Wet/Sono-Chemical Synthesis of Enzymatic Two-Dimensional MnO2 Nanosheets for Synergistic Catalysis-Enhanced Phototheranostics

Fluorescence and photothermal dual-modal image guided integrated diagnosis and treatment

The early diagnosis and real-time monitoring of cancer are great significance for the establishment of integrated diagnosis and treatment systems. In this study, organic molecules as an all-in-one phototheranostic named FL-DPP2 nanoparticles was developed for monitoring the location and size of tumour and for achieving photo and gene synergistic therapy. The photothermal conversion efficiency (η) of FL-DPP2 nanoparticles reached 29.4 % and the quantum yield of 1O2 production was 38 %. In addition, it can deliver the p53 gene into nucleus rapidly under laser irradiation, which induced synergistic cancer cells apoptosis with effective tumor growth inhibition. This work provided an innovative strategy to design and constructed all-in-one nanoplatforms for clinical phototheranostics to realize dual-modal image guided integrated diagnosis and treatment.

Tumor Pro-Senescence Strategy to Enhance Mild Photothermal Therapy of Diffuse Large B-Cell Lymphoma

Diffuse large B-cell lymphoma (DLBCL) presents a substantial clinical challenge due to its aggressive nature and resistance to conventional therapies, thereby developing novel treatment strategies is critical. In this work, we take advantage of the insensitivity of heat shock protein (HSP) expression in senescent tumor cells to combine mild photothermal therapy (MPTT) for efficient DLBCL treatment. Insensitivity to HSPs implies that cells are less capable of activating their usual stress protection mechanisms during MPTT, which reduces their tolerance to heat damage. Consequently, the treatment can more effectively destroy target cells at lower temperatures while minimizing the risk of thermal injury to surrounding healthy tissues. Abemaciclib can inhibit CDK4/6 activity, thereby inhibiting Rb phosphorylation to suppress the activity of the E2F transcription factor and prevent the transition from G1 to S phase, leading to cell cycle arrest and ultimately cellular senescence. The experimental results indicated that abemaciclib effectively promoted the senescence of DLBCL cells, accompanied by a significant reduction in HSP70 expression. Subsequently, a novel near-infrared (NIR) absorbing organic polymer photothermal agent (PYIT-OD) with excellent optical properties and photostability was used for MPTT. The integration of pro-senescence strategies with MPTT, as evidenced by both in vitro and in vivo experimental outcomes, markedly enhanced treatment efficacy, effectively reducing damage to normal tissues at mild temperatures and enhancing antitumor effects. This work not only reveals potential biological mechanisms but also provides theoretical foundations and practical guidance for developing more precise and less toxic DLBCL treatment regimens in clinical practice.

NIR-II Photosensitizer-Based Nanoparticles Defunctionalizing Mitochondria to Overcome Tumor Self-Defense by Promoting Heat Shock Protein 40

Inherent self-defense pathways within malignant tumors include the action of heat shock proteins (HSPs) and often impede photothermal therapy efficacy. Interestingly, HSP40 inhibits glycolysis and disrupts mitochondrial function to overcome tumor self-defense mechanisms and exhibits a tumor-suppressive effect. Reactive oxygen species (ROS), especially hydroxyl radicals, generated by type-I photodynamic therapy inhibit adenosine triphosphate (ATP) production and lead to ATP-independent HSP40 overexpression during heat stress. However, the regulatory mechanisms linking heat and hydroxyl radicals to induce HSP40 expression remain unclear. Therefore, it is imperative to elucidate the underlying mechanism governing the induction of HSP40 expression during heat stress and explore its potential as a promising therapeutic strategy against tumor development. By strategically modifying the aza-BODIPY structure to precisely distribute the excited-state energy, we have demonstrated that HSP40 specific expression is correlated with the proportion of heat to hydroxyl radicals rather than their individual levels. This orchestrated NIR-II photosensitizer-based nanoparticles reduced tumor glycolysis and disrupted ATP production, driving cell apoptosis and amplifying the efficacy of photothermal therapy. Silencing and compensation of HSPs under heat and ROS stress represent a promising and effective strategy for overcoming tumor self-defense mechanisms in cancer therapy.

Manganese-based nanoenzymes: from catalytic chemistry to design principle and antitumor/antibacterial therapy

Manganese (Mn)-based materials have been extensively investigated for a wide range of biomedical applications owing to their remarkable catalytic chemistry, magnetic resonance imaging (MRI) capacity, biodegradability, low toxicity, and good biosafety. In this review, we first elaborate on the catalytic principle of Mn-based nanoenzymes for antitumor and antibacterial therapy, followed by a comprehensive discussion of the interesting structural design engineering strategies used to achieve multi-dimensional Mn-based nanoarchitectures, such as zero-dimensional (0D) nanoparticles, 1D nanotubes, 2D nanosheets, 3D hollow porous Mn ball, and core-shell nanostructures. Moreover, the therapeutic applications of different Mn-based nanoenzymes, including manganese dioxide (MnO2)-based nanoenzymes that can trigger catalytic reactions, Mn2+-doped metal nanoenzymes and Mn2+-coordinated nanoenzymes that promote hydroxyl/reactive oxygen species (ROS) generation, and MnO2-based micro/nanorobots that can effectively penetrate tumor tissues, are critically reviewed. Finally, a brief overview of the potential challenges faced in the development of Mn-based nanoenzymes is presented, along with a comparative and balanced discussion of future prospects.

Design of novel dual-emitting ratiometric fluorescence system based on FMT-CDs and MnO2 NS for sensitive isoniazid detection in urine sample

In this work, a simple and sensitive ratiometric fluorescence probe to detect isoniazid (INH) was developed on the basis of carbon dots and MnO2 nanosheets (MnO2 NS). Nitrogen-doped carbon dots (FMT-CDs) were synthesized by microwave method using formononetin (FMT) in ammonia water. The oxidase-like activity of MnO2 NS was utilized to oxidize non-fluorescent o-phenylenediamine (OPD) to 2, 3-diaminophenazine (DAP) with orange fluorescence. It was demonstrated that DAP could effectively quench the fluorescence of FMT-CDs through the inner filtering effect (IFE). Due to the reducing nature of INH, MnO2 NS was decomposed and thus lost its oxidase-like activity after the addition of INH. Therefore, the production of DAP was reduced, and the fluorescence intensity was decreased, while IFE on FMT-CDs was weakened and the fluorescence of FMT-CDs was recovered. Based on the above principle, a sensitive method for the detection of INH was established based on the fluorescence intensity ratio of the two fluorescent substances, FMT-CDs and DAP, and was successfully applied to the detection of INH in human urine samples. The limit of detection (LOD) could reach to 0.16 μM in human urine samples.

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.

Recent Development of Nanozymes for Combating Bacterial Drug Resistance: A Review

The World Health Organization has warned that without effective action, deaths from drug-resistant bacteria can exceed 10 million annually, making it the leading cause of death. Conventional antibiotics are becoming less effective due to rapid bacterial drug resistance and slowed new antibiotic development, necessitating new strategies. Recently, materials with catalytic/enzymatic properties, known as nanozymes, have been developed, inspired by natural enzymes essential for bacterial eradication. Unlike recent literature reviews that broadly cover nanozyme design and biomedical applications, this review focuses on the latest advancements in nanozymes for combating bacterial drug resistance, emphasizing their design, structural characteristics, applications in combination therapy, and future prospects. This approach aims to promote nanozyme development for combating bacterial drug resistance, especially towards clinical translation.

Anti-Tumor Strategies Targeting Nutritional Deprivation: Challenges and Opportunities

Higher and richer nutrient requirements are typical features that distinguish tumor cells from AU: cells, ensuring adequate substrates and energy sources for tumor cell proliferation and migration. Therefore, nutrient deprivation strategies based on targeted technologies can induce impaired cell viability in tumor cells, which are more sensitive than normal cells. In this review, nutrients that are required by tumor cells and related metabolic pathways are introduced, and anti-tumor strategies developed to target nutrient deprivation are described. In addition to tumor cells, the nutritional and metabolic characteristics of other cells in the tumor microenvironment (including macrophages, neutrophils, natural killer cells, T cells, and cancer-associated fibroblasts) and related new anti-tumor strategies are also summarized. In conclusion, recent advances in anti-tumor strategies targeting nutrient blockade are reviewed, and the challenges and prospects of these anti-tumor strategies are discussed, which are of theoretical significance for optimizing the clinical application of tumor nutrition deprivation strategies.

Emerging Roles of Nanozyme in Tumor Metabolism Regulation: Mechanisms, Applications, and Future Directions

Nanozymes, nanomaterials with intrinsic enzyme activity, have garnered significant attention in recent years due to their catalytic abilities comparable to natural enzymes, cost-effectiveness, high catalytic activities, and stability against environmental fluctuations. As functional analogs of natural enzymes, nanozymes participate in various critical metabolic processes, including glucose metabolism, lactate metabolism, and the maintenance of redox homeostasis, all of which are essential for normal cellular functions. However, disruptions in these metabolic pathways frequently promote tumorigenesis and progression, making them potential therapeutic targets. While several therapies targeting tumor metabolism are currently in clinical or preclinical stages, their efficacy requires further enhancement. Consequently, nanozymes that target tumor metabolism are regarded as a promising therapeutic strategy. Despite extensive studies investigating the application of nanozymes in tumor metabolism, relevant reviews are relatively scarce. This article first introduces the physicochemical properties and biological behaviors of nanozymes. Subsequently, we analyze the role of nanozymes in tumor metabolism and explore their potential applications in tumor therapy. In conclusion, this review aims to foster innovative research in related fields and advance the development of nanozyme-based strategies for cancer diagnostics and therapeutics.

Bacteria/Nanozyme Composites: New Therapeutics for Disease Treatment

Bacterial therapy is recognized as a cost-effective treatment for several diseases. However, its development is hindered by limited functionality, weak inherent therapeutic effects, and vulnerability to harsh microenvironmental conditions, leading to suboptimal treatment activity. Enhancing bacterial activity and therapeutic outcomes emerges as a pivotal challenge. Nanozymes have garnered significant attention due to their enzyme-mimic activities and high stability. They enable bacteria to mimic the functions of gene-edited bacteria expressing the same functional enzymes, thereby improving bacterial activity and therapeutic efficacy. This review delineates the therapeutic mechanisms of bacteria and nanozymes, followed by a summary of strategies for preparing bacteria/nanozyme composites. Additionally, the synergistic effects of such composites in biomedical applications such as gastrointestinal diseases and tumors are highlighted. Finally, the challenges of bacteria/nanozyme composites are discussed and propose potential solutions. This study aims to provide valuable insights to offer theoretical guidance for the advancement of nanomaterial-assisted bacterial therapy.

Manganese-doped liquid metal nanoplatforms for cellular uptake and glutathione depletion-enhanced photothermal and chemodynamic combination tumor therapy

Chemodynamic therapy (CDT) involves the catalysis of in situ overexpressed hydrogen peroxide (H2O2) into highly toxic reactive oxygen species (ROS) to treat tumors. However, the efficacy of CDT is greatly hampered by limited cellular internalization efficiency, ROS scavenging by glutathione (GSH), and slow reaction rate. To overcome the current limitations of CDT, a manganese-doped and polyethylene glycol (PEG)-modified liquid metal (LM)-silica nanoplatform (labeled as Mn-LMOP) with varying stiffness is constructed to achieve synergistic photothermal therapy (PTT) and CDT, which can further induce immunogenic cell death (ICD) in tumors to enhance the anti-tumour effects. Significantly, benefiting from the increased stiffness, the Mn-LMOP nanoparticles (NPs) can enhance cellular uptake and lysosomal escape, and gradually accumulate in tumor sites. Moreover, manganese-doped NPs exhibite good photothermal effects and can rapidly reacte with intratumoral GSH to produce Mn2+, inhibiting GSH-mediated ROS clearance and promoting the efficiency of CDT. This combined treatment strategy can activate the immune response of the tumors, which holds the promise of photothermal/chemodynamic/immune multimodal therapeutic effects. This LM-based nanosystem will provide a paradigm for enhanced CDT/PTT combination anti-tumour efficacy. STATEMENT OF SIGNIFICANCE: Chemodynamic therapy (CDT) is a promising drug-free treatment approach characterized by its low invasiveness and minimal side effect. However, CDT encounters challenges such as high levels of glutathione (GSH), low Fenton-like reaction rate, and inefficient cellular uptake in tumor tissues. Here, a manganese-doped liquid metal (LM) nanomaterial was designed to achieve synergistic photothermal therapy (PTT) and CDT. This innovative strategy enhanced cellular uptake by adjusting the mechanical property of nanoparticles (NPs) and facilitated the consumption of GSH, while simultaneously accelerating the Fenton-like reaction rate with the assistance of PTT-mediated hyperthermia. This combined CDT/PTT strategy also activated the immune response within the tumor, demonstrating significant therapeutic potential.

Nanozyme as Tumor Energy Homeostasis Disruptor to Augment Cascade Catalytic Therapy

Breaking the balance of the tumor microenvironment and reshaping it sustainably remain major challenges in lung cancer treatment. Here, a "tumor energy homeostasis disruptor", the Cu2O@Au nanozyme was developed, which exhibits excellent glucose oxidase-like activity, enabling it to be used for starvation therapy and as a mimic peroxidase for chemodynamic therapy (CDT), producing •OH. Cu2O@Au nanozymes consume glucose at the tumor site to block the tumor's energy supply, produce H2O2 continuously, and lower the pH to enhance the efficiency of CDT, initiating a cascade reaction that leads to a storm of reactive oxygen species (ROS). Furthermore, Cu2O@Au nanozyme consumes glutathione and reduces the expression of the SLC7A11 (xCT) protein to decrease cancer cell uptake of cysteine, further enhancing the burst of ROS, resulting in lipid peroxidation in tumor cells and ultimately leading to ferroptosis. The excellent photothermal performance of Cu2O@Au can further enhance CDT. Additionally, Cu2O@Au nanozyme also has computed tomography (CT) and photothermal imaging capabilities. In conclusion, Cu2O@Au nanozymes, acting as tumor energy homeostasis disruptor, can effectively inhibit tumor growth and successfully achieve the synergistic effects of starvation therapy/CDT/photothermal therapy (PTT). This multifunctional nanozyme holds promise for providing valuable insights and therapeutic strategies for cancer treatment.

Manganese oxide nanomaterials: bridging synthesis and therapeutic innovations for cancer treatment

The advent of precision medicine in oncology emphasizes the urgent need for innovative therapeutic strategies that effectively integrate diagnosis and treatment while minimizing invasiveness. Manganese oxide nanomaterials (MONs) have emerged as a promising class of nanocarriers in biomedicine, particularly for targeted drug delivery and the therapeutic management of tumors. These nanomaterials are characterized by exceptional responsiveness to the tumor microenvironment (TME), high catalytic efficiency, favorable biodegradability, and advanced capabilities in magnetic resonance imaging. These attributes significantly enhance drug delivery, facilitate real-time bioimaging, and enable early tumor detection, thereby improving the precision and effectiveness of cancer therapies. This review highlights the significant advancements in the synthesis and therapeutic applications of MONs, beginning with a comprehensive overview of key synthetic methods, including thermal decomposition, potassium permanganate reduction, exfoliation, adsorption-oxidation, and hydro/solvothermal techniques. We delve into the preparation of MONs and H-MnO₂-based nanomaterials, emphasizing their chemical properties, surface modifications, and toxicity profiles, which are critical for their clinical application. Moreover, we discuss the notable applications of H-MnO₂-based nanomaterials in pH-responsive drug release, overcoming multidrug resistance (MDR), immunotherapy, and the development of nanovaccines for synergistic cancer treatments. By addressing the current challenges in the clinical translation of MONs, we propose future research directions for overcoming these obstacles. By underscoring the potential of MONs to transform cancer treatment paradigms, this review aims to inspire further investigations into their multifunctional applications in oncology, thus ultimately contributing to more effective and personalized therapeutic strategies.

Peptide-Functionalized Inorganic Oxide Nanomaterials for Solid Cancer Imaging and Therapy

The diagnosis and treatment of solid tumors have undergone significant advancements marked by a trend toward increased specificity and integration of imaging and therapeutic functions. The multifaceted nature of inorganic oxide nanomaterials (IONs), which boast optical, magnetic, ultrasonic, and biochemical modulatory properties, makes them ideal building blocks for developing multifunctional nanoplatforms. A promising class of materials that have emerged in this context are peptide-functionalized inorganic oxide nanomaterials (PFIONs), which have demonstrated excellent performance in multifunctional imaging and therapy, making them potential candidates for advancing solid tumor diagnosis and treatment. Owing to the functionalities of peptides in tumor targeting, penetration, responsiveness, and therapy, well-designed PFIONs can specifically accumulate and release therapeutic or imaging agents at the solid tumor sites, enabling precise imaging and effective treatment. This review provides an overview of the recent advances in the use of PFIONs for the imaging and treatment of solid tumors, highlighting the superiority of imaging and therapeutic integration as well as synergistic treatment. Moreover, the review discusses the challenges and prospects of PFIONs in depth, aiming to promote the intersection of the interdisciplinary to facilitate their clinical translation and the development of personalized diagnostic and therapeutic systems by optimizing the material systems.

Catalytic Nanoparticles in Biomedical Applications: Exploiting Advanced Nanozymes for Therapeutics and Diagnostics

Catalytic nanoparticles (CNPs) as heterogeneous catalyst reveals superior activity due to their physio-chemical features, such as high surface-to-volume ratio and unique optical, electric, and magnetic properties. The CNPs, based on their physio-chemical nature, can either increase the reactive oxygen species (ROS) level for tumor and antibacterial therapy or eliminate the ROS for cytoprotection, anti-inflammation, and anti-aging. In addition, the catalytic activity of nanozymes can specifically trigger a specific reaction accompanied by the optical feature change, presenting the feasibility of biosensor and bioimaging applications. Undoubtedly, CNPs play a pivotal role in pushing the evolution of technologies in medical and clinical fields, and advanced strategies and nanomaterials rely on the input of chemical experts to develop. Herein, a systematic and comprehensive review of the challenges and recent development of CNPs for biomedical applications is presented from the viewpoint of advanced nanomaterial with unique catalytic activity and additional functions. Furthermore, the biosafety issue of applying biodegradable and non-biodegradable nanozymes and future perspectives are critically discussed to guide a promising direction in developing span-new nanozymes and more intelligent strategies for overcoming the current clinical limitations.

Tunable Structured 2D Nanobiocatalysts: Synthesis, Catalytic Properties and New Horizons in Biomedical Applications

2D materials have offered essential contributions to boosting biocatalytic efficiency in diverse biomedical applications due to the intrinsic enzyme-mimetic activity and massive specific surface area for loading metal catalytic centers. Since the difficulty of high-quality synthesis, the varied structure, and the tough choice of efficient surface loading sites with catalytic properties, the artificial building of 2D nanobiocatalysts still faces great challenges. Here, in this review, a timely and comprehensive summarization of the latest progress and future trends in the design and biotherapeutic applications of 2D nanobiocatalysts is provided, which is essential for their development. First, an overview of the synthesis-structure-fundamentals and structure-property relationships of 2D nanobiocatalysts, both metal-free and metal-based is provided. After that, the effective design of the active sites of nanobiocatalysts is discussed. Then, the progress of their applied research in recent years, including biomedical analysis, biomedical therapeutics, pharmacokinetics, and toxicology is systematically highlighted. Finally, future research directions of 2D nanobiocatalysts are prospected. Overall, this review to provide cutting-edge and multidisciplinary guidance for accelerating future developments and biomedical applications of 2D nanobiocatalysts is expected.

Manganese-derived biomaterials for tumor diagnosis and therapy

Manganese (Mn) is widely recognized owing to its low cost, non-toxic nature, and versatile oxidation states, leading to the emergence of various Mn-based nanomaterials with applications across diverse fields, particularly in tumor diagnosis and therapy. Systematic reviews specifically addressing the tumor diagnosis and therapy aspects of Mn-derived biomaterials are lacking. This review comprehensively explores the physicochemical characteristics and synthesis methods of Mn-derived biomaterials, emphasizing their role in tumor diagnostics, including magnetic resonance imaging, photoacoustic and photothermal imaging, ultrasound imaging, multimodal imaging, and biodetection. Moreover, the advantages of Mn-based materials in tumor treatment applications are discussed, including drug delivery, tumor microenvironment regulation, synergistic photothermal, photodynamic, and chemodynamic therapies, tumor immunotherapy, and imaging-guided therapy. The review concludes by providing insights into the current landscape and future directions for Mn-driven advancements in the field, serving as a comprehensive resource for researchers and clinicians.

Targeting starvation therapy for diabetic bacterial infections with endogenous enzyme-triggered hyaluronan-modified nanozymes in the infection microenvironment

The high-glycemic microenvironment of diabetic wounds promotes bacterial proliferation, leading to persistent infections and delayed wound healing. This poses a significant threat to human health, necessitating the development of new nanodrug visualization platforms. In this study, we designed and synthesized cascade nano-systems modified with targeted peptide and hyaluronic acid for diabetic infection therapy. The nano-systems were able to target the site of infection using LL-37, and in the microenvironment of wound infection, the hyaluronic acid shell of the nano-systems was degraded by endogenous hyaluronidase. This precise degradation released a cascade of nano-enzymes on the surface of the bacteria, effectively destroying their cytoskeleton. Additionally, the metals in the nano-enzymes provided a photo-thermal effect, accelerating wound healing. The cascade nano-visualization platform demonstrated excellent bactericidal efficacy in both in vitro antimicrobial assays and in vivo diabetic infection models. In conclusion, this nano-system employs multiple approaches including targeting, enzyme-catalyzed therapy, photothermal therapy, and chemodynamic therapy to kill bacteria and promote healing. The Ag@Pt-Au-LYZ/HA-LL-37 formulation shows great potential for the treatment of diabetic wounds.

Single-atom nanozymes shines diagnostics of gastrointestinal diseases

Various clinical symptoms of digestive system, such as infectious, inflammatory, and malignant disorders, have a profound impact on the quality of life and overall health of patients. Therefore, the chase for more potent medicines is both highly significant and urgent. Nanozymes, a novel class of nanomaterials, amalgamate the biological properties of nanomaterials with the catalytic activity of enzymes, and have been engineered for various biomedical applications, including complex gastrointestinal diseases (GI). Particularly, because of their distinctive metal coordination structure and ability to maximize atom use efficiency, single-atom nanozymes (SAzymes) with atomically scattered metal centers are becoming a more viable substitute for natural enzymes. Traditional nanozyme design strategies are no longer able to meet the current requirements for efficient and diverse SAzymes design due to the diversification and complexity of preparation processes. As a result, this review emphasizes the design concept and the synthesis strategy of SAzymes, and corresponding bioenzyme-like activities, such as superoxide dismutase (SOD), peroxidase (POD), oxidase (OXD), catalase (CAT), and glutathione peroxidase (GPx). Then the various application of SAzymes in GI illnesses are summarized, which should encourage further research into nanozymes to achieve better application characteristics.

Critical learning from industrial catalysis for nanocatalytic medicine

Systematical and critical learning from industrial catalysis will bring inspiration for emerging nanocatalytic medicine, but the relevant knowledge is quite limited so far. In this review, we briefly summarize representative catalytic reactions and corresponding catalysts in industry, and then distinguish the similarities and differences in catalytic reactions between industrial and medical applications in support of critical learning, deep understanding, and rational designing of appropriate catalysts and catalytic reactions for various medical applications. Finally, we summarize/outlook the present and potential translation from industrial catalysis to nanocatalytic medicine. This review is expected to display a clear picture of nanocatalytic medicine evolution.

Size-matching compositing nanoprobe of AIE-type gold nanocluster supramolecular nanogels wrapped by hypergravity-tailored MnO2 nanosheets for cellular glutathione detection

Compositing has been the main approach for material creation via wisely combining material components with different properties. MnO2 nanosheets (MNSs) with thin 2 D morphology are usually applied to composite molecules or nanomaterials for biosensing and bioimaging applications. However, such composition is actually structurally unmatched, albeit performance matching. Here, a series of benefits merely on the basis of structural match have been unearthed via tailoring MNSs with four sizes by synthesis under controllable hypergravity field. The classical fluorophore-quencher couple was utilized as the subject model, where the soft supramolecular nanogels based on aggregation-induced emission (AIE)-active gold nanoclusters were wrapped by MNSs of strong absorption. By comparative study of one-on-one wrapping and one-to-many encapsulation with geometrical selection of different MNSs, we found that the one-on-one wrapping model protected weakly-bonded nanogels from combination-induced distortion and strengthened nanogel networks via endowing exoskeleton. Besides, wrapping pattern and size-match significantly enhanced the quenching efficiency of MNSs towards the emissive nanogels. More importantly, the well-wrapped nanocomposites had considerable enhanced biological compatibility with much lower cytotoxicity and higher transfection capacity than the untailored MNSs composite and could serve as cellular glutathione detection.

Two-dimensional nanomaterials induced nano-bio interfacial effects and biomedical applications in cancer treatment

Two-dimensional nanomaterials (2D NMs), characterized by a large number of atoms or molecules arranged in one dimension (typically thickness) while having tiny dimensions in the other two dimensions, have emerged as a pivotal class of materials with unique properties. Their flat and sheet-like structure imparts distinctive physical, chemical, and electronic attributes, which offers several advantages in biomedical applications, including enhanced surface area for efficient drug loading, surface-exposed atoms allowing precise chemical modifications, and the ability to form hierarchical multilayer structures for synergistic functionality. Exploring their nano-bio interfacial interactions with biological components holds significant importance in comprehensively and systematically guiding safe applications. However, the current lack of in-depth analysis and comprehensive understanding of interfacial effects on cancer treatment motivates our ongoing efforts in this field. This study provides a comprehensive survey of recent advances in utilizing 2D NMs for cancer treatment. It offers insights into the structural characteristics, synthesis methods, and surface modifications of diverse 2D NMs. The investigation further delves into the formation of nano-bio interfaces during their in vivo utilization. Notably, the study discusses a wide array of biomedical applications in cancer treatment. With their potential to revolutionize therapeutic strategies and outcomes, 2D NMs are poised at the forefront of cancer treatment, holding the promise of transformative advancements.

"Three-in-One" Nanozyme Composite for Augmented Cascade Catalytic Tumor Therapy

Cascade catalytic reaction exhibits simple procedure and high efficiency, such as that from the orderly assembly of different enzymes in biological systems. Mimicking of the natural cascade procedure becomes critical, but the orderly assembly of different enzymes is still challenging. Herein, single Au-Pt nanozyme is reported with "three-in-one" functions to initiate cascade conversions for O2 supply as mimic catalase, H2 O2 production with its glucose oxidase-like property, and • OH generation as mimic peroxidase for chemodynamic therapy (CDT). Thus, the complex assembly and cross-talk among the different enzymes are avoided. To this end, metastable Cu2 O NPs, as scaffolds, are used to anchor ultrasmall Au-Pt nanozyme, while metal-organic framework (MOF) is used to encapsulate the nanozyme for tumor microenvironment response and shielding protein adsorption. Pluronic F127 is then modified on the surface to improve hydrophilicity and biocompatibility of the composite. The endogenous acidity and glutathione in tumor degrade MOF to expose nanozyme for cascade catalytic CDT. The high photothermal conversion ability also enhances the CDT, while Cu2+ ions consume GSH to further improve CDT efficiency as augmented cascade catalytic tumor therapy. Thus, a new paradigm is provided with drug-free single nanozyme for improving tumor therapeutic efficacy and minimizing side effects.

The Emerging Landscape for Combating Resistance Associated with Energy-Based Therapies via Nanomedicine

Cancer represents a serious disease with significant implications for public health, imposing substantial economic burden and negative societal consequences. Compared to conventional cancer treatments, such as surgery and chemotherapy, energy-based therapies (ET) based on athermal and thermal ablation provide distinct advantages, including minimally invasive procedures and rapid postoperative recovery. Nevertheless, due to the complex pathophysiology of many solid tumors, the therapeutic effectiveness of ET is often limited. Nanotechnology offers unique opportunities by enabling facile material designs, tunable physicochemical properties, and excellent biocompatibility, thereby further augmenting the outcomes of ET. Numerous nanomaterials have demonstrated the ability to overcome intrinsic therapeutic resistance associated with ET, leading to improved antitumor responses. This comprehensive review systematically summarizes the underlying mechanisms of ET-associated resistance (ETR) and highlights representative applications of nanoplatforms used to mitigate ETR. Overall, this review emphasizes the recent advances in the field and presents a detailed account of novel nanomaterial designs in combating ETR, along with efforts aimed at facilitating their clinical translation.

An NIR-II-photoresponsive CoSnO3 nanozyme for mild photothermally augmented nanocatalytic cancer therapy

The main challenges of nanozyme-based tumor catalytic therapy (NCT) lie in the unsatisfactory catalytic activity accompanied by a complex tumor microenvironment (TME). A few nanozymes have been designed to possess both enzyme-like catalytic activities and photothermal properties; however, the previously reported nanozymes mainly utilize the inefficient and unsafe NIR-I laser, which has a low maximum permissible exposure limit and a limited penetration depth. Herein, we report for the first time an all-in-one strategy to realize mild NIR-II photothermally amplified NCT by synthesizing amorphous CoSnO3 nanocubes with efficient triple enzyme-like catalytic activities and photothermal conversion properties. The presence of Co2+ and Sn4+ endows CoSnO3 nanocubes with the triple enzyme-like catalytic activities, not only achieving enhanced reactive oxygen species (ROS) generation through the Co2+-mediated peroxidase-like catalytic reaction to generate ˙OH and Sn4+-mediated depletion of overexpressed GSH, but also realizing the catalytic decomposition of endogenous H2O2 for relieving tumor hypoxia. More importantly, the obtained CoSnO3 nanocubes with a high photothermal conversion efficiency of 82.1% at 1064 nm could achieve mild hyperthermia (43 °C), which further improves the triple enzyme-like catalytic activities of the CoSnO3 nanozyme. The synergetic therapeutic efficacy of the NIR-II-responsive CoSnO3 nanozyme through mild NIR-II PTT-enhanced NCT could realize all-in-one multimodal tumor therapy to completely eliminate tumors without recurrence. This study will open a new avenue to explore NIR-II-photoresponsive nanozymes for efficient tumor therapy.

Trinity Strategy: Enabling Perovskite as Hydrophilic and Efficient Fluorescent Nanozyme for Constructing Biomarker Reporting Platform

Water instability and sensing homogeneity are the Achilles' heel of CsPbX3 NPs in biological fluids application. This work reports the preparation of Mn2+:CsPbCl3@SiO2 yolk-shell nanoparticles (YSNPs) in aqueous solutions created through the integration of ligand, surface, and crystal engineering strategies. The SN2 reaction between 4-chlorobutyric acid (CBA) and oleylamine (OAm) yields a zwitterionic ligand that facilitates the dispersion of YSNPs in water, while the robust SiO2 shell enhances their overall stability. Besides, Mn2+ doping in YSNPs not only introduces a second emission center but also enables potential postsynthetic designability, leading to the switching from YSNPs to MnO2@YSNPs with excellent oxidase (OXD)-like activity. Theoretical calculations reveal that electron transfer from CsPbCl3 to in situ MnO2 and the adsorption-desorption process of 3,3',5,5'-tetramethylbenzidine (TMB) synergistically amplify the OXD-like activity. In the presence of ascorbic acid (AA), Mn4+ in MnO2@YSNPs (fluorescent nanozyme) is reduced to Mn2+ and dissociated, thereby inhibiting the OXD-like activity and triggering fluorescence "turn-on/off", i.e., dual-mode recognition. Finally, a biomarker reporting platform based on MnO2@YSNPs fluorescent nanozyme is constructed with AA as the reporter molecule, and the accurate detection of human serum alkaline phosphatase (ALP) is realized, demonstrating the vast potential of perovskites in biosensing.

The energetic and physical concept of gold nanorod-dependent fluorescence in cancer treatment and development of new photonic compounds|review

The optical features of gold nanorods (GNR) may be precisely controlled by manipulating their size, shape, and aspect ratio. This review explores the impact of these parameters on the optical tuning of (GNR). By altering the experimental conditions, like the addition of silver ions during the seed-mediated growth process, the aspect ratio of (GNR) may be regulated. The shape is trans from spherical to rod-like structures resulting in noticeable changes in the nanoparticles surface plasmons resonance (SPR) bands. The longitudinal SPR band, associated with electron oscillations along the long axis, exhibits a pronounced red shift into the (NIR) region as the aspect ratio increases. In contrast, the transverse SPR band remains relate unchanged. Using computational methods like the discrete dipole approximation (DDA) allows for analyzing absorption, scattering, and total extinction features of gold (G) nanoparticles. Studies have shown that increasing the aspect ratio enhances the scattering efficiency, indicating a higher scattering quantum yield (QY). These findings highlight the importance of size, shape, and aspect ratio in controlling the optical features of (GNR) providing valuable insights for various uses in nanophotonics and plasmonic-dependent fluorescence in cancer treatment and developing new photonic compound NRs.

Black Phosphorus/MnO2 Nanocomposite Disrupting Bacterial Thermotolerance for Efficient Mild-Temperature Photothermal Therapy

The emergence of multi-drug resistant (MDR) pathogens is a major public health concern, posing a substantial global economic burden. Photothermal therapy (PTT) at mild temperature presents a promising alternative to traditional antibiotics due to its biological safety and ability to circumvent drug resistance. However, the efficacy of mild PTT is limited by bacterial thermotolerance. Herein, a nanocomposite, BP@Mn-NC, comprising black phosphorus nanosheets and a manganese-based nanozyme (Mn-NZ) is developed, which possesses both photothermal and catalytic properties. Mn-NZ imparts glucose oxidase- and peroxidase-like properties to BP@Mn-NC, generating reactive oxygen species (ROS) that induce lipid peroxidation and malondialdehyde accumulation across the bacterial cell membrane. This process disrupts unprotected respiratory chain complexes exposed on the bacterial cell membrane, leading to a reduction in the intracellular adenosine triphosphate (ATP) content. Consequently, mild PTT mediated by BP@Mn-NC effectively eliminates MDR infections by specifically impairing bacterial thermotolerance because of the dependence of bacterial heat shock proteins (HSPs) on ATP molecules for their proper functioning. This study paves the way for the development of a novel photothermal strategy to eradicate MDR pathogens, which targets bacterial HSPs through ROS-mediated inhibition of bacterial respiratory chain activity.

Nanozymes based on octahedral platinum nanocrystals with {111} surface facets: glucose oxidase mimicking activity in electrochemical sensors

The ability of shape-controlled octahedral Pt nanoparticles to act as nanozyme mimicking glucose oxidase enzyme is reported. Extended {111} particle surface facets coupled with a size comparable to natural enzymes and easy-to-remove citrate coating give high affinity for glucose, comparable to the enzyme as proven by the steady-state kinetics of glucose electrooxidation. The easy and thorough removal of the citrate coating, demonstrated by X-ray photoelectron spectroscopy analysis, allows a highly stable deposition of the nanozymes on the electrode. The glucose electrochemical detection (at -0.2 V vs SCE) shows a linear response between 0.36 and 17 mM with a limit of detection of 110 μM. A good reproducibility has been achieved, with an average relative standard deviation (RSD) value of 9.1% (n = 3). Similarly, a low intra-sensor variability has been observed, with a RSD of 6.6% (n = 3). Moreover, the sensor shows a long-term stability with reproducible performances for at least 2 months (RSD: 7.8%). Tests in saliva samples show the applicability of Pt nanozymes to commercial systems for non-invasive monitoring of hyperglycemia in saliva, with recoveries ranging from 92 to 98%.

Mechanism underlying the effect of MnO2 nanosheets for A549 cell chemodynamic therapy

MnO2 nanosheets (MnO2NSs) were synthesized by one-step method, and MnO2NSs were applied to A549 cell chemodynamic Therapy (CDT). The cytotoxicity, redox ability, and reactive oxygen species production of MnO2NSs have been investigated, and differences in cell metabolism during CDT were determined using liquid chromatography-mass spectrometry (LC-MS/MS). In addition, the metabolites of A549 lung cancer cells affected by MnO2NSs treatment are identified; metabolite differences were identified by PCA, PLS-DA, orthogonal PLS-DA, and other methods; and these differences were analyzed using non-targeted metabolomics. We found that A549 cells which were treated by MnO2NSs have 17 different metabolites and 9 metabolic pathways that varied markedly. Owing to their unique composition, structure, and physicochemical properties, MnO2NSs and their composites have become a favored type of nanomaterial used for CDT in cancer therapy. This work provides insights into the mechanism underlying the effects of MnO2NSs on the tumor microenvironment of A549 lung cancer cells, effectively making up for the deficiency of the study on cellular mechanism of CDT-induced apoptosis of cancer cells. It could aid the development of cancer CDT treatment strategies and help improve the use of nanomaterials in the clinical field.

Antioxidant and Prooxidant Nanozymes: From Cellular Redox Regulation to Next-Generation Therapeutics

Nanozymes, nanomaterials with enzyme-mimicking activity, have attracted tremendous interest in recent years owing to their ability to replace natural enzymes in various biomedical applications, such as biosensing, therapeutics, drug delivery, and bioimaging. In particular, the nanozymes capable of regulating the cellular redox status by mimicking the antioxidant enzymes in mammalian cells are of great therapeutic significance in oxidative-stress-mediated disorders. As the distinction of physiological oxidative stress (oxidative eustress) and pathological oxidative stress (oxidative distress) occurs at a fine borderline, it is a great challenge to design nanozymes that can differentially sense the two extremes in cells, tissues and organs and mediate appropriate redox chemical reactions. In this Review, we summarize the advances in the development of redox-active nanozymes and their biomedical applications. We primarily highlight the therapeutic significance of the antioxidant and prooxidant nanozymes in various disease model systems, such as cancer, neurodegeneration, and cardiovascular diseases. The future perspectives of this emerging area of research and the challenges associated with the biomedical applications of nanozymes are described.

Emerging antibacterial nanozymes for wound healing

Wound infections continuously impose a huge economic and social burden on public healthcare. Despite the effective treatment of bacteria-infected wounds after using traditional antibiotics, the misuse of antibiotics usually causes the spread of bacterial resistance and decreases therapeutic outcomes. Therefore, the development of efficient antibacterial agents is urgently needed. Nanozymes, as a new generation of artificial enzymes, combine the intrinsic abilities of nanomaterials and natural enzymes. Recently, nanozymes has been widely developed to kill bacteria and treat wound infections by catalyzing the generation of various reactive oxygen species. Thus, this new concept of "antibacterial nanozymes" will promote the further advances of connecting nanozymes and bacterial elimination. To highlight these achievements, we summarize different types of antibacterial nanozymes for wound healing. It is believed that such a promising therapeutic strategy of developing antibacterial nanozymes will make a great contribution in the field of skin regeneration. We expect that antibacterial nanozymes will play the significant roles in both basic research and clinical applications.

Nanozyme-integrated microneedle patch for enhanced therapy of cutaneous squamous cell carcinoma by breaking the gap between H2O2 self-supplying chemodynamic therapy and photothermal therapy

Cutaneous squamous cell carcinoma (cSCC) is one of the most common skin cancers with increasing incidence worldwide. However, it is still challenging to prevent the relapse of cSCC due to poor drug penetration across the stratum corneum. Herein, we report the design of a microneedle patch loaded with MnO2/Cu2O nanosheets and combretastatin A4 (MN-MnO2/Cu2O-CA4) for the enhanced therapy of cSCC. The prepared MN-MnO2/Cu2O-CA4 patch could effectively deliver adequate drugs locally into the tumor sites. Moreover, the glucose oxidase (GOx)-mimicking activity of MnO2/Cu2O could catalyze glucose to produce H2O2, which combined with the released Cu to induce a Fenton-like reaction to efficiently generate hydroxyl radicals for chemodynamic therapy. Meanwhile, the released CA4 could inhibit cancer cell migration and tumor growth by disrupting the tumor vasculature. Moreover, MnO2/Cu2O was endowed with the ability of photothermal conversion under the irradiation of near-infrared (NIR) laser, which could not only kill the cancer cells but also promote the efficiency of the Fenton-like reaction. Significantly, the photothermal effect did not compromise the GOx-like activity of MnO2/Cu2O, which guaranteed enough production of H2O2 for the sufficient generation of hydroxyl radicals. This work may open avenues for constructing MN-based multimodal treatment for the efficient therapy of skin cancers.

Nanomaterials with Glucose Oxidase-Mimicking Activity for Biomedical Applications

Glucose oxidase (GOD) is an oxidoreductase that catalyzes the aerobic oxidation of glucose into hydrogen peroxide (H₂O₂) and gluconic acid, which has been widely used in industrial raw materials production, biosensors and cancer treatment. However, natural GOD bears intrinsic disadvantages, such as poor stability and a complex purification process, which undoubtedly restricts its biomedical applications. Fortunately, several artificial nanomaterials have been recently discovered with a GOD-like activity and their catalytic efficiency toward glucose oxidation can be finely optimized for diverse biomedical applications in biosensing and disease treatments. In view of the notable progress of GOD-mimicking nanozymes, this review systematically summarizes the representative GOD-mimicking nanomaterials for the first time and depicts their proposed catalytic mechanisms. We then introduce the efficient modulation strategy to improve the catalytic activity of existing GOD-mimicking nanomaterials. Finally, the potential biomedical applications in glucose detection, DNA bioanalysis and cancer treatment are highlighted. We believe that the development of nanomaterials with a GOD-like activity will expand the application range of GOD-based systems and lead to new opportunities of GOD-mimicking nanomaterials for various biomedical applications.

Manganese-Based Tumor Immunotherapy

As an essential micronutrient, manganese (Mn) participates in various physiological processes and plays important roles in host immune system, hematopoiesis, endocrine function, and oxidative stress regulation. Mn-based nanoparticles are considered to be biocompatible and show versatile applications in nanomedicine, in particular utilized in tumor immunotherapy in the following ways: 1) acting as a biocompatible nanocarrier to deliver immunotherapeutic agents for tumor immunotherapy; 2) serving as an adjuvant to regulate tumor immune microenvironment and enhance immunotherapy; 3) activating host's immune system through the cGAS-STING pathway to trigger tumor immunotherapy; 4) real-time monitoring tumor immunotherapy effect by magnetic resonance imaging (MRI) since Mn²⁺ ions are ideal MRI contrast agent which can significantly enhance the T₁ -weighted MRI signal after binding to proteins. This comprehensive review focuses on the most recent progress of Mn-based nanoplatforms in tumor immunotherapy. The characteristics of Mn are first discussed to guide the design of Mn-based multifunctional nanoplatforms. Then the biomedical applications of Mn-based nanoplatforms, including immunotherapy alone, immunotherapy-involved multimodal synergistic therapy, and imaging-guided immunotherapy are discussed in detail. Finally, the challenges and future developments of Mn-based tumor immunotherapy are highlighted.

Rough Nanovaccines Boost Antitumor Immunity Through the Enhancement of Vaccination Cascade and Immunogenic Cell Death Induction

Nanovaccines have attracted intense interests for efficient antigen delivery and tumor-specific immunity. It is challenging to develop a more efficient and personalized nanovaccine to maximize all steps of the vaccination cascade by exploiting the intrinsic properties of nanoparticles. Here, biodegradable nanohybrids (MP) composed of manganese oxide nanoparticles and cationic polymers are synthesized to load a model antigen ovalbumin to form MPO nanovaccines. More interestingly, MPO could serve as autologous nanovaccines for personalized tumor treatment taking advantage of in situ released tumor-associated antigens induced by immunogenic cell death (ICD). The intrinsic properties of MP nanohybrids including morphology, size, surface charge, chemical, and immunoregulatory functions are fully exploited to enhance of all steps of the cascade and induce ICD. MP nanohybrids are designed to efficiently encapsulate antigens by cationic polymers, drain to lymph nodes by appropriate size, be internalized by dendritic cells (DCs) by rough morphology, induce DC maturation through cGAS-STING pathway, and enhance lysosomal escape and antigen cross-presentation through the "proton sponge effect". The MPO nanovaccines are found to efficiently accumulate in lymph nodes and elicit robust specific T-cell immune responses to inhibit the occurrence of ovalbumin-expressing B16-OVA melanoma. Furthermore, MPO demonstrate great potential to serve as personalized cancer vaccines through the generation of autologous antigen depot through ICD induction, activation of potent antitumor immunity, and reversal of immunosuppression. This work provides a facile strategy for the construction of personalized nanovaccines by exploiting the intrinsic properties of nanohybrids.

Development of Two-Dimensional Functional Nanomaterials for Biosensor Applications: Opportunities, Challenges, and Future Prospects

New possibilities for the development of biosensors that are ready to be implemented in the field have emerged thanks to the recent progress of functional nanomaterials and the careful engineering of nanostructures. Two-dimensional (2D) nanomaterials have exceptional physical, chemical, highly anisotropic, chemically active, and mechanical capabilities due to their ultra-thin structures. The diversity of the high surface area, layered topologies, and porosity found in 2D nanomaterials makes them amenable to being engineered with surface characteristics that make it possible for targeted identification. By integrating the distinctive features of several varieties of nanostructures and employing them as scaffolds for bimolecular assemblies, biosensing platforms with improved reliability, selectivity, and sensitivity for the identification of a plethora of analytes can be developed. In this review, we compile a number of approaches to using 2D nanomaterials for biomolecule detection. Subsequently, we summarize the advantages and disadvantages of using 2D nanomaterials in biosensing. Finally, both the opportunities and the challenges that exist within this potentially fruitful subject are discussed. This review will assist readers in understanding the synthesis of 2D nanomaterials, their alteration by enzymes and composite materials, and the implementation of 2D material-based biosensors for efficient bioanalysis and disease diagnosis.

Recent Advances in Hydrogel-Based Phototherapy for Tumor Treatment

Phototherapeutic agent-based phototherapies activated by light have proven to be safe modalities for the treatment of various malignant tumor indications. The two main modalities of phototherapies include photothermal therapy, which causes localized thermal damage to target lesions, and photodynamic therapy, which causes localized chemical damage by generated reactive oxygen species (ROS). Conventional phototherapies suffer a major shortcoming in their clinical application due to their phototoxicity, which primarily arises from the uncontrolled distribution of phototherapeutic agents in vivo. For successful antitumor phototherapy, it is essential to ensure the generation of heat or ROS specifically occurs at the tumor site. To minimize the reverse side effects of phototherapy while improving its therapeutic performance, extensive research has focused on developing hydrogel-based phototherapy for tumor treatment. The utilization of hydrogels as drug carriers allows for the sustained delivery of phototherapeutic agents to tumor sites, thereby limiting their adverse effects. Herein, we summarize the recent advancements in the design of hydrogels for antitumor phototherapy, offer a comprehensive overview of the latest advances in hydrogel-based phototherapy and its combination with other therapeutic modalities for tumor treatment, and discuss the current clinical status of hydrogel-based antitumor phototherapy.

Targeting STING Activation by Antigen-Inspired MnO2 Nanovaccines Optimizes Tumor Radiotherapy

Immune checkpoint blockers therapy can improve the radiotherapy-induced immunosuppression by enhancing interferon secretion, but still suffer from low clinical response rate and potential adverse effects. Mn²⁺ -mediated activation of interferon gene stimulator (STING) pathway provides an alternative for combination radioimmunotherapy of tumor. However, it is still a challenge for specific delivery of Mn²⁺ to innate immune cells and targeting activation of STING pathway. Herein, a novel antigen-inspired MnO₂ nanovaccine is fabricated as Mn²⁺ source and functionalized with mannose, enabling it to target innate immune cells to activate the STING pathway. Meanwhile, the release of Mn²⁺ in the intracellular lysosomes can also be for magnetic resonance imaging to monitor the dynamic distribution of nanovaccines in vivo. The targeting activation of STING pathway can enhance radiotherapy-induced immune responses for inhibiting local and distant tumors, and resisting tumor metastasis. The study proposes an optimized radiotherapy strategy through targeting STING activation of antigen-inspired nanovaccines.

Smart Biomimetic Nanozymes for Precise Molecular Imaging: Application and Challenges

New nanotechnologies for imaging molecules are widely being applied to visualize the expression of specific molecules (e.g., ions, biomarkers) for disease diagnosis. Among various nanoplatforms, nanozymes, which exhibit enzyme-like catalytic activities in vivo, have gained tremendously increasing attention in molecular imaging due to their unique properties such as diverse enzyme-mimicking activities, excellent biocompatibility, ease of surface tenability, and low cost. In addition, by integrating different nanoparticles with superparamagnetic, photoacoustic, fluorescence, and photothermal properties, the nanoenzymes are able to increase the imaging sensitivity and accuracy for better understanding the complexity and the biological process of disease. Moreover, these functions encourage the utilization of nanozymes as therapeutic agents to assist in treatment. In this review, we focus on the applications of nanozymes in molecular imaging and discuss the use of peroxidase (POD), oxidase (OXD), catalase (CAT), and superoxide dismutase (SOD) with different imaging modalities. Further, the applications of nanozymes for cancer treatment, bacterial infection, and inflammation image-guided therapy are discussed. Overall, this review aims to provide a complete reference for research in the interdisciplinary fields of nanotechnology and molecular imaging to promote the advancement and clinical translation of novel biomimetic nanozymes.

Low-dimensional nanomaterials as an emerging platform for cancer diagnosis and therapy

The burden of cancer is increasing, being widely recognized as one of the main reasons for deaths among humans. Despite the tremendous efforts that have been made worldwide to stem the progression and metastasis of cancer, morbidity and mortality in malignant tumors have been clearly rising and threatening human health. In recent years, nanomedicine has come to occupy an increasingly important position in precision oncotherapy, which improves the diagnosis, treatment, and long-term prognosis of cancer. In particular, LDNs with distinctive physicochemical capabilities have provided great potential for advanced biomedical applications, attributed to their large surface area, abundant surface binding sites, and good cellular permeation properties. In addition, LDNs can integrate CT/MR/US/PAI and PTT/PDT/CDT/NDDS into a multimodal theranostic nanoplatform, enabling targeted therapy and efficacy assessments for cancer. This review attempts to concisely summarize the classification and major properties of LDNs. Simultaneously, we particularly emphasize their applications in the imaging, diagnosis, and treatment of cancerous diseases.

Amylase degradation enhanced NIR photothermal therapy and fluorescence imaging of bacterial biofilm infections

Effective treatment of bacterial biofilm-related infections is a great challenge for the medical community. During the formation of biofilms, bacteria excrete extracellular polymeric substances (EPS), including polysaccharides, proteins, nucleic acids, etc., to encapsulate themselves and form a "fort-like" structure, which greatly reduces the efficiency of therapeutic agents. Herein, we prepared a nanoagent (MnO₂-amylase-PEG-ICG nanosheets, MAPI NSs) with biofilm degradation capability for efficient photothermal therapy and fluorescence imaging of methicillin-resistant Staphylococcus aureus (MRSA) biofilm infections. MAPI NSs were constructed by sequentially modifying α-amylase, polyethylene glycol (PEG), and indocyanine green (ICG) on manganese dioxide nanosheets (MnO₂ NSs). Experimental results exhibited that MAPI NSs could accumulate in infected tissues after intravenous injection, degrade in the acidic biofilm microenvironment, and release the loaded ICG for near-infrared (NIR) fluorescence imaging of the infected tissues. Importantly, MAPI NSs could efficiently eliminate MRSA biofilm infections in mice by α-amylase enhanced photothermal therapy. In addition, MAPI NSs exhibited neglectable toxicity towards mice. Given the superior properties of MAPI NSs, the enzyme-degradation enhanced therapeutic strategy presented in this work offers a promising solution for effectively combating biofilm infectious diseases.

Hypoxia Alleviated and One Photo-Triggered Thermal/Dynamic Nanoplatform for Immunogenic Cell Death-Initiated Cancer Immunotherapy

Immunogenic cell death (ICD) induced by treatment modalities like chemotherapy, radiotherapy, and photothermal and photodynamic therapy has shown great potential to improve the low response rate of various solid tumors in cancer immunotherapy. However, extensive studies have revealed that the efficacy of cancer treatment is limited by the hypoxia and immunosuppression in the tumor microenvironment (TME). To address these challenges, a hypoxia alleviated and one phototriggered thermal/dynamic nanoplatform based on MnO₂@PDA/ICG-BSA (MPIB) is developed for oxygen (O₂) self-supply enhanced cancer phototherapy (PT). First, MnO₂ transfers intracellular overexpression H₂O₂ into O₂ in the acidic TME through its catalase-like activity to improve the hypoxia and also provide O₂ for the following photodynamic therapy. Then, under single NIR-808 nm light irradiation (called the "phototherapeutic window"), excellent photothermal and photodynamic performance of the MPIB is activated for combined PT. Finally, assisted with immune adjuvant cytosine-phospho-guanine, obvious ICD and systemic antitumor immunity was elicited in PT-treated mice and demonstrated significant growth inhibition on distant tumors. This MPIB-based nanoplatform highlights the promise to overcome the limitations of hypoxia and also challenges of immunosuppressive tumor microenvironments for improved cancer immunotherapy.

Facile synthesis of phycocyanin/polydopamine hierarchical nanocomposites for synergizing PTT/PDT against cancer

The exceptional biocompatibility and biosafety of natural proteins have made them a popular choice for tumor therapy in recent years, but their therapeutic effectiveness is severely constrained by factors including physiological instability, insufficient delivery, limited accumulation in tumor cells, etc. Here, a novel Mn-doped phycocyanin (Pc)/polydopamine (PDA) hierarchical nanostructure (MnPc@P) with excellent optical absorption, photothermal conversion, and photodynamic performances, is first designed and fabricated by a simply one-pot reaction, which not only successfully encapsulates natural protein Pc with intact activity in the nanostructure of MnPc@P but also gives them better biocompatibility. Upon laser irradiation, PDA-mediated hyperthermia and Pc-induced ROS elevation in tumor cells have been demonstrated, leading to drastic tumor cell death via combined PTT/PDT effect, greater than single PTT or PDT. In general, the expert fusion of Pc and PDA into a single nanomedicine opens fascinating perspectives in the delivery of natural proteins and tumor therapy.

Platelet-Covered Nanocarriers for Targeted Delivery of Hirudin to Eliminate Thrombotic Complication in Tumor Therapy

Most patients are at high risk of thrombosis during cancer treatment. However, the major discrepancy in the therapeutic mechanisms and microenvironment between tumors and thrombosis makes it challenging for a panacea to treat cancer while being able to eliminate the risk of thrombosis. Herein, we developed a biomimetic MnOx/Ag₂S nanoflower platform with platelet membrane modification (MnOx@Ag₂S@hirudin@platelet membrane: MAHP) for the long-term release of anticoagulant drugs to treat thrombosis together with tumor therapy. This MAHP platform could achieve the targeted delivery of hirudin to the thrombus site and perform the controlled release under the irradiation of near-infrared light, demonstrating effective removal of the thrombus. Moreover, MAHP could inhibit tumor progression and prolong the survival time of mice with thromboembolic complications.

Biomimetic Yolk-Shell Nanocatalysts for Activatable Dual-Modal-Image-Guided Triple-Augmented Chemodynamic Therapy of Cancer

Fenton reaction-based chemodynamic therapy (CDT), which applies metal ions to convert less active hydrogen peroxide (H₂O₂) into more harmful hydroxyl peroxide (·OH) for tumor treatment, has attracted increasing interest recently. However, the CDT is substantially hindered by glutathione (GSH) scavenging effect on ·OH, low intracellular H₂O₂ level, and low reaction rate, resulting in unsatisfactory efficacy. Here, a cancer cell membrane (CM)-camouflaged Au nanorod core/mesoporous MnO₂ shell yolk-shell nanocatalyst embedded with glucose oxidase (GOD) and Dox (denoted as AMGDC) is constructed for synergistic triple-augmented CDT and chemotherapy of tumor under MRI/PAI guidance. Benefiting from the homologous adhesion and immune escaping property of the cancer CM, the nanocatalysts can target tumor and gradually accumulate in tumor site. For triple-augmented CDT, first, the MnO₂ shell reacts with intratumoral GSH to generate Mn²⁺ and glutathione disulfide, which achieves Fenton-like ion delivery and weakening of GSH-mediated scavenging effect, leading to GSH depletion-enhanced CDT. Second, the intratumoral glucose can be oxidized to H₂O₂ and gluconic acid by GOD, achieving supplementary H₂O₂-enhanced CDT. Next, the AuNRs absorbing in NIR-II elevate the local tumor temperature upon NIR-II laser irradiation, achieving photothermal-enhanced CDT. Dox is rapidly released for adjuvant chemotherapy due to responsive degradation of MnO₂ shell. Moreover, GSH-activated PAI/MRI can be used to monitor CDT process. This study provides a great paradigm for enhancing CDT-mediated antitumor efficacy.