State-of-the-art advances of copper-based nanostructures in the enhancement of chemodynamic therapy

A DNA damage-amplifying nanoagent for cancer treatment via two-way regulation of redox dyshomeostasis and downregulation of tetrahydrofolate

DNA damage-based therapy is widely used in cancer treatment, yet its therapeutic efficacy is constrained by the redox homeostasis and DNA damage repair mechanisms of tumor cells. To address these limitations and enhance the efficacy of DNA damage-based therapy, HA-CuH@MTX, a copper-histidine metal-organic complex (CuH) loaded with methotrexate (MTX) and modified with hyaluronic acid (HA), was developed to amplify the DNA damage induced. In vitro experiments demonstrated that the presence of both Cu+ and Cu2+ in HA-CuH@MTX enables two-way regulated redox dyshomeostasis (RDH), achieved through Cu+-catalyzed generation of •OH and Cu2+-mediated consumption of glutathione, thereby facilitating efficient DNA oxidative damage. In addition, DNA damage repair is synergistically inhibited by impairing nucleotide synthesis via histidine metabolism and MTX downregulation of tetrahydrofolate, a crucial raw material in nucleotide synthesis. In vivo experiments with 4T1 tumor-bearing mice demonstrate 83.6 % inhibition of tumor growth by HA-CuH@MTX. This work provides a new strategy to amplify the DNA damage caused by DNA damage-based cancer therapies, and holds great potential for improving their therapeutic efficacy.

Dual pH/redox-responsive size-switchable polymeric nano-carrier system for tumor microenvironment DTX release

Innovation chemotherapeutic nano drug delivery systems (NDDSs) with various pharmacological achievement have become one of the hopeful therapeutic strategies in cancer therapy. This study focused on low pH, and high levels of glutathione (GSH) as two prominent characteristics of the tumor microenvironment (TME) to design a novel TME-targeted pH/redox dual-responsive P (AMA-co-DMAEMA)-b-PCL-SS-PCL-b-P (AMA-co-DMAEMA) nanoparticles (NPs) for deep tumor penetration and targeted anti-tumor therapy. The positively charged NPs exhibit strong electrostatic interactions with negatively charged cell membranes, significantly enhancing cellular uptake. Moreover, these NPs possess the unique size-shrinkable property, transitioning from 98.24 ± 27.78 to 45.56 ± 20.62 nm within the TME. This remarkable size change fosters an impressive uptake of approximately 100% by MDA-MB-231 cells within just 30 min, thereby greatly improving drug delivery efficiency. This size switchability enables passive targeting through the enhanced permeability and retention (EPR) effect, facilitating deep penetration into tumors. The NPs also demonstrate improved pH/redox-triggered drug release (∼70% at 24 h) within the TME and exhibit no toxicity in cell viability test. The cell cycle results of treated cells with docetaxel (DTX)-loaded NPs revealed G2/M (84.6 ± 1.16%) arrest. The DTX-loaded NPs showed more apoptosis (62.6 ± 3.7%) than the free DTX (51.8 ± 3.2%) in treated cells. The western blot and RT-PCR assays revealed that apoptotic genes and proteins expression of treated cells were significantly upregulated with the DTX-loaded NPs vs. the free DTX (Pvalue<.001). In conclusion, these findings suggest that this novel-engineered NPs holds promise as a TME-targeted NDDS.

A self-assembled copper-artemisinin nanoprodrug as an efficient reactive oxygen species amplified cascade system for cancer treatment

Chemodynamic therapy (CDT) is a tumor-specific intervention methodology, which is based on the upregulation of reactive oxygen species (ROS) content by triggering the Fenton or Fenton-like reaction within the tumor microenvironment (TME). However, there are still challenges in achieving high-efficiency CDT on account of both the limited intracellular hydrogen peroxide (H2O2) and delivery efficiency of Fenton metal ions. Copper-based nanotherapeutic systems have attracted extensive attention and have been widely applied in the construction of nanotherapeutic systems and multimodal synergistic therapy. Herein, we propose a strategy to synergize chemotherapy drugs that upregulate intracellular ROS content with chemodynamic therapy and construct an artemisinin-copper nanoprodrug for proof-of-concept. With the proposed biomimetic self-assembly strategy, we successfully construct an injectable nanoprodrug with suitable size distribution and high drug loading content (68.1 wt%) through the self-assembly of amphiphilic artemisinin prodrug and copper ions. After reaching the TME, both Cu2+ ions and free AH drugs can be released from AHCu nanoprodrugs. Subsequently, the disassembled Cu2+ ions are converted into Cu+ ions by consuming the intracellular GSH. The generated Cu+ ions serve as a highly efficient Fenton-like reagent for robust ROS generation from both AH and tumor-over-produced H2O2. Results show that the nanoprodrug can realize the cascade amplification of ROS generation via artemisinin delivery and subsequent in situ Fenton-like reaction and a high tumor inhibition rate of 62.48% in vivo. This work provides a promising strategy for the design and development of an efficient nanoprodrug for tumor-specific treatment.

Manganese-enriched prussian blue nanohybrids with smaller electrode potential and lower charge transfer resistance to enhance combination therapy

Prussian blue (PB) is authenticated in clinical treatment, while it generally exhibits unfavorable chemodynamic therapy (CDT) performance. Herein, we developed manganese-doped prussian blue (PBM) nanoparticles to significantly enhance both CDT and photothermal therapy (PTT) effect. The lower redox potential of Mn3+/2+ (0.088 V) in PBM against that of Fe2+/3+ (0.192 V) in PB leads to favorable electron transfer of PBM with respect to PB. Besides, PBM has a lower charge-transfer resistance (Rct) of 2.98 Ω than 4.83 Ω of PB. Once PBM entering the tumor microenvironment (TME), Mn3+ may be readily reduced by glutathione (GSH) and therein to enhance intracellular oxidative stress. Meanwhile, the superoxide dismutase (SOD)-like activity of PBM facilitates the conversion of endogenous superoxide (O2•-) into H2O2. Mn2+ subsequently catalyzes H2O2 to generate toxic hydroxyl radicals (•OH). Notably, the PBM plus laser irradiation can effectively trigger a robust immunogenic cell death (ICD) due to the combination therapy of CDT and PTT. Additionally, the mice treated by PBM followed by laser irradiation efficiently avoided splenomegaly and lung metastasis, along with significant up-regulation of the Stimulator of Interferon Genes (STING) expression. Overall, PBM significantly inhibits tumor growth and metastasis, making it a promising multifunctional nanoplatform for cancer treatment.

A copper missile-triggered power coalescence and death vortex within tumor cell mitochondria for synergistic cuproptosis/phototherapy/chemotherapy

The importance of copper homeostasis in mitochondria and copper-triggered modality of mitochondrial cell death have been confirmed. However, the existing copper-based nanoplatforms are focused on synergistic therapies while the intracellular therapeutic targets are relatively scattered. Effective integration of all targets within mitochondria to generate power coalescence remains a challenge. Herein, we developed a novel copper-based delivery system to trigger power coalescence and death vortex within tumor cell mitochondria. Specifically, a mitochondrial targeting "copper missile" loaded with curcumin (termed as Cur@CuS-TPP-HA, CCTH) was designed for cuproptosis/phototherapy/chemotherapy synergistic anti-tumor therapy. Once the CCTH NPs are shuttled to the mitochondria, near-infrared (NIR) irradiation initiates the release of copper ions and curcumin for in situ drug accumulation in cancer cell mitochondria. An excess of copper ions and curcumin can activate cuproptosis and mitochondrial apoptosis pathways, respectively. When combined, they can cause an increase in reactive oxygen species (ROS), damage to mitochondrial DNA (mt-DNA), and a decrease in energy supply, thereby leading to a "vicious circle" of mitochondrial damage that further enhances the tumor-killing efficacy. As a consequence, this "copper missile" exhibits advanced anti-tumor effects as verified through in vitro assessments and in vivo evaluations using the 4T1 breast tumor model, providing a promising approach for cuproptosis-based synergistic anti-tumor therapy.

Platelet Membrane Coated Cu9S8-SNAP for Targeting NIR-II Mild Photothermal Enhanced Chemodynamic/Gas Therapy of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a highly aggressive and uncommon subtype of breast cancer with a poor prognosis. It is crucial to prioritise the creation of a nanotherapeutic method that is highly selective and actively targeting TNBC. This study explores a new nanosystem, Cu9S8-SNAP@PM (C-S@P), composed of Cu9S8-SNAP coated with a platelet membrane (PM). The purpose of this nanosystem is to cure TNBC using multimodal therapy. The utilisation of PM-coated nanoparticles (NPs) enables active targeting, leading to the efficient accumulation of C-S@P within the tumour. The Cu9S8 component within these NPs serves the potential to exert photothermal therapy (PTT) and chemodynamic therapy (CDT). Simultaneously, the S-Nitroso-N-Acetylvanicillamine (SNAP) component enables nitric oxide (NO) gas therapy (GT). Furthermore, when exposed to NIR-II laser light, Cu9S8 not only increases the temperature of the tumour area for PTT, but also boosts CDT and stimulates the release of NO through thermal reactions to improve the effectiveness of GT. Both in vitro and in vivo experimental results validate that C-S@P exhibits minimal side effects and represents a multifunctional nano-drug targeted at tumors for efficient treatment. This approach promises significant potential for TNBC therapy and broader applications in oncology.

Serum copper assessment in patients with polycystic ovary syndrome and tubal infertility: A retrospective 5-year study

The association between serum copper and polycystic ovary syndrome (PCOS) lacks definitive conclusions, and the intricate interactions with in vitro fertilization (IVF) cycle characteristics in infertility remain insufficiently explored. This retrospective study included 560 patients with tubal infertility (no-PCOS) and 266 patients with PCOS undergoing IVF at the Affiliated Suzhou Hospital of Nanjing Medical University from January 2018 to December 2022. Patients' basic characteristics, hormonal and metabolic parameters, essential trace elements, and IVF cycle characteristics were measured and analyzed. The results revealed a significantly elevated serum copper level in the PCOS group compared to the control group [17.27 (15.54, 19.67) vs 15.4 (13.87, 17.35), μmol/L; p < .001]. Spearman correlation analyses revealed a significant positive correlation between serum copper concentration and body mass index (BMI), fasting glucose (FG), triglyceride (TG), total cholesterol (TC), and low-density lipoprotein (LDL) in the no-PCOS group. Additionally, a notable negative correlation with high-density lipoprotein (HDL) was observed (r = -.184, p < .001). Within the PCOS group, serum copper concentration correlated significantly with BMI (r = .198, p = .004) and TG (r = .214, p = .002). The linear trend analysis indicated no significant relationship between serum copper concentration and ovarian response as well as preimplantation outcomes in both groups after adjusting for confounding factors. Our study provided evidence of elevated serum copper concentration in PCOS patients, closely associated with lipid metabolism but showing no correlation with IVF outcomes. These findings provide valuable real-world data, enriching our nuanced understanding of the role of copper in female fertility.

A Copper Silicate-Based Multifunctional Nanoplatform with Glutathione Depletion and Hypoxia Relief for Synergistic Photodynamic/Chemodynamic Therapy

Chemodynamic therapy (CDT) alone cannot achieve sufficient therapeutic effects due to the excessive glutathione (GSH) and hypoxia in the tumor microenvironment (TME). Developing a novel strategy to improve efficiency is urgently needed. Herein, we prepared a copper silicate nanoplatform (CSNP) derived from colloidal silica. The Cu(II) in CSNP can be reduced to Cu(I), which cascades to induce a subsequent CDT process. Additionally, benefiting from GSH depletion and oxygen (O2) generation under 660 nm laser irradiation, CSNP exhibits both Fenton-like and hypoxia-alleviating activities, contributing to the effective generation of superoxide anion radical (•O2-) and hydroxyl radical (•OH) in the TME. Furthermore, given the suitable band-gap characteristic and excellent photochemical properties, CSNP can also serve as an efficient type-I photosensitizer for photodynamic therapy (PDT). The synergistic CDT/PDT activity of CSNP presents an efficient antitumor effect and biosecurity in both in vitro and in vivo experiments. The development of an all-in-one nanoplatform that integrates Fenton-like and photosensing properties could improve ROS production within tumors. This study highlights the potential of silicate nanomaterials in cancer treatment.

Fe-based cyclically catalyzing double free radical nanogenerator for tumor-targeted chemodynamic therapy

The prosperity of chemodynamic therapy provides a new strategy for tumor treatment. However, the lack of reactive oxygen species and the specific reductive tumor microenvironment have limited the further development of chemodynamic therapy. Herein, we reported a Fe-based cyclically catalyzing double free radical system for tumor therapy by catalyzing exogenous potassium persulfate (K2S2O8) and endogenous hydrogen peroxide (H2O2). Sufficient amounts of Fe3+ and S2O82- were delivered to tumor sites via tumor-targeted hyaluronic acid (HA) encapsulated mesoporous silica nanoparticles (MSNs) and released under the dual stimulation of acid and hyaluronidase (HAase) in the tumor microenvironment. Fe3+ was reduced to Fe2+ by the reducing agents of loaded tannic acid (TA) and intracellular glutathione (GSH), and Fe2+ was subsequently reacted with S2O82- and endogenous H2O2 to produce two types of ROS (˙OH and SO4-˙), showing an excellent anti-tumor effect. This process not only supplied Fe2+ for the catalysis of active substances, but also reduced the concentration of reduced substances in cells, which was conducive to the existence of free radicals for the efficient killing of tumor cells. Therefore, this iron-based catalysis of exogenous and exogenous active substances to realize a dual-radical oncotherapy nanosystem would provide a new perspective for chemodynamic therapy.

Nanomedicine-induced cell pyroptosis to enhance antitumor immunotherapy

Immunotherapy is a therapeutic modality designed to elicit or augment an immune response against malignancies. Despite the immune system's ability to detect and eradicate neoplastic cells, certain neoplastic cells can elude immune surveillance and elimination through diverse mechanisms. Therefore, antitumor immunotherapy has emerged as a propitious strategy. Pyroptosis, a type of programmed cell death (PCD) regulated by Gasdermin (GSDM), is associated with cytomembrane rupture due to continuous cell expansion, which results in the release of cellular contents that can trigger robust inflammatory and immune responses. The field of nanomedicine has made promising progress, enabling the application of nanotechnology to enhance the effectiveness and specificity of cancer therapy by potentiating, enabling, or augmenting pyroptosis. In this review, we comprehensively examine the paradigms underlying antitumor immunity, particularly paradigms related to nanotherapeutics combined with pyroptosis; these treatments include chemotherapy (CT), hyperthermia therapy, photodynamic therapy (PDT), chemodynamic therapy (CDT), ion-interference therapy (IIT), biomimetic therapy, and combination therapy. Furthermore, we thoroughly discuss the coordinated mechanisms that regulate these paradigms. This review is expected to enhance the understanding of the interplay between pyroptosis and antitumor immunotherapy, broaden the utilization of diverse nanomaterials in pyroptosis-based antitumor immunotherapy, and facilitate advancements in clinical tumor therapy.

Osteosarcoma-targeted Cu and Ce based oxide nanoplatform for NIR II fluorescence/magnetic resonance dual-mode imaging and ros cascade amplification along with immunotherapy

BACKGROUND

As the lethal bone tumor, osteosarcoma often frequently occurs in children and adolescents with locally destructive and high metastasis. Distinctive kinds of nanoplatform with high therapeutical effect and precise diagnosis for osteosarcoma are urgently required. Multimodal optical imaging and programmed treatment, including synergistic photothermal-chemodynamic therapy (PTT-CDT) elicits immunogenetic cell death (ICD) is a promising strategy that possesses high bio-imaging sensitivity for accurate osteosarcoma delineating as well as appreciable therapeutic efficacy with ignorable side-effects.

METHODS AND RESULTS

In this study, mesoporous Cu and Ce based oxide nanoplatform with Arg-Gly-Asp (RGD) anchoring is designed and successfully constructed. After loading with indocyanine green, this nanoplatform can be utilized for precisely targeting and efficaciously ablating against osteosarcoma via PTT boosted CDT and the closely following ICD stimulation both in vitro and in vivo. Besides, it provides off-peak fluorescence bio-imaging in the second window of near-infrared region (NIR II, 1000-1700 nm) and Magnetic resonance signal, serves as the dual-mode contrast agents for osteosarcoma tissue discrimination.

CONCLUSION

Tumor targeted Cu&Ce based mesoporous nanoplatform permits efficient osteosarcoma suppression and dual-mode bio-imaging that opens new possibility for effectively diagnosing and inhibiting the clinical malignant osteosarcoma.

Remote Manipulation of TRPV1 Signaling by Near-Infrared Light-Triggered Nitric Oxide Nanogenerators for Specific Cancer Therapy

Specific activation of transient receptor potential vanilloid member 1 (TRPV1) channels provides a new avenue for cancer treatment by inducing excessive Ca2+ influx. However, controllable manipulation of TRPV1 signaling for clinical application has remained elusive due to the challenge in finding a mild and effective method of exerting external stimulus without adverse side effects in living systems. Herein, a TRPV1-targeting near-infrared (NIR) triggered nitric oxide (NO)-releasing nanoplatform (HCuS@PDA-TRPV1/BNN6) based on polydopamine (PDA) coated hollow copper sulfide nanoparticles (HCuS NPs) is developed for specific cancer therapy. Upon NIR irradiation, the NO donor BNN6 encapsulated in NIR-responsive nanovehicles can locally generate NO to activate TRPV1 channels and induce Ca2+ influx. This NIR controlled mode enables the nanoplatform to exert its therapeutic effects below the apoptotic threshold temperature (43°C), minimizing the photothermal damage to normal tissue. Integrating this special NO-mediated therapy with HCuS NPs mediated chemodynamic therapy, the designed nanoplatform exhibits a boosted anticancer activity with negligible systematic toxicity. Together, this study provides a promising strategy for site-specific cancer therapy by spatiotemporally controlled activation of surface ion channels, thus offering a solution to an unmet clinical need in cancer treatment.

pH-Responsive Hyaluronic Acid Nanomicelles for Photodynamic /Chemodynamic Synergistic Therapy Trigger Immunogenicity and Oxygenation

Cancer metastasis and invasion are closely related to tumor cell immunosuppression and intracellular hypoxia. Activation of immunogenicity and intracellular oxygenation are effective strategies for cancer treatment. In this study, multifunctional nanomicelle hyaluronic acid and cinnamaldehyde is self-assembled into nanomicelles (HPCNPs) were constructed for immunotherapy and tumor cell oxygenation. The Schiff base was constructed of HPCNPs with pyropheophorbide a-Cu (PPa-Cu). HPCNPs are concentrated in tumor sites under the guidance of CD44 proteins, and under the stimulation of tumor environment (weakly acidic), the Schiff base is destroyed to release free PPa. HPCNPs with photodynamic therapeutic functions and chemokinetic therapeutic functions produce a large number of reactive oxygen species (1O2 and •OH) under exogenous (laser) and endogenous (H2O2) stimulations, causing cell damage, and then inducing immunogenic cell death (ICD). ICD markers (CRT and ATP) and immunoactivity markers (IL-2 and CD8) were characterized by immunofluorescence. Downregulation of Arg1 protein proved that the tumor microenvironment changed from immunosuppressive type (M2) to antitumor type (M1). The oxidation of glutathione by HPCNP cascades to amplify the concentration of reactive oxygen species. In situ oxygenation by HPCNPs based on a Fenton-like reaction improves the intracellular oxygen level. In vitro and in vivo experiments demonstrated that HPCNPs combined with an immune checkpoint blocker (α-PD-L1) effectively ablated primary tumors, effectively inhibited the growth of distal tumors, and increased the oxygen level in tumor cells.

Construction of a Cuproptosis-Related Gene Signature for Predicting Prognosis in Gastric Cancer

This study aimed to develop and validate a cuproptosis-related gene signature for the prognosis of gastric cancer. The data in TCGA GC TPM format from UCSC were extracted for analysis, and GC samples were randomly divided into training and validation groups. Pearson correlation analysis was used to obtain cuproptosis-related genes co-expressed with 19 Cuproptosis genes. Univariate Cox and Lasso regression analyses were used to obtain cuproptosis-related prognostic genes. Multivariate Cox regression analysis was used to construct the final prognostic risk model. The risk score curve, Kaplan-Meier survival curves, and ROC curve were used to evaluate the predictive ability of Cox risk model. Finally, the functional annotation of the risk model was obtained through enrichment analysis. Then, a six-gene signature was identified in the training cohort and verified among all cohorts using Cox regression analyses and Kaplan-Meier plots, demonstrating its independent prognostic significance for gastric cancer. In addition, ROC analysis confirmed the significant predictive potential of this signature for the prognosis of gastric cancer. Functional enrichment analysis was mainly related to cell-matrix function. Therefore, a new cuproptosis-related six-gene signature (ACLY, FGD6, SERPINE1, SPATA13, RANGAP1, and ADGRE5) was constructed for the prognosis of gastric cancer, allowing for tailored prediction of outcome and the formulation of novel therapeutics for gastric cancer patients.

The Tao of Copper Metabolism: From Physiology to Pathology

As a transitional metal, copper plays a crucial role in maintaining the normal physiological activities of mammals. The intracellular copper concentration is meticulously regulated to maintain extremely low levels through homeostatic regulation. Excessive accumulation of free copper in cells can have deleterious effects, as observed in conditions such as Wilson's disease. Moreover, data accumulated over the past few decades have revealed a crucial role of copper imbalance in tumorigenesis, progression and metastasis. Recently, cuproptosis, also known as copper-induced cell death, has been proposed as a novel form of cell death. This discovery offers new prospects for treating copperrelated diseases and provides a promising avenue for developing copper-responsive therapies, particularly in cancer treatment. We present a comprehensive overview of the Yin- Yang equilibrium in copper metabolism, particularly emphasising its pathophysiological alterations and their relevance to copper-related diseases and malignancies.

Multifunctional mesoporous silica nanoparticles for biomedical applications

Mesoporous silica nanoparticles (MSNs) are recognized as a prime example of nanotechnology applied in the biomedical field, due to their easily tunable structure and composition, diverse surface functionalization properties, and excellent biocompatibility. Over the past two decades, researchers have developed a wide variety of MSNs-based nanoplatforms through careful design and controlled preparation techniques, demonstrating their adaptability to various biomedical application scenarios. With the continuous breakthroughs of MSNs in the fields of biosensing, disease diagnosis and treatment, tissue engineering, etc., MSNs are gradually moving from basic research to clinical trials. In this review, we provide a detailed summary of MSNs in the biomedical field, beginning with a comprehensive overview of their development history. We then discuss the types of MSNs-based nanostructured architectures, as well as the classification of MSNs-based nanocomposites according to the elements existed in various inorganic functional components. Subsequently, we summarize the primary purposes of surface-functionalized modifications of MSNs. In the following, we discuss the biomedical applications of MSNs, and highlight the MSNs-based targeted therapeutic modalities currently developed. Given the importance of clinical translation, we also summarize the progress of MSNs in clinical trials. Finally, we take a perspective on the future direction and remaining challenges of MSNs in the biomedical field.

Iron and copper: critical executioners of ferroptosis, cuproptosis and other forms of cell death

Regulated cell death (RCD) is a regulable cell death that involves well-organized signaling cascades and molecular mechanisms. RCD is implicated in fundamental processes such as organ production and tissue remodeling, removing superfluous structures or cells, and regulating cell numbers. Previous studies have not been able to reveal the complete mechanisms, and novel methods of RCD are constantly being proposed. Two metal ions, iron (Fe) and copper (Cu) are essential factors leading to RCDs that not only induce ferroptosis and cuproptosis, respectively but also lead to cell impairment and eventually diverse cell death. This review summarizes the direct and indirect mechanisms by which Fe and Cu impede cell growth and the various forms of RCD mediated by these two metals. Moreover, we aimed to delineate the interrelationships between these RCDs with the distinct pathways of ferroptosis and cuproptosis, shedding light on the complex and intricate mechanisms that govern cellular survival and death. Finally, the prospects outlined in this review suggest a novel approach for investigating cell death, which may involve integrating current therapeutic strategies and offer a promising solution to overcome drug resistance in certain diseases. Video Abstract.

Strategies to engineer various nanocarrier-based hybrid catalysts for enhanced chemodynamic cancer therapy

Chemodynamic therapy (CDT) is a newly developed cancer-therapeutic modality that kills cancer cells by the highly toxic hydroxyl radical (˙OH) generated from the in situ triggered Fenton/Fenton-like reactions in an acidic and H2O2-overproduced tumor microenvironment (TME). By taking the advantage of the TME-activated catalytic reaction, CDT enables a highly specific and minimally-invasive cancer treatment without external energy input, whose efficiency mainly depends on the reactant concentrations of both the catalytic ions and H2O2, and the reaction conditions (including pH, temperature, and amount of glutathione). Unfortunately, it suffers from unsatisfactory therapy efficiency for clinical application because of the limited activators (i.e., mild acid pH and insufficient H2O2 content) and overexpressed reducing substance in TME. Currently, various synergistic strategies have been elaborately developed to increase the CDT efficiency by regulating the TME, enhancing the catalytic efficiency of catalysts, or combining with other therapeutic modalities. To realize these strategies, the construction of diverse nanocarriers to deliver Fenton catalysts and cooperatively therapeutic agents to tumors is the key prerequisite, which is now being studied but has not been thoroughly summarized. In particular, nanocarriers that can not only serve as carriers but are also active themselves for therapy are recently attracting increasing attention because of their less risk of toxicity and metabolic burden compared to nanocarriers without therapeutic capabilities. These therapy-active nanocarriers well meet the requirements of an ideal therapy system with maximum multifunctionality but minimal components. From this new perspective, in this review, we comprehensively summarize the very recent research progress on nanocarrier-based systems for enhanced CDT and the strategies of how to integrate various Fenton agents into the nanocarriers, with particular focus on the studies of therapy-active nanocarriers for the construction of CDT catalysts, aiming to guide the design of nanosystems with less components and more functionalities for enhanced CDT. Finally, the challenges and prospects of such a burgeoning cancer-theranostic modality are outlooked to provide inspirations for the further development and clinical translation of CDT.

Aptamer and DNAzyme-Functionalized Cu-MOF Hybrid Nanozymes for the Monitoring and Management of Bacteria-Infected Wounds

Metal-organic frameworks (MOFs) with peroxidase (POD)-like activity have great potential for combating drug-resistant bacterial infections. However, the use of POD-like activities is severely limited by low oxygen levels and high levels of glutathione (GSH) within the microenvironment of bacterial infection. Herein, G-quadruplex/hemin DNAzyme-aptamer probes and tannic acid-chelated Au nanoparticle (Au-TA)-decorated Cu-based MOF nanosheets (termed GATC) with triple-enzyme activities were developed for visual detection and efficient antibacterial therapy. First, the monometallic MOFs (Cu-ZIF) showed the best catalytic and loading capacity performance compared with the bimetallic MOFs (CoCu-ZIF and ZnCu-ZIF). Then, Cu-MOFs, Au-TA, and DNAzyme improve the POD-like activity to generate more hydroxyl radicals (•OH) to kill bacteria. GATC can bind to bacteria through aptamer recognition, increasing the bacterial surface contact area for efficient antibacterial activity. GATC can decompose H2O2 into O2 to alleviate hypoxia and improve the microenvironment due to its catalase (CAT)-like activity. In addition, GATC exhibited GSH peroxidase-like activity, which can avoid the loss of •OH and result in bacterial death more easily. Compared with previous studies, GATC exhibited extraordinary bactericidal ability at an extremely low dosage of 3 μg/mL against methicillin-resistant Staphylococcus aureus (MRSA). Notably, the GATC-catalyzed chromogenic reaction could accurately monitor the MRSA infection treatment process. Overall, this work could establish a therapeutic platform for the monitoring and management of bacteria-infected wounds.

A metal ions-mediated natural small molecules carrier-free injectable hydrogel achieving laser-mediated photo-Fenton-like anticancer therapy by synergy apoptosis/cuproptosis/anti-inflammation

Tumor microenvironment (TME) plays an important role in the tumorigenesis, proliferation, invasion and metastasis. Thereby developing synergistic anticancer strategies with multiple mechanisms are urgent. Copper is widely used in the treatment of tumor chemodynamic therapy (CDT) due to its excellent laser-mediated photo-Fenton-like reaction. Additionally, copper can induce cell death through cuproptosis, which is a new modality different from the known death mechanisms and has great promise in tumor treatment. Herein, we report a natural small molecules carrier-free injectable hydrogel (NCTD Gel) consisted of Cu²⁺-mediated self-assembled glycyrrhizic acid (GA) and norcantharidin (NCTD), which are mainly governed by coordination and hydrogen bonds. Under 808 nm laser irradiation, NCTD Gel can produce reactive oxygen species (ROS), consume glutathione (GSH) and overcome hypoxia in TME, leading to synergistically regulate TME via apoptosis, cuproptosis and anti-inflammation. In addition, NCTD Gel's CDT display high selectivity and good biocompatibility as it relies on the weak acidity and H₂O₂ overexpression of TME. Notably, NCTD Gel's components are originated from clinical agents and its preparation process is easy, green and economical, without any excipients. This study provides a new carrier-free hydrogel synergistic antitumor strategy, which has a good prospect in industrial production and clinical transformation.

Advance Progress in Assembly Mechanisms of Carrier-Free Nanodrugs for Cancer Treatment

Nanocarriers have been widely studied and applied in the field of cancer treatment. However, conventional nanocarriers still suffer from complicated preparation processes, low drug loading, and potential toxicity of carriers themselves. To tackle the hindrance, carrier-free nanodrugs with biological activity have received increasing attention in cancer therapy. Extensive efforts have been made to exploit new self-assembly methods and mechanisms to expand the scope of carrier-free nanodrugs with enhanced therapeutic performance. In this review, we summarize the advanced progress and applications of carrier-free nanodrugs based on different types of assembly mechanisms and strategies, which involved noncovalent interactions, a combination of covalent bonds and noncovalent interactions, and metal ions-coordinated self-assembly. These carrier-free nanodrugs are introduced in detail according to their assembly and antitumor applications. Finally, the prospects and existing challenges of carrier-free nanodrugs in future development and clinical application are discussed. We hope that this comprehensive review will provide new insights into the rational design of more effective carrier-free nanodrug systems and advancing clinical cancer and other diseases (e.g., bacterial infections) infection treatment.

Drug-loaded hybrid hydrogels for sonodynamic-chemodyanmic therapy and tumor metastasis suppression

Introduction: Although various therapies have been adopted to treat cancer, metastasis of tumor cells still is a big challenge that compromises therapeutic benefits. Methods: We herein report an injectable drug-loaded hybrid hydrogel that can achieve sonodynamic therapy (SDT) and chemodyanmic therapy (CDT) combined action and suppression of tumor metastasis. This alginate (ALG)-based hydrogel (termed as AMPS) contains manganese dioxide (MnO2) nanoparticles as the CDT agents, an organic polymer as the sonosensitizer, and a SIS3 drug as metastasis inhibitor. Results: AMPS is formed via the chelation of ALG by Ca2+ in tumor microenvironment, in which MnO2 nanoparticles mediate CDT via Fenton-like reaction and the organic polymers enable SDT under ultrasound (US) irradiation by generating singlet oxygen (1O2), allowing for combinational action of CDT and SDT. In addition, SIS3 is released from AMPS hydrogels to inhibit the metastasis of tumor cells. As such, the AMPS enables a combinational action of SDT and CDT to greatly inhibit the growths of subcutaneous tumors in living mice and also completely suppress the tumor metastasis in lungs and livers. Conclusion: This study thus offers a hybrid hydrogel platform for combinational therapy and metastasis suppression simultaneously.

Multifaceted Roles of Copper Ions in Anticancer Nanomedicine

The significantly increased copper level in tumor tissues and serum indicates the close association of copper ions with tumor development, making copper ions attractive targets in the development of novel tumor treatment methods. The advanced nanotechnology developed in the past decades provides great potential for tumor therapy, among which Cu-based nanotherapeutic systems have received greater attention. Herein, the multifaceted roles of copper ions in cancer progression are summarized and the recent advances in the copper-based nanostructures or nanomedicines for different kinds of tumor therapies including copper depletion therapy, copper-based cytotoxins, copper-ion-based chemodynamic therapy and its combination with other treatments, and copper-ion-induced ferroptosis and cuproptosis activation are discussed. Furthermore, the perspectives for the further development of copper-ion-based nanomedicines for tumor therapy and clinic translation are presented by the authors.

Inorganic nanoparticle agents for enhanced chemodynamic therapy of tumours

With the recent interest in the role of oxidative species/radicals in diseases, inorganic nanomaterials with redox activities have been extensively investigated for their potential use in nanomedicine. While many studies focusing on relieving oxidative stress to prevent pathogenesis and to suppress the progression of diseases have shown considerable success, another approach for increasing oxidative stress using nanomaterials to kill malignant cells has suffered from low efficiency despite its wide applicability to various targets. Chemodynamic therapy (CDT) is an emerging technique that can resolve such a problem by exploiting the characteristic tumour microenvironment to achieve high selectivity. In this review, we summarize the recent strategies and underlying mechanisms that have been used to improve the CDT performance using inorganic nanoparticles. In addition to the design of CDT agents, the effects of contributing factors, such as the acidity and the levels of hydrogen peroxide and antioxidants in the tumour microenvironment, together with their modulation and application in combination therapy, are presented. The challenges lying ahead of future clinical translation of this rapidly advancing technology are also discussed.

Tumor-Associated Macrophages Regulating a Polymer Nanoplatform for Synergistic Treatment of Breast Tumors

Tumor-associated macrophages (TAMs) play a critical role in tumor progression and metastasis. Modulation of TAM polarization is one of the most effective strategies to change the immunosuppressive tumor microenvironment (TME). In this study, organic polymer nanoparticles (CPHT) were prepared using hyaluronic acid (HA)-conjugated disulfide-bonded polyethylene imide (PEIS) as a carrier through a self-assembly strategy. These nanoparticles were modified by transferrin (Tf) and loaded with chlorin e6 (Ce6). The results showed that CPHT had good dispersion with a particle size of about 30 nm. CPHT gradually disintegrated under the exposure with a high concentration of glutathione (GSH) in tumor cells, proving the possibility for the controlled release of Ce6 and photodynamic therapy. An in vitro test showed that the uptake of CPHT in tumor cells was mediated by both HA and Tf, indicating the active tumor-targeting capacity of CPHT. CPHT significantly downregulated the ratio of CD206/CD86 and triggered the upregulation of immune factors such as TNF-α and iNOS, suggesting the repolarization of TAMs. We also found that CPHT effectively induced ferroptosis in tumor cells through lipid peroxide accumulation, GSH depletion, and downregulation of lipid peroxidase (GPX4) expression. Animal experiments confirmed that CPHT not only effectively inhibited the growth of tumors in situ but also significantly decelerated the growth of the distal tumor. Elevated levels of CD86 and IFN-γ and decreased expression of CD206 were observed at the tumor sites post CPHT treatment. These results confirmed the value of CPHT as a multifunctional nanoplatform that can tune the TME and provide new hope for tumor treatment.

Activating Nanomedicines with Electromagnetic Energy for Deep-Tissue Induction of Immunogenic Cell Death in Cancer Immunotherapy

Immunotherapy is an attractive approach for cancer therapy, while its antitumor efficacy is still limited, especially for non-immunogenic tumors. Nanomedicines can be utilized to convert the non-immunogenic "cold" tumors to immunogenic "hot" tumors via inducing immunogenic cell death (ICD), thereby promoting the antitumor immune response. Some nanomedicines that can produce local heat and reactive oxygen species upon the stimulation of electromagnetic energy are the main candidates for inducing the ICD effect. However, their applications are often restricted due to the poor tissue penetration depths of electromagnetic energy, such as light. By contrast, ultrasound, X-ray, alternating magnetic field, and microwave show excellent tissue penetration depths and thereby can be used for sonodynamic therapy, radiotherapy, magnetic hyperthermia therapy, and microwave ablation therapy, all of which can effectively induce ICD. Herein, the combination of deep-tissue electromagnetic energy with nanomedicines for inducing ICD and cancer immunotherapy are summarized. In particular, the designs of nanomedicines to amplify ICD effect in the presence of deep-tissue electromagnetic energy and sensitize tumors to various immunotherapies will be discussed. At the end of this review, a brief conclusion and discussion of current challenges and further perspectives in this subfield are provided.

Synergistic ferroptosis-starvation therapy for bladder cancer based on hyaluronic acid modified metal-organic frameworks

Bladder cancer (BCa) is one of the most common malignancies of the urinary tract. Metastasis and recurrence of BCa are the leading causes of poor prognosis, and only a few patients can benefit from current first-line treatments such as chemotherapy and immunotherapy. It is urgent to develop more effective therapeutic method with low side effects. Here, a cascade nanoreactor, ZIF-8/PdCuAu/GOx@HA (ZPG@H), is proposed for starvation therapy and ferroptosis of BCa. The ZPG@H nanoreactor was constructed by co-encapsulation of PdCuAu nanoparticles and glucose oxidase into zeolitic imidazolate framework-8 (ZIF-8) modified by hyaluronic acid. The vitro results indicated that ZPG@H enhanced intracellular reactive oxygen species levels and reduced mitochondrial depolarization in the tumor microenvironment. Therefore, the integrated advantages of starvation therapy and chemodynamic therapy endow ZPG@H with a perfect ferroptosis inducing ability. This effectiveness, combined with its excellent biocompatibility and biosafety, means that ZPG@H could make a critical contribution to the development of novel BCa treatments.

Metal-rich cascade nanosystem for dual-pathway ferroptosis resistance regulation and photothermal effect for efficient tumor combination therapy

Despite the therapeutic response of ferroptosis in various tumors, ferroptosis resistance has been found in numerous studies, significantly hindering the progress of ferroptosis anti-tumor therapy. Herein, we propose a metal-rich cascade nanosystem (Simvastatin-HMPB-Mn@GOx) combined with the dual-pathway regulation of ferroptosis resistance and photothermal therapy for efficient tumor combination therapy. The manganese-bonded hollow mesoporous Prussian blue (HMPB-Mn) serves as the photothermal agent and metal donor, and dissociates multivalent metal ions Mn²⁺, Fe³⁺ and Fe²⁺ to consume glutathione and amplify the Fenton reaction. Glucose oxidase (GOx) absorbed serves as the converter to provide hydrogen peroxide (H₂O₂) for the cascade Fenton reaction, causing a high burst of hydroxyl radicals (˙OH) and lipid peroxidation. Simvastatin innovatively acts as a 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) inhibitor to decrease the expression of coenzyme Q10 (CoQ10) and glutathione peroxidase 4 (GPX4), eventually defeating ferroptosis resistance. The nanosystem acted in both classical and non-classical ferroptosis pathways and showed significant ferroptosis- and hyperthermia-induced anti-tumor efficacy both in vitro and in vivo. Thus, this study offers a promising way for ferroptosis and phototherapy to achieve complete tumor regression.

Optimization of PVDF-TrFE Based Electro-Conductive Nanofibers: Morphology and In Vitro Response

In this study, morphology and in vitro response of electroconductive composite nanofibers were explored for biomedical use. The composite nanofibers were prepared by blending the piezoelectric polymer poly(vinylidene fluoride-trifluorethylene) (PVDF-TrFE) and electroconductive materials with different physical and chemical properties such as copper oxide (CuO), poly(3-hexylthiophene) (P3HT), copper phthalocyanine (CuPc), and methylene blue (MB) resulting in unique combinations of electrical conductivity, biocompatibility, and other desirable properties. Morphological investigation via SEM analysis has remarked some differences in fiber size as a function of the electroconductive phase used, with a reduction of fiber diameters for the composite fibers of 12.43% for CuO, 32.87% for CuPc, 36.46% for P3HT, and 63% for MB. This effect is related to the peculiar electroconductive behavior of fibers: measurements of electrical properties showed the highest ability to transport charges of methylene blue, in accordance with the lowest fibers diameters, while P3HT poorly conducts in air but improves charge transfer during the fiber formation. In vitro assays showed a tunable response of fibers in terms of viability, underlining a preferential interaction of fibroblast cells to P3HT-loaded fibers that can be considered the most suitable for use in biomedical applications. These results provide valuable information for future studies to be addressed at optimizing the properties of composite nanofibers for potential applications in bioengineering and bioelectronics.

Ultrasound nanomedicine and materdicine

The conventional microbubble-based ultrasound biomedicine clinically plays a vital role in providing the dynamic detection of macro and microvasculature and disease theranostics. However, the intrinsic limitation of particle size severely decreases the treatment effectiveness due to their vascular transport characteristics, which promotes the development and application of multifunctional ultrasound-responsive nanomaterials. Herein, we put forward a research field of "ultrasound nanomedicine and materdicine", referring to the interdiscipline of ultrasound, nanobiotechnology and materials, which seeks to produce specific biological effects for addressing the challenges faced and dilemma of conventional ultrasound medicine. We comprehensively summarize the state-of-the-art scientific advances in the latest progress in constructing ultrasound-based platforms and ultrasound-activated sonosensitizers, ranging from the synthesis strategies, biological functions to ultrasound-triggered therapeutic applications. Ultimately, the unresolved challenges and clinical-translation potentials of ultrasound nanomedicine and materdicine are discussed and prospected in this evolving field.

Polydopamine nanoparticles coated with a metal-polyphenol network for enhanced photothermal/chemodynamic cancer combination therapy

Polydopamine nanoparticles (PDA NPs) are commonly used for photothermal therapy (PTT) of cancer because of their good biocompatibility and photothermal conversion capability. However, it is difficult to achieve a good tumor inhibition effect with a single PTT of PDA. Therefore, in this work, we prepared a combined anticancer nanosystem for enhanced chemodynamic therapy (CDT)/PTT by coating PDAs with an (-)-epigallocatechin gallate (EGCG)/iron (Fe) metal-polyphenol network (MPN). The MPN shell of this nanosystem named EGCG@PDA is degraded by the weakly acidic environment intracellular, releasing EGCG and Fe³⁺. EGCG inhibits the expression of heat shock proteins (HSPs) in cancer cells, thus eliminating their thermal protection against cancer cells for enhanced PTT. Meanwhile, the reductive EGCG can also reduce Fe³⁺ to Fe²⁺, to catalyze the decomposition of overexpressed hydrogen peroxide (H₂O₂) in cancer cells to generate strong oxidative hydroxyl radicals (OH), i.e., catalyzing the Fenton reaction, for CDT. After the Fenton reaction, the re-oxidized Fe ions can be reduced again by EGCG and reused to catalyze the Fenton reaction, which can achieve enhanced CDT. Both in vitro and in vivo studies have shown that EGCG@PDA has low dark toxicity and good anticancer effects. It is expected to be used for precision cancer therapy.

Cupric-ion-promoted fabrication of oxygen-replenishing nanotherapeutics for synergistic chemo and photodynamic therapy against tumor hypoxia

Mixing a glutathione (GSH)-responsive carboxy zinc(II) phthalocyanine (ZnPc*) and CuSO₄·5H₂O in water with or without the presence of the anticancer drug SN38 resulted in the formation of self-assembled nanotherapeutics labeled as ZnPc*/Cu/SN38@NP and ZnPc*/Cu@NP, respectively. The Cu²⁺ ions not only promoted the self-assembly of the carboxy phthalocyanine through metal complexation, but also catalyzed the transformation of H₂O₂ to oxygen via a catalase-like reaction, rendering an oxygen-replenishing property to the nanosystems. Both nanosystems exhibited high stability in aqueous media, but the nanoparticles disassembled gradually in an acidic or GSH-enriched environment and inside human colorectal adenocarcinoma HT29 cells, releasing the encapsulated therapeutic components. The disassembly process together with the activation by the intracellular GSH led to relaxation of the intrinsic quenching of the nanophotosensitizers and restoration of the photoactivities of ZnPc*. Under a hypoxic condition, ZnPc*/Cu/SN38@NP could attenuate the intracellular hypoxia level and maintain the photodynamic activity due to its Cu²⁺-promoted oxygen-replenishing ability. The photodynamic effect of ZnPc* and the anticancer effect of SN38 worked cooperatively, causing substantial apoptotic cell death. The dual therapeutic actions could also effectively inhibit the tumor growth in HT29 tumor-bearing nude mice without initiating notable adverse effects to the mice. STATEMENT OF SIGNIFICANCE: The oxygen-dependent nature of photodynamic therapy generally reduces its efficacy against tumor hypoxia, which is a common characteristic of advanced solid tumors and usually leads to resistance toward various anticancer therapies. We report herein a facile approach to assemble a glutathione-responsive carboxy phthalocyanine-based photosensitizer and an anticancer drug in aqueous media, in which Cu(II) ions were used to promote the self-assembly through metal complexation and catalyze the conversion of H₂O₂ to oxygen through a catalase-like reaction, making the resulting nanoparticles possessing an oxygen-replenishing property that could promote the photodynamic effect against hypoxic cancer cells and tumors. The use of Cu(II) ions to achieve the aforementioned dual functions in the fabrication of advanced nano-photosensitizing systems has not been reported.

Metal-polyphenol nanodots loaded hollow MnO2 nanoparticles with a "dynamic protection" property for enhanced cancer chemodynamic therapy

Chemodynamic therapy (CDT) is a novel cancer therapeutic strategy. However, barriers such as high glutathione (GSH) concentration and low concentration of metal ions intracellular reduce its treatment effect. In this work, a nanosystem named GA-Fe@HMDN-PEI-PEG with a "dynamic protection" property was reported for enhanced cancer CDT. Mesoporous hollow manganese dioxide (MnO₂) nanoparticle (HMDN) was prepared to load gallic acid-ferrous (GA-Fe) nanodots fabricated from gallic acid (GA) and ferrous ion (Fe²⁺). Then the pores of HMDN were blocked by polyethyleneimine (PEI), which was then grafted with methoxy poly(ethylene glycol) (mPEG) through a pH-sensitive benzoic imine bond. mPEG could protect the nanoparticles (NPs) against the nonspecific uptake by normal cells and enhance their accumulation in the tumor. However, in the slightly acidic tumor microenvironment, hydrolysis of benzoic imine led to DePEGylation to reveal PEI for enhanced uptake by cancer cells. The reaction between HMDN and GSH could consume GSH and obtain manganese ion (Mn²⁺) for the Fenton-like reaction for CDT. GA-Fe nanodots could also offer Fe for the Fenton reaction, and reductive GA could reduce the high-valence ions to low-valence for reusing in Fenton and Fenton-like reactions. These properties allowed GA-Fe@HMDN-PEI-PEG for precise medicine with a high utilization rate and common side effects.

3-Bromopyruvate-Loaded Ti3C2 MXene/Cu2O Nanosheets for Photoacoustic Imaging-Guided and Hypoxia-Relieving Enhanced Photothermal/Chemodynamic Therapy

Chemodynamic therapy (CDT) is an innovative and effective treatment that relies on the Fenton or Fenton-like reaction, in which endogenous H₂O₂ overproduction is converted into cytotoxic hydroxyl radicals (^•OH) to suppress tumor growth. Nevertheless, the therapeutic efficiency of CDT is severely restricted by undesirable properties, such as reaction conditions and catalyst performance. Herein, a 2D Ti₃C₂ MXene/Cu₂O nanosheet (MCP NS)-based multifunctional nanoplatform (3-BP@MCG NSs) has been constructed, in which glucose oxidase (GOx) and respiration inhibitor 3-bromopyruvate (3-BP) are sequentially embedded. In this structure, the copper-based catalyst Cu₂O releases Cu⁺ in an acid-triggered manner in the tumor microenvironment (TME), which activates the Fenton-like reaction to catalyze the generation of ^•OH for CDT. The composite has excellent photothermal properties and a high-resolution photoacoustic imaging (PAI) capability in the near-infrared (NIR) region, and especially under NIR irradiation, the photothermal effect generated by the nanosheets accelerates catalysis. GOx is a natural enzyme catalyst for depleting glucose and oxygen content in cells, upregulating H₂O₂ levels in situ, and thereby improving the therapeutic effect of CDT. What is more, the supported 3-BP not only reduces oxygen consumption to alleviate hypoxia levels but also inhibits the glycolysis process and lowers ATP levels by suppressing hexokinase activity. As a result, 3-BP@MCG NSs optimize the unique properties of MCP NSs, GOx, and 3-BP via mutual promotion, realizing self-enhanced PTT/CDT synergistic therapy. This work establishes an emerging strategy for highly efficient PAI-guided integrated treatment and provides a proof of concept for the cooperation of hypoxia relief and in situ H₂O₂ and NIR synergistic enhancement to improve therapeutic efficiency.

A Novel Biodegradable Nanoplatform for Tumor Microenvironments Responsive Bimodal Magnetic Resonance Imaging and Sonodynamic/Ion Interference Cascade Therapy

The unsatisfactory therapeutic effect and long-term adverse effect markedly prevent inorganic nanomaterials from clinical transformation. In light of this, we developed a novel biodegradable theranostic agent (MnCO₃:Ho³⁺@DOX/Ca₃(PO₄)₂@BSA, HMCDB) based on the sonosensitizer manganese carbonate (MnCO₃) coating with calcium phosphate (Ca₃(PO₄)₂) and simultaneously loaded it with the chemotherapeutic drug doxorubicin (DOX). Due to the mild acidity of the tumor microenvironment (TME), the Ca₃(PO₄)₂ shell degraded first, releasing substantial quantities of calcium ions (Ca²⁺) and DOX. Meanwhile, with the ultrasound (US) irradiation, MnCO₃ produced enough reactive oxygen species (ROS) to cause oxidative stress in the cells, resulting in accumulation of Ca²⁺. Consequently, the cascade effect significantly amplified the therapeutic effect. Importantly, the nanocomposite can be completely degraded and cleared from the body, demonstrating that it was a promising theranostic agent for tumor therapy. Furthermore, the doped holmium ions (Ho³⁺) and in situ generation of manganese ions (Mn²⁺) in TME endow the nanoagent with the ability for tumor-specific bimodality T₁/T₂-weighted magnetic resonance imaging (MRI). This novel nanoplatform with low toxicity and biodegradability holds great potential for cancer diagnosis and treatment.

Core-Coordinated Elliptic Polymer Nanoparticles Loading Copper(II) and Chlorambucil for Cooperative Chemodynamic/Chemotherapy

Chemodynamic therapy (CDT) reflects an innovative cancer treatment modality; however, to enhance its relatively low therapeutic efficiency, rational combination with extra therapeutic modes is highly appreciated. Here, core-coordinated amphiphilic, elliptic polymer nanoparticles (Cu/CBL-POEGEA NPs) are constructed via the self-assembly of a glutathione (GSH)-responsive polymer-drug conjugate, bearing side-chain acylthiourea (ATU) motifs which behave as ligands capable of coordinating Cu(II), such a design is featured by combined chemo (CT)/CDT with dual GSH depletion collectively triggered by the Cu(II) reduction reaction and disulfide bond breakage. To do so, an amphiphilic random copolymer poly[oligo(ethylene glycol)ethyl acrylate-co-thiourea] [P(OEGEA-co-ATU)] is synthesized, followed by conjugation of chlorambucil (CBL) to ATU motifs linked via a disulfide bond, thus yielding the targeted P[OEGEA-co-(ATU-g-CBL)]. In such a system, hydrophilic POEGEA serves as the biocompatible section and ATU motifs coordinate Cu(II), resulting in core-coordinated elliptic Cu/CBL-POEGEA NPs. Benefitting from the GSH-induced reduction reaction, Cu(II) is converted into Cu(I) and subsequently react with endogenous H₂O₂ to create ^•OH, realizing GSH-depletion-promoted CDT. Additionally, the disulfide bond endows GSH-responsive CBL release and provokes further GSH decline, finally realizing combined CDT/CT toward enhancing antitumor outcomes, and in vitro as well as in vivo studies indeed reveal remarkable efficacy. Such a system can provide valuable advantages to create novel nanomedicines toward cascade antitumor therapy.

Recent advances in near-infrared-II hollow nanoplatforms for photothermal-based cancer treatment

Near-infrared-II (NIR-II, 1000–1700 nm) light-triggered photothermal therapy (PTT) has been regarded as a promising candidate for cancer treatment, but PTT alone often fails to achieve satisfactory curative outcomes. Hollow nanoplatforms prove to be attractive in the biomedical field owing to the merits including good biocompatibility, intrinsic physical-chemical nature and unique hollow structures, etc. On one hand, hollow nanoplatforms themselves can be NIR-II photothermal agents (PTAs), the cavities of which are able to carry diverse therapeutic units to realize multi-modal therapies. On the other hand, NIR-II PTAs are capable of decorating on the surface to combine with the functions of components encapsulated inside the hollow nanoplatforms for synergistic cancer treatment. Notably, PTAs generally can serve as good photoacoustic imaging (PAI) contrast agents (CAs), which means such kind of hollow nanoplatforms are also expected to be multifunctional all-in-one nanotheranostics. In this review, the recent advances of NIR-II hollow nanoplatforms for single-modal PTT, dual-modal PTT/photodynamic therapy (PDT), PTT/chemotherapy, PTT/catalytic therapy and PTT/gas therapy as well as multi-modal PTT/chemodynamic therapy (CDT)/chemotherapy, PTT/chemo/gene therapy and PTT/PDT/CDT/starvation therapy (ST)/immunotherapy are summarized for the first time. Before these, the typical synthetic strategies for hollow structures are presented, and lastly, potential challenges and perspectives related to these novel paradigms for future research and clinical translation are discussed.

Multifunctional nanotheranostics for near infrared optical imaging-guided treatment of brain tumors

Malignant brain tumors, a heterogeneous group of primary and metastatic neoplasms in the central nervous system (CNS), are notorious for their highly invasive and devastating characteristics, dismal prognosis and low survival rate. Recently, near-infrared (NIR) optical imaging modalities including fluorescence imaging (FLI) and photoacoustic imaging (PAI) have displayed bright prospect in innovation of brain tumor diagnoses, due to their merits, like noninvasiveness, high spatiotemporal resolution, good sensitivity and large penetration depth. Importantly, these imaging techniques have been widely used to vividly guide diverse brain tumor therapies in a real-time manner with high accuracy and efficiency. Herein, we provide a systematic summary of the state-of-the-art NIR contrast agents (CAs) for brain tumors single-modal imaging (e.g., FLI and PAI), dual-modal imaging (e.g., FLI/PAI, FLI/magnetic resonance imaging (MRI) and PAI/MRI) and triple-modal imaging (e.g., MRI/FLI/PAI and MRI/PAI/computed tomography (CT) imaging). In addition, we update the most recent progress on the NIR optical imaging-guided therapies, like single-modal (e.g., photothermal therapy (PTT), chemotherapy, surgery, photodynamic therapy (PDT), gene therapy and gas therapy), dual-modal (e.g., PTT/chemotherapy, PTT/surgery, PTT/PDT, PDT/chemotherapy, PTT/chemodynamic therapy (CDT) and PTT/gene therapy) and triple-modal (e.g., PTT/PDT/chemotherapy, PTT/PDT/surgery, PTT/PDT/gene therapy and PTT/gene/chemotherapy). Finally, we discuss the opportunities and challenges of the CAs and nanotheranostics for future clinic translation.

MOF-coated upconversion nanoconstructs for synergetic photo-chemodynamic/oxygen-elevated photodynamic therapy

Excessive production of intracellular reactive oxygen species (ROS) can induce apoptosis of cancer cells; however, it is often limited by severe triggering conditions and hypoxic microenvironments of solid tumors. To address these issues, herein, we have designed a MOF-coated upconversion nanoconstruct (UCTSCF, referring to UC@Ce6/TFS@mSiO₂@MIL-100(Cu/Fe)) for synergetic photochemodynamic therapy (PCT)/oxygen-elevated photodynamic therapy (PDT). The MOF (MIL-100(Fe)) coating with Cu-doping was designed to catalyze H₂O₂ overexpression in cancer cells to generate the most cytotoxic ˙OH via chemodynamic therapy (CDT). It is noted that UC, representing 808 nm driven upconversion nanoparticles with high tissue penetration depth/low over-heating effects, was designed to provide intense blue light which can relieve the severe triggering conditions of CDT via PCT. Furthermore, the functional layer of the photosensitizer chlorin e6 (Ce6) and O₂-carrying triethoxy(1H,1H,2H,2H-nonafluorohexyl)silane (TFS) co-doped mesoporous silicon (Ce6/TFS@mSiO₂) can cause oxygen-elevated ¹O₂ production upon 671 nm light irradiation. In such a simple ROS generation nanoplatform, we heighten the antitumor effect via oxygen-elevated synergetic tumor PCT/PDT.

New anti-cancer explorations based on metal ions

Due to the urgent demand for more anti-cancer methods, the new applications of metal ions in cancer have attracted increasing attention. Especially the three kinds of the new mode of cell death, including ferroptosis, calcicoptosis, and cuproptosis, are of great concern. Meanwhile, many metal ions have been found to induce cell death through different approaches, such as interfering with osmotic pressure, triggering biocatalysis, activating immune pathways, and generating the prooxidant effect. Therefore, varieties of new strategies based on the above approaches have been studied and applied for anti-cancer applications. Moreover, many contrast agents based on metal ions have gradually become the core components of the bioimaging technologies, such as MRI, CT, and fluorescence imaging, which exhibit guiding significance for cancer diagnosis. Besides, the new nano-theranostic platforms based on metal ions have experimentally shown efficient response to endogenous and exogenous stimuli, which realizes simultaneous cancer therapy and diagnosis through a more controlled nano-system. However, most metal-based agents have still been in the early stages, and controlled clinical trials are necessary to confirm or not the current expectations. This article will focus on these new explorations based on metal ions, hoping to provide some theoretical support for more anti-cancer ideas.

Drug-Induced Self-Assembly Cascade Nanoreactor for Synergistic Tumor Therapy

The construction of completely biocompatible and biodegradable tumor suppressors by a simple and reliable method is essential for the clinical application of cancer-targeted drugs. Herein, by inserting glucose oxidase (GOx), catalase (CAT), and chlorin e6 (Ce6) into human serum albumin (HSA) assembly molecules, we constructed a cancer-targeted cascade bioreactor for synergistic starvation and photodynamic therapy (PDT). The modification of HSA could block the GOx activity and reduce the cytotoxicity of normal cells and organs. Through active targeting and passive enhanced permeability and retention effect, the loading of AS1411 could promote the cascade bioreactors to effectively target nucleolin-overexpressed tumors. Once internalized by cancer cells, as a result of catalyzing hydrogen peroxide (H₂O₂) to produce oxygen (O₂), the protein nano-cascade reactor promoted microenvironmental oxygenation, which would subsequently lead to an increase in cytotoxic singlet oxygen (¹O₂) production under light irradiation as well as the decomposition of intracellular glucose. In vitro and in vivo studies showed that the cascaded nanoreactors could significantly enhance therapeutic efficacy through synergistic starvation therapy and enhanced PDT as well as chemotherapy. This cascade strategy will be demonstrated in clinical applications with huge potential.

Nanotechnology Advances in the Detection and Treatment of Cancer: An Overview

Over the last few years, progress has been made across the nanomedicine landscape, in particular, the invention of contemporary nanostructures for cancer diagnosis and overcoming complexities in the clinical treatment of cancerous tissues. Thanks to their small diameter and large surface-to-volume proportions, nanomaterials have special physicochemical properties that empower them to bind, absorb and transport high-efficiency substances, such as small molecular drugs, DNA, proteins, RNAs, and probes. They also have excellent durability, high carrier potential, the ability to integrate both hydrophobic and hydrophilic compounds, and compatibility with various transport routes, making them especially appealing over a wide range of oncology fields. This is also due to their configurable scale, structure, and surface properties. This review paper discusses how nanostructures can function as therapeutic vectors to enhance the therapeutic value of molecules; how nanomaterials can be used as medicinal products in gene therapy, photodynamics, and thermal treatment; and finally, the application of nanomaterials in the form of molecular imaging agents to diagnose and map tumor growth.

Metal-based nano-delivery platform for treating bone disease and regeneration

Owing to their excellent characteristics, such as large specific surface area, favorable biosafety, and versatile application, nanomaterials have attracted significant attention in biomedical applications. Among them, metal-based nanomaterials containing various metal elements exhibit significant bone tissue regeneration potential, unique antibacterial properties, and advanced drug delivery functions, thus becoming crucial development platforms for bone tissue engineering and drug therapy for orthopedic diseases. Herein, metal-based drug-loaded nanomaterial platforms are classified and introduced, and the achievable drug-loading methods are comprehensively generalized. Furthermore, their applications in bone tissue engineering, osteoarthritis, orthopedic implant infection, bone tumor, and joint lubrication are reviewed in detail. Finally, the merits and demerits of the current metal-based drug-loaded nanomaterial platforms are critically discussed, and the challenges faced to realize their future applications are summarized.

Copper-based nanomaterials for cancer theranostics

Copper-based nanomaterials (Cu-based NMs) with favorable biocompatibility and unique properties have attracted the attention of many biomedical researchers. Cu-based NMs are one of the most widely studied materials in cancer treatment. In recent years, great progress has been made in the field of biomedicine, especially in the treatment and diagnosis of tumors. This review begins with the classification of Cu-based NMs and the recent synthetic strategies of Cu-based NMs. Then, according to the abundant and special properties of Cu-based NMs, their application in biomedicine is summarized in detail. For biomedical imaging, such as photoacoustic imaging, positron emission tomography imaging, and multimodal imaging based on Cu-based NMs are summarized, as well as strategies to improve the diagnostic effectiveness. Moreover, a series of unique structures and functions as well as the underlying property activity relationship of Cu-based NMs were shown to highlight their promising therapeutic performance. Cu-based NMs have been widely used in monotherapies, such as photothermal therapy (PTT) and chemodynamic therapy (CDT). Moreover, the sophisticated design in composition, structure, and surface fabrication of Cu-based NMs can endow these NMs with more modalities in cancer diagnosis and therapy. To further improve the efficiency of cancer treatment, combined therapy based on Cu-based NMs was introduced in detail. Finally, the challenges, critical factors, and future prospects for the clinical translation of Cu-based NMs as multifunctional theranostic agents were also considered and discussed. The aim of this review is to provide a better understanding and key consideration for the rational design of this increasingly important new paradigm of Cu-based NMs as theranostic agents. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Diagnostic Tools > In Vivo Nanodiagnostics and Imaging.

Multifunctional nanosystems sequentially regulating intratumor Fenton chemistry by remodeling the tumor microenvironment to reinforce chemodynamic therapy

The particularity of the tumor microenvironment (TME) significantly limits the efficiency of chemodynamic therapy (CDT). Although various measures have been taken to improve the efficiency of CDT, how to organically integrate them into one nanosystem to achieve efficient synergy for CDT according to predetermined procedures is still an urgent problem to be solved. This work reported a multifunctional nanosystem, TP_I@PP_CAI, which comprised the inner triphenylphosphine modified D-α-Tocopheryl polyethylene glycol 1000 succinate (TPGS-PPh₃) micelles loading iron-oxide nanoparticles (IONs), and the outer poly (dopamine-co-protocatechuic acid) (PDA-PA, PP) coating modified with carbonic anhydrase IX inhibitor (CAI). TP_I@PP_CAI remodeled TME by sequential function adjustment to make it suitable for the efficient Fenton reactions: CAI first inhibited the overexpressed CA IX to result in intracellular acidification, which combined with near-infrared light (NIR) irradiation to accelerate the PP coating degradation, thereby promoting the exposure and disintegration of the inner micellar structure to release TPGS-PPh₃ and IONs. The TPGS-PPh₃ further elevated the intracellular ROS basal level by targeting and interfering with the mitochondrial function. Therefore, the TME was transformed into an acidic microenvironment with high ROS levels, which vigorously promoted the Fenton reaction mediated by IONs with the aid of photothermal effect induced by PP coating via NIR irradiation, ultimately earning high-efficiency CDT on xenograft MDA-MB-231 tumor-bearing mice. This study improved the efficiency of Fenton reaction in biological systems through the practical design of nanostructures and provided a novel thought for ROS-mediated therapy.

Copper-based metal-organic frameworks for biomedical applications

Metal-organic frameworks (MOFs) are a class of important porous, crystalline materials composed of metal ions (clusters) and organic ligands. Owing to the unique redox chemistry, photochemical and electrical property, and catalytic activity of Cu^2+/+, copper-based MOFs (Cu-MOFs) have been recently and extensively explored in various biomedical fields. In this review, we first make a brief introduction to the synthesis of Cu-MOFs and their composites, and highlight the recent synthetic strategies of two most studied representatives, three-dimensional HKUST-1 and two-dimensional Cu-TCPP. The recent advances of Cu-MOFs in the applications of cancer treatment, bacterial inhibition, biosensing, biocatalysis, and wound healing are summarized and discussed. Furthermore, we propose a prospect of the future development of Cu-MOFs in biomedical fields and beyond.