Fe-Doped Polyoxometalate as Acid-Aggregated Nanoplatform for NIR-II Photothermal-Enhanced Chemodynamic Therapy

Polyoxometalate-Containing Nanocomposite Hydrogels for Cascade-Catalytic and Photothermal Dually Enhanced Chemodynamic Therapy

Chemodynamic therapy (CDT) has emerged as a transformative paradigm in the realm of reactive oxygen species (ROS)-mediated cancer therapies. However, the lack of endogenous hydrogen peroxide (H2O2) in tumors and the low catalytic efficiency of traditional Fenton catalysts limit the therapeutic effect of CDT. Herein, an injectable nanocomposite hydrogel (HA-DOPA/W-POM/1-S-S-PEG@GOx) based on the hyaluronic acid-dopamine (HA-DOPA) matrix is designed to deliver tungsten-based polyoxometalates (W-POM) and peptide nanomicelles (1-S-S-PEG@GOx) for achieving cascade-catalytic and photothermal dually enhanced CDT. Upon tumor cell uptake, 1-S-S-PEG@GOx specifically responds to endogenous glutathione and disassembles to release glucose oxidase (GOx), which catalyzes the oxidation of glucose to produce H2O2. On the one hand, W-POM functions as peroxidase-like nanozymes to convert H2O2 into a hydroxyl radical (·OH) under the aid of GOx, enhancing the efficacy of CDT through cascade-catalytic reactions (i.e., glucose to H2O2 to ·OH). On the other hand, W-POM acts as a photothermal therapy agent, generating mild heat under near-infrared laser irradiation to achieve photothermal-enhanced CDT. This cascade-catalytic and photothermal dually enhanced CDT triggers an intracellular ROS storm, leading to apoptosis and ferroptosis of tumor cells. Importantly, in situ administration of HA-DOPA/W-POM/1-S-S-PEG@GOx alongside laser irradiation showcases enhanced antitumor efficacy and satisfactory biocompatibility in vivo, which holds great potential for the development of functional nanomedicine toward targeted tumor therapy.

NO-producing Arg-sCNDs for combined photothermal and gas effects in cancer cell ablation

Photothermal therapy (PTT) and gas therapy (GT) were used in combination to enhance the antitumor effect by leveraging the dual cytotoxic mechanisms of nitric oxide (NO) and peroxynitrite (ONOO-), along with the localized heating capability of photothermal materials. Arginine-supra-carbon nanodots (Arg-sCNDs) were obtained through a one-pot hydrothermal method without subsequent modification, allowing them to produce endogenous NO and photothermal effects on a single platform. The photothermal conversion efficiency of Arg-sCNDs reaches 77.09% and 58.01% under 730 nm and 808 nm irradiation, respectively. Arg-sCNDs demonstrated good killing and ablation effects on cancer cells and had minimal side effects on normal cells. The photothermal and NO effects reinforce each other. The cell apoptosis mechanism was demonstrated through measurements of cell temperature, NO levels, ONOO- levels, and mitochondrial membrane potential. Therefore, the in vitro study demonstrated that Arg-sCNDs with dual functions present broad application prospects in tumor cell ablation.

Large-capacity DNA vectors based on rolling circle amplification with multivalent aptamers delivery copper sulfide for the synergistic treatment of Cancer through chemo/Photothermal/Chemodynamic therapy in vitro

Developing multifunctional nanomedicines represents a frontier. We have engineered a high-capacity DNA vector basing rolling circle amplification for the delivery of copper sulfide nanoparticles (CuS NPs) and doxorubicin (DOX), coupled with multivalent aptamers (MA) that precisely target tumors, culminating in a multifunctional nanoplatform (RMAL1Cu@DOX), which combines the chemotherapy (CT)/photothermal therapy (PTT)/chemodynamic therapy (CDT). The vector (RMAL1) boasts exceptional biocompatibility and incorporates multiple copy units, enabling the precise loading of numerous CuS NPs, forming RMAL1Cu which possesses a robust photothermal effect and superior Fenton-like catalytic activity, heralding a project of minimally invasive dual-mode (PTT/CDT) therapy. Furthermore, the abundance of G-C of RMAL1 enabled effective DOX encapsulation through π-π interactions to construct RMAL1Cu@DOX. The MA integrated into RMAL1Cu@DOX is pivotal in enhancing the targeting of tumors and in preventing non-specific release of CuS and DOX, enabling an integrated CT/PTT/CDT. Data indicate that 1 nM of RMAL1Cu could load 270 nM of DOX with an impressive loading capacity of 77 %, and modification with MA, its tumor-targeting ability was amplified by 51-fold and significantly bolstered in vitro imaging outcomes, and the synergistic killing of B16 was as 67.3 %. This innovative nanoplatform offers a comprehensive and holistic strategy for the treatment of malignant tumors.

Phytochemical-Loaded Thermo-responsive Liposome for Synergistic Treatment of Methicillin-Resistant Staphylococcus aureus Infection

The ever-increasing emergence and prevalence of multidrug-resistant bacteria accelerate the desire for the development of new antibacterial strategies. Although antibacterial phytochemicals are a promising approach for long-term treatment of resistant bacteria, their low antibacterial activity and poor solubility hinder their practical applications. Here, the natural antibacterial compound sanguinarine (SG) together with gallic acid-ferrous coordination nanoparticles (GA-Fe(II) NPs) was encapsulated in a near-infrared (NIR)-activated thermo-responsive liposome. By virtue of the photothermal effect of GA-Fe(II) NPs, the nanoplatform released SG on demand upon NIR irradiation. Additionally, the heat can boost the Fenton reaction triggered by GA-Fe(II) NPs to generate hydroxyl radicals and perform sterilization. By coupling with photothermal therapy, chemodynamic therapy, and SG-based pharmacotherapy, the platform showed enhanced antibacterial efficiency and an antibiofilm effect toward methicillin-resistant Staphylococcus aureus and reduced the risk of developing new bacterial resistance. This antibacterial system displayed excellent antibacterial activity in a methicillin-resistant S. aureus-caused skin abscess, demonstrating its potential clinical application. Moreover, transcription analysis clarified that the platform achieved a synergistic antibacterial effect by attacking the cell membrane, inducing energy metabolism disorder, inhibiting nucleic acid synthesis, etc. The developed NIR-controlled phytochemical-loaded platform offers new possibilities for killing antibiotic-resistant bacteria and avoiding bacterial resistance, making it contributory in the fields of anti-infective therapy and precision medicine.

Heterostructure Nanozyme with Hyperthermia-Amplified Enzyme-Like Activity and Controlled Silver Release for Synergistic Antibacterial Therapy

Heterostructure nanozymes as antibiotic-free antimicrobial agents exhibit great potential for multidrug-resistant (MDR) bacterial strains elimination. However, realization of heterostructure antimicrobials with enhanced interfacial interaction for synergistically amplified antibacterial therapy is still a great challenge. Herein, oxygen-vacancy-enriched glucose modified MoOx (G-MoOx) is exploited as a reducing agent to spontaneously reduce Ag (I) into Ag (0) that in situ grows onto the surface of G-MoOx. The resultant Ag doped G-MoOx (Ag/G-MoOx) heterostructure displays augmenting photothermal effect and NIR-enhanced oxidase-like activity after introducing Ag nanoparticles. What's more, NIR hyperthermia accelerate Ag+ ions release from Ag nanoparticles. Introduction of Ag greatly enhances antimicrobial activities of Ag/G-MoOx against MDR bacteria, especially the hybrid loading with 1 wt% Ag NPs exhibiting antibacterial efficacy up to 99.99% against Methicillin-resistant Staphylococcus aureus (MRSA, 1×106 CFU mL-1).

cRGD-based MRI imaging-enhanced nanoplatform helps DOX target pancreatic cancer

This project aims to construct cRGD functionalized mesoporous silica nanoparticles and cRGD modified mesoporous silica nanoparticles for the diagnosis and treatment of tumors, providing new ideas for targeted therapy of tumors. The mesoporous silica nanoparticles were doped with gadolinium in situ to provide excellent imaging; cRGD was coupled on the particle surface to confer particle targeting; and hyaluronic acid was loaded onto the particles by electrostatic adsorption, thereby improving the biocompatibility of the particles and prolonging their in vivo circulation time.Taking pancreatic cancer as a model, we studied its targeting ability to pancreatic cancer and its phagocytosis to cancer cells; Using methods such as cell growth experiments and flow cytometry, the anti-cancer effect and pro apoptotic effect of the system were studied. In vivo distribution, tumor targeting and therapeutic efficacy of nanoparticles evaluated in a mouse model of pancreatic cancer with loaded tumors.Evaluate the bioavailability and enrichment of nanoparticles in tumor tissue using MRI technology. Evaluate the therapeutic effect and safety through changes in tumor volume, histopathological examination, and prognosis. Characterization of the synthesis results proved that cRGD-HA-DOX-Gd2O3@MSN (cHDG@MSN) was successfully synthesized with a particle size of 230.83 ± 12.36 nm.In vitro drug release experiments of DOX were carried out at different pH values (5.5 and 7.4), where the release was only up to 22.65% at pH 7.4, whereas DOX release was increased up to 78.75% at pH = 5.5.The results confirm the pH responsiveness of this nanocarrier platform.The results of cytotoxicity studies showed that cHDG@MSN itself is not cytotoxic. Biosafety evaluation and hemolysis test results confirmed that the probe is highly biocompatible.Notably, Gd3+ significantly enhanced the T1 contrast of the system according to MR imaging results.The apoptosis rates of SW1990 cells treated with PBS, DOX and cHDG@MSN in flow cytometry were 13.97%, 18.38% and 29.02%, respectively, demonstrating the effectiveness of the nanoprobes at the cellular level. Animal experiments demonstrated the effectiveness of nanoprobes at the pathological level and imaging level.Cells and animals demonstrated that cHDG@MSN effectively inhibited the proliferation of pancreatic cancer cells. This research further verified the pH sensitivity of the constructed compound drug delivery system to achieve accurate diagnosis and treatment of pancreatic cancer tumor cells.

A Highly Biocompatible Polyoxotungstate with Fenton-like Reaction Activity for Potent Chemodynamic Therapy of Tumors

Integrating Fenton chemistry and nanomedicine into cancer therapy has significantly promoted the development of chemodynamic therapy (CDT). Nanoscale polyoxometalates (POMs), with their reversible redox properties, exhibit promising potential in developing outstanding CDT drugs by exploring their Fenton-like catalytic reactivity in tumor environments. However, such research is still in its infancy due to the challenges of acquiring POMs that are both easily prepared and possess ideal therapeutic effects, physiological solubility, biocompatibility and safety. In this work, we report the synthesis of a new crystalline antimonotungstate {Dy2Sb2W7O23(OH)(DMF)2(SbW9O33)2} (1, DMF=N, N-dimethylformamide) with gram-scale high yield via a facile "one-pot" solvothermal reaction. 1 exhibits not only a soluble and water-stable POM nanocluster, but also excellent catalytic activity for hydroxyl radical-generating Fenton-like reactions. Further biomedical studies reveal that 1 can trigger cell apoptosis and promote lipid peroxidation, exhibiting high cytotoxicity and selectivity towards B16-F10 mouse melanoma cancer cells with an IC50 value of 4.75 μM. Especially, 1 can inhibit melanoma growth in vivo with favorable biosafety, achieving a 5.2-fold reduction in tumor volume and a weight loss of 76.0 % at the dose of 70 μg/kg. This research not only demonstrates the immense potential of antimonotungstates in CDT drug development for the first time but also provides new insights and directions for the development of novel anticancer drugs.

Applications of nanotheranostics in the second near-infrared window in bioimaging and cancer treatment

Achieving accurate and efficient tumor imaging is crucial in the field of tumor treatment, as it facilitates early detection and precise localization of tumor tissues, thereby informing therapeutic strategies and surgical interventions. The optical imaging technology within the second near-infrared (NIR-II) window has garnered significant interest for its remarkable benefits, such as enhanced tissue penetration depth, superior signal-to-background ratio (SBR), minimal tissue autofluorescence, reduced photon attenuation, and lower tissue scattering. This review explained the design and optimization strategies of nano-agents responsive to the NIR-II window, such as single-walled carbon nanotubes, quantum dots, lanthanum-based nanomaterials, and noble metal nanomaterials. These nano-agents enable non-invasive, deep-tissue imaging with high spatial resolution in the NIR-II window, and their superior optical properties significantly improve the accuracy, efficiency, and versatility of imaging-guided tumor treatments. And we discussed the characteristics and advantages of fluorescence imaging (FL)/photoacoustic imaging (PA) in NIR-II window, providing a comprehensive overview of the latest research progress of different nano-agents in FL/PA imaging-guided tumor therapy. Furthermore, we exhaustively reviewed the latest applications of multifunctional nano-phototherapy technologies carried out by NIR-II light including photothermal therapy (PTT), photodynamic therapy (PDT), and combined modalities like photothermal-chemodynamic therapy (PTT-CDT), photothermal-chemotherapy (PTT-CT), and photothermal- immunotherapy (PTT-IO). These imaging-guided integrated tumor therapy approaches within the NIR-II window have gradually matured over the past decade and are expected to become a safe and effective non-invasive tumor treatment. Finally, we outlined the prospects and challenges of development and innovation of the NIR-II integrated diagnosis and therapy nanoplatform. This review aims to provide insightful perspectives for future advancements in NIR-II optical tumor diagnosis and integrated treatment platforms.

POM-Based Hydrogels for Efficient Synergistic Chemodynamic/Low-Temperature Photothermal Antibacterial Therapy

Bacterial infection of wound surfaces has posed a significant threat to human health and represents a formidable challenge in the clinical treatment. In this study, a novel antimicrobial hydrogel utilizing POM is synthesized as the primary component, with gelatin and sodium alginate as the structural framework. The resultant hydrogel demonstrates exceptional mechanical properties and viscoelasticity attributed to the hydrogen-bonded cross-linking between POM and gelatin, as well as the ionic cross-linking between sodium alginate and Ca2+. In addition, the integration of CuS nanoparticles conferred photothermal properties to the hydrogel system. To address the concerns regarding the potential thermal damage to the surrounding normal cells, this study employs a LT-PTT combined with CDT approach to achieve the enhanced antimicrobial efficacy while minimizing the inadvertent harm to the healthy cells. The findings suggested that POM-based hydrogels, serving as an inorganic-organic hybrid material, will represent a promising antimicrobial solution and offer valuable insights for the development of the non-antibiotic materials.

Tumor therapy utilizing dual-responsive nanoparticles: A multifaceted approach integrating calcium-overload and PTT/CDT/chemotherapy

The advancement of rational nano drug delivery systems offers robust tools for achieving synergistic therapeutic outcomes in tumor treatment. In this study, we present the development of pH and near-infrared laser dual-responsive nanoparticles (DOX-CuS@CaCO3@PL-PEG, DCCP NPs) based on calcium carbonate, utilizing a one-pot gas diffusion reaction. These nanoparticles enable combined photothermal therapy (PTT), chemodynamic therapy (CDT), chemotherapy, and Ca2+-overloading synergistic therapy. Doxorubicin (DOX) and copper sulfide (CuS) NPs were co-loaded in CaCO3, followed by PEG surface functionalization. The presence of PEG enhanced the stability of DCCP NPs in aqueous environments. Controlled release of DOX, CuS NPs, and Ca2+ occurs specifically in the acidic tumor microenvironment. Released DOX enhances chemotherapy efficiency, while CuS NPs, upon laser irradiation, induce thermal damage, promoting further drug release and cellular uptake. Additionally, CuS NPs in our system consume excess GSH and generate toxic hydroxyl radicals (·OH) through a Fenton-like reaction, contributing to CDT. These radicals not only directly eliminate tumor cells but also disrupt mitochondrial Ca2+ buffering capacity. Furthermore, Ca2+ released from CaCO3 induces Ca2+-overloading, intensifying mitochondrial disruption and oxidative damage. The synergistic combination of PTT, CDT, chemotherapy, and Ca2+-overloading showcases significant therapeutic potential, indicating broad applications in tumor therapy. This multifaceted approach holds promise for advancing the field of tumor therapeutics.

Tadpole-Like Carbon Nanotube with Fe Nanoparticle Encapsulated at the Head and Zn Single-Atom Anchored on the Body: One-Pot Carbonization for Tetramodal Synergistic Cancer Therapy

Precise integration of diverse therapeutic approaches into nanomaterials is the key to the development of multimodal synergistic cancer therapy. In this work, tadpole-like carbon nanotubes with Fe nanoparticle encapsulated at the head and Zn single-atom anchored on the body (Fe@CNT-Zn) is precisely designed and facilely prepared via one-pot carbonization. In vitro studies revealed the integration of chemotherapy (CT), chemodynamic therapy (CDT), photothermal therapy (PTT), and photodynamic therapy (PDT) in Fe@CNT-Zn as well as the near-infrared light (NIR)-responsive cascade therapeutic efficacy. Furthermore, in vivo studies demonstrated the NIR-triggered cascade-amplifying synergistic cancer therapy in a B16 tumor-bearing mouse model. The results not only showcased the Fe@CNT-Zn as a potential tetramodal therapeutic platform, but also demonstrated a proof-of-concept on metal-organic framework-based "one stone for multiple birds" strategy for in situ functionalization of carbon materials.

Sub-Nanosheet Induced Inverse Growth of Negative Valency Au Clusters for Tumor Treatment by Enhanced Oxidative Stress

Cluster aggregation states are thermodynamically favored at the subnanoscale, for which an inverse growth from nanoparticles to clusters may be realized on subnanometer supports. Herein, we develop Au-polyoxometalate-layered double hydroxide (Au-POM-LDH) sub-1 nm nanosheets (Sub-APL) based on the above strategy, where sub-1 nm Au clusters with negative valence are generated by the in situ disintegration of Au nanoparticles on POM-LDH supports. Sub-1 nm Au clusters with ultrahigh surface atom ratios exhibit remarkable efficiency for glutathione (GSH) depletion. The closely connected sub-1 nm Au with negative valence and POM hetero-units can promote the separation of hole-electrons, resulting in the enhanced reactive oxygen species (ROS) generation under ultrasound (US). Besides, the reversible redox of Mo in POM is able to deplete GSH and trigger chemodynamic therapy (CDT) simultaneously, further enhancing the oxidative stress. Consequently, the Sub-APL present 2-fold ROS generation under US and 7-fold GSH depletion compared to the discrete Au and POM-LDH mixture. Therefore, the serious imbalance of redox in the TME caused by the sharp increase of ROS and rapid decrease of GSH leads to death of tumor ultimately.

Photothermal therapy of xenografted tumor by carbon nanoparticles-Fe(II) complex

Due to the unique structure, carbon nanomaterials could convert near-infrared (NIR) light into heat efficiently in tumor ablation using photothermal therapy (PTT). However, none of them has been applied in clinical treatment, because they have not been approved for clinical evaluations and the precise temperature control facility is scarce. In this study, we designed a temperature-responsive controller for PTT and used carbon nanoparticles-Fe(II) complex (CNSI-Fe) as photothermal conversion agent (PTA) for PTT of tumor in vitro and in vivo. CNSI-Fe was an innovative drug under the evaluations in clinical trials. CNSI-Fe showed excellent photothermal conversion ability in water to increase the water temperature by 40 °C within 5 min under irradiation of 808 nm laser at 0.5 W/cm2. The temperature was precisely controlled at 52 °C for both in vitro and in vivo tumor inhibition. CNSI-Fe with NIR irradiation showed higher tumor cell inhibition than CNSI. In tumor bearing mice, CNSI-Fe with NIR irradiation achieved an inhibition rate of 84.7 % and 71.4 % of them were completely cured. Mechanistically, CNSI-Fe under NIR irradiation induced the radical generation, oxidative damage and ferroptosis to kill tumor. In addition, CNSI-Fe showed good biosafety during PTT according to hematological, serum biological and histopathological examinations. These results indicated that the combination of chemotherapy and PTT provided higher antitumor efficiency using CNSI-Fe as PTA.

High-temperature PTT/CDT coordination nanoplatform realizing exacerbated hypoxia for enhancing hypoxia-activated chemotherapy to overcome tumor drug resistance

BACKGROUND

Hypoxia-activated prodrugs present new opportunities for safe and effective tumor drug resistance therapy due to their high selectivity for hypoxic cells. However, the uneven distribution of oxygen in solid tumor and insufficient hypoxia in the tumor microenvironment greatly limit its therapeutic efficacy.

RESULTS

In this paper, a novel AQ4N-Mn(II)@PDA coordination nanoplatform was designed and functionalized with GMBP1 to target drug-resistant tumor cells. Its excellent photothermal conversion efficiency could achieve local high-temperature photothermal therapy in tumors, which could not only effectively exacerbate tumor hypoxia and thus improve the efficacy of hypoxia-activated chemotherapy of AQ4N but also significantly accelerate Mn2+-mediated Fenton-like activity to enhance chemodynamic therapy. Moreover, real-time monitoring of blood oxygen saturation through photoacoustic imaging could reflect the hypoxic status of tumors during treatment. Furthermore, synergistic treatment effectively inhibited tumor growth and improved the survival rate of mice bearing orthotopic drug-resistant tumors.

CONCLUSIONS

This study not only provided a new idea for PTT combined with hypoxia-activated chemotherapy and CDT for drug-resistant tumors but also explored a vital theory for real-time monitoring of hypoxia during treatment.

Metallic Copper-Based Dual-Enzyme Biomimetic Nanoplatform for Mild Photothermal Enhancement of Anticancer Catalytic Activity

Background: Chemodynamic therapy (CDT) is recognized as a promising cancer treatment. Recently, copper sulfide nanostructures have been extensively employed as Fenton-like reagents that catalyze the formation of acutely toxic hydroxyl radicals (·OH) from hydrogen peroxide (H2O2). However, CDT therapeutic potency is restricted by the tumor microenvironment (TME), such as insufficient amounts of hydrogen peroxide, excessive glutathione levels, etc. To address these disadvantages, glucose oxidase (GOx) or catalase (CAT) can be utilized to enhance CDT, while low therapeutic efficacy still inhibits their future applications. Our previous study revealed that mild photothermal effect could boost the CDT catalytic effectiveness as well as GOx enzyme activity over a range. Results: We engineered and constructed a hollow CuS nanoplatform loaded with GOx and CAT, coating with macrophage membranes (M@GOx-CAT@CuS NPs). The nanoplatforms allowed enhancement of the reactive oxygen species creation rate and GOx catalytic activeness of CDT through mild phototherapy directed by photoacoustic imaging. After actively targeting vascular cell adhesion molecule-1 (VCAM-1) in cancer cells mediated by macrophage membrane coating, M@GOx-CAT@CuS NPs released GOx and CAT under near-infrared irradiation. GOx catalyzed the formation of H2O2 and gluconic acid with glucose, creating a better catalytic environment for CDT. Meanwhile, CAT-catalyzed H2O2 decomposition to generate sufficient oxygen, appropriately alleviating the oxygen shortage in the TME. In addition, starvation effects decreased adenosine triphosphate levels and further underregulated heat shock protein expression to reduce the heat resistance of tumor cells, resulting in a better mild phototherapy outcome. Both in vitro and in vivo experiments demonstrated that the newly developed M@GOx-CAT@CuS nanoplatform has remarkable synergistic anticancer therapeutic effects. Conclusion: The cascade reaction-enhanced biomimetic nanoplatform opens up a new avenue for precision tumor diagnostic and therapeutic research.

EGCG-vanadium nanomedicine with neutral pH Fenton reaction activity inhibits heat shock proteins for enhanced photothermal/chemodynamic therapy

A burgeoning interest has recently focused on the development of nanomedicine to integrate noninvasive photothermal therapy (PTT) and chemodynamic therapy (CDT) for synergistic tumor treatments, owing to PTT's amplification effect on CDT. However, challenges emerge as hyperthermia often induces an unwarranted overexpression of cytoprotective heat shock proteins (HSPs), thereby curtailing PTT efficacy. Additionally, the nearly neutral tumor intracellular pH (pHi ≈ 7.2) that handicaps the Fenton reaction poses a leading limitation to CDT. Addressing these hurdles, we introduce EVP, a nanomedicine developed through the straightforward assembly of epigallocatechin gallate (EGCG), vanadium sulfate (VOSO4), and Pluronic F-127 (PF127). EVP comprehensively downregulates overexpressed HSPs (HSP 60, 70, 90) through the collaborative action of EGCG and vanadyl (VO2+). Moreover, the tumor intracellular pH-processed Fenton-like reaction by VO2+ ensures highly efficient hydroxyl radicals (OH) production in cytosols, overcoming the stringent acidity requirement for CDT. Additionally, the hyperthermia induced by PTT augments OH production, further enhancing CDT efficacy. In vitro and in vivo experiments validate EVP's excellent biocompatibility and potent tumor inhibition, highlighting its substantial potential in tumor therapy.

Red blood cell membrane-coated functionalized Cu-doped metal organic framework nanoformulations as a biomimetic platform for improved chemo-/chemodynamic/photothermal synergistic therapy

Nanoformulations for combining chemotherapy, chemodynamic therapy, and photothermal therapy have enormous potential in tumor treatment. Coating nanoformulations with cell membranes endows them with homologous cellular mimicry, enabling nanoformulations to acquire new functions and properties, including homologous targeting and long circulation in vivo, and can enhance internalization by homologous cancer cells. Herein, we fused multifunctional biomimetic nanoformulations based on Cu-doped zeolitic imidazolate framework-8 (ZIF-8). Hydroxycamptothecin (HCPT), a clinical anti-tumor drug, was encapsulated into ZIF-8, which was subsequently coated with polydopamine (PDA) and red blood cell membrane. The as-fabricated biomimetic nanoformulations showed an enhanced cell uptake in vitro and the potential to prolong blood circulation in vivo, producing effective synergistic chemotherapy, chemodynamic therapy, and photothermal therapy under the 808 nm laser irradiation. Together, the biomimetic nanoformulations showed a prolonged blood circulation and evasion of immune recognition in vivo to provide a bio-inspired strategy which may have the potential for the multi-synergistic therapy of breast cancer.

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.

Dual chemodynamic/photothermal therapeutic nanoplatform based on DNA-functionalized prussian blue

The combination of chemodynamic therapy and photothermal therapy has a promising application owing to its impressive anti-cancer effects. However, the degradability of the material and the lack of targeting severely limit its further clinical application. Herein, DNAs containing nucleolin aptamer (AS1411) and different bases sequences were used to functionalize PB NPs for the targeted treatment. Compared to prussian blue, DNA-functionalized prussian blue does not reduce the photothermal properties of prussian blue. Moreover, DNA confers DNA-functionalized prussian blue targeting and higher enzymatic activity, thereby achieving a more effective combination of chemodynamic and photothermal treatment. The therapeutic efficacy of this nanoplatform was evaluated in vivo and in vitro experiments, exhibiting that DNA-functionalized prussian blue nanozyme can maximize the precise control of the therapeutic effect, reduce the toxic and side effects caused by non-specific accumulation on other normal cells, and effectively achieve targeted killing of cancer cells. This work demonstrates that DNA-functionalized prussian blue can improve the efficiency of combined tumor treatment and enhance the application value of prussian blue in tumor treatment, which is expected to provide theoretical support for clinical application.

Overcoming challenges in cancer treatment: Nano-enabled photodynamic therapy as a viable solution

Cancer presents a formidable challenge, necessitating innovative therapies that maximize effectiveness while minimizing harm to healthy tissues. Nanotechnology has emerged as a transformative force in cancer treatment, particularly through nano-enabled photodynamic therapy (NE-PDT), which leverages precise and targeted interventions. NE-PDT capitalizes on photosensitizers activated by light to generate reactive oxygen species (ROS) that initiate apoptotic pathways in cancer cells. Nanoparticle enhancements optimize this process, improving drug delivery, selectivity, and ROS production within tumors. This review dissects NE-PDT's mechanistic framework, showcasing its potential to harness apoptosis as a potent tool in cancer therapy. Furthermore, the review explores the synergy between NE-PDT and complementary treatments like chemotherapy, immunotherapy, and targeted therapies, highlighting the potential to amplify apoptotic responses, enhance immune recognition of cancer cells, and inhibit resistance mechanisms. Preclinical and clinical advancements in NE-PDT demonstrate its efficacy across various cancer types. Challenges in translating NE-PDT into clinical practice are also addressed, emphasizing the need for optimizing nanoparticle design, refining dosimetry, and ensuring long-term safety. Ultimately, NE-PDT represents a promising approach in cancer therapy, utilizing the intricate mechanisms of apoptosis to address therapeutic hurdles. The review underscores the importance of understanding the interplay between nanoparticles, ROS generation, and apoptotic pathways, contributing to a deeper comprehension of cancer biology and novel therapeutic strategies. As interdisciplinary collaborations continue to thrive, NE-PDT offers hope for effective and targeted cancer interventions, where apoptosis manipulation becomes central to conquering cancer. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Fe/Cu-AuNP nanocomposites as enzyme-like catalysts to modulate the tumor microenvironment for enhanced synergistic cancer therapy

The intensive investigation of chemodynamic therapy (CDT) for tumor eradication revealed that the therapeutic effects of this ROS-mediated therapy are limited by endogenous reductants and inefficient Fenton-like reactions. In this study, we developed a new Fe/Cu-AuNP-PEG nanocomposite to enhance CDT and provide a synergistic treatment for tumors. The Fe/Cu-AuNP-PEG nanocomposite demonstrated effective ˙OH production and high photothermal conversion efficiency under 808 nm illumination, which promoted the ˙OH production, thereby enhancing the CDT efficacy and exhibiting a synergistic treatment for cancer. More importantly, the Fe/Cu-AuNP-PEG nanocomposite showed the ability to deplete GSH and catalyze glucose to generate H2O2, which facilitated the Fenton-like reaction and reduced the antioxidant properties of tumors, further improving the efficacy of CDT. Therefore, the Fe/Cu-AuNP-PEG nanocomposite, with horseradish peroxidase-like, glutathione peroxidase-like, and glucose oxidase-like activities, is a promising anti-tumor agent for integrating enhanced CDT and photothermal therapy (PTT) with the enhancement of synergistic therapeutic effects.

Optimized strategies of ROS-based nanodynamic therapies for tumor theranostics

Reactive oxygen species (ROS) play a crucial role in regulating the metabolism of tumor growth, metastasis, death and other biological processes. ROS-based nanodynamic therapies (NDTs) are becoming attractive due to non-invasive, low side effects and tumor-specific advantages. NDTs have rapidly developed into numerous branches, such as photodynamic therapy, chemodynamic therapy, sonodynamic therapy and so on. However, the complexity of the tumor microenvironment and the limitations of existing sensitizers have greatly restricted the therapeutic effects of NDTs, which heavily rely on ROS levels. To address the limitations of NDTs, various strategies have been developed to increase ROS yield, which is an urgent aspect for the positive development of NDTs. In this review, the nanodynamic potentiation strategies in terms of unique properties and universalities of NDTs are comprehensively outlined. We mainly summarize the current dilemmas faced by each NDT and the respective solutions. Meanwhile, the NDTs universalities-based potentiation strategies and NDTs-based combined treatments are elaborated. Finally, we conclude with a discussion of the key issues and challenges faced in the development and clinical transformation of NDTs.

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.

Iron-chelated semiconducting oligomer nanoparticles for NIR-II fluorescence imaging-guided enhanced chemodynamic/photothermal combination therapy

Chemodynamic therapy (CDT) has attracted increasing attention owing to its high tumor specificity and low number of side effects. However, the low absolute concentration of reactive oxygen species (ROS) within tumor cells restricts the CDT efficacy. Herein, we use dihydroartemisinin (DHA) to enhance the CDT efficacy and combine photothermal therapy (PTT) to further improve the anticancer effect. To achieve such a goal, an iron-containing semiconducting oligomer nanoparticle (DHA@FePSOD) is prepared by loading DHA into a Fe3+-chelated NIR-II fluorescent semiconducting oligomer (FePSOD). The Fe3+ ion within DHA@FePSOD can be reduced to the Fe2+ ion by glutathione (GSH) and subsequently catalyze the decomposition of hydrogen peroxide (H2O2) into the highly toxic hydroxyl radical (˙OH) for CDT. The loaded DHA may be further reduced by Fe2+ and generate a DHA radical to enhance the CDT efficacy. In addition, DHA@FePSOD shows a good photothermal effect and intense NIR-II fluorescence signal under 808 nm laser irradiation. Both in vitro and in vivo studies prove the better anticancer effect of DHA@FePSOD than FePSOD, which is attributed to the loaded DHA. Furthermore, DHA@FePSOD can effectively accumulate into a tumor and delineate the tumor via NIR-II fluorescence imaging. This study thus provides an efficient approach for developing a NIR-II fluorescence imaging-guided enhanced chemodynamic/photothermal combination therapeutic nanoplatform.

pH-Activated Ce-Doped Molybdenum Oxide Nanoclusters for Tumor Microenvironment Responsive Photothermal and Chemodynamic Therapy

Molybdenum-based nanomaterials have shown promise for anticancer treatment due to their strong photothermal and redox-activated capabilities. Herein, we have fabricated cerium-doped MoO_x (Ce-MoO_v) with tunable Mo/Ce molar ratios by a one-pot method and investigated their effect on chemodynamic therapy (CDT) and photothermal therapy (PTT). It is found that Ce-MoO_v can self-assemble into nanoclusters in acidic conditions and the increasing Ce amount will generate oxygen vacancy defects and induce the valence change of Mo⁶⁺/Mo⁵⁺ and Ce⁴⁺/Ce³⁺, which leads to strong near-infrared absorption with high photothermal conversion efficiency of 71.31 and 49.86% for 808 and 1064 nm. Other than photothermal conversion, the materials demonstrate pH-/glutathione (GSH)-activated photoacoustic (PA) imaging capability in vitro. In addition, Ce-MoO_v acts as a CDT reagent capable of converting endogenous H₂O₂ to two types of reactive oxygen species (^•OH, ¹O₂) while depleting GSH. Ce-MoO_v demonstrates an excellent therapeutic effect against HCT116 cells and effectively reduces the intracellular GSH level and significantly increases the number of reactive radicals under 1064 nm laser irradiation as compared with the no-laser group in vitro. This work provides a new paradigm using lanthanide-doped polymetallic oxides for pH-/GSH-responsive photothermal/chemodynamic therapy with PA imaging ability.

Photoelectrochemical biosensor based on SiW12@CdS quantum dots for the highly sensitive detection of HPV 16 DNA

A highly sensitive biosensor for detecting HPV 16 DNA was prepared based on Keggin-type polyoxometalate (SiW₁₂)-grafted CdS quantum dots (SiW₁₂@CdS QDs) and colloidal gold nanoparticles (Au NPs), which exhibited remarkable selectivity and sensitivity upon target DNA detection because of its excellent photoelectrochemical (PEC) response. Here, an enhanced photoelectronic response ability was achieved with the strong association of SiW₁₂@CdS QDs by polyoxometalate modification, which was developed through a convenient hydrothermal process. Furthermore, on Au NP-modified indium tin oxide slides, a multiple-site tripodal DNA walker sensing platform coupled with T7 exonuclease was successfully fabricated with SiW₁₂@CdS QDs/NP DNA as a probe for detecting HPV 16 DNA. Due to the remarkable conductivity of Au NPs, the photosensitivity of the as-prepared biosensor was improved in an I3-/I- solution and avoided the use of other regents toxic to living organisms. Finally, under optimized conditions, the as-prepared biosensor protocol demonstrated wide linear ranges (15-130 nM), with a limit of detection of 0.8 nM and high selectivity, stability, and reproducibility. Moreover, the proposed PEC biosensor platform offers a reliable pathway for detecting other biological molecules with nano-functional materials.

An Activatable Phototheranostic Nanoplatform for Tumor Specific NIR-II Fluorescence Imaging and Synergistic NIR-II Photothermal-Chemodynamic Therapy

The phototheranostics in the second near-infrared window (NIR-II) have proven to be promising for the precise cancer theranostics. However, the non-responsive and "always on" imaging mode lacks the selectivity, leading to the poor diagnosis specificity. Herein, a tumor microenvironment (TME) activated NIR-II phototheranostic nanoplatform (Ag₂ S-Fe(III)-DBZ Pdots, AFD NPs) is designed based on the principle of Förster resonance energy transfer (FRET). The AFD NPs are fabricated through self-assembly of Ag₂ S QDs (NIR-II fluorescence probe) and ultra-small semiconductor polymer dots (DBZ Pdots, NIR-II fluorescence quencher) utilizing Fe(III) as coordination nodes. In normal tissues, the AFD NPs maintain in "off" state, due to the FRET between Ag₂ S QDs and DBZ Pdots. However, the NIR-II fluorescence signal of AFD NPs can be rapidly "turn on" by the overexpressed GSH in tumor tissues, achieving a superior tumor-to-normal tissue (T/NT) signal ratio. Moreover, the released Pdots and reduced Fe(II) ions provide NIR-II photothermal therapy (PTT) and chemodynamic therapy (CDT), respectively. The GSH depletion and NIR-II PTT effect further aggravate CDT mediated oxidative damage toward tumors, achieving the synergistic anti-tumor therapeutic effect. The work provides a promising strategy for the development of TME activated NIR-II phototheranostic nanoprobes.

Second near-infrared photoactivatable nanomedicines for enhanced photothermal-chemodynamic therapy of cancer

Nanomedicines have been widely used for cancer therapy, while controlling their activity for effective and safe treatment remains a big challenge. Herein, we report the development of a second near-infrared (NIR-II) photoactivatable enzyme-loaded nanomedicine for enhanced cancer therapy. Such a hybrid nanomedicine contains a thermoresponsive liposome shell loaded with copper sulfide nanoparticles (CuS NPs) and glucose oxidase (GOx). The CuS nanoparticles mediate the generation of local heat under 1064 nm laser irradiation, which not only can be used for NIR-II photothermal therapy (PTT), but also leads to the destruction of the thermal-responsive liposome shell to achieve the on-demand release of CuS nanoparticles and GOx. In a tumor microenvironment, GOx oxidizes glucose to produce hydrogen peroxide (H₂O₂) that acts as a medium to promote the efficacy of chemodynamic therapy (CDT) by CuS nanoparticles. This hybrid nanomedicine enables the synergetic action of NIR-II PTT and CDT to obviously improve efficacy without remarkable side effects via NIR-II photoactivatable release of therapeutic agents. Such a hybrid nanomedicine-mediated treatment can achieve complete ablation of tumors in mouse models. This study provides a promising nanomedicine with photoactivatable activity for effective and safe cancer therapy.

Ultrasound-enhanced cascade chemodynamic tumor nanotherapy with lactic acid-enabled hydrogen peroxide self-production

Chemodynamic therapy (CDT) is an effective therapeutic modality for cancer treatment with the action of a catalytic Fenton-like chemoreactive process. To furnish sufficient hydrogen peroxide (H₂O₂) for CDT, catalysts similar to superoxide dismutase are designed to be in cooperation with nanoplatforms. In this work, we rationally integrate lactate oxidase (LOD) with ultrasmall superparamagnetic iron oxide nanoparticles (USPION) to achieve high efficiency of the cascade Fenton reaction for efficient tumor therapy. During the sequential reaction, LOD converts lactic acid into H₂O₂ and pyruvate (PA) in situ, and then USPION with peroxidase-like activity generates large amounts of toxic hydroxyl radicals (˙OH) under the action of H₂O₂. Moreover, the reaction effectively utilizes the excess lactic acid of the tumor microenvironment (TME) as a new target of cancer treatment. To further achieve high-performance tumor treatment, ultrasound has been introduced for augmenting this specific chemoreactive tumor therapy, which can affect cancer cells mainly through sonoporation, cavitation, and thermal effect. With the effects of ultrasound irradiation, this work has constructed an efficient oncology treatment system for tumors. Moreover, the presence of USPION is highly desirable for contrast-enhanced T₁-weighted MRI for monitoring the therapeutic process of cancer in real time.

Self-Assembled Aza-BODIPY and Iron(III) Nanoparticles for Photothermal-Enhanced Chemodynamic Therapy in the NIR-II Window

Despite its promising potential in cancer treatment, synergistic photothermal/chemodynamic therapy remains underdeveloped with regard to the utilization of metal-organic materials under second near-infrared (NIR-II) laser excitation. Herein, we report a three-dimensional network constructed via the metal coordination between catechol-functionalized aza-boron dipyrromethenes and iron ions (ABFe), which was further encapsulated by F127 to obtain ABFe nanoparticles (NPs) for combined photothermal/chemodynamic therapy. ABFe NPs exhibited intense absorption in the NIR-II range and negligible fluorescence. Upon 1064 nm laser irradiation, ABFe NPs showed high photothermal conversion efficiency (PCE = 55.0%) and excellent photothermal stability. The results of electron spin resonance spectra and o-phenylenediamine chromaticity spectrophotometry proved that ABFe NPs were capable of generating harmful reactive oxygen species from hydrogen peroxide for chemodynamic therapy, which was promoted by photothermal performance. Notably, in vitro and in vivo experiments demonstrated the great potential of ABFe NPs in photoacoustic imaging and photothermal-enhanced chemodynamic therapy under NIR-II laser irradiation. Therefore, the current work presents a prospective NIR-II excitation therapeutic nanomedicine for combination therapy, offering a novel strategy for simultaneously achieving extended NIR absorption of aza-BODIPY and enhanced chemodynamic therapy with metal-organic materials.

Nanostructures as Photothermal Agents in Tumor Treatment

Traditional methods of tumor treatment such as surgical resection, chemotherapy, and radiation therapy have certain limitations, and their treatment effects are not always satisfactory. As a new tumor treatment method, photothermal therapy based on nanostructures has attracted the attention of researchers due to its characteristics of minimally invasive, low side effects, and inhibition of cancer metastasis. In recent years, there has been a variety of inorganic or organic nanostructures used in the field of photothermal tumor treatment, and they have shown great application prospects. In this paper, the advantages and disadvantages of a variety of nanomaterials/nanostructures as photothermal agents (PTAs) for photothermal therapy as well as their research progress are reviewed. For the sake of clarity, the recently reported nanomaterials/nanostructures for photothermal therapy of tumor are classified into five main categories, i.e., carbon nanostructures, noble metal nanostructures, transition metal sulfides, organic polymer, and other nanostructures. In addition, future perspectives or challenges in the related field are discussed.

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.

Recyclable Endogenous H2 S Activation of Self-Assembled Nanoprobe with Controllable Biodegradation for Synergistically Enhanced Colon Cancer-Specific Therapy

Excessive production of hydrogen sulfide (H₂ S) plays a crucial role in the progress of colon cancer. Construction of tumor-specific H₂ S-activated smart nanoplatform with controllable biodegradation is of great significance for precise and sustainable treatment of colon cancer. Herein, an endogenous H₂ S triggered Co-doped polyoxometalate (POM-Co) cluster with self-adjustable size, controlled biodegradation, and sustainable cyclic depletion of H₂ S/glutathione (GSH) is designed for synergistic enhanced tumor-specific photothermal and chemodynamic therapy. The designed POM-Co nanocluster holds H₂ S responsive "turn-on" photothermal property in colon cancer via self-assembling to form large-sized POM-CoS, enhancing the accumulation at tumor sites. Furthermore, the formed POM-CoS can gradually biodegrade, resulting in release of Co²⁺ and Mo⁶⁺ for Co(II)-catalyzed •OH production and Russell mechanism-enabled ¹ O₂ generation with GSH consumption, respectively. More importantly, the degraded POM-CoS is reactivated by endogenous H₂ S for recyclable and sustainable consumption of H₂ S and GSH, resulting in tumor-specific photothermal/chemodynamic continuous therapy. Therefore, this study provides an opportunity of designing tumor microenvironment-driven nanoprobes with controllable biodegradation for precise and sustainable anti-tumor therapy.

Iron-Based Hollow Nanoplatforms for Cancer Imaging and Theranostics

Over the past decade, iron (Fe)-based hollow nanoplatforms (Fe-HNPs) have attracted increasing attention for cancer theranostics, due to their high safety and superior diagnostic/therapeutic features. Specifically, Fe-involved components can serve as magnetic resonance imaging (MRI) contrast agents (CAs) and Fenton-like/photothermal/magnetic hyperthermia (MTH) therapy agents, while the cavities are able to load various small molecules (e.g., fluorescent dyes, chemotherapeutic drugs, photosensitizers, etc.) to allow multifunctional all-in-one theranostics. In this review, the recent advances of Fe-HNPs for cancer imaging and treatment are summarized. Firstly, the use of Fe-HNPs in single T1-weighted MRI and T2-weighted MRI, T1-/T2-weighted dual-modal MRI as well as other dual-modal imaging modalities are presented. Secondly, diverse Fe-HNPs, including hollow iron oxide (IO) nanoparticles (NPs), hollow matrix-supported IO NPs, hollow Fe-complex NPs and hollow Prussian blue (PB) NPs are described for MRI-guided therapies. Lastly, the potential clinical obstacles and implications for future research of these hollow Fe-based nanotheranostics are discussed.

Supramolecular Self-Assemblies with Self-Supplying H2O2 and Self-Consuming GSH Property for Amplified Chemodynamic Therapy

Fe-based chemodynamic therapy (CDT) has become one potential method for cancer therapy due to its lower side effect and tumor-specific property. During the process of CDT, the lack of active targeting and biodegradable ability, insufficient endogenous H₂O₂, and overexpressed GSH in the tumor were responsible for the unsatisfactory therapeutic performance. Hence, we report host-guest interaction-based supramolecular polymers (HGSPs) that were constructed with the biomacromolecule β-cyclodextrin-grafted hyaluronic acid (HA-CD) as the active targeting host unit and hydrophobic ROS-responsive ferrocene-(phenylboronic acid pinacol ester) (Fc-BE) as the guest unit. HGSPs can further self-assemble into self-assemblies (HGSAs) and encapsulate PA as the prooxidant. After CD44-receptor-mediated cellular internalization, HGSAs could disassemble and release PA to elevate the H₂O₂ level for the production of higher cytotoxic hydroxyl radicals (^•OH) through the Fc-induced Fenton reaction. Moreover, quinone methide (QM) was generated to downregulate antioxidant GSH. The enhancement of H₂O₂ and consumption of GSH were favorable for CDT due to the amplified oxidative stress. In vivo experimental results indicated that HGSAs@PA might be used as an active targeting amplified CDT agent.

Manganese-based hollow nanoplatforms for MR imaging-guided cancer therapies

Theranostic nanoplatforms integrating diagnostic and therapeutic functions have received considerable attention in the past decade. Among them, hollow manganese (Mn)-based nanoplatforms are superior since they combine the advantages of hollow structures and the intrinsic theranostic features of Mn2+. Specifically, the hollow cavity can encapsulate a variety of small-molecule drugs, such as chemotherapeutic agents, photosensitizers and photothermal agents, for chemotherapy, photodynamic therapy (PDT) and photothermal therapy (PTT), respectively. After degradation in the tumor microenvironment (TME), the released Mn2+ is able to act simultaneously as a magnetic resonance (MR) imaging contrast agent (CA) and as a Fenton-like agent for chemodynamic therapy (CDT). More importantly, synergistic treatment outcomes can be realized by reasonable and optimized design of the hollow nanosystems. This review summarizes various Mn-based hollow nanoplatforms, including hollow MnxOy, hollow matrix-supported MnxOy, hollow Mn-doped nanoparticles, hollow Mn complex-based nanoparticles, hollow Mn-cobalt (Co)-based nanoparticles, and hollow Mn-iron (Fe)-based nanoparticles, for MR imaging-guided cancer therapies. Finally, we discuss the potential obstacles and perspectives of these hollow Mn-based nanotheranostics for translational applications. Mn-based hollow nanoplatforms such as hollow MnxOy nanoparticles, hollow matrix-supported MnxOy nanoparticles, Mn-doped hollow nanoparticles, Mn complex-based hollow nanoparticles, hollow Mn-Co-based nanoparticles and hollow Mn-Fe-based nanoparticles show great promise in cancer theranostics.

Fabrication of injectable hydrogels from an anticancer peptide for local therapeutic delivery and synergistic photothermal-chemotherapy

The susceptibility of anticancer peptides to proteolytic degradation is often considered as a major weakness that limits systemic therapeutic applications. However, localized delivery of anticancer peptides via injectable hydrogels is expected to improve drug efficacy and reduce systemic toxicity. Herein, an injectable hydrogel with drug releasing properties, NIR responsiveness and pH sensitivity was developed from an anticancer peptide (KL), Fe³⁺ ions and protocatechualdehyde via dynamic and reversible interactions. Benefiting from the formation of Fe(III)-catechol complexes between Fe³⁺ ions and protocatechualdehyde within gel networks, the obtained hydrogel exhibited intrinsic NIR absorption properties for photothermal ablation of tumor cells, and remote light control of drug release. Besides, the pH-labile imine bonds between KL and protocatechualdehyde endowed the injectable gel with pH sensitivity for sustained release of KL under a mildly acidic environment, inducing membrane destabilization and facilitating the cell uptake of DOX for combinational chemotherapy. Both in vitro and in vivo experiments revealed that the injectable hydrogel exhibited a synergistic therapeutic effect on inhibiting tumor growth via combinational photothermal-chemotherapy. Therefore, this work provides a promising attempt to develop a therapeutic hydrogel from an anticancer peptide, which could work as a localized drug delivery platform for synergistic photothermal-chemotherapy.

Intelligent Bi2Se3@Cu2-xSe heterostructures with enhanced photoabsorption and photoconversion efficiency for tri-modal imaging guided combinatorial cancer therapy by near-infrared Ⅱ light

A novel nanoplatform that supports multimodal imaging has been designed for deep tumor therapy. In this study, Bi₂Se₃@Cu_2-xSe heterojunction nanocomposites with tunable spectral absorption, effective electron-hole separation and high photothermal conversion efficiency were prepared for the combination therapy of phototherapy (PT), chemodynamic therapy (CDT) and radiotherapy (RT). By adjusting the doping ratio, the heterojunction nanoparticles show obvious tunable ability of local surface plasmon resonance and the ability to promote electron-hole separation with significantly enhanced reactive oxygen species production capacity. The band structure and charge density difference calculated by density functional theory further reveal that the change of band gap and the decrease of free carriers can regulate the spectral absorption of nanomaterials and promote electron-hole separation. In addition, the photothermal conversion properties of low carrier density semiconductors are related to their inherent deep level defects. The formation of heterojunctions making the Se atoms deviate from the Bi₂Se₃ lattice, resulting in more deep level defects and stronger photothermal conversion properties. Meanwhile, this nanoplatform presented features similar to catalase activities and glutathione (GSH) consumption characteristics, which was capable of effectively alleviate the tumor-specific hypoxia environment to enhance the efficacy of O₂-dependent photodynamic therapy (PDT) and radiotherapy (RT) and depletion GSH to prevent the reduction of therapeutic efficacy due to the clearance of reactive oxygen species. In addition to therapeutic enhancement, heterojunction nanomaterials have excellent nuclear magnetic resonance imaging (MRI), infrared thermal imaging (IR) and computed tomography (CT) properties due to their significant paramagnetism and excellent photothermal conversion and X-ray attenuation capacities. In conclusion, our findings provide a new strategy for designing multi-function and efficient nanoplatform to treat tumor.

Enhanced postoperative cancer therapy by iron-based hydrogels

Surgical resection is a widely used method for the treatment of solid tumor cancers. However, the inhibition of tumor recurrence and metastasis are the main challenges of postoperative tumor therapy. Traditional intravenous or oral administration have poor chemotherapeutics bioavailability and undesirable systemic toxicity. Polymeric hydrogels with a three-dimensional network structure enable on-site delivery and controlled release of therapeutic drugs with reduced systemic toxicity and have been widely developed for postoperative adjuvant tumor therapy. Among them, because of the simple synthesis, good biocompatibility, biodegradability, injectability, and multifunctionality, iron-based hydrogels have received extensive attention. This review has summarized the general synthesis methods and construction principles of iron-based hydrogels, highlighted the latest progress of iron-based hydrogels in postoperative tumor therapy, including chemotherapy, photothermal therapy, photodynamic therapy, chemo-dynamic therapy, and magnetothermal-chemical combined therapy, etc. In addition, the challenges towards clinical application of iron-based hydrogels have also been discussed. This review is expected to show researchers broad perspectives of novel postoperative tumor therapy strategy and provide new ideas in the design and application of novel iron-based hydrogels to advance this sub field in cancer nanomedicine.

Tumor acidity-activatable photothermal/Fenton nanoagent for synergistic therapy

Intracellular formation of therapeutic agents has become one of the effective ways for cancer-specific treatment. Herein, a tumor acidity-activatable photothermal/Fenton nanoagent (denoted as CoPy) was constructed based on oxidized zeolitic imidazolate framework-67 (oxZIF-67) nanosheet and pyrrole (Py) monomer for synergistic therapy. The CoPy showed negligible toxicity to normal cell models RAW264.7 and 3T3 cell lines, and could be degraded by ascorbic acid in normal physiological conditions. However, once uptaken by 4T1 cells, the acidic pH led to the release of Co³⁺, which served as a strong oxidant to induce the polymerization of Py to form polypyrrole (PPy) for site-specific photothermal therapy (PTT). Most appealingly, the PPy could chelate the generated Co²⁺ in the polymerization process to initiate the Fenton-like reaction, which was more capable to produce highly toxic hydroxyl radical (•OH) for chemodynamic therapy (CDT) compared to the free Co²⁺ ones. In vitro and in vivo experiments demonstrated that all functionalities on CoPy worked collaboratively, and 78% of tumors were inhibited through cooperative PTT/CDT. Such a novel therapeutic nanoagent with tumor selectivity opens new opportunities for combinational treatment paradigms.

Multifunctional nanocarrier with self-catalytic production of nitric oxide for photothermal and gas-combined therapy of tumor

Single treatment often faces the problem that it cannot completely eradicate tumor and inhibit the tumor metastasis. In order to overcome this shortcoming, multi-modal tumor treatment has attracted widespread attention. In the present article, based on ascorbyl palmitate (PA) and l-arginine (l-Arg), a multifunctional nanocarrier is designed for synergetic treatment of tumor with photothermal and nitric oxide (NO) gas therapy. Firstly, PA and l-Arg were self-assembled to form novel functional micelles, PL, with high biosafety using electrostatic interaction and hydrogen bonding. The functional micelles could self-catalyze to produce NO at the tumor site. Then, Ag₂S quantum dots having fluorescence imaging and photothermal properties were encapsulated to obtain the nanocarrier, A@PL. The results show that A@PL had a hydrated size of around 78 nm and presented good stability within 30 d. Moreover, in vitro studies indicate that it was efficient with regards to NO self-generating capacity, whereas the photothermal conversion efficiency was as high as 34% under near-infrared light irradiation. The cytotoxicity results show that, when the concentration of A@PL was as high as 2 mM, the survival rate of 3 T3 cells was still 78.23%, proving that the probe has good safety characteristics. Fluorescence imaging results show that its maximum enrichment can be achieved at the tumor site after tail vein injection for 3 h, and out of the body after 24 h, indicating good internal circulation. The in vivo studies show that the rate of inhibition of tumor using the nanocarrier was as high as 98%, and almost overcame the problem of tumor recurrence caused by single treatment, thus presenting a significant tumor treatment effect. This new multifunctional nanocarrier with self-catalytic production of NO provides a new idea for the efficient treatment of tumors.

POD Nanozyme optimized by charge separation engineering for light/pH activated bacteria catalytic/photodynamic therapy

The current feasibility of nanocatalysts in clinical anti-infection therapy, especially for drug-resistant bacteria infection is extremely restrained because of the insufficient reactive oxygen generation. Herein, a novel Ag/Bi₂MoO₆ (Ag/BMO) nanozyme optimized by charge separation engineering with photoactivated sustainable peroxidase-mimicking activities and NIR-II photodynamic performance was synthesized by solvothermal reaction and photoreduction. The Ag/BMO nanozyme held satisfactory bactericidal performance against methicillin-resistant Staphylococcus aureus (MRSA) (~99.9%). The excellent antibacterial performance of Ag/BMO NPs was ascribed to the corporation of peroxidase-like activity, NIR-II photodynamic behavior, and acidity-enhanced release of Ag⁺. As revealed by theoretical calculations, the introduction of Ag to BMO made it easier to separate photo-triggered electron-hole pairs for ROS production. And the conduction and valence band potentials of Ag/BMO NPs were favorable for the reduction of O₂ to ·O₂⁻. Under 1064 nm laser irradiation, the electron transfer to BMO was beneficial to the reversible change of Mo⁵⁺/Mo⁶⁺, further improving the peroxidase-like catalytic activity and NIR-II photodynamic performance based on the Russell mechanism. In vivo, the Ag/BMO NPs exhibited promising therapeutic effects towards MRSA-infected wounds. This study enriches the nanozyme research and proves that nanozymes can be rationally optimized by charge separation engineering strategy.

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.

Recent Advances in Single Fe-Based Nanoagents for Photothermal-Chemodynamic Cancer Therapy

Monomodal cancer therapies are often unsatisfactory, leading to suboptimal treatment effects that result in either an inability to stop growth and metastasis or prevent relapse. Thus, synergistic strategies that combine different therapeutic modalities to improve performance have become the new research trend. In this regard, the integration of photothermal therapy (PTT) with chemodynamic therapy (CDT), especially PTT/CDT in the second near-infrared (NIR-II) biowindow, has been demonstrated to be a highly efficient and relatively safe concept. With the rapid development of nanotechnology, nanoparticles can be designed from specific elements, such as Fe, that are equipped with both PTT and CDT therapeutic functions. In this review, we provide an update on the recent advances in Fe-based nanoplatforms for combined PTT/CDT. The perspectives on further improvement of the curative efficiency are described, highlighting the important scientific obstacles that require resolution in order to reach greater heights of clinical success. We hope this review will inspire the interest of researchers in developing novel Fe-based nanomedicines for multifunctional theranostics.

NIR-II Functional Materials for Photoacoustic Theranostics

Photoacoustic imaging (PAI) has attracted great attention in the diagnosis and treatment of diseases due to its noninvasive properties. Especially in the second near-infrared (NIR-II) window, PAI can effectively avoid the interference of tissue spontaneous fluorescence and light scattering, and obtain high resolution images with deeper penetration depth. Because of its ideal spectral absorption and high conversion efficiency, NIR-II PA contrast agents overcome the absorption or emission of NIR-II light by endogenous biomolecules. In recent years, a series of NIR-II PA contrast agents have been developed to improve the performance of PAI in disease diagnosis and treatment. In this paper, the research progress of NIR-II PA contrast agents and their applications in biomedicine are reviewed. PA contrast agents are classified according to their composition, including inorganic contrast agents, organic contrast agents, and hybrid organic-inorganic contrast agents. The applications of NIR-II PA contrast agents in medical imaging are described, such as cancer imaging, inflammation detection, brain disease imaging, blood related disease imaging, and other biomedical application. Finally, the research prospects and breakthrough of NIR-II PA contrast agents are discussed.

Mn doped Prussian blue nanoparticles for T1/T2 MR imaging, PA imaging and Fenton reaction enhanced mild temperature photothermal therapy of tumor

BACKGROUND

Combining the multimodal imaging and synergistic treatment in one platform can enhance the therapeutic efficacy and diagnosis accuracy.

RESULTS

In this contribution, innovative Mn-doped Prussian blue nanoparticles (MnPB NPs) were prepared via microemulsion method. MnPB NPs demonstrated excellent T1 and T2 weighted magnetic resonance imaging (MRI) enhancement in vitro and in vivo. The robust absorbance in the near infrared range of MnPB NPs provides high antitumor efficacy for photothermal therapy (PTT) and photoacoustics imaging property. Moreover, with the doping of Mn, MnPB NPs exhibited excellent Fenton reaction activity for chemodynamic therapy (CDT). The favorable trimodal imaging and Fenton reaction enhanced mild temperature photothermal therapy in vitro and in vivo were further confirmed that MnPB NPs have significant positive effectiveness for integration of diagnosis and treatment tumor.

CONCLUSIONS

Overall, this Mn doped Prussian blue nanoplatform with multimodal imaging and chemodynamic/mild temperature photothermal co-therapy provides a reliable tool for tumor treatment.

Targeted carbon monoxide delivery combined with chemodynamic, chemotherapeutic and photothermal therapies for enhanced antitumor efficacy

Polydopamine-coated hollow mesoporous copper sulfide loaded with DHA and CO-releasing molecules selectively delivered DHA and CO to tumor cells under 808 nm light irradiation, demonstrating multimodal synergistic antitumor efficacy.