, mechanisms and applications

Immunotherapy harnesses the inherent immune system in the body to generate systemic antitumor immunity, offering a promising modality for defending against cancer. However, tumor immunosuppression and evasion seriously restrict the immune response rates in clinical settings. Catalytic nanomedicines can transform tumoral substances/metabolites into therapeutic products in situ, offering unique advantages in antitumor immunotherapy. Through catalytic reactions, both tumor eradication and immune regulation can be simultaneously achieved, favoring the development of systemic antitumor immunity. In recent years, with advancements in catalytic chemistry and nanotechnology, catalytic nanomedicines based on nanozymes, photocatalysts, sonocatalysts, Fenton catalysts, electrocatalysts, piezocatalysts, thermocatalysts and radiocatalysts have been rapidly developed with vast applications in cancer immunotherapy. This review provides an introduction to the fabrication of catalytic nanomedicines with an emphasis on their structures and engineering strategies. Furthermore, the catalytic substrates and state-of-the-art applications of nanocatalysts in cancer immunotherapy have also been outlined and discussed. The relationships between nanostructures and immune regulating performance of catalytic nanomedicines are highlighted to provide a deep understanding of their working mechanisms in the tumor microenvironment. Finally, the challenges and development trends are revealed, aiming to provide new insights for the future development of nanocatalysts in catalytic immunotherapy.

Nanozyme-Based Regulation of Cellular Metabolism and Their Applications

Metabolism is the sum of the enzyme-dependent chemical reactions, which produces energy in catabolic process and synthesizes biomass in anabolic process, exhibiting high similarity in mammalian cell, microbial cell, and plant cell. Consequently, the loss or gain of metabolic enzyme activity greatly affects cellular metabolism. Nanozymes, as emerging enzyme mimics with diverse functions and adjustable catalytic activities, have shown attractive potential for metabolic regulation. Although the basic metabolic tasks are highly similar for the cells from different species, the concrete metabolic pathway varies with the intracellular structure of different species. Here, the basic metabolism in living organisms is described and the similarities and differences in the metabolic pathways among mammalian, microbial, and plant cells and the regulation mechanism are discussed. The recent progress on regulation of cellular metabolism mainly including nutrient uptake and utilization, energy production, and the accompanied redox reactions by different kinds of oxidoreductases and their applications in the field of disease therapy, antimicrobial therapy, and sustainable agriculture is systematically reviewed. Furthermore, the prospects and challenges of nanozymes in regulating cell metabolism are also discussed, which broaden their application scenarios.

Employing Noble Metal-Porphyrins to Engineer Robust and Highly Active Single-Atom Nanozymes for Targeted Catalytic Therapy in Nasopharyngeal Carcinoma

Single-atom nanozymes (SANzymes) emerge as promising alternatives to conventional enzymes. However, chemical instability limits their application. Here, a systematic synthesis of highly active and stable SANzymes is presented by leveraging noble metal-porphyrins. Four noble metal-porphyrins are successfully synthesized to mimic the active site of natural peroxidases through atomic metal-N coordination anchored to the porphyrin center. These noble metal-porphyrins are integrated into a stable and biocompatible Zr-based metal-organic framework (MxP, x denoting Ir, Ru, Pt, and Pd). Among these, MIrP demonstrates superior peroxidase-like activity (685.61 U mg-1 ), catalytic efficiency, and selectivity compared to horseradish peroxidase (267.71 U mg-1 ). Mechanistic investigations unveil heightened catalytic activity of MIrP arises from its robust H2 O2 adsorption capacity, unique rate-determining step, and low energy threshold. Crucially, MIrP exhibits remarkable chemical stability under both room temperature and high H2 O2 concentrations. Further, through modification with (-)-Epigallocatechin-3-Gallate, a natural ligand for Epstein-Barr virus (EBV)-encoded latent membrane protein 1, targeted SANzyme (MIrPHE) tailored for EBV-associated nasopharyngeal carcinoma is engineered. This study not only presents an innovative strategy for augmenting the catalytic activity and chemical stability of SANzymes but also highlights the substantial potential of MIrP as a potent nanomedicine for targeted catalytic tumor therapy.

The application of peroxidase mimetic nanozymes in cancer diagnosis and therapy

In recent decades, scholarly investigations have predominantly centered on nanomaterials possessing enzyme-like characteristics, commonly referred to as nanozymes. These nanozymes have emerged as viable substitutes for natural enzymes, offering simplicity, stability, and superior performance across various applications. Inorganic nanoparticles have been extensively employed in the emulation of enzymatic activity found in natural systems. Nanoparticles have shown a strong ability to mimic a number of enzyme-like functions. These systems have made a lot of progress thanks to the huge growth in nanotechnology research and the unique properties of nanomaterials. Our presentation will center on the kinetics, processes, and applications of peroxidase-like nanozymes. In this discourse, we will explore the various characteristics that exert an influence on the catalytic activity of nanozymes, with a particular emphasis on the prevailing problems and prospective consequences. This paper presents a thorough examination of the latest advancements achieved in the domain of peroxidase mimetic nanozymes in the context of cancer diagnosis and treatment. The primary focus is on their use in catalytic cancer therapy, alongside chemotherapy, phototherapy, sonodynamic therapy, radiation, and immunotherapy. The primary objective of this work is to offer theoretical and technical assistance for the prospective advancement of anticancer medications based on nanozymes. Moreover, it is anticipated that this will foster the investigation of novel therapeutic strategies aimed at achieving efficacious tumor therapy.

Thermoresponsive injectable self-healing hydrogel containing polydopamine-coated Fe/Mo-doped TiO2 nanoparticles for efficient synergistic sonodynamic-chemodynamic-photothermal-chemo therapy

A smart hydrogel loading multifunctional nanoparticles and anticancer drugs was designed to achieve synergistic therapy against tumors with high efficiency and specificity. The thermoresponsive injectable self-healing hydrogel was prepared through the Schiff base between aldehyde-functionalized poly(2-(2-methoxyethoxy) ethyl methacrylate)-co-oligo(ethylene glycol) methacrylate-co-2-hydroxyethyl methacrylate) (P(MEO2MA-co-OEGMA-co-HEMA), APMOH) and hydroxypropyl chitosan (HPCS). The polydopamine-coated Fe/Mo-doped titanium dioxide nanoparticles (PDA@dTiO2 NPs) were prepared and dispersed into the hydrogel with anticancer drug doxorubicin (DOX). PDA@dTiO2 NPs as sonosensitizers can convert oxygen into singlet oxygen (1O2) under ultrasound (US) irradiation, achieving sonodynamic therapy (SDT). They were also considered nanoenzymes, generating oxygen to supply an oxygen source for SDT, producing hydroxyl radical (·OH) to achieve chemodynamic therapy (CDT), and eliminating glutathione (GSH) to enhance the level of oxidative stress. After near-infrared (NIR) irradiation, the temperature of the hydrogel increased due to the photothermal ability of the polydopamine (PDA) layer. When the temperature reached the hydrogel's lower critical solution temperature (LCST), the hydrophilic-hydrophobic transformation occurred, and the hydrogel volume contracted. Consequently, the release rate of PDA@dTiO2 NPs and DOX increased, improving the therapeutic effects. The nanocomposite hydrogel system can achieve synergistic sonodynamic-chemodynamic-photothermal-chemo therapy (SDT-CDT-PTT-CT) for tumors, providing a novel platform for synergistic tumor treatment.

Polyoxometalates as Potential Artificial Enzymes toward Biological Applications

Artificial enzymes, as alternatives to natural enzymes, have attracted enormous attention in the fields of catalysis, biosensing, diagnostics, and therapeutics because of their high stability and low cost. Polyoxometalates (POMs), a class of inorganic metal oxides, have recently shown great potential in mimicking enzyme activity due to their well-defined structure, tunable composition, high catalytic efficiency, and easy storage properties. This review focuses on the recent advances in POM-based artificial enzymes. Different types of POMs and their derivatives-based mimetic enzyme functions are covered, as well as the corresponding catalytic mechanisms (where available). An overview of the broad applications of representative POM-based artificial enzymes from biosensing to theragnostic is provided. Insight into the current challenges and the future directions for POMs-based artificial enzymes is discussed.

Differential identification of GSH for acute coronary syndrome using a colorimetric sensor based on nanoflower-like artificial nanozymes

The ability to detect glutathione (GSH) concentrations in human blood offered a simple and non-invasive method to monitor changes associated with cardiovascular diseases, cancers and diabetes. We showed the potential of employing catalytically active protein-directed nanoflower-like artificial nanozymes (apo-TF-MnOx NFs) by bio-mineralization method to produce simple and visible colorimetric sensor for GSH. The experiments proved that apo-TF-MnOx NFs exhibited peroxidase, catalase- and superoxide dismutase-like activities, but the most notable feature was the excellent peroxidase-like activity, which could efficiently catalyze the oxidation reaction of 3,3',5,5'- tetramethylbenzidine (TMB) in the existence of hydrogen peroxide (H2O2) to generate a blue product. Some outcomes also indicated that the apo-TF-MnOx NFs had stronger peroxidase-like activity, which was proved by the Michaelis-Menten constant (Km) and maximum initial velocity (Vmax). Hence, we used the peroxidase-like activity to develop a GSH colorimetric biosensor. Fortunately, the colorimetric platform exhibited a sensitive response to H2O2 and GSH in the range of 5 μМ to 300 μМ and 0.5 μМ to 35 μМ with a limit of detection of 3.29 μM and 0.15 μM (S/N = 3) under optimal conditions. The feasibility of the simple method was confirmed by qualitative detection of H2O2 and GSH in blood samples from acute coronary syndrome patients. A key outcome of our study was the ability to realized differential identification of GSH for acute coronary syndrome and healthy human without invasive treatment which was an advantage over other methods. This work not only proposed a new type of nanozymes, but also showed the multiple advantages of the apo-TF-MnOx NFs for the construction of biosensors. Thus, we believe that apo-TF-MnOx NFs with strong peroxidase-like activity can be employed as nanozymes and be widely applied in the fields of medicine and biological sensors.

Flower-like porous BCN assembled by nanosheets for paclitaxel delivery

Developing smart drug delivery systems has become a feasible solution to overcome the challenges in cancer chemotherapeutics. In this work, porous boron carbon nitride (ZBCN) nanomaterials with flower-like structures assembled with BCN nanosheets were synthesized by using ZIF-L as a template. The rich hydroxyl groups on the BCN surfaces make it highly dispersible and stable in aqueous solutions. Additionally, ZBCN exhibits stable photoluminescence properties that can be utilized for cellular uptake and tracking of drug delivery. Furthermore, the flower-like ZBCN structure contributes to a large specific surface area of up to 340 m2 g-1 and a pore volume of 1.03 cm3 g-1; and the presence of rich macropores results in a high drug loading capacity of 116 wt% for paclitaxel. In vitro and in vivo anticancer experiments demonstrated that ZBCN exhibits excellent performance in delivering anticancer drugs, with in vivo tumor inhibition of 58%. This study presents a novel template method for preparing porous BCN nanomaterials, offering a promising platform for high-performance anticancer drug delivery.

Smart Nanozymes for Cancer Therapy: The Next Frontier in Oncology

Nanomaterials that mimic the catalytic activity of natural enzymes in the complex biological environment of the human body are called nanozymes. Recently, nanozyme systems have been reported with diagnostic, imaging, and/or therapeutic capabilities. Smart nanozymes strategically exploit the tumor microenvironment (TME) by the in situ generation of reactive species or by the modulation of the TME itself to result in effective cancer therapy. This topical review focuses on such smart nanozymes for cancer diagnosis, and therapy modalities with enhanced therapeutic effects. The dominant factors that guide the rational design and synthesis of nanozymes for cancer therapy include an understanding of the dynamic TME, structure-activity relationships, surface chemistry for imparting selectivity, and site-specific therapy, and stimulus-responsive modulation of nanozyme activity. This article presents a comprehensive analysis of the subject including the diverse catalytic mechanisms of different types of nanozyme systems, an overview of the TME, cancer diagnosis, and synergistic cancer therapies. The strategic application of nanozymes in cancer treatment can well be a game changer in future oncology. Moreover, recent developments may pave the way for the deployment of nanozyme therapy into other complex healthcare challenges, such as genetic diseases, immune disorders, and ageing.

Oxidase-like V2C MXene nanozyme with inherent antibacterial properties for colorimetric sensing

The microbial environment greatly affects the performance of colourimetric sensors, especially the interference of bacteria in the sample detected. This paper reports the fabrication of an antibacterial colorimetric sensor based on V₂C MXene synthesized via simple intercalation and stripping. The prepared V₂C nanosheets can mimic oxidase activity towards 3,3',5,5'-tetramethylbenzidine (TMB) oxidation without exogenously adding H₂O₂. Further mechanistic studies showed that V₂C nanosheets could effectively activate the oxygen adsorbed on their surface, which in turn causes an increase in the bond length and a decrease in the magnetic moment of oxygen through electron transfer from the nanosheet surface to O₂. The V₂C nanosheets also exhibited excellent broad-spectrum antibacterial activity through the outbreak of reactive oxygen species. Owing to its unique catalytic activity and the inherent antibacterial ability for mimicking oxidase, a colorimetric sensing platform was developed to effectively determine L-cysteine levels at a detection limit of 30.0 nM (S/N = 3). It is impressive that the detection results of L-cysteine in various complex microbial environments are also very satisfactory. This study broadens the biological use of MXene-based nanomaterials through their satisfactory enzymatic activity and provides a simple and efficient colorimetric strategy for detection techniques used in complex microbial environments.

Design of size uniform and controllable covalent organic framework nanoparticles for high-performance anticancer drug delivery

Covalent organic frameworks (COFs) receive much attention in biomedicine because of their unique adsorption, optical and biological properties, as well as highly variable structures. However, preparation of nanosized COFs with uniform and controllable size is still a challenge. Herein, we develop a facile interfacial method to prepare the COF nanoparticles (COFNPs) with the uniform size of 30-50 nm from p-benzoquinone (BQ) and 4-[1,2,2-tris(4-aminophenyl)ethenyl]aniline (TPEA) by Michael addition. The TPEA-BQ COFNPs show positive zeta potential and effectively load the hydrophobic anticancer drug camptothecin (CPT) with the capacity of up to 127wt%, and remarkably improved the CPT dispersibility in water due to the retention of quinone structure. In vitro assay reveals CPT@ TPEA-BQ significantly reduced cell viability to 29% after 24 h incubation, much lower than that of free CPT (51%) at the same concentration of 10 μg mL^-1. Further in vivo experiment confirms the high anticancer drug delivery performance of the designed TPEA-BQ COFNPs. After 20 days of injection treatment, the CPT loaded in TPEA-BQ COFNPs inhibits the tumor growth by 60%, much higher than that of free CPT group (23%). This work demonstrates the feasibility to design advanced drug delivery systems based on highly structure-tunable COF system.

Nonmetal Graphdiyne Nanozyme-Based Ferroptosis-Apoptosis Strategy for Colon Cancer Therapy

Ferroptosis-apoptosis, a new modality of induced cell death dependent on reactive oxygen species, has drawn tremendous attention in the field of nanomedicine. A metal-free ferroptosis-apoptosis inducer was reported based on boron and nitrogen codoped graphdiyne (BN-GDY) that possesses efficient glutathione (GSH) depletion capability and concurrently induces ferroptosis by deactivation of GSH-dependent peroxidases 4 (GPX4) and apoptosis by downregulation of Bcl2. The high catalytic activity of BN-GDY is explicated by both kinetic experiments and density functional theory (DFT) calculations of Gibbs free energy change during hydrogen peroxide (H₂O₂) decomposition. In addition, a unique sequence Bi-Bi mechanism is discovered, which is distinct from the commonly reported ping-pong Bi-Bi mechanism of most peroxidase mimics and natural enzymes. We anticipate that this nonmetal ferroptosis-apoptosis therapeutic concept by carbon-based nanomaterials would provide proof-of-concept evidence for nanocatalytic medicines in cancer therapy.

Peroxidase Mimetic Nanozymes in Cancer Phototherapy: Progress and Perspectives

Nanomaterial-mediated cancer therapeutics is a fast developing field and has been utilized in potential clinical applications. However, most effective therapies, such as photodynamic therapy (PDT) and radio therapy (RT), are strongly oxygen-dependent, which hinders their practical applications. Later on, several strategies were developed to overcome tumor hypoxia, such as oxygen carrier nanomaterials and oxygen generated nanomaterials. Among these, oxygen species generation on nanozymes, especially catalase (CAT) mimetic nanozymes, convert endogenous hydrogen peroxide (H2O2) to oxygen (O2) and peroxidase (POD) mimetic nanozymes converts endogenous H2O2 to water (H2O) and reactive oxygen species (ROS) in a hypoxic tumor microenvironment is a fascinating approach. The present review provides a detailed examination of past, present and future perspectives of POD mimetic nanozymes for effective oxygen-dependent cancer phototherapeutics.