A Ferrocene-Functionalized Covalent Organic Framework for Enhancing Chemodynamic Therapy via Redox Dyshomeostasis

Facile Preparation of a Thienoisoindigo-Based Nanoscale Covalent Organic Framework with Robust Photothermal Activity for Cancer Therapy

The covalent organic frameworks (COFs) so far are usually built with small aromatic subunits, which makes their absorption spectra mainly located in the high-energy part of the visible region. In this work, we have developed a COF with a low band gap by integrating electron-deficient thienoisoindigo and electron-rich triphenylamine. The intramolecular charge-transfer effect combining the extended length of the π-conjugated backbone of COF endow it with broad absorption even to the second near-infrared region. After optimizing the solvent, a uniform size and colloidal stable COF is obtained. Benefiting from the coplanar structure of the monomer, this COF achieves a considerable photothermal conversion efficiency (PCE) of 48.2%. With these advantages, it displays convincing cancer cell killing effect upon laser irradiation in vitro or in vivo. This work provides a simple and practical method to acquire promising a COF-based phototherapy reagent that is applied in biomedicine field.

Engineering Multienzyme-Mimicking Covalent Organic Frameworks as Pyroptosis Inducers for Boosting Antitumor Immunity

The engineering of a series of multienzyme-mimicking covalent organic frameworks (COFs), COF-909-Cu, COF-909-Fe, and COF-909-Ni, as pyroptosis inducers, remodeling the tumor microenvironment to boost cancer immunotherapy, is reported. Mechanistic studies reveal that these COFs can serve as hydrogen peroxide (H2 O2 ) homeostasis disruptors to elevate intracellular H2 O2 levels, and they not only exhibit excellent superoxide dismutase (SOD)-mimicking activity and convert superoxide radicals (O2 •- ) to H2 O2 to facilitate H2 O2 generation, but also possess outstanding glutathione peroxidase (GPx)-mimicking activity and deplete glutathione (GSH) to alleviate the scavenging of H2 O2 . Meanwhile, the outstanding photothermal therapy properties of these COFs can accelerate the Fenton-like ionization process to facilitate their chemodynamic therapy efficiency. One member, COF-909-Cu, can robustly induce gasdermin E (GSDME)-dependent pyroptosis and remodel the tumor microenvironment to trigger durable antitumor immunity, thus promoting the response rate of αPD-1 checkpoint blockade and successfully restraining tumor metastasis and recurrence.

Multifunctional Nanomaterials for Ferroptotic Cancer Therapy

Patient outcomes from the current clinical cancer therapy remain still far from satisfactory. However, in recent years, several biomedical discoveries and nanotechnological innovations have been made, so there is an impetus to combine these with conventional treatments to improve patient experience and disease prognosis. Ferroptosis, a term first coined in 2012, is an iron-dependent regulated cell death (RCD) based on the production of reactive oxygen species (ROS) and the consequent oxidization of polyunsaturated fatty acids (PUFAs). Many nanomaterials that can induce ferroptosis have been explored for applications in cancer therapy. In this review, we summarize the recent developments in ferroptosis-based nanomaterials for cancer therapy and discuss the future of ferroptosis, nanomedicine, and cancer therapy.

A Multifunctional Nanoplatform Based on Fenton-like and Russell Reactions of Cu, Mn Bimetallic Ions Synergistically Enhanced ROS Stress for Improved Chemodynamic Therapy

Chemodynamic therapy (CDT) based intracellular chemical reactions to produce highly cytotoxic reactive oxygen species has received wide attention. However, low efficiency of single CDT in weakly acidic pH and glutathione (GSH) overexpressed tumor cells has limited its clinical application. For this study were prepared two-dimensional metal-organic framework (MOF) to improve CDT efficiency based on the combined action of bimetallic CDT, consumption of overexpressed glutathione (GSH) in cells, folic acid (FA) induced tumor targeting and triphenylphosphine (TPP) induced mitochondrial targeting. With the use of Cu(II) as the central ion and tetrakis(4-carboxyphenyl)porphyrin (TCPP) as the ligand, two-dimensional Cu-MOF nanosheets were prepared, which were surface modified by manganese dioxide based on the in situ redox reaction between poly(allylamine hydrochloride) (PAH) and KMnO₄ to obtain Cu-MOF@MnO₂. Then FA and TPP were coupled with the nanosheets to form the title nanoplatform. Comprehensive physiochemical research has suggested that Cu(II) and MnO₂ constituents in the nanoplatform could consume intracellular GSH and hydrogen peroxide to generate hydroxyl radicals through a Fenton-like reaction; meanwhile Cu(II) could undergo a Russell reaction to produce cytotoxic singlet oxygen. Detailed in vitro and in vivo biological experiments have revealed a good biosafety profile and a high tumor suppression effect. Therefore, the present research has realized multiple and efficient CDT effects with the aid of the sequential targeting of FA/TPP, also providing a strategy for the development of CDT drugs based on polymetallic organic frameworks.

Ferroptosis in cancer and cancer immunotherapy

The hallmark of tumorigenesis is the successful circumvention of cell death regulation for achieving unlimited replication and immortality. Ferroptosis is a newly identified type of cell death dependent on lipid peroxidation which differs from classical programmed cell death in terms of morphology, physiology and biochemistry. The broad spectrum of injury and tumor tolerance are the main reasons for radiotherapy and chemotherapy failure. The effective rate of tumor immunotherapy as a new treatment method is less than 30%. Ferroptosis can be seen in radiotherapy, chemotherapy, and tumor immunotherapy; therefore, ferroptosis activation may be a potential strategy to overcome the drug resistance mechanism of traditional cancer treatments. In this review, the characteristics and causes of cell death by lipid peroxidation in ferroptosis are briefly described. In addition, the three metabolic regulations of ferroptosis and its crosstalk with classical signaling pathways are summarized. Collectively, these findings suggest the vital role of ferroptosis in immunotherapy based on the interaction of ferroptosis with tumor immunotherapy, chemotherapy and radiotherapy, thus, indicating the remarkable potential of ferroptosis in cancer treatment.

Recent advances of cancer chemodynamic therapy based on Fenton/Fenton-like chemistry

Applying Fenton chemistry in the tumor microenvironment (TME) for cancer therapy is the most significant feature of chemodynamic therapy (CDT). Owing to the mild acid and overexpressed H2O2 in TME, more cytotoxic hydroxyl radicals (˙OH) are generated in tumor cells via Fenton and Fenton-like reactions. Without external stimulus and drug resistance generation, reactive oxygen species (ROS)-mediated CDT exhibits a specific and desirable anticancer effect and has been seen as a promising strategy for cancer therapy. However, optimizing the treatment efficiency of CDT in TME is still challenging because of the limited catalytic efficiency of CDT agents and the strong cancer antioxidant capacity in TME. Hence, scientists are trying their best to design and fabricate many more CDT agents with excellent catalytic activity and remodeling TME for optimal CDT. In this perspective, the latest progress of CDT is discussed, with some representative examples presented. Consequently, promising strategies for further optimizing the efficiency of CDT guided by Fenton chemistry are provided. Most importantly, several feasible ways of developing CDT in the future are offered for reference.

Emerging porous organic polymers for biomedical applications

This review summarizes and discusses the recent progress in porous organic polymers for diverse biomedical applications such as drug delivery, biomacromolecule immobilization, phototherapy, biosensing, bioimaging, and antibacterial applications.

A vinyl-decorated covalent organic framework for ferroptotic cancer therapy via visible-light-triggered cysteine depletion

Intracellular cysteine depletion induced by a COF-based click photoreaction achieves effective cancer therapy by ferroptosis.

A targeted and efficient CDT system with photocatalytic supplement of H2O2 and hydroxyl radical production at a neutral pH

The bottleneck problems of chemodynamic therapy (CDT) are the dependence on an acidic pH (2.0-4.0), insufficient H2O2 level in tumor tissues and potential systematic toxicity of inorganic nanomaterials-based CDT agents....

Nanocatalyst-Mediated Chemodynamic Tumor Therapy

Traditional tumor treatments, including chemotherapy, radiotherapy, photodynamic therapy, and photothermal therapy, are developed and used to treat different types of cancer. Recently, chemodynamic therapy (CDT) has been emerged as a novel cancer therapeutic strategy. CDT utilizes Fenton or Fenton-like reaction to generate highly cytotoxic hydroxyl radicals (•OH) from endogenous hydrogen peroxide (H₂ O₂ ) to kill cancer cells, which displays promising therapeutic potentials for tumor treatment. However, the low catalytic efficiency and off-target side effects of Fenton reaction limit the biomedical application of CDT. In this regard, various strategies are implemented to potentiate CDT against tumor, including retrofitting the tumor microenvironment (e.g., increasing H₂ O₂ level, decreasing reductive substances, and reducing pH), enhancing the catalytic efficiency of nanocatalysts, and other strategies. This review aims to summarize the development of CDT and summarize these recent progresses of nanocatalyst-mediated CDT for antitumor application. The future development trend and challenges of CDT are also discussed.

Post-synthetic modifications in porous organic polymers for biomedical and related applications

Porous organic polymers (POPs) are prepared by crosslinked polymerization of multidimensional rigid aromatic building blocks. Generally, POPs can be classified into crystalline covalent organic frameworks (COFs) and other poorly crystalline or amorphous porous polymers. Due to their remarkable intrinsic properties, such as high porosity, stability, tunability, and presence of numerous building blocks, several new POPs are being developed for application across various scientific fields. The essential sensitive functional groups needed for specific applications are not sustained under harsh POP preparation conditions. The recently developed post-synthetic modification (PSM) strategies for POPs have enabled their advanced applications that are otherwise restricted. Owing to the advanced PSM strategies POPs have experienced a blossoming resurgence with diverse functions, particularly in biomedical applications, such as bioimaging tools, drugs, enzymes, gene or protein delivery systems, phototherapy, and cancer therapy. This tutorial review focuses on the recently developed PSM strategies for POPs, especially for biomedical applications, and their future perspectives as promising bioapplicable materials.

Ferroptosis in cancer therapeutics: a materials chemistry perspective

Ferroptosis, distinct from apoptosis, is a regulated form of cell death caused by lipid peroxidation that has attracted extensive research interest since it was first defined in 2012. Over the past five years, an increasing number of studies have revealed the close relationship between ferroptosis and materials chemistry, in particular nanobiotechnology, and have concluded that nanotechnology-triggered ferroptosis is an efficient and promising antitumor strategy that provides an alternative therapeutic approach, especially for apoptosis-resistant tumors. In this review, we summarize recent advances in ferroptosis-induced tumor therapy at the intersection of materials chemistry, redox biology, and tumor biology. The biological features and molecular mechanisms of ferroptosis are first outlined, followed by a summary of the feasible strategies to induce ferroptosis using nanomaterials and the applications of ferroptosis in combined tumor therapy. Finally, the existing challenges and future development directions in this emerging field are discussed, with the aim of promoting the progress of ferroptosis-based oncotherapy in materials science and nanoscience and enriching the antitumor arsenal.

Nanoparticles for Ferroptosis Therapy in Cancer

Ferroptosis is a regulated cell death mechanism holding promise for anticancer therapy. Numerous small molecules inducing ferroptosis have been reported thus far. However, these compounds suffer from important drawbacks including poor solubility, systemic toxicity, and scarce tumor targeting ability that have limited their clinical success. The notion that nanoparticles inducing ferroptosis show better preclinical profiles compared to small molecules and overcome resistance to apoptosis has opened a new scenario for cancer treatment. Due to peculiar chemical-physical properties, nanoparticles can be loaded with anticancer drugs or decorated with tumor-selecting molecules. These features allow for drug combination treatment as well as tumor targeting. In the review, we summarize and discuss the available information concerning nanoparticles inducing ferroptosis endowed with different peculiarities and suitable for therapeutic purposes including nanoparticles for (i) antitumor drug delivery, (ii) tumor targeting, (iii) immunomodulation, and (iv) radiofrequency ablation, hyperthermia, and photodynamic therapy.

Targeting ferroptosis-based cancer therapy using nanomaterials: strategies and applications

As an iron-dependent mode of programmed cell death induced by lipid peroxidation, ferroptosis plays an important role in cancer therapy. The metabolic reprogramming in tumor microenvironment allows the possibility of targeting ferroptosis in cancer treatment. Recent studies reveal that nanomaterials targeting ferroptosis have prospects for the development of new cancer treatments. However, the design ideas of nanomaterials targeting ferroptosis sometimes vary. Therefore, in addition to the need for a systematic summary of these ideas, new ideas and insights are needed to make possible the construction of nanomaterials for effectively targeting this cell death pathway. At the same time, further optimization of nanomaterials design is required to make them appropriate for clinical treatment. In this context, we summarize this cross-cutting research area covering from the known mechanism of ferroptosis to providing feasible ideas for nanomaterials design as well as their clinical application. We aim to provide new insights and enlightenment for the next step in developing new nanomaterials for cancer treatment.

Covalent Organic Framework-Derived Carbonous Nanoprobes for Cancer Cell Imaging

Covalent organic frameworks (COFs) have emerged as promising materials for biomedical applications, but their functions remain to be explored and the potential toxicity concerns should be resolved. Herein, it is presented that carbonization significantly enhances the fluorescence quenching efficiency and aqueous stability of nanoscale COFs. The probes prepared by physisorbing dye-labeled nucleic acid recognition sequences onto the carbonized COF nanoparticles (termed C-COF) were employed for cell imaging, which could effectively light up biomarkers (survivin and TK1 mRNA) in living cells. The C-COF has enhanced photothermal conversion capacity, indicating that the probes are also promising candidates for photothermal therapy. The potential toxicity concern from the aromatic rigid building units of COFs was detoured by carbonization. Overall, carbonization is a promising strategy for developing biocompatible and multifunctional COF-derived nanoprobes for biomedical applications. This work may inspire more versatile COF-derived nanoprobes for bioanalysis and nanomedicine.