Enhanced chemodynamic therapy at weak acidic pH based on g-C3N4-supported hemin/Au nanoplatform and cell apoptosis monitoring during treatment

Tumor-targeted delivery of hyaluronic acid/polydopamine-coated Fe2+-doped nano-scaled metal-organic frameworks with doxorubicin payload for glutathione depletion-amplified chemodynamic-chemo cancer therapy

Chemodynamic therapy (CDT), an emerging cancer treatment modality, uses multivalent metal elements to convert endogenous hydrogen peroxide (H2O2) to toxic hydroxyl radicals (•OH) via a Fenton or Fenton-like reaction, thus eliciting oxidative damage of cancer cells. However, the antitumor potency of CDT is largely limited by the high glutathione (GSH) concentration and low catalytic efficiency in the tumor sites. The combination of CDT with chemotherapy provides a promising strategy to overcome these limitations. In this work, to enhance antitumor potency by tumor-targeted and GSH depletion-amplified chemodynamic-chemo therapy, the hyaluronic acid (HA)/polydopamine (PDA)-decorated Fe2+-doped ZIF-8 nano-scaled metal-organic frameworks (FZ NMs) were fabricated and utilized to load doxorubicin (DOX), a chemotherapy drug, via hydrophobic, π-π stacking and charge interactions. The attained HA/PDA-covered DOX-carrying FZ NMs (HPDFZ NMs) promoted DOX and Fe2+ release in weakly acidic and GSH-rich milieu and exhibited acidity-activated •OH generation. Through efficient CD44-mediated endocytosis, the HPDFZ NMs internalized by CT26 cells not only prominently enhanced •OH accumulation by consuming GSH via PDA-mediated Michael addition combined with Fe2+/Fe3+ redox couple to cause mitochondria damage and lipid peroxidation, but also achieved intracellular DOX release, thus eliciting apoptosis and ferroptosis. Importantly, the HPDFZ NMs potently inhibited CT26 tumor growth in vivo at a low DOX dose and had good biosafety, thereby showing promising potential in tumor-specific treatment.

Efficient reduction of antibiotic resistance genes and mobile genetic elements in organic waste composting via fenton-like treatment

Livestock manure harbors antibiotic resistance genes (ARGs), and aerobic composting (AC) is widely adopted for waste management. However, mitigating ARG resurgence in later stages remains challenging. This work aims to curb ARGs rebounding through a Fenton-like reaction during food waste and swine manure co-composting. Results revealed that 0.025 % zerovalent iron (ZVI) + 0.5 % hydrogen peroxide (H2O2) facilitated maximum ARG, mobile genetic elements (MGEs), and 16 s rRNA removal with reductions of 2.68, 2.69, and 1.4 logs. Spectroscopic analysis confirmed Fenton-like reaction and cell apoptosis analysis indicated that 0.025 % ZVI and 0.5 % H2O2 treatment had the maximum early apoptosis, least observed, and normal cells on day 30. Redundancy analysis highlighted the influence of bacterial communities and physicochemical properties on ARGs, with MGEs playing a crucial role in Fenton treatments. Our findings suggest incorporating ZVI and H2O2 in composting can significantly reduce ARGs and enhance waste management practices.

Machine Learning-Driven SERS Nanoendoscopy and Optophysiology

A frontier of analytical sciences is centered on the continuous measurement of molecules in or near cells, tissues, or organs, within the biological context in situ, where the molecular-level information is indicative of health status, therapeutic efficacy, and fundamental biochemical function of the host. Following the completion of the Human Genome Project, current research aims to link genes to functions of an organism and investigate how the environment modulates functional properties of organisms. New analytical methods have been developed to detect chemical changes with high spatial and temporal resolution, including minimally invasive surface-enhanced Raman scattering (SERS) nanofibers using the principles of endoscopy (SERS nanoendoscopy) or optical physiology (SERS optophysiology). Given the large spectral data sets generated from these experiments, SERS nanoendoscopy and optophysiology benefit from advances in data science and machine learning to extract chemical information from complex vibrational spectra measured by SERS. This review highlights new opportunities for intracellular, extracellular, and in vivo chemical measurements arising from the combination of SERS nanosensing and machine learning.

A ferroptosis-reinforced nanocatalyst enhances chemodynamic therapy through dual H2O2 production and oxidative stress amplification

The existence of a delicate redox balance in tumors usually leads to cancer treatment failure. Breaking redox homeostasis by amplifying oxidative stress and reducing glutathione (GSH) can accelerate cancer cell death. Herein, we construct a ferroptosis-reinforced nanocatalyst (denoted as HBGL) to amplify intracellular oxidative stress via dual H2O2 production-assisted chemodynamic therapy (CDT). Specifically, a long-circulating liposome is employed to deliver hemin (a natural iron-containing substrate for Fenton reaction and ferroptosis), β-lapachone (a DNA topoisomerase inhibitor with H2O2 generation capacity for chemotherapy), and glucose oxidase (which can consume glucose for starvation therapy and generate H2O2). HBGL can achieve rapid, continuous, and massive H2O2 and •OH production and GSH depletion in cancer cells, resulting in increased intracellular oxidative stress. Additionally, hemin can reinforce the ferroptosis-inducing ability of HBGL, which is reflected in the downregulation of glutathione peroxidase-4 and the accumulation of lipid peroxide. Notably, HBGL can disrupt endo/lysosomes and impair mitochondrial function in cancer cells. HBGL exhibits effective tumor-killing ability without eliciting obvious side effects, indicating its clinical translation potential for synergistic starvation therapy, chemotherapy, ferroptosis therapy, and CDT. Overall, this nanocatalytic liposome may be a promising candidate for achieving potentiated cancer treatment.

Recent Advances in Polyoxometalate Based Nanoplatforms Mediated Reactive Oxygen Species Cancer Therapy

The potential of reactive oxygen species (ROS) cancer therapy in tumor treatment has been greatly enhanced by the introduction of catalytically superior polyoxometalate (POM)-based nanoplatforms, mainly composed of atomic clusters consisting of pre-transition metals and oxygen. These nanoplatforms have unique advantages, such as Fenton activity at neutral pH, induction of cellular ferroptosis instead of just apoptosis, and sensitivity to external field stimulation. However, there are also inevitable challenges such as neutralization of ROS by the antioxidant system of the tumor microenvironment (TME), hypoxia, and limited hydrogen peroxide concentrations. This review article aims to provide an overview of recent research advancements in POM-based nanoplatforms for ROS therapy from the perspective of chemical reactions and biological processes, addressing endogenous and exogenous factors that affect the antitumor efficacy. Endogenous factors include the mechanism of ROS generation by POM, the impact of pH and antioxidant systems on POM, and the various manners of tumor cell death. Exogenous stimuli mainly include light, heat, X-rays, and electricity. The article analyzes the specific mechanisms of action of each influencing factor in the first two sections, concluding with the limitations of the present study and some possible directions for future research.

Microenvironment Restruction of Emerging 2D Materials and their Roles in Therapeutic and Diagnostic Nano-Bio-Platforms

Engineering advanced therapeutic and diagnostic nano-bio-platforms (NBPFs) have emerged as rapidly-developed pathways against a wide range of challenges in antitumor, antipathogen, tissue regeneration, bioimaging, and biosensing applications. Emerged 2D materials have attracted extensive scientific interest as fundamental building blocks or nanostructures among material scientists, chemists, biologists, and doctors due to their advantageous physicochemical and biological properties. This timely review provides a comprehensive summary of creating advanced NBPFs via emerging 2D materials (2D-NBPFs) with unique insights into the corresponding molecularly restructured microenvironments and biofunctionalities. First, it is focused on an up-to-date overview of the synthetic strategies for designing 2D-NBPFs with a cross-comparison of their advantages and disadvantages. After that, the recent key achievements are summarized in tuning the biofunctionalities of 2D-NBPFs via molecularly programmed microenvironments, including physiological stability, biocompatibility, bio-adhesiveness, specific binding to pathogens, broad-spectrum pathogen inhibitors, stimuli-responsive systems, and enzyme-mimetics. Moreover, the representative therapeutic and diagnostic applications of 2D-NBPFs are also discussed with detailed disclosure of their critical design principles and parameters. Finally, current challenges and future research directions are also discussed. Overall, this review will provide cutting-edge and multidisciplinary guidance for accelerating future developments and therapeutic/diagnostic applications of 2D-NBPFs.

Electrospinning of n-hemin/PAN Nanocomposite Membranes and Its Photo-Enhanced Enzyme-like Catalysis

Hemin possesses great potential in eliminating organic pollutants due to its mild reaction condition, light-harvesting efficiency, and environmental friendliness. However, it has drawbacks such as being easy to aggregate and hard to recycle, and poor stability should be improved in practical application. Herein, the subject developed an electrospinning approach to enable the hemin particulates to be immobilized onto polyacrylonitrile (PAN) nanofibers stably. Hydrogen peroxide (H₂O₂) was adopted as an oxidant in the system to simulate the enzymatic catalysis of hemin in an organism. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflection spectroscopy (DRS), and electron spin resonance spectroscopy (ESR) analysis was employed to discuss the morphology, structure, and mechanism of the prepared n-hemin/PAN nanocomposite membranes, and 0.02 mmol L^-1 of the rhodamine B (RhB) removal activity in different conditions was also verified with these membranes. The kinetic studies showed that n-hemin/PAN nanocomposite membranes maintained excellent properties both in adsorption and degradation. Around 42% RhB could be adsorbed in the dark, while 91% RhB decolorized under xenon lamp irradiation in 110 min, suggesting the catalytic performance of n-hemin/PAN was greatly driven by light irradiation. Differing from the axial coordinated hemin complexes, n-hemin/PAN would catalyze hydrogen peroxide into •OH radicals rather than •OOH and high-valent metal-oxo species. This work provides an effective way to support hemin as nanocomposite membranes, in which the molecular interaction between polymer and hemin made their light adsorption an obvious red shift.

Bortezomib prodrug catalytic nanoreactor for chemo/chemodynamic therapy and macrophage re-education

Chemodynamic therapy (CDT), an emerging tumor-specific therapeutic modality, is frequently restrained by insufficient intratumoral Fenton catalysts and increasingly inefficient catalysis caused by the continuous consumption of limited H₂O₂ within tumors. Herein, we engineered a pH-responsive bortezomib (BTZ) polymer prodrug catalytic nanoreactor (HeZn@HA-BTZ) capable of self-supplying Fenton catalyst and H₂O₂. It is aimed for tumor-specific chemo/chemodynamic therapy via oxidative stress and endoplasmic reticulum (ER) stress dual-amplification and macrophage repolarization. A catechol‑boronate bond-based hyaluronic acid-BTZ prodrug HA-DA-BTZ was modified on Hemin and Zn²⁺ coordination nanoscale framework (HeZn), an innovative CDT inducer, to construct He-Zn@HA-BTZ. He-Zn@HA-BTZ with good stability and superior peroxidase-like activity preferentially accumulated at tumor sites and be actively internalized by tumor cells. Under the cleavage of catechol‑boronate bond in acidic endo/lysosomes, pre-masked BTZ was rapidly released to induce ubiquitinated protein aggregation, robust ER stress and elevated H₂O₂ levels. The amplified H₂O₂ was further catalyzed by HeZn via Fenton-catalytic reactions to produce hypertoxic •OH, enabling cascaded oxidative stress amplification and long-lasting effective CDT, which in turn aggravated BTZ-induced ER stress. Eventually, a dual-amplification of oxidative stress and ER stress was achieved to initiate cell apoptosis/necrosis with reduced BTZ toxicity. Intriguingly, He-Zn@HA-BTZ could repolarize macrophages from M2 to antitumor M1 phenotype for potential tumor therapy. This "all in one" prodrug nanocatalytic reactor not only enriches the CDT inducer library, but provides inspirational strategy for simultaneous oxidative stress and ER stress based excellent cancer therapy.

Research Progress on Improving the Efficiency of CDT by Exacerbating Tumor Acidification

In recent years, chemodynamic therapy (CDT) has received extensive attention as a novel means of cancer treatment. The CDT agents can exert Fenton and Fenton-like reactions in the acidic tumor microenvironment (TME), converting hydrogen peroxide (H₂O₂) into highly toxic hydroxyl radicals (·OH). However, the pH of TME, as an essential factor in the Fenton reaction, does not catalyze the reaction effectively, hindering its efficiency, which poses a significant challenge for the future clinical application of CDT. Therefore, this paper reviews various strategies to enhance the antitumor properties of nanomaterials by modulating tumor acidity. Ultimately, the performance of CDT can be further improved by inducing strong oxidative stress to produce sufficient ·OH. In this paper, the various acidification pathways and proton pumps with potential acidification functions are mainly discussed, such as catalytic enzymes, exogenous acids, CAIX, MCT, NHE, NBCn1, etc. The problems, opportunities, and challenges of CDT in the cancer field are also discussed, thereby providing new insights for the design of nanomaterials and laying the foundation for their future clinical applications.

Extended π-Conjugative Carbon Nitride for Single 1064 nm Laser-Activated Photodynamic/Photothermal Synergistic Therapy and Photoacoustic Imaging

The synergetic photodynamic/photothermal therapy, activated via a single-second near-infrared (NIR-II) laser and guided by photoacoustic imaging (PAI), receives significant attention for precise in vivo therapy. However, due to the lack of a corresponding theranostic agent, it faces a great challenge for practical clinical implementation. Here, we present a single diagnostic and therapeutic nanoplatform named carbon nitride nanoparticles (CN-NPs) for efficient NIR-II PAI-guided photodynamic therapy (PDT)/photothermal therapy (PTT). The CN-NPs were obtained by incorporating an aromatic compound (PTCDA) with a large π-structure into melem by high-temperature polymerization. The absorption of the obtained CN-NPs was significantly enhanced compared with pristine melem. Under 1064 nm laser illumination, sufficient reactive oxygen species (ROS) generated by CN-NPs could reduce the mitochondrial membrane potential. Moreover, the CN-NPs exhibited an efficient PTT effect through improved photothermal stability and high photo-to-heat conversion efficiency (47.6%). We were also able to monitor the accumulation and metabolism of CN-NPs in vivo of mice in real time using PAI. The in vivo experiments proved that the CN-NPs could inhibit tumor growth and recurrence completely under 1064 nm. Thus, the proposed innovative strategy would open a new avenue to explore and construct NIR-II responsive nanoplatforms with enhanced performance and safety for multimodal phototheranostics.

Tumor microenvironment-responsive fenton nanocatalysts for intensified anticancer treatment

Chemodynamic therapy (CDT) based on Fenton or Fenton-like reactions is an emerging cancer treatment that can both effectively fight cancer and reduce side effects on normal cells and tissues, and it has made important progress in cancer treatment. The catalytic efficiency of Fenton nanocatalysts(F-NCs) directly determines the anticancer effect of CDT. To learn more about this new type of therapy, this review summarizes the recent development of F-NCs that are responsive to tumor microenvironment (TME), and detailedly introduces their material design and action mechanism. Based on the deficiencies of them, some effective strategies to significantly improve the anticancer efficacy of F-NCs are highlighted, which mainly includes increasing the temperature and hydrogen peroxide concentration, reducing the pH, glutathione (GSH) content, and the dependence of F-NCs on acidic environment in the TME. It also discusses the differences between the effect of multi-mode therapy with external energy (light and ultrasound) and the single-mode therapy of CDT. Finally, the challenges encountered in the treatment process, the future development direction of F-NCs, and some suggestions are analyzed to promote CDT to enter the clinical stage in the near future.

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.

Fabrication of tailored rod-shaped carbon nitride, g-C3N4, decorated with MoSe2 flowers for the catalytic reduction of nitrophenol, organic dye degradation and biocompatibility studies

A facile hydrothermal approach was used to synthesize a self-assembled tailored rod-shaped g-C3N4 anchored with molybdenum diselenide (MoSe2) flowers.

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....

Optimization of Fenton process on removing antibiotic resistance genes from excess sludge by single-factor experiment and response surface methodology

Excess sludge contains large amounts of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs), posing a risk for human health. However, most current studies usually ignored their abundance and removal in excess sludge. Therefore, this study aimed to reduce ARGs/MGEs in sludge by Fenton process, and applied single-factor experiment (SFE) and response surface methodology (RSM) to optimize the Fenton reaction condition for higher removal rates of ARGs/MGEs. The results demonstrated that the removal rates of target genes by SFE optimized condition ranged from 10.91% to 66.86%, while the removal rates caused by RSM optimized condition were 48.02% - 76.36%, indicating RSM was a useful tool to improve the removal rates of ARGs in excess sludge. Additionally, the scanning electron microscope and cell apoptosis results suggested that the Fenton treatment altered the structure of sludge and reduced the numbers of normal cells, thus causing the reductions of target genes.

Catalytically Active CoFe2O4 Nanoflowers for Augmented Sonodynamic and Chemodynamic Combination Therapy with Elicitation of Robust Immune Response

A hypoxic and acidic tumor microenvironment (TME) plays a significant role in cancer development through complex cellular signaling networks, and it is thus challenging to completely eradicate tumors via monotherapy. Here, PEGylated CoFe₂O₄ nanoflowers (CFP) with multiple enzymatic activities, serving as bioreactors responsive to TME cues, were synthesized via a typical solvothermal method for augmented sonodynamic therapy (SDT) and chemodynamic therapy (CDT) with elicitation of robust immune response. The CFP occupying multivalent elements (Co^2+/3+, Fe^2+/3+) exhibited strong Fenton-like and catalase-like activity. In another aspect, CFP itself is a brand-new sonosensitizer for high-performance SDT based on ultrasound-triggered electron (e^-)/hole (h⁺) pair separation from the energy band with promptness and high efficiency. With efficient enrichment in tumorous tissue as revealed by magnetic resonance imaging, CPF could generate ^•OH for CDT relying on Fenton-like reactions. Moreover, catalase-mimicking CFP could react with endogenous H₂O₂ to generate molecular oxygen, and high O₂ level may promote the production of ¹O₂ for SDT. What's more, the reactive oxygen species obtained from combined SDT/CDT could efficiently trigger immunogenic cell death through a synergistic therapy based on the elicitation of antitumor immunity with the aid of an immune checkpoint blockade for the sake of suppressing primary and distant tumors as well as lung metastasis. Taken together, this paradigm delivers useful insights for developing in-coming nanocomposites based on cobalt ferrite for cancer theranostics.