A tumor-targeted theranostic nanomedicine with strong absorption in the NIR-II biowindow for image-guided multi-gradient therapy

A novel reactive oxygen species nano-amplifier for tumor-targeted photoacoustic imaging and synergistic therapy

Intracellular redox homeostasis and the type of exogenous Fenton reagent play crucial roles in determining the efficacy of chemodynamic therapy (CDT). Herein, we succeeded for the first time in preparing ultrasmall copper sulfide (CuS) nanodots (1-2 nm)-embedded hollow mesoporous organosilica nanoparticle (HMON), which served as an ideal nanocarrier to load both 3-amino-1,2,4-triazole (3-AT) and disulfiram (DSF) after folate-polyethylene glycol-silane (FA-PEG-Silane) modification. The as-prepared nanoplatform (3-AT/DSF@CuS/HMON-FA, denoted as ADCuSi-FA) was found to regulate intracellular redox homeostasis once internalized by 4T1 cells, showing rapid glutathione (GSH)-responsive 3-AT, DSF and Cu+ ions release. Specifically, 3-AT restrained the endogenous hydrogen peroxide (H2O2) consumption by suppressing catalase (CAT) activity, thereby augmenting hydroxyl radical (OH) generation via Cu+-based Fenton-like reaction. DSF, upon complexation with Cu2+, exhibited enhanced chemotherapeutic efficacy, while the by-product Cu+ ions further boosted the efficacy of CDT. Additionally, CuS nanodots enabled near-infrared-II (NIR-II) photothermal therapy (PTT) and facilitated photoacoustic (PA) imaging, with the ensuing hyperthermia expediting the CDT process. As expected, the tumor growth was dramatically inhibited with PTT/chemotherapy co-synergized CDT. This work offers an innovative paradigm for cooperative cancer treatment as well as new insights into the fabrication of biodegradable inorganic/organic hybrid materials.

Recent research progress on metal ions and metal-based nanomaterials in tumor therapy

Tumors, as a disease that seriously threatens human health, have always been a major challenge in the field of medicine. Currently, the main methods of tumor treatment include surgery, radiotherapy, chemotherapy, etc., but these traditional treatment methods often have certain limitations. In addition, tumor recurrence and metastasis are also difficult problems faced in clinical treatment. In this context, the importance of metal-based nanomaterials in tumor therapy is increasingly highlighted. Metal-based nanomaterials possess unique physical, chemical, and biological properties, providing new ideas and methods for tumor treatment. Metal-based nanomaterials can achieve targeted therapy for tumors through various mechanisms, reducing damage to normal tissues; they can also serve as drug carriers, improving the stability and bioavailability of drugs; at the same time, some metal-based nanomaterials also have photothermal, photodynamic, and other characteristics, which can be used for phototherapy of tumors. This review examines the latest advances in the application of metal-based nanomaterials in tumor therapy within past 5 years, and presents prospective insights into the future applications.

Cuproptosis: A new mechanism for anti-tumour therapy

As an indispensable trace metal element in the organism, copper acts as a key catalytic cofactor in a wide range of biological processes. Copper homeostasis disorders can be caused by either copper excess or deficiency, and copper homeostasis disorders will affect the normal physiological functions of cells and induce cell death through a variety of mechanisms, such as the emerging cuproptosis model. The imbalance of copper homeostasis will lead to the occurrence of cancer, and copper is a key factor in cell signalling, so copper is involved in the development of cancer by promoting cell proliferation, angiogenesis and metastasis, etc. The therapeutic role of Cuproptosis as a hotspot of research in cancer has also attracted much attention. Therefore, this paper comprehensively searches the literature to review the roles and mechanisms of Cuproptosis in the treatment of malignant tumours, aiming to provide new insights into the role and mechanism of Cuproptosis in anti-malignant tumour therapy and present novel ideas and methods.

Recent advances in chemotherapy for cancer therapy over Cu-based nanocatalysts

Recently, the emerging chemotherapy (CDT) has provided a new biocompatibility pathway for cancer therapy. Among them, Cu-based nanocatalysts with good biocompatibility and Fenton-like catalytic efficiency are considered to be a promising approach for enhancing CDT and CDT-involved multimodal synergies to improve the effectiveness of catalytic cancer therapy. Meanwhile, the emerging in situ therapy strategy promoted by Cu-based nanocatalysts has proven to exhibit attractive clinical application potential in replacing traditional chemotherapy and radiotherapy for cancer therapy with significant toxic side effects. In this work, the recent progress of various Cu-based nanocatalysts in cancer therapy was reviewed, especially the remarkable achievements in the catalytic treatment of cancer in the tumor microenvironment using CDT and CDT-involved multimodal synergies. In addition, the development expectations and challenges of Cu-based nanocatalysts in the field of cancer therapy were briefly summarized and discussed. We expect that this review will contribute to the development of Cu-based nanocatalysts for cancer therapy.

Stimuli-Responsive Covalent Organic Frameworks for Cancer Therapy

Chemotherapy as a common anticancer therapeutic modality is often challenged by various obstacles such as poor stability, low solubility, and severe side effects of chemotherapeutic agents as well as multidrug resistance of cancerous cells. Nanoparticles in the role of carriers for chemotherapeutic drugs and platforms for combining different therapeutic approaches have effectively participated in overcoming such drawbacks. In particular, nanoparticles able to induce their therapeutic effect in response to specific stimuli like tumor microenvironment characteristics (e.g., hypoxia, acidic pH, high levels of glutathione, and overexpressed hydrogen peroxide) or extrinsic stimulus of laser light bring about more precise and selective treatments. Among them, nanostructures of covalent organic frameworks (COFs) have drawn great interest in biomedical fields during recent years. Possessing large surface area, high porosity, structural stability, and customizable architecture, these biocompatible porous crystalline polymers properly translate to promising platforms for drug delivery and induction of combination therapies. With the focus on stimuli-responsive characteristics of nanoscale COFs, this study aims to propose an overview of their potentiality in cancer treatment on the basis of chemotherapy alone or in combination with sonodynamic, chemodynamic, photodynamic, and photothermal therapies.

Tumor Microenvironment Specific Regulation Ca-Fe-Nanospheres for Ferroptosis-Promoted Domino Synergistic Therapy and Tumor Immune Response

Reactive oxygen species (ROS)-mediated emerging treatments exhibit unique advantages in cancer therapy in recent years. While the efficacy of ROS-involved tumor therapy is greatly restricted by complex tumor microenvironment (TME). Herein, a dual-metal CaO2@CDs-Fe (CCF) nanosphere, with TME response and regulation capabilities, are proposed to improve ROS lethal power by a multiple cascade synergistic therapeutic strategy with domino effect. In response to weak acidic TME, CCF will decompose, accompanied with intracellular Ca2+ upregulated and abundant H2O2 and O2 produced to reverse antitherapeutic TME. Then the exposed CF cores can act as both Fenton agent and sonosensitizer to generate excessive ROS in the regulated TME for enhanced synergistic CDT/SDT. In combination with calcium overloading, the augmented ROS induced oxidative stress will cause more severe mitochondrial damage and cellular apoptosis. Furthermore, CCF can also reduce GPX4 expression and enlarge the lipid peroxidation, causing ferroptosis and apoptosis in parallel. These signals of damage will finally initiate damage-associated molecular patterns to activate immune response and to realize excellent antitumor effect. This outstanding domino ROS/calcium loading synergistic effect endows CCF with excellent anticancer effect to efficiently eliminate tumor by apoptosis/ferroptosis/ICD both in vitro and in vivo.

In vivo synergistic tumor therapies based on copper sulfide photothermal therapeutic nanoplatforms

Tumor cells may be eliminated by increasing their temperature. This is achieved via photothermal therapy (PTT) by penetrating the tumor tissue with near-infrared light and converting light energy into heat using photothermal agents. Copper sulfide nanoparticles (CuS NPs) are commonly used as PTAs in PTT. In this review, we aimed to discuss the synergism between tumor PTT with CuS NPs and other therapies such as chemotherapy, radiotherapy, dynamic therapies (photodynamic, chemodynamic, and sonodynamic therapy), immunotherapy, gene therapy, gas therapy, and magnetic hyperthermia. Furthermore, we summarized the results obtained with a combination of two treatments and at least two therapies, with PTT as one of the included therapies. Finally, we summarized the benefits and drawbacks of various therapeutic options and state of the art CuS-based PTT and provided future directions for such therapies.

Recent advances in glucose oxidase-based nanocarriers for tumor targeting therapy

Glucose oxidase (GOx) can specifically catalyze the conversion of β-d-glucose into gluconic acid and hydrogen peroxide (H2O2) in the presence of oxygen, making it promising for tumor starvation therapy and oxidative therapy. However, GOx's immunogenicity, poor in vivo stability, short half-life, and potential systemic toxicity, limit its application in cancer therapy. Nanocarriers are capable of improving the pharmacological properties of therapeutic drugs (e.g. stability, circulating half-life, and tumor accumulation) and lower toxicity, hence resolving GOx issues and enhancing its efficacy. Although the application of targeted nanocarriers based on GOx has recently flourished, this field has not yet been reviewed and evaluated. Herein, we initially examined the mechanism of GOx-based nanocarriers for enhanced tumor therapy. Also, we present a comprehensive and up-to-date review that highlights GOx-based nanocarriers for tumor targeting therapy. This review expands on GOx-based nano-targeted combination therapies from both passive and active targeting perspectives, meanwhile, active targeting is further classified into ligand-mediated targeting and physical-mediated targeting. Furthermore, this review also emphasizes the present challenges and promising advancements.

Multifunctional polysaccharide nanoprobes for biological imaging

Imaging and tracking biological targets or processes play an important role in revealing molecular mechanisms and disease states. Bioimaging via optical, nuclear, or magnetic resonance techniques enables high resolution, high sensitivity, and high depth imaging from the whole animal down to single cells via advanced functional nanoprobes. To overcome the limitations of single-modality imaging, multimodality nanoprobes have been engineered with a variety of imaging modalities and functionalities. Polysaccharides are sugar-containing bioactive polymers with superior biocompatibility, biodegradability, and solubility. The combination of polysaccharides with single or multiple contrast agents facilitates the development of novel nanoprobes with enhanced functions for biological imaging. Nanoprobes constructed with clinically applicable polysaccharides and contrast agents hold great potential for clinical translations. This review briefly introduces the basics of different imaging modalities and polysaccharides, then summarizes the recent progress of polysaccharide-based nanoprobes for biological imaging in various diseases, emphasizing bioimaging with optical, nuclear, and magnetic resonance techniques. The current issues and future directions regarding the development and applications of polysaccharide nanoprobes are further discussed.

Copper-instigated modulatory cell mortality mechanisms and progress in oncological treatment investigations

Copper, a transition metal, serves as an essential co-factor in numerous enzymatic active sites and constitutes a vital trace element in the human body, participating in crucial life-sustaining activities such as energy metabolism, antioxidation, coagulation, neurotransmitter synthesis, iron metabolism, and tetramer deposition. Maintaining the equilibrium of copper ions within biological systems is of paramount importance in the prevention of atherosclerosis and associated cardiovascular diseases. Copper induces cellular demise through diverse mechanisms, encompassing reactive oxygen species responses, apoptosis, necrosis, pyroptosis, and mitochondrial dysfunction. Recent research has identified and dubbed a novel regulatory cell death modality-"cuprotosis"-wherein copper ions bind to acylated proteins in the tricarboxylic acid cycle of mitochondrial respiration, resulting in protein aggregation, subsequent downregulation of iron-sulfur cluster protein expression, induction of proteotoxic stress, and eventual cell death. Scholars have synthesized copper complexes by combining copper ions with various ligands, exploring their significance and applications in cancer therapy. This review comprehensively examines the multiple pathways of copper metabolism, copper-induced regulatory cell death, and the current status of copper complexes in cancer treatment.

Second Near-Infrared Plasmonic Nanomaterials for Photoacoustic Imaging and Photothermal Therapy

Photoacoustic imaging (PAI) and imaging-guided photothermal therapy (PTT) in the second near-infrared window (NIR-II, 1000-1700 nm) have received increasing attention owing to their advantages of greater penetration depth and higher signal-to-noise ratio. Plasmonic nanomaterials with tunable optical properties and strong light absorption provide an alternative to dye molecules, showing great prospects for phototheranostic applications. In this review, the research progress in principally modulating the optical properties of plasmonic nanomaterials, especially affecting parameters such as size, morphology, and surface chemical modification, is introduced. The commonly used plasmonic nanomaterials in the NIR-II window, including noble metals, semiconductors, and heterostructures, are then summarized. In addition, the biomedical applications of these NIR-II plasmonic nanomaterials for PAI and PTT in phototheranostics are highlighted. Finally, the perspectives and challenges for advancing plasmonic nanomaterials for practical use and clinical translation are discussed.

A biomineralized bi-functional hybrid nanoflower to effectively combat bacteria via a glucose-powered cascade catalytic reaction

The bacterial resistance due to the abuse of conventional antibiotics is regarded as a major problem for bacterial-induced infections and chronic wound healing. There is an urgent need to explore alternative antimicrobial strategies and functional materials with excellent antibacterial efficacy. Herein, guanosine monophosphate (GMP) and glucose oxidase (GOD) were coordinated with copper ions to obtain a bi-functional hybrid nanoflower (Cu-GMP/GODNF) as a cascade catalyst for promoting antibacterial efficacy. Besides the efficient conversion of glucose to hydrogen peroxide, the produced gluconic acid by loading GOD can supply a compatible catalytic environment to substantially improve the peroxidase activity for generating more toxic reactive oxygen species (ROS). So, the glucose-powered cascade catalytic reaction effectively killed bacteria. Moreover, H₂O₂ self-supplied by glucose can reduce harmful side effects of exogenous H₂O₂. Meanwhile, the adhesion between the Cu-GMP/GODNF and the bacterial membrane can enhance the antibacterial efficacy. Therefore, the achieved bi-functional hybrid nanoflower exhibited high efficiency and biocompatibility for killing bacteria in diabetes-related infections.

Dual H2 O2 -Amplified Nanofactory for Simultaneous Self-Enhanced NIR-II Fluorescence Activation Imaging and Synergistic Tumor Therapy

Activatable fluorescence imaging in the second near-infrared window (NIR-II FL, 1000-1700 nm) is of great significance for accurate tumor diagnosis and targeting therapy. However, the clinical translation of most stimulus-activated nanoprobes is severely restricted by insufficient tumor response and out-of-synchronization theranostic process. Herein, an intelligent nanofactory AUC-GOx/Cel that possesses the "external supply, internal promotion" dual H₂ O₂ -amplification strategy for homologous activated tumor theranostic is designed. This nanofactory is constructed via a two-step biomineralization method using Au-doped Ag₂ S as a carrier for glucose oxidase (GOx) and celastrol, followed by the growing of CuS to "turn off" the NIR-II FL signal. In the overexpressed H₂ O₂ tumor-microenvironment, the CuS featuring a responsive-degradability behavior can effectively release Cu ions, resulting in the "ON" state of NIR-II FL and Fenton-like activity. The exposed GOx can realize the intratumoral H₂ O₂ supply (external supply) via the effective conversion of glucose, and mediating tumor-starvation therapy; the interaction of celastrol and mitochondria can offer a substantial increase in the endogenous H₂ O₂ level (internal promotion), thereby significantly promoting the chemodynamic therapy (CDT) efficacy. Meanwhile, the dual H₂ O₂ -enhancement performance will in turn accelerate the degradation of AUC-GOx/Cel, and achieve a positive feedback mechanism for self-reinforcing CDT.

High Performance Gold Nanorods@DNA Self-Assembled Drug-Loading System for Cancer Thermo-Chemotherapy in the Second Near-Infrared Optical Window

In terms of synergistic cancer therapy, biological nanomaterials with a second near-infrared (NIR-II) window response can greatly increase photothermal effects and photoacoustic imaging performance. Herein, we report a novel stimuli-responsive multifunctional drug-loading system which was constructed by integrating miniature gold nanorods (GNR) as the NIR-II photothermal nanorods and cyclic ternary aptamer (CTA) composition as a carrier for chemotherapy drugs. In this system, doxorubicin hydrochloride (DOX, a chemotherapy drug) binds to the G-C base pairs of the CTA, which exhibited a controlled release behavior based on the instability of G-C base pairs in the slightly acidic tumor microenvironment. Upon the 1064 nm (NIR-II biowindow) laser irradiation, the strong photothermal and promoted cargo release properties endow gold nanorods@CTA (GNR@CTA) nanoparticles displaying excellent synergistic anti-cancer effect. Moreover, the GNR@CTA of NIR also possesses thermal imaging and photoacoustic (PA) imaging properties due to the strong NIR region absorbance. This work enables to obtaining a stimuli-responsive “all-in-one” nanocarrier, which are promising candidate for bimodal imaging diagnosis and chemo-photothermal synergistic therapy.

Chemodynamic Therapy via Fenton and Fenton-Like Nanomaterials: Strategies and Recent Advances

Chemodynamic therapy (CDT), a novel cancer therapeutic strategy defined as the treatment using Fenton or Fenton-like reaction to produce •OH in the tumor region, was first proposed by Bu, Shi, and co-workers in 2016. Recently, with the rapid development of Fenton and Fenton-like nanomaterials, CDT has attracted tremendous attention because of its unique advantages: 1) It is tumor-selective with low side effects; 2) the CDT process does not depend on external field stimulation; 3) it can modulate the hypoxic and immunosuppressive tumor microenvironment; 4) the treatment cost of CDT is low. In addition to the Fe-involved CDT strategies, the Fenton-like reaction-mediated CDT strategies have also been proposed, which are based on many other metal elements including copper, manganese, cobalt, titanium, vanadium, palladium, silver, molybdenum, ruthenium, tungsten, cerium, and zinc. Moreover, CDT has been combined with other therapies like chemotherapy, radiotherapy, phototherapy, sonodynamic therapy, and immunotherapy for achieving enhanced anticancer effects. Besides, there have also been studies that extend the application of CDT to the antibacterial field. This review introduces the latest advancements in the nanomaterials-involved CDT from 2018 to the present and proposes the current limitations as well as future research directions in the related field.

Fenton/Fenton-like metal-based nanomaterials combine with oxidase for synergistic tumor therapy

Chemodynamic therapy (CDT) catalyzed by transition metal and starvation therapy catalyzed by intracellular metabolite oxidases are both classic tumor treatments based on nanocatalysts. CDT monotherapy has limitations including low catalytic efficiency of metal ions and insufficient endogenous hydrogen peroxide (H₂O₂). Also, single starvation therapy shows limited ability on resisting tumors. The “metal-oxidase” cascade catalytic system is to introduce intracellular metabolite oxidases into the metal-based nanoplatform, which perfectly solves the shortcomings of the above-mentioned monotherapiesIn this system, oxidases can not only consume tumor nutrients to produce a “starvation effect”, but also provide CDT with sufficient H₂O₂ and a suitable acidic environment, which further promote synergy between CDT and starvation therapy, leading to enhanced antitumor effects. More importantly, the “metal-oxidase” system can be combined with other antitumor therapies (such as photothermal therapy, hypoxia-activated drug therapy, chemotherapy, and immunotherapy) to maximize their antitumor effects. In addition, both metal-based nanoparticles and oxidases can activate tumor immunity through multiple pathways, so the combination of the “metal-oxidase” system with immunotherapy has a powerful synergistic effect. This article firstly introduced the metals which induce CDT and the oxidases which induce starvation therapy and then described the “metal-oxidase” cascade catalytic system in detail. Moreover, we highlight the application of the “metal-oxidase” system in combination with numerous antitumor therapies, especially in combination with immunotherapy, expecting to provide new ideas for tumor treatment.

H2O2 self-supplying degradable epitope imprinted polymers for targeted fluorescence imaging and chemodynamic therapy

Chemodynamic therapy (CDT), the ability to transform H₂O₂ into a highly toxic hydroxyl radical (˙OH) through a Fenton or Fenton like reaction to kill cancer cells, enables selective tumor therapy. However, the effect is seriously limited by the insufficiency of endogenous H₂O₂ in cancer cells. Additionally, the specific recognition of epitope imprinting plays an important role in targeting cancer cell markers. In this work, we prepared H₂O₂ self-supplying degradable epitope molecularly imprinted polymers (MIP) for effective CDT, employing fluorescent calcium peroxide (FCaO₂) as an imaging probe and a source of H₂O₂, the exposed peptide in the CD47 extracellular region as the template, copper acrylate as one of the functional monomers and N,N'-bisacrylylcystamine (BAC) as a cross-linker. MIP with recognition sites can specifically target CD47-positive cancer cells to achieve fluorescence imaging. Under the reduction of glutathione (GSH), the MIP were degraded and the exposed FCaO₂ reacted with water to continuously produce H₂O₂ in the slightly acidic environment in cancer cells. The self-supplied H₂O₂ produced ˙OH through a Fenton like catalytic reaction mediated by copper ions in the MIP framework, inducing cancer cell apoptosis. Therefore, the MIP nano-platform, which was capable of specific recognition of the cancer cell marker, H₂O₂ self-supply and controlled treatment, was successfully used for targeted CDT.

Carbon-Defect-Driven Boron Carbide for Dual-Modal NIR-II/Photoacoustic Imaging and Photothermal Therapy

Recently, tremendous attention has been evoked in the discovery of defect-engineered nanomaterials for near-infrared second window (NIR-II)-driven cancer therapy. Herein, we have constructed a novel type of carbon defects enriched in boron carbide nanomaterial (denoted as B₄C@C) through reacting B₄C and glucose by a hydrothermal method. The carbon defect concentration in B₄C@C has been significantly increased after coating with glucose; thus, B₄C@C exhibited a distinct photothermal response under the NIR-II window and the efficiency of photothermal conversion is determined to reach 45.4%, which is higher than the carbon-based nanomaterials in the NIR-II region. Both Raman spectra and X-ray photoelectron spectroscopy (XPS) spectra reveal that B₄C@C has rich sp²-hybridized carbon defects and effectively increases the NIR-II window light absorption capacity, thus enhancing the nonradiative recombination rate and improving the NIR-II photothermal effect. Furthermore, the B₄C@C nanosheets allows for tumor phototherapy and simultaneous photoacoustic imaging. This work indicates the huge potential of B₄C@C as a novel photothermal agent, which might arise much attention in exploring boron-based nanomaterials for the advantage of cancer therapy.

Active-Targeting NIR-II Phototheranostics in Multiple Tumor Models Using Platelet-Camouflaged Nanoprobes

Cancer phototheranostics in the second near-infrared window (NIR-II, 1000-1700 nm) has recently attracted much attention owing to its high efficacy and good safety compared with that in the first near-infrared window (NIR-I, 650-950 nm). However, the lack of theranostic nanoagents with active-targeting features limits its further application in cancer precision therapies. Herein, we constructed platelet-camouflaged nanoprobes with active-targeting characteristics for NIR-II cancer phototheranostics. The as-prepared biomimetic nanoprobes can not only escape phagocytosis by macrophages but also specifically bind to CD44 on the surface of most cancer cells. We evaluated the active-targeting performance of biomimetic nanoprobes in pancreatic cancer, breast cancer, and glioma mouse models and achieved NIR-II photoacoustic imaging with a high signal-to-background ratio and photothermal treatment with excellent tumor growth inhibition. Our results show the great potential of platelet-camouflaged nanoprobes with NIR-II active-targeting features for cancer precision diagnosis and efficient therapies.