A pH/GSH/Glucose Responsive Nanozyme for Tumor Cascade Amplified Starvation and Chemodynamic Theranostics

Cascade nanozymes based on glucose oxidase modified gold nanoclusters for enhanced synergistic cancer therapy via activated autophagy and apoptosis

Although cascade strategy based on starvation therapy and nanozymes synergistic therapy has shown its unique advantages in tumor treatment, the relatively large size of integrated nanoplatform and protective autophagy greatly reduces the therapeutic effects. Herein, we report an ultra-small cascade nanozyme for enhanced synergistic cancer therapy by using glucose oxidase (GOx) capped gold nanoclusters (AuNCs@GOx). The constructed AuNCs@GOx integrates starvation therapy, chemo-dynamic therapy (CDT) and autophagy modulation, which realizes efficient tumor treatment. GOx converts glucose into gluconic acid and H2O2, followed by the transformation from H2O2 to high-toxic ·OH via peroxidase mimic AuNCs. Notably, AuNCs@GOx activate autophagy via inhibiting the PI3K/AKT/mTOR signaling pathway and activating AMPK/mTOR/ULK1 signaling pathway in Hela cells, thereby synergizing with mitochondrial apoptosis to induce tumor cell death. In vitro experiments using multiple cancer cell lines (SKOV-3, MCF-7, HT-29, Hela and 4 T1) and normal cells (GES-1 and 293 T) demonstrates that AuNCs@GOx could specifically and significantly suppress the cancer cells growth without damaging the normal cells. Furthermore, AuNCs@GOx could effectively inhibit 4 T1 tumor growth with good biocompatibility in vivo. Overall, the introduction of AuNCs@GOx into tumor cells realizes effective cascade treatment of tumor, which induces enhanced CDT and starvation therapy through activating autophagy-mediated death pathway and inducing apoptosis.

Manganese-Based Natural Photosensitive Protein Nanocomplex for Image-Guided Multimodal Synergistic Cancer Therapy

Photodynamic therapy (PDT) is widely utilized in cancer treatment as a noninvasive strategy. Phycocyanin (PC), a natural water-soluble photosensitizer with nontoxic properties, shows promise as a PDT candidate. However, the limitations of PC when used alone in PDT for cancer treatment, such as inadequate tumor delivery and weak efficacy, must be addressed. Herein, an efficient theranostic manganese (Mn)-based PC nanocomplex (PC@Mn) was synthesized through a straightforward one-pot self-assembly reaction for synergistic antitumor therapy. The PC@Mn nanoparticles were found to have a suitable size (∼129 nm) and demonstrated excellent biocompatibility and biosafety. Importantly, these nanoparticles exhibited enhanced biodistribution with improved tumor targeting and retention properties. When combined with 650 nm laser irradiation, PC@Mn showed a significant enhancement in the PDT effect in vivo. Additionally, PC@Mn displayed promising magnetic resonance (MR) imaging capabilities, with a high relaxation rate (r1 = 10.14 mM-1 s-1) and an extended imaging time window (4 h). This feature enables real-time monitoring of the nanoparticles' distribution within tumors, facilitating precise determination of the optimal PDT treatment time. Overall, the study highlights PC@Mn as a simple, safe, and highly efficient strategy for synergistic antitumor therapy. Its ability to combine PDT with MR imaging for real-time guidance represents an efficient approach to cancer treatment, promising improved therapeutic outcomes and potential clinical applications in the future.

Manganese-Based Nanotherapeutics for Targeted Treatment of Breast Cancer

Breast cancer (BC) is one of the most common cancers among women and is associated with high mortality. Traditional modalities, including surgery, radiotherapy, and chemotherapy, have achieved certain advancements but continue to combat challenges including harm to healthy tissues, resistance to treatment, and adverse drug reactions. The rapid advancements in nanotechnology recently facilitated the exploration of innovative strategies for breast cancer therapy. Manganese-based nanotherapeutics have attracted great attention because of their unique characteristics such as tunable structures/morphologies, versatility, magnetic/optical properties, strong catalytic activities, excellent biodegradability, and biocompatibility. In this review, we highlighted different types of Mn-based nanotherapeutics to modulate TME, including metal-immunotherapy, alleviating tumor hypoxia, and increasing reactive oxygen species production, and we emphasized its role in magnetic resonance imaging (MRI)-guided therapy, photoacoustic imaging, and theranostic-based therapy along with a therapeutic carrier, all of which were discussed in the context of breast cancer. Hopefully, the present review will provide insights into the current landscape and future directions of multifunctional applications of Mn-based nanotherapeutics in the field of breast cancer treatment.

Nanomaterials in cancer starvation therapy: pioneering advances, therapeutic potential, and clinical challenges

Gaining significant attention in recent years, starvation therapy based on the blocking nutrients supply to cancer cells via blood occlusion and metabolic interventions is a promisingly novel approach in cancer treatment. However, there are many crucial obstacles to overcome to achieve effective treatment, for example, poor-targeting delivery, cellular hypoxia, adverse effects, and ineffective monotherapy. The starvation-based multitherapy based on multifunctional nanomaterials can narrow these gaps and pave a promising way for future clinical translation. This review focuses on the progression in nanomaterials-mediated muti-therapeutic modalities based on starvation therapy in recent years and therapeutic limitations that prevent their clinical applications. Moreover, unlike previous reviews that focused on a single aspect of the field, this comprehensive review presents a broader perspective on starvation therapy by summarising advancements across its various therapeutic strategies.

Hetero-Trimetallic Atom Catalysts Enable Targeted ROS Generation and Redox Signaling for Intensive Apoptosis and Ferroptosis

Reactive oxygen species (ROS) play crucial roles in cellular metabolic processes by acting as primary intracellular chemical substrates and secondary messengers for cellular signal modulation. However, the artificial engineering of nanozymes to generate ROS is restricted by their low catalytic efficiency, high toxicity, and off-target consumption. Herein, hetero-trimetallic atom catalysts (TACs) anchored on a stable symmetrical pyramid structure are designed in the presence of N and P surface ligands from cross-linked polyphosphazene interlayer-coated MIL-101(Fe). The 3D network TACs with a uniform dispersion of Cu, Co, and Fe hetero-single atoms effectively tailor the active sites to avoid metal sintering, thereby providing sufficient catalytic activity for ROS blooms. Nanovesicle membranes facilitate the stable accumulation of nanozymes with homologous targeting, recognition, and endocytosis, effectively addressing the potentially high toxicity and off-target defects. Therefore, the outcome of the in situ ROS-bloom acts as a redox signal for directly regulating oxidative stress in the tumor microenvironment. Meanwhile, ROS intervene in the glutathione peroxidase 4, long-chain acyl-CoA synthetase 4, and cysteinyl aspartate specific proteinase-3 pathways as second messengers, fostering the proclivity toward apoptosis and lipid peroxidation-regulated ferroptosis pathway concurrently, thereby highlighting the application prospects of TACs in the biomedical field.

Rational Design of Nanozymes for Engineered Cascade Catalytic Cancer Therapy

Nanozymes have shown significant potential in cancer catalytic therapy by strategically catalyzing tumor-associated substances and metabolites into toxic reactive oxygen species (ROS) in situ, thereby inducing oxidative stress and promoting cancer cell death. However, within the complex tumor microenvironment (TME), the rational design of nanozymes and factors like activity, reaction substrates, and the TME itself significantly influence the efficiency of ROS generation. To address these limitations, recent research has focused on exploring the factors that affect activity and developing nanozyme-based cascade catalytic systems, which can trigger two or more cascade catalytic processes within tumors, thereby producing more therapeutic substances and achieving efficient and stable cancer therapy with minimal side effects. This area has shown remarkable progress. This Perspective provides a comprehensive overview of nanozymes, covering their classification and fundamentals. The regulation of nanozyme activity and efficient strategies of rational design are discussed in detail. Furthermore, representative paradigms for the successful construction of cascade catalytic systems for cancer treatment are summarized with a focus on revealing the underlying catalytic mechanisms. Finally, we address the current challenges and future prospects for the development of nanozyme-based cascade catalytic systems in biomedical applications.

Emerging engineered nanozymes: current status and future perspectives in cancer treatments

Composite nanozymes are composed of enzymes with similar or different catalytic capabilities and have higher catalytic activity than a single enzyme. In recent years, composite nanozymes have emerged as novel nanomaterial platforms for multiple applications in various research fields, where they are used to produce oxygen, consume glutathione, or produce toxic reactive oxygen species (ROS) for cancer therapy. The therapeutic approach using composite nanozymes is known as chemo-dynamic therapy (CDT). Some composite nanozymes also show special photothermal conversion effects, enabling them to be combined with pioneering cancer treatments, such as photodynamic therapy (PDT), photothermal therapy (PTT) and sonodynamic therapy (SDT), and enhance the anti-cancer effects. In this study, the classification and catalytic performances of composite nanozymes are reviewed, along with their advantages and synthesis methods. Furthermore, the applications of composite nanozymes in the treatment of cancers are emphasized, and the prospective challenges in the future are discussed.

Current advances in nanozyme-based nanodynamic therapies for cancer

Nanozymes are nano-catalysis materials with enzyme-like activities, which can repair the defects of natural enzyme such as harsh catalytic conditions, and harness their strengths to treat tumor. The emerging nanodynamic therapies improved drug selectivity and decreased drug tolerance, while causing efficient cell apoptosis through the generated reactive oxygen species (ROS). Nanodynamic therapies based on nanozymes can improve the complicated tumor microenvironment (TME) to reduce the defect rate of nanodynamic therapies, and provide more options for tumor treatment. This review summarized the characteristics and applications of nanozymes with different activities and the factors influencing the activity of nanozymes. We also focused on the application of nanozymes in nanodynamic therapies, including photodynamic therapy (PDT), chemodynamic therapy (CDT), and sonodynamic therapy (SDT). Moreover, we discussed the strategies for optimizing nanodynamic therapies based on nanozymes for tumor treatment in detail, and provided a systematic review of tactics for synergies with other tumor therapies. Ultimately, we analyzed the shortcomings of nanodynamic therapies based on nanozymes and the relevant research prospect, which would provide sufficient evidence and lay a foundation for further research. STATEMENT OF SIGNIFICANCE: 1. The novelty and significance of the work with respect to the existing literatures. (1) Recent advances in nanozyme-based nanodynamic therapies are comprehensively and systematically reviewed, and strategies to address the limitations and challenges of current therapies based on nanozymes are discussed firstly. (2) The mechanism of nanozymes in nanodynamic therapies is described for the first time. The synergistic therapies, prospects, and challenges of nanozyme-based nanodynamic therapies are innovatively discussed. 2. The scientific impact and interest to our readership. This review focuses on the recent progress of nanozyme-based nanodynamic therapies. This review indicates the way forward for the combined treatment of nanozymes and nanodynamic therapies, and lays a foundation for facilitating theoretical development in clinic.

Ultrasmall iridium-encapsulated porphyrin metal-organic frameworks for enhanced photodynamic/catalytic therapy by producing reactive oxygen species storm

Transition metal-coordinated porphyrin metal-organic frameworks (MOFs) were perspective in photodynamic therapy (PDT) and catalytic therapy. However, the tumor hypoxia and the insufficient endogenous hydrogen peroxide (H2O2) seriously limited their efficacies. Herein, by encapsulating ultrasmall iridium (Ir) and modifying glucose oxidase (GOx), an iron-coordinated porphyrin MOF (Fe-MOF) nanoplatform (Fe-MOF@Ir/GOx) was designed to strengthen PDT/catalytic therapy by producing reactive oxygen species (ROS) storm. In this nanoplatform, Fe-MOF showed glutathione (GSH)-responsive degradation, by which porphyrin, GOx and ultrasmall Ir were released. Moreover, ultrasmall Ir possessed dual-activities of catalase (CAT)-like and peroxidase (POD)-like, which provided sufficient oxygen (O2) to enhance PDT efficacy, and hydroxyl radical (·OH) production was also improved by combining Fenton reaction of Fe2+. Further, GOx catalyzed endogenous glucose produced H2O2, also reduced pH value, which accelerated Fenton reaction and resulted in generation of ROS storm. Therefore, the developed Fe-MOF@Ir/GOx nanoplatform demonstrated enhanced PDT/catalytic therapy by producing ROS storm, and also provided a promising strategy to promote degradation/metabolism of inorganic nanoplatforms.

Transition-metal-based nanozymes for biosensing and catalytic tumor therapy

Nanozymes, as an emerging class of enzyme mimics, have attracted much attention due to their adjustable catalytic activity, low cost, easy modification, and good stability. Researchers have made great efforts in developing and applying high-performance nanozymes. Recently, transition-metal-based nanozymes have been designed and widely developed because they possess unique photoelectric properties and high enzyme-like catalytic activities. To highlight these achievements and help researchers to understand the research status of transition-metal-based nanozymes, the development of transition-metal-based nanozymes from material characteristics to biological applications is summarized. Herein, we focus on introducing six categories of transition-metal-based nanozymes and highlight their progress in biomarker sensing and catalytic therapy for tumors. We hope that this review can guide the further development of transition-metal-based nanozymes and promote their practical applications in cancer diagnosis and treatment.

Nanozymes-Mediated Cascade Reaction System for Tumor-Specific Diagnosis and Targeted Therapy

Cascade reactions are described as efficient and versatile tools, and organized catalytic cascades can significantly improve the efficiency of chemical interworking between nanozymes. They have attracted great interest in many fields such as chromogenic detection, biosensing, tumor diagnosis, and therapy. However, how to selectively kill tumor cells by enzymatic reactions without harming normal cells, as well as exploring two or more enzyme-engineered nanoreactors for cascading catalytic reactions, remain great challenges in the field of targeted and specific cancer diagnostics and therapy. The latest research advances in nanozyme-catalyzed cascade processes for cancer diagnosis and therapy are described in this article. Here, various sensing strategies are summarized, for tumor-specific diagnostics. Targeting mechanisms for tumor treatment using cascade nanozymes are classified and analyzed, "elements" and "dimensions" of cascade nanozymes, types, designs of structure, and assembly modes of highly active and specific cascade nanozymes, as well as a variety of new strategies of tumor targeting based on the cascade reaction of nanozymes. Finally, the integrated application of the cascade nanozymes systems in tumor-targeted and specific diagnostic therapy is summarized, which will lay the foundation for the design of more rational, efficient, and specific tumor diagnostic and therapeutic modalities in the future.

Microenvironment-sensitive nanozymes for tissue regeneration

Tissue defect is one of the significant challenges encountered in clinical practice. Nanomaterials, including nanoparticles, nanofibers, and metal-organic frameworks, have demonstrated an extensive potential in tissue regeneration, offering a promising avenue for future clinical applications. Nonetheless, the intricate landscape of the inflammatory tissue microenvironment has engendered challenges to the efficacy of nanomaterial-based therapies. This quandary has spurred researchers to pivot towards advanced nanotechnological remedies for overcoming these therapeutic constraints. Among these solutions, microenvironment-sensitive nanozymes have emerged as a compelling instrument with the capacity to reshape the tissue microenvironment and enhance the intricate process of tissue regeneration. In this review, we summarize the microenvironmental characteristics of damaged tissues, offer insights into the rationale guiding the design and engineering of microenvironment-sensitive nanozymes, and explore the underlying mechanisms that underpin these nanozymes' responsiveness. This analysis includes their roles in orchestrating cellular signaling, modulating immune responses, and promoting the delicate process of tissue remodeling. Furthermore, we discuss the diverse applications of microenvironment-sensitive nanozymes in tissue regeneration, including bone, soft tissue, and cartilage regeneration. Finally, we shed our sights on envisioning the forthcoming milestones in this field, prospecting a future where microenvironment-sensitive nanozymes contribute significantly to the development of tissue regeneration and improved clinical outcomes.

Biomedical applications of stimuli-responsive nanomaterials

Nanomaterials have aroused great interests in drug delivery due to their nanoscale structure, facile modifiability, and multifunctional physicochemical properties. Currently, stimuli-responsive nanomaterials that can respond to endogenous or exogenous stimulus display strong potentials in biomedical applications. In comparison with conventional nanomaterials, stimuli-responsive nanomaterials can improve therapeutic efficiency and reduce the toxicity of drugs toward normal tissues through specific targeting and on-demand drug release at pathological sites. In this review, we summarize the responsive mechanism of a variety of stimulus, including pH, redox, and enzymes within pathological microenvironment, as well as exogenous stimulus such as thermal effect, magnetic field, light, and ultrasound. After that, biomedical applications (e.g., drug delivery, imaging, and theranostics) of stimuli-responsive nanomaterials in a diverse array of common diseases, including cardiovascular diseases, cancer, neurological disorders, inflammation, and bacterial infection, are presented and discussed. Finally, the remaining challenges and outlooks of future research directions for the biomedical applications of stimuli-responsive nanomaterials are also discussed. We hope that this review can provide valuable guidance for developing stimuli-responsive nanomaterials and accelerate their biomedical applications in diseases diagnosis and treatment.

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.

A comprehensive exploration of the latest innovations for advancements in enhancing selectivity of nanozymes for theranostic nanoplatforms

Nanozymes have captured significant attention as a versatile and promising alternative to natural enzymes in catalytic applications, with wide-ranging implications for both diagnosis and therapy. However, the limited selectivity exhibited by many nanozymes presents challenges to their efficacy in diagnosis and raises concerns regarding their impact on the progression of disease treatments. In this article, we explore the latest innovations aimed at enhancing the selectivity of nanozymes, thereby expanding their applications in theranostic nanoplatforms. We place paramount importance on the critical development of highly selective nanozymes and present innovative strategies that have yielded remarkable outcomes in augmenting selectivities. The strategies encompass enhancements in analyte selectivity by incorporating recognition units, refining activity selectivity through the meticulous control of structural and elemental composition, integrating synergistic materials, fabricating selective nanomaterials, and comprehensively fine-tuning selectivity via approaches such as surface modification, cascade nanozyme systems, and manipulation of external stimuli. Additionally, we propose optimized approaches to propel the further advancement of these tailored nanozymes while considering the limitations associated with existing techniques. Our ultimate objective is to present a comprehensive solution that effectively addresses the limitations attributed to non-selective nanozymes, thus unlocking the full potential of these catalytic systems in the realm of theranostics.

Multimodal imaging and photothermal/chemodynamic therapy of cervical cancer using GSH-responsive MoS2@MnO2 theranostic nanoparticles

The development of nanoparticles capable of inducing reactive oxygen species (ROS) formation has become an important strategy for cancer therapy. Simultaneously, the preparation of multifunctional nanoparticles that respond to the tumor microenvironment is crucial for the diagnosis and treatment of tumors. In this study, we designed a Molybdenum disulfide (MoS2) core coated with Manganese dioxide (MnO2), which possessed a good photothermal effect and could produce Fenton-like Mn2+ in response to highly expressed glutathione (GSH) in the tumor microenvironment, thereby generating a chemodynamic therapy (CDT). The nanoparticles were further modified with Methoxypoly(Ethylene Glycol) 2000 (mPEG-NH2) to improve their biocompatibility, resulting in the formation of MoS2@MnO2-PEG. These nanoparticles were shown to possess significant Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) imaging capabilities, making them useful in tumor diagnosis. In vitro and in vivo experiments demonstrated the antitumor ability of MoS2@MnO2-PEG, with a significant killing effect on tumor cells under combined treatment. These nanoparticles hold great potential for CDT/photothermal therapy (PTT) combined antitumor therapy and could be further explored in biomedical research.