Cascaded Nanozyme with In Situ Enhanced Photothermal Capacity for Tumor-Specific and Self-Replenishing Cancer Therapy

Emerging glucose oxidase-delivering nanomedicines for enhanced tumor therapy

Abnormalities in glucose metabolism have been shown to characterize malignant tumors. Glucose depletion by glucose oxidase (GOD) has shown great potential in tumor therapy by causing tumor starvation. Since 2017, nanomedicines have been designed and utilized to deliver GOD for more precise and effective glucose modulation, which can overcome intrinsic limitations of different cancer therapeutic modalities by remodeling the tumor microenvironment to enhance antitumor therapy. To date, the topic of GOD-delivering nanomedicines for enhancing tumor therapy has not been comprehensively summarized. Herein, this review aims to provide an overview and discuss in detail recent advances in GOD delivery and directly involved starvation therapy strategies, GOD-sensitized various tumor therapy strategies, and GOD-mediated multimodal antitumor strategies. Finally, the challenges and outlooks for the future progress of the emerging tumor therapeutic nanomedicines are discussed. This review provides intuitive and specific insights to a broad audience in the fields of nanomedicines, biomaterials, and cancer therapy.

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.

Immobilized Multi-Enzyme/Nanozyme Biomimetic Cascade Catalysis for Biosensing Applications

Multiple enzyme-induced cascade catalysis has an indispensable role in the process of complex life activities, and is widely used to construct robust biosensors for analyzing various targets. The immobilized multi-enzyme cascade catalysis system is a novel biomimetic catalysis strategy that immobilizes various enzymes with different functions in stable carriers to simulate the synergistic catalysis of multiple enzymes in biological systems, which enables high stability of enzymes and efficiency enzymatic cascade catalysis. Nanozymes, a type of nanomaterial with intrinsic enzyme-like characteristics and excellent stabilities, are also widely applied instead of enzymes to construct immobilized cascade systems, achieving better catalytic performance and reaction stability. Due to good stability, reusability, and remarkably high efficiency, the immobilized multi-enzyme/nanozyme biomimetic cascade catalysis systems show distinct advantages in promoting signal transduction and amplification, thereby attracting vast research interest in biosensing applications. This review focuses on the research progress of the immobilized multi-enzyme/nanozyme biomimetic cascade catalysis systems in recent years. The construction approaches, factors affecting the efficiency, and applications for sensitive biosensing are discussed in detail. Further, their challenges and outlooks for future study are also provided.

Nanozyme-based synergistic therapeutic strategies against tumors

Cancer remains a global health threat, with traditional treatments limited by adverse effects and drug resistance. Nanozyme-based catalytic therapy with high stability and controllable activity provides targeted and specific in situ tumor treatment to address these challenges. More intriguingly, the tremendous advances in nanotechnology have enabled nanozymes to rival the catalytic activity of natural enzymes, presenting an exciting opportunity for innovating antitumor nanodrugs. This review systematically summarizes the latest progresses in nanozyme-based anticancer catalytic therapy, with a particular focus on various synergistic antitumor strategies, including other functional enzymes, drugs, exogenous stimuli and radiotherapy. These combinations not only enhance the efficacy of cancer treatment and reduce systemic toxicity but also offer insights into the development of potent antitumor nanodrugs.

Catalytic Biomaterials-Activated In Situ Chemical Reactions: Strategic Modulation and Enhanced Disease Treatment

Chemical reactions underpin biological processes, and imbalances in critical biochemical pathways within organisms can lead to the onset of severe diseases. Within this context, the emerging field of "Nanocatalytic Medicine" leverages nanomaterials as catalysts to modulate fundamental chemical reactions specific to the microenvironments of diseases. This approach is designed to facilitate the targeted synthesis and localized accumulation of therapeutic agents, thus enhancing treatment efficacy and precision while simultaneously reducing systemic side effects. The effectiveness of these nanocatalytic strategies critically hinges on a profound understanding of chemical kinetics and the intricate interplay of reactions within particular pathological microenvironments to ensure targeted and effective catalytic actions. This review methodically explores in situ catalytic reactions and their associated biomaterials, emphasizing regulatory strategies that control therapeutic responses. Furthermore, the discussion encapsulates the crucial elements-reactants, catalysts, and reaction conditions/environments-necessary for optimizing the thermodynamics and kinetics of these reactions, while rigorously addressing both the biochemical and biophysical dimensions of the disease microenvironments to enhance therapeutic outcomes. It seeks to clarify the mechanisms underpinning catalytic biomaterials and evaluate their potential to revolutionize treatment strategies across various pathological conditions.

P-selectin-targeted Polyguluronate sulfate-copper peroxide Nanomicelles for Chemodynamic therapy of breast Cancer

The exploration of efficient and safe chemodynamic therapy (CDT)-based cancer treatment is expected but still faces challenges. Herein, a kind of multifunctional nanomicelles was constructed for CDT, combined with biocompatible polysaccharides as nanocarriers, pH responsiveness and active targeting of P-selectin overexpressed tumors. The P-selectin-targeted ligand, polyguluronate sulfate (PGS), complexed with copper peroxide to form PGS-Cu nanomicelles by electrostatic interactions. Under acidic conditions, PGS-Cu nanomicelles released copper ions with H2O2 and were able to produce •OH by Fenton-like reaction. In vitro data demonstrated PGS-Cu nanomicelles had high selectivity targeting P-selectin over-expressed cancer cells and induced cell death via CDT. In vivo evaluation showed PGS-Cu nanomicelles were enriched in tumor tissues and significantly inhibited tumor growth. This study identified that PGS-Cu nanomicelles could be a highly effective strategy for CDT cancer treatment.

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.

Injectable Therapeutic Hydrogel with H2O2 Self-Supplying and GSH Consumption for Synergistic Chemodynamic/Low-Temperature Photothermal Inhibition of Postoperative Tumor Recurrence and Wound Infection

Postoperative tumor recurrence and wound infection remain significant clinical challenges in surgery, often requiring adjuvant therapies. The combination treatment of photothermal therapy (PTT) and chemodynamic therapy (CDT) has proven to be effective in cancer treatment and wound infection. However, the hyperthermia during PTT increases the risk of normal tissue damage, severely impeding its application. Moreover, the efficacy of CDT is limited by insufficient hydrogen peroxide (H2O2) and excessive glutathione (GSH) levels at tumor or infection sites. Herein, an injectable and multifunctional CuO2@Au hydrogel system (CuO2@Au Gel) is developed for synergistic CDT and low-temperature PTT (LTPTT) to prevent tumor recurrence and bacterial wound infections. CuO2@Au Gel is constructed by embedding therapeutic CuO2@Au into low-melting point agarose hydrogel. In vitro and in vivo experiments confirm that the CuO2@Au in CuO2@Au Gel is capable of self-supplying H2O2 and depleting GSH, exhibiting effective CDT effect in acidic tumor or bacterial infected microenvironment. Additionally, it exhibits favorable photothermal conversion ability, inducing localized temperature elevation and synergistically enhancing CDT efficiency. The prepared CuO2@Au Gel demonstrates efficient tumor ablation capability in post-surgery recurrence mouse models and exhibits promising anti-infective efficiency in bacterial infection wound models, indicating significant potential in adjuvant therapy for post-surgical treatment and recovery.

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.

Nanozymes in cancer immunotherapy: metabolic disruption and therapeutic synergy

Over the past decade, there has been a growing emphasis on investigating the role of immunotherapy in cancer treatment. However, it faces challenges such as limited efficacy, a diminished response rate, and serious adverse effects. Nanozymes, a subset of nanomaterials, demonstrate boundless potential in cancer catalytic therapy for their tunable activity, enhanced stability, and cost-effectiveness. By selectively targeting the metabolic vulnerabilities of tumors, they can effectively intensify the destruction of tumor cells and promote the release of antigenic substances, thereby eliciting immune clearance responses and impeding tumor progression. Combined with other therapies, they synergistically enhance the efficacy of immunotherapy. Hence, a large number of metabolism-regulating nanozymes with synergistic immunotherapeutic effects have been developed. This review summarizes recent advancements in cancer immunotherapy facilitated by nanozymes, focusing on engineering nanozymes to potentiate antitumor immune responses by disturbing tumor metabolism and performing synergistic treatment. The challenges and prospects in this field are outlined. We aim to provide guidance for nanozyme-mediated immunotherapy and pave the way for achieving durable tumor eradication.

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.

NIR-II Light-Driven Genetically Engineered Exosome Nanocatalysts for Efficient Phototherapy against Glioblastoma

Glioblastoma (GBM) poses a significant therapeutic challenge due to its invasive nature and limited drug penetration through the blood-brain barrier (BBB). In response, here we present an innovative biomimetic approach involving the development of genetically engineered exosome nanocatalysts (Mn@Bi2Se3@RGE-Exos) for efficient GBM therapy via improving the BBB penetration and enzyme-like catalytic activities. Interestingly, a photothermally activatable multiple enzyme-like reactivity is observed in such a nanosystem. Upon NIR-II light irradiation, Mn@Bi2Se3@RGE-Exos are capable of converting hydrogen peroxide into hydroxyl radicals, oxygen, and superoxide radicals, providing a peroxidase (POD), oxidase (OXD), and catalase (CAT)-like nanocatalytic cascade. This consequently leads to strong oxidative stresses to damage GBM cells. In vitro, in vivo, and proteomic analysis further reveal the potential of Mn@Bi2Se3@RGE-Exos for the disruption of cellular homeostasis, enhancement of immunological response, and the induction of cancer cell ferroptosis, showcasing a great promise in anticancer efficacy against GBM with a favorable biosafety profile. Overall, the success of this study provides a feasible strategy for future design and clinical study of stimuli-responsive nanocatalytic medicine, especially in the context of challenging brain cancers like GBM.

Construction and evaluation of a nanosystem that combines acidification promoted chemodynamic therapy and intracellular drug release monitoring

Triple-negative breast cancer (TNBC) is a highly invasive subtype of breast cancer that seriously affects women's physical and mental health. Chemodynamic therapy (CDT) induces cell death by specifically generating Fenton/Fenton-like reactions within tumor cells. However, the weak acidity of the tumor microenvironment (TME) greatly weakens the effectiveness of CDT. This work constructed a kind of P-CAIDF/PT nanoparticles (NPs), composed of two Pluronic F127 (PF127) based polymers: one was PF127-CAI (P-CAI), composed by connecting PF127 with the carbonic anhydrase IX (CA IX) inhibitor (CAI); the other was PF127-SS-TPE (PT), composed of PF127 and the aggregation-induced emission molecule, tetraphenylethylene (TPE), via the linkage of disulfide bonds. The two polymers were employed to construct the doxorubicin (DOX) and ferrocene (Fc) co-loaded P-CAIDF/PT NPs through the film dispersion method. After being administrated via i.v., P-CAIDF/PT could be accumulated in the TME by the enhanced permeability and retention (EPR) effect and engulfed by tumor cells. P-CAI induced intracellular acidification by inhibiting the overexpressed CA IX, thus promoting CDT by enhancing the Fc-mediated Fenton reaction. The acidification-enhanced CDT combined with the DOX-mediated chemotherapy could improve the therapeutic effect on TNBC. Moreover, P-CAIDF/PT also monitored the intracellular drug release processes through the fluorescence resonance energy transfer (FRET) effect depending on the inherent DOX/TPE pair. In conclusion, the P-CAIDF/PT nanosystem can achieve the combination therapy of acidification-enhanced CDT and chemotherapy as well as therapy monitoring, thus providing new ideas for the design and development of TNBC therapeutic agents.