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

Recent developments in photothermal therapy: a bibliometric and visual analysis

Photothermal therapy (PTT) has recently garnered significant attention as a prominent noninvasive treatment modality for a broad spectrum of diseases. Despite the increasing volume of scholarly output over the last 20 years, a holistic synthesis that delineates worldwide research trajectories remains elusive. We undertook a bibliometric analysis of the literature from 2004 to 2023, aiming to delineate the prevailing focal points and illuminate prospective research avenues. Research articles on PTT were retrieved from the Web of Science Core Collection. Using tools such as CiteSpace, VOSviewer, and Bibliometrix, we comprehensively analyzed and visualized 11,184 published academic PTT papers. China has the highest number of publications. Journals related to PTT are primarily comprised of interdisciplinary and comprehensive journals. Research associated with PTT has focused primarily on its antitumor properties. Current focal areas in this domain include the synergistic combination of PTT with photodynamic therapy, immunological mechanisms of PTT to enhance its therapeutic efficacy, integrated use of PTT with nanoenzyme catalysis, and the role of PTT in antimicrobial applications. This bibliometric analysis provides an initial comprehensive examination of the medical applications of PTT, offering insights into the global research landscape, key areas of interest, and emerging trends, thereby serving as a valuable reference for future studies in this field.

COF-Derived Carbon Materials: Synthesis Strategies and Emerging Applications

Covalent organic framework (COF)-derived carbon materials seamlessly inherit the periodic porous architecture and high specific surface area of their precursors, while simultaneously enabling the confinement of nanoparticles in designated regions. This unique feature mitigates agglomeration, enhances intrinsic properties, and imparts novel functionalities to the resulting materials. Consequently, COF-derived carbon materials have garnered significant attention across diverse fields, including energy, environmental remediation, and biomedical applications. Despite this burgeoning interest, a comprehensive review encompassing the synthesis, classification, and multifaceted applications of these materials remains scarce. In this context, the state-of-the-art advancements in COF-derived carbon materials are reviewed systematically here. It categorizes the materials, delineates their primary synthesis strategies, and highlights their versatile applications in catalysis, electrochemical energy storage, water treatment, sensing, and cancer therapy. Lastly, fresh insights into the challenges and future prospects of COF-derived carbon materials, paving the way for their expanded exploration and utilization are offered here.

Smart Bioorthogonal Catalytic Factory for Glaucoma Therapy

Glaucoma is characterized by high intraocular pressure (IOP), oxidative stress, and distinct optic nerve damage. Natural enzymes have unparalleled advantages in the treatment of glaucoma due to their high efficiency, specificity, and selectivity. However, their poor stability and recoverability have constrained their application. The selection of good immobilization carriers is an effective strategy to protect natural enzymes. Here, we employ a mild room-temperature aqueous-phase enzyme immobilization technique to immobilize superoxide dismutase and catalase. Then, l-arginine is added to the pores and further modified with DSPE-mPEG to construct a bioorthogonal catalytic factory (SC@COF-L-D) with excellent biocompatibility. This strategy greatly protects the natural enzyme from inactivation and improves the operational stability. SC@COF-L-D can scavenge a large amount of reactive oxygen species to reduce oxidative/nitrative damage and activate the soluble guanylate cyclase pathway, thereby lowering the IOP for effective treatment of glaucoma. This work provides a paradigm for the design of materials for glaucoma 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.

Carbon-based nanozymes for cancer therapy and diagnosis: A review

Carbon-based nanozymes (CNs) have emerged as a significant innovation in targeted cancer therapy, demonstrating great potential for advancing cancer diagnosis and treatment. With exceptional catalytic properties, remarkable biocompatibility, and the ability to precisely target cancer cells, CNs provide a promising avenue for the development of novel oncological therapies. By functionalizing their surfaces with targeting ligands, such as antibodies or peptides, CNs can specifically recognize and bind to cancer cells. This targeted approach ensures that therapeutic agents are delivered directly to the tumor site, minimizing off-target effects, and reducing systemic toxicity. Additionally, the enzyme-like activities of CNs, when combined with conventional therapies such as chemotherapeutics, photothermal therapy, and photodynamic therapy, or other modalities can enhance therapeutic outcomes. Integrating CNs into clinical practice could significantly improve therapeutic efficacy, reduce probable side effects, enhance patient outcomes, and drive a shift towards more personalized cancer care. Besides, CNs can also be employed in biosensors and diagnostic nanomaterials, enabling rapid, selective, and highly accurate detection of specific biomarkers. Their versatile functionalities open new avenues for refining imaging techniques, ultimately contributing to early diagnosis and better clinical decision-making. This review consolidates recent studies exploring CNs in cancer targeting, highlighting both their diagnostic and therapeutic potential in oncology.

Covalent organic framework derived single-atom copper nanozymes for the detection of amyloid-β peptide and study of amyloidogenesis

Sensitive and accurate detection of the amyloid-β (Aβ) monomer is of fundamental significance for early diagnosis of Alzheimer's disease (AD). Herein, inspired by the specific Cu-Aβ monomer coordination, a cutting-edge colorimetric assay based on single-atom Cu anchored N-doped carbon nanospheres (Cu-NCNSs) was developed for Aβ monomer detection and an amyloidogenesis study. By directly pyrolyzing Cu2+-incorporated covalent organic frameworks (COFs), the resulting Cu-NCNSs with a high loading of Cu (8.04 wt %) exhibited outstanding peroxidase-like activity. The strong binding affinity of Aβ monomer to Cu-NCNSs effectively inhibited their catalytic activity, providing the basis for the colorimetric assay. The Cu-NCNSs-based sensor showed a detection limit of 1.182 nM for Aβ monomer, surpassing traditional techniques in terms of efficiency, accuracy and simplicity. Moreover, the system was successfully utilized for Aβ monomer detection in rat cerebrospinal fluid (CSF). Notably, the distinct inhibitory effects of monomeric and aggregated Aβ species on the catalytic activity of Cu-NCNSs were allowed for monitoring of the dynamic aggregation process of Aβ. Compared to thioflavin T (ThT), the most widely used amyloid dye, the detection system exhibited greater sensitivity towards toxic Aβ oligomers, which was crucial for early AD diagnosis and treatment. Our work not only sheds light on the rational design of highly active single-atom nanozymes from COFs but also expands the potential applications of nanozymes in early disease diagnosis.

Probing the Active Nitrogen Species in Nitrogen-Doped Carbon Nanozymes for Enhanced Oxidase-Like Activity

Nitrogen doping emerges as a potent approach to enhance the oxidase-like activity of carbon nanozymes. However, the unclear knowledge of the active nitrogen species within nitrogen-doped carbon nanozymes hinders the advancement of high-performance carbon nanozymes. Herein, a group of nitrogen-doped carbon (N/C) nanozymes with controllable nitrogen dopants are successfully synthesized via a dicyandiamide-assisted pyrolysis method. The intrinsic connection between different nitrogen configurations (pyridinic N, pyrrolic N, and graphitic N) in N/C nanozymes and the oxidase-like performance are experimentally investigated. The results confirm pyridinic N is the active nitrogen species in N/C nanozymes for enhanced oxidase-like activity. Theoretical calculations further reveal the potential regulatory mechanism is pyridinic N can increase the local charge density of neighboring carbon atoms and accelerate the adsorption and activation of molecular oxygen. Notably, the optimized N/C nanozyme with the highest pyridinic N ratio presents impressive oxidase-like performance, surpassing most of the previously reported oxidase-like materials. Moreover, the optimized N/C nanozyme exhibits excellent antibacterial properties and can be easily incorporated into common medical and hygiene products to give them spontaneous antibacterial properties. The work will facilitate the rational design of carbon nanozymes with high-performance oxidase-like activity for applications in the antibacterial field.

New horizons for the therapeutic application of nanozymes in cancer treatment

The advent of nanozymes has revolutionized approaches to cancer diagnosis and therapy, introducing innovative strategies that address the limitations of conventional treatments. Nanozyme nanostructures with enzyme-mimicking catalytic abilities exhibit exceptional stability, biocompatibility, and customizable functions, positioning them as promising tools for cancer theranostics. By emulating natural enzyme reactions, nanozymes can selectively target and eradicate cancer cells, minimizing harm to adjacent healthy tissues. Nanozymes can also be functionalized with specific targeting ligands, allowing for the precise delivery and regulated release of therapeutic agents, improving treatment effectiveness and reducing adverse effects. However, issues such as biocompatibility, selectivity, and regulatory compliance remain critical challenges for the clinical application of nanozymes. This review provides an overview of nanozymes, highlighting their unique properties, various classifications, catalytic activities, and diverse applications in cancer treatments. The strategic oncological deployment of nanozymes could profoundly impact future advancements in personalized medicine, highlighting recent progress and prospective directions in enzyme-mimetic approaches for cancer treatment. This review summarizes an overview of nanozymes, highlighting their unique properties, various classifications, catalytic activities, and diverse applications in cancer treatments.

Nanozyme-mediated glutathione depletion for enhanced ROS-based cancer therapies: a comprehensive review

Nanozymes can improve reactive oxygen species (ROS)-based cancer therapies by targeting cancer cells' antioxidant defense mechanisms, particularly glutathione (GSH) depletion, to overcome ROS-resistant cancer cells. Nanozymes, innovative enzyme-mimetic nanomaterials, can generate ROS, alter the tumor microenvironment (TME), and synergize with photodynamic therapy (PDT), chemodynamic therapy (CDT), radiotherapy, and immunotherapy. This review shows how nanozymes catalyze ROS generation, selectively deplete GSH, and target cancer elimination, offering clear advantages over standard therapies. Nanozymes selectively target cancer cells' antioxidant defenses to improve PDT, CDT, and radiation therapies. To maximize nanozyme-based cancer treatment efficacy, biodistribution, biocompatibility, and tumor heterogeneity must be assessed. To improve cancer treatment, multifunctional, stimuli-responsive nanozymes and synergistic combination drugs should be developed.

Cu3(HITP)2 with peroxidase- and ascorbic acid oxidase-like catalytic activity for fluorescence/chemiluminescence sensing of ascorbic acid

Nanomaterials with intrinsic enzyme mimicking activity have achieved widespread application. However, developing novel nanomaterials with multienzyme mimicry activity remains challenging. Herein, Cu3(HITP)2 (HITP = 2,3,6,7,10,11-hexaiminotriphenylene) with ascorbic acid oxidase (AAO)- and peroxidase (POD)-like activity are successfully synthesized. Cu3(HITP)2 exhibits excellent AAO-like activity and can specifically catalyze the oxidation reaction of ascorbic acid (AA). Dehydroascorbic acid (DHAA) obtained from the oxidation of AA is allowed to react with nonfluorescent o-phenylenediamine (OPD) to form 3-(1,2-dihydrox-yethyl) furo[3,4-b]quinoxaline-1-one (DFQ) with strong fluorescence emission. Moreover, Cu3(HITP)2 is able to catalyze the chemiluminescence (CL) reaction of ABEI-H2O2 to generate a strong and glow-type emission based on its POD activity. Inspired by the multienzyme mimicry activity of Cu3(HITP)2, the simple and sensitive fluorescence and chemiluminescence sensing platforms are successfully constructed and applied for the detection of AA. The sensors show high sensitivity and excellent selectivity. We believe that this multienzyme mimicry activity nanomaterial not only can be used to construct the multiple-mode biosensing platform, but also enables the extensive applications in the fields of biomedicine, energy, and environment.

Heterojunction semiconductor nanocatalysts as cancer theranostics

Cancer nanotechnology is a promising area of cross-disciplinary research aiming to develop facile, effective, and noninvasive strategies to improve cancer diagnosis and treatment. Catalytic therapy based on exogenous stimulus-responsive semiconductor nanomaterials has shown its potential to address the challenges under the most global medical needs. Semiconductor nanocatalytic therapy is usually triggered by the catalytic action of hot electrons and holes during local redox reactions within the tumor, which represent the response of nontoxic semiconductor nanocatalysts to pertinent internal or external stimuli. However, careful architecture design of semiconductor nanocatalysts has been the major focus since the catalytic efficiency is often limited by facile hot electron/hole recombination. Addressing these challenges is vital for the progress of cancer catalytic therapy. In recent years, diverse strategies have been developed, with heterojunctions emerging as a prominent and extensively explored method. The efficiency of charge separation under exogenous stimulation can be heightened by manipulating the semiconducting performance of materials through heterojunction structures, thereby enhancing catalytic capabilities. This review summarizes the recent applications of exogenous stimulus-responsive semiconducting nanoheterojunctions for cancer theranostics. The first part of the review outlines the construction of different heterojunction types. The next section summarizes recent designs, properties, and catalytic mechanisms of various semiconductor heterojunctions in tumor therapy. The review concludes by discussing the challenges and providing insights into their prospects within this dynamic and continuously evolving field of research.

Biodegradable Cascade-Amplified Nanotheranostics for Photoacoustic-Guided Synergistic PTT/CDT/Starvation Antitumor in the NIR-II Window

The development of nanoassemblies, activated by the tumor microenvironment, capable of generating photothermal therapy (PTT) and amplifying the "ROS (·OH) storm," is essential for precise and effective synergistic tumor treatment. Herein, an innovative cascade-amplified nanotheranostics based on biodegradable Pd-BSA-GOx nanocomposite for NIR-II photoacoustic imaging (PAI) guides self-enhanced NIR-II PTT/chemodynamic therapy (CDT)/starvation synergistic therapy. The Pd-BSA-GOx demonstrates the ability to selectively convert overexpressed H2O2 into strongly toxic ·OH by a Pd/Pd2+-mediated Fenton-like reaction at a lower pH level. Simultaneously, the GOx generates H2O2 and gluconic acid, effectively disrupting nutrient supply and instigating tumor starvation therapy. More importantly, the heightened levels of H2O2 and increased acidity greatly enhance the Fenton-like reactivity, generating a significant "·OH storm," thereby achieving Pd2+-mediated cascade-amplifying CDT. The specific PTT facilitated by undegraded Pd accelerates the Fenton-like reaction, establishing a positive feedback process for self-enhancing synergetic PTT/CDT/starvation therapy via the NIR-II guided-PAI. Therefore, the multifunctional nanotheranostics presents a simple and versatile strategy for the precision diagnosis and treatment of tumors.

Pyridine-Bridged Covalent Organic Frameworks with Adjustable Band Gaps as Intelligent Artificial Enzymes for Light-Augmented Biocatalytic Sensing

One of the biggest challenges in biotechnology and medical diagnostics is finding extremely sensitive and adaptable biosensors. Since metal-based enzyme-mimetic biocatalysts may lead to biosafety concerns on accumulative toxicity, it is essential to synthesize metal-free enzyme-mimics with optimal biocatalytic activity and superior selectivity. Here, the pyridine-bridged covalent organic frameworks (COFs) with specific oxidase-like (OXD-like) activities as intelligent artificial enzymes for light-augmented biocatalytic sensing of biomarkers are disclosed. Because of the adjustable bandgaps of pyridine structures on the photocatalytic properties of the pristine COF structures, the pyridine-bridged COF exhibit efficient, selective, and light-responsive OXD-like biocatalytic activity. Moreover, the pyridine-bridged COF structures show tunable and light-augmented biocatalytic detection capabilities, which outperform the recently reported state-of-the-art OXD-mimics regarding biosensing efficiency. Notably, the pyridine-bridged COF exhibits efficient and multifaceted diagnostic activity, including the extremely low limit of detection (LOD), which enables visual assays for abundant reducibility biomarkers. It is believed that this design will offer unique metal-free biocatalysts for high-sensitive and low-cost colorimetric detection and also provide new insights to create highly efficient enzyme-like COF materials via linkage-modulation strategies for future biocatalytic applications.

Hydroxyl radical-mediated synthesis of carbonyl functionalized graphene quantum dots-like as enzyme mimics with tunable fluorescence emission

The synthesis of graphene quantum dots-like enriched with specific oxygenated groups (o-GQDs) exhibiting great catalytic performance offers a promising tool for diagnosis and biomedicine, but introducing specific oxygen groups remains a challenge. Here, we propose a mild synthetic protocol for producing regulated fluorescence emission (from blue to yellow) carbonyl functionalized GQDs with double catalytic function through Fe3O4-catalyzed hydroxyl radical (·OH) oxidation the precursors like graphene oxide, polyaniline (PANI) and polydopamine (PDA). The method can be carried out at room temperature than the traditional high-temperature oxidation in concentrated acid. Interestingly, o-GQDs exhibit excellent peroxidase (POD)- and ascorbate oxidase-like activity. XPS characterization showed a significant increase in carbonyl content in o-GQDs compared to the precursor, even a 14-fold increase in blue-emitting iron-doped GQDs (b-Fe-GQDs). The introduction of Fe3O4 during the synthesis process results in a minor degree of Fe doping, which enhances the catalytic activity of b-Fe-GQDs through coordination with N. Based on this feature, highly sensitive single-signal and ultra-selective dual-signal methods for alkaline phosphatase detection were developed. This low cost and safe synthesis strategy paves the way for practical usage of o-GQDs.

Advances in H2O2-supplying materials for tumor therapy: synthesis, classification, mechanisms, and applications

Hydrogen peroxide (H2O2) as a reactive oxygen species produced by cellular metabolism can be used in antitumor therapy. However, the concentration of intracellular H2O2 limits its application. Some materials could enhance the concentration of intracellular H2O2 to strengthen antitumor therapy. In this review, the recent advances in H2O2-supplying materials in terms of promoting intracellular H2O2 production and exogenous H2O2 supply are summarized. Then the mechanism of H2O2-supplying materials for tumor therapy is discussed from three aspects: reconstruction of the tumor hypoxia microenvironment, enhancement of oxidative stress, and the intrinsic anti-tumor ability of H2O2-supplying materials. In addition, the application of H2O2-supplying materials for tumor therapy is discussed. Finally, the future of H2O2-supplying materials is presented. This review aims to provide a novel idea for the application of H2O2-supplying materials in tumor therapy.

Porphyrin-based covalent organic frameworks from design, synthesis to biological applications

Covalent organic frameworks (COFs) constitute a class of highly functional porous materials composed of lightweight elements interconnected by covalent bonds, characterized by structural order, high crystallinity, and large specific surface area. The integration of naturally occurring porphyrin molecules, renowned for their inherent rigidity and conjugate planarity, as building blocks in COFs has garnered significant attention. This strategic incorporation addresses the limitations associated with free-standing porphyrins, resulting in the creation of well-organized porous crystal structures with molecular-level directional arrangements. The unique optical, electrical, and biochemical properties inherent to porphyrin molecules endow these COFs with diversified applications, particularly in the realm of biology. This review comprehensively explores the synthesis and modulation strategies employed in the development of porphyrin-based COFs and delves into their multifaceted applications in biological contexts. A chronological depiction of the evolution from design to application is presented, accompanied by an analysis of the existing challenges. Furthermore, this review offers directional guidance for the structural design of porphyrin-based COFs and underscores their promising prospects in the field of biology.

Synergistic effect of photothermal and magnetic hyperthermia for in situ activation of Fenton reaction in tumor microenvironment for chemodynamic therapy

Traditional cancer treatments are ineffective and cause severe adverse effects. Thus, the development of chemodynamic therapy (CDT) has the potential for in situ catalysis of endogenous molecules into highly toxic species, which would then effectively destroy cancer cells. However, the shortage of high-performance nanomaterials hinders the broad clinical application of this approach. In present study, an effective therapeutic platform was developed using a simple hydrothermal method for the in-situ activation of the Fenton reaction within the tumor microenvironment (TME) to generate substantial quantities of •OH and ultimately destroy cancer cells, which could be further synergistically increased by photothermal therapy (PHT) and magnetic hyperthermia (MHT) aided by FeMoO4 nanorods (NRs). The produced FeMoO4 NRs were used as MHT/PHT and Fenton catalysts. The photothermal conversion efficiency of the FeMoO4 NRs was 31.75 %. In vitro and \ experiments demonstrated that the synergistic combination of MHT/PHT/CDT notably improved anticancer efficacy. This work reveals the significant efficacy of CDT aided by both photothermal and magnetic hyperthermia and offers a feasible strategy for the use of iron-based nanoparticles in the field of biomedical applications.