Carbon-dot-supported atomically dispersed gold as a mitochondrial oxidative stress amplifier for cancer treatment

Potential Efficacy of Herbal Medicine-Derived Carbon Dots in the Treatment of Diseases: From Mechanism to Clinic

Carbon dots (CDs), a crucial component of nanomaterials, are zero-dimensional nanomaterials with carbon as the backbone structure and smaller than 10 nm. Due to their beneficial characteristics, they are widely used in biomedical fields such as biosensors, drug delivery, bio-imaging, and interactions with DNA. Interestingly, a novel type of carbon dot, generated by using herbal medicines as synthetic raw materials, has emerged as the most recent incomer in the family of CDs with the extensive growth in the number of materials selected for carbon dots synthesis. Herbal medicine-derived carbon dots (HM-CDs) have been employed in the biomedical industry, and are rapidly emerging as "modern nanomaterials" due to their unique structures and exceptional capabilities. Emerging trends suggest that their specific properties can be used in bleeding disorders, gastrointestinal disorders, inflammation-related diseases, and other common intractable diseases including cancer, menopausal syndrome, central nervous system disorders, and pain of various forms and causes. In addition, HM-CDs have been found to have organ-protective and antioxidant properties, as evidenced by extensive studies. This research provides a more comprehensive understanding of the biomedical applications of HM-CDs for the aforementioned disorders and investigates the intrinsic pharmacological activities and mechanisms of these HM-CDs to further advance their clinical applications.

A nanocomposite competent to overcome cascade drug resistance in ovarian cancer via mitochondria dysfunction and NO gas synergistic therapy

Ovarian cancer (OC) is one of the most common and recurring malignancies in gynecology. Patients with relapsed OC always develop "cascade drug resistance" (CDR) under repeated chemotherapy, leading to subsequent failure of chemotherapy. To overcome this challenge, amphiphiles (P1) carrying a nitric oxide (NO) donor (Isosorbide 5-mononitrate, ISMN) and high-density disulfide are synthesized for encapsulating mitochondria-targeted tetravalent platinum prodrug (TPt) to construct a nanocomposite (INP@TPt). Mechanism studies indicated that INP@TPt significantly inhibited drug-resistant cells by increasing cellular uptake and mitochondrial accumulation of platinum, depleting glutathione, and preventing apoptosis escape through generating highly toxic peroxynitrite anion (ONOO-). To better replicate the microenvironmental and histological characteristics of the drug resistant primary tumor, an OC patient-derived tumor xenograft (PDXOC) model in BALB/c nude mice was established. INP@TPt showed the best therapeutic effects in the PDXOC model. The corresponding tumor tissues contained high ONOO- levels, which were attributed to the simultaneous release of O2•- and NO in tumor tissues. Taken together, INP@TPt-based systematic strategy showed considerable potential and satisfactory biocompatibility in overcoming platinum CDR, providing practical applications for ovarian therapy.

Confining Prepared Ultrasmall Nanozymes Loading ATO for Lung Cancer Catalytic Therapy/Immunotherapy

Nanozymes with inherent enzyme-mimicking catalytic properties combat malignant tumor progression via catalytic therapy, while the therapeutic efficacy still needs to be improved. In this work, ultrasmall platinum nanozymes (nPt) in a confined domain of a wormlike pore channel in gold nanobipyramidal-mesoporous silica dioxide nanocomposites, producing nanozyme carriers AP-mSi with photoenhanced peroxidase ability, are innovatively synthesized. Afterward, based on the prepared AP-mSi, a lung-cancer nanozymes probe (AP-HAI) is ingeniously produced by removing the SiO2 template, modifying human serum albumin, and loading atovaquone molecules (ATO) as well as IR780. Under NIR light irradiation, inner AuP and IR780 collaborate for photothermal process, thus facilitating the peroxidase-like catalytic process of H2 O2 . Additionally, loaded ATO, a cell respiration inhibitor, can impair tumor respiration metabolism and cause oxygen retention, hence enhancing IR780's photodynamic therapy (PDT) effectiveness. As a result, IR780's PDT and nPt nanozymes' photoenhanced peroxidase-like ability endow probes a high ROS productivity, eliciting antitumor immune responses to destroy tumor tissue. Systematic studies reveal that the obvious reactive oxygen species (ROS) generation is obtained by the strategy of using nPt nanozymes and reducing oxygen consumption by ATO, which in turn enables lung-cancer synergetic catalytic therapy/immunogenic-cell-death-based immunotherapy. The results of this work would provide theoretical justification for the practical use of photoenhanced nanozyme probes.

Polyphenolic Carbon Quantum Dots with Intrinsic Reactive Oxygen Species Amplification for Two-Photon Bioimaging and In Vivo Tumor Therapy

Recent studies indicate that mitochondrial dysfunctions and DNA damage have a critical influence on cell survival, which is considered one of the therapeutic targets for cancer therapy. In this study, we demonstrated a comparative study of the effect of polyphenolic carbon quantum dots (CQDs) on in vitro and in vivo antitumor efficacy. Dual emissive (green and yellow) shape specific polyphenolic CQDs (G-CQDs and Y-CQDs) were synthesized from easily available nontoxic precursors (phloroglucinol), and the antitumor property of the as-synthesized probe was investigated as compared to round-shaped blue emissive CQDs (B-CQDs) derived from well-reported precursor citric acid and urea. The B-CQDs had a nuclei-targeting property, and G-CQDs and Y-CQDs had mitochondria-targeting properties. We have found that the polyphenol containing CQDs (at a dose of 100 μg mL-1) specifically attack mitochondria by excess accumulation, altering the metabolism, inhibiting branching pattern, imbalanced Bax/Bcl-2 homeostasis, and ultimately generating oxidative stress levels, leading to oxidative stress-induced cell death in cancer cells in vitro. We show that G-CQDs are the main cause of oxidative stress in cancer cells because of their ability to produce sufficient •OH- and 1O2 radicals, evidenced by electron paramagnetic resonance spectroscopy and a terephthalic acid test. Moreover, the near-infrared absorption properties of the CQDs were exhibited in two-photon (TP) emission, which was utilized for TP cellular imaging of cancer cells without photobleaching. The in vivo antitumor test further discloses that intratumoral injection of G-CQDs can significantly augment the treatment efficacy of subcutaneous tumors without any adverse effects on BalB/c nude mice. We believe that shape-specific polyphenolic CQD-based nanotheranostic agents have a potential role in tumor therapy, thus proving an insight on treatment of malignant cancers.

NIR-II femtosecond laser ignites MXene as photoacoustic bomb for continuous high-precision tumor blasting

Recently, photoacoustic (PA) cavitation-mediated therapy has become the focus of research owing to its advantage of inhibiting drug or radiation resistance; however, its application is limited because it relies on nanodroplets with one-time action. Herein, we demonstrate a femtosecond-laser-pumped ultrafast PA cavitation technique for highly efficient shockwave theranostics using niobium carbide (Nb2C) coated with polyvinylpyrrolidone-40000 (PVP), producing sustainable PA cavitation with non-phase-change nanoprobes, which effectively gets rid of the dependence on nanodroplets, guaranteeing multiple treatments. Under femtosecond (fs) laser irradiation, given that the thermal confinement regime could be well satisfied, the Nb2C-PVP nanosheets (NSs) were quickly heated, forming localized overheated nanospots with the temperature exceeding the phase-transition threshold of the surroundings, leading to precise cavitation and explosion at the tumor sites. The experiments at the cellular level showed the significant anti-tumor effects of this method. Notably, the mouse model experiments showed a relative tumor volume inhibition rate of more than 90%, demonstrating the high precision and good efficacy of the proposed anti-tumor method. This method provides a sustainable and highly effective strategy for PA theranostics, indicating its great potential for clinical applications.

Cu2+ -Anchored Carbon Nano-Photocatalysts for Visible Water Splitting to Boost Hydrogen Cuproptosis

Both hydrogen (H2 ) and copper ions (Cu+ ) can be used as anti-cancer treatments. However, the continuous generation of H2 molecules and Cu+ in specific sites of tumors is challenging. Here we anchored Cu2+ on carbon photocatalyst (Cu@CDCN) to allow the continuous generation of H2 and hydrogen peroxide (H2 O2 ) in tumors using the two-electron process of visible water splitting. The photocatalytic process also generated redox-active Cu-carbon centers. Meanwhile, the Cu2+ residues reacted with H2 O2 (the obstacle to the photocatalytic process) to accelerate the two-electron process of water splitting and cuprous ion (Cu+ ) generation, in which the Cu2+ residue promoted a pro-oxidant effect with glutathione through metal-reducing actions. Both H2 and Cu+ induced mitochondrial dysfunction and intracellular redox homeostasis destruction, which enabled hydrogen therapy and cuproptosis to inhibit cancer cell growth and suppress tumor growth. Our research is the first attempt to integrate hydrogen therapy and cuproptosis using metal-enhanced visible solar water splitting in nanomedicine, which may provide a safe and effective cancer treatment.

Single-atom catalysts-based catalytic ROS clearance for efficient psoriasis treatment and relapse prevention via restoring ESR1

Psoriasis is a common inflammatory disease of especially high recurrence rate (90%) which is suffered by approximately 3% of the world population. The overexpression of reactive oxygen species (ROS) plays a critical role in psoriasis progress. Here we show that biomimetic iron single-atom catalysts (FeN4O2-SACs) with broad-spectrum ROS scavenging capability can be used for psoriasis treatment and relapse prevention via related gene restoration. FeN4O2-SACs demonstrate attractive multiple enzyme-mimicking activities based on atomically dispersed Fe active structures, which are analogous to those of natural antioxidant enzymes, iron superoxide dismutase, human erythrocyte catalase, and ascorbate peroxidase. Further, in vitro and in vivo experiments show that FeN4O2-SACs can effectively ameliorate psoriasis-like symptoms and prevent the relapse with augmented efficacy compared with the clinical drug calcipotriol. Mechanistically, estrogen receptor 1 (ESR1) is identified as the core protein upregulated in psoriasis treatment through RNA sequencing and bioinformatic analysis. Together, this study provides a proof of concept of psoriasis catalytic therapy (PCT) and multienzyme-inspired bionics (MIB).

Recastable assemblies of carbon dots into mechanically robust macroscopic materials

Assembly of nanoparticles into macroscopic materials with mechanical robustness, green processability, and recastable ability is an important and challenging task in materials science and nanotechnology. As an emerging nanoparticle with superior properties, macroscopic materials assembled from carbon dots will inherit their properties and further offer collective properties; however, macroscopic materials assembled from carbon dots solely remain unexplored. Here we report macroscopic films assembled from carbon dots modified by ureido pyrimidinone. These films show tunable fluorescence inherited from carbon dots. More importantly, these films exhibit collective properties including self-healing, re-castability, and superior mechanical properties, with Young's modulus over 490 MPa and breaking strength over 30 MPa. The macroscopic films maintain original mechanical properties after several cycles of recasting. Through scratch healing and welding experiments, these films show good self-healing properties under mild conditions. Moreover, the molecular dynamics simulation reveals that the interplay of interparticle and intraparticle hydrogen bonding controls mechanical properties of macroscopic films. Notably, these films are processed into diverse shapes by an eco-friendly hydrosetting method. The methodology and results in this work shed light on the exploration of functional macroscopic materials assembled from nanoparticles and will accelerate innovative developments of nanomaterials in practical applications.

Single-atom nanozymes: classification, regulation strategy, and safety concerns

Nanozymes, nanomaterials possessing enzymatic activity, have been studied extensively by researchers. However, their complex composition, low density of active sites, and inadequate substrate selectivity have hindered the maturation and widespread acceptance of nanozymes. Single-atom nanozymes (SAzymes) with atomically dispersed active sites are leading the field of catalysis due to their exceptional performance. The maximum utilization rate of atoms, low cost, well-defined coordination structure, and active sites are the most prominent advantages of SAzymes that researchers favor. This review systematically categorizes SAzymes based on their support type and describes their specific applications. Additionally, we discuss regulation strategies for SAzyme activity and provide a comprehensive summary of biosafety challenges associated with these enzymes.

Amplification of oxidative stress by lipid surface-coated single-atom Au nanozymes for oral cancer photodynamic therapy

Single-atom nanozymes (SANs) are the latest trend in biomaterials research and promote the application of single atoms in biological fields and the realization of protein catalysis in vivo with inorganic nanoparticles. Carbon quantum dots (CDs) have excellent biocompatibility and fluorescence properties as a substrate carrying a single atom. It is difficult to break through pure-phase single-atom materials with quantum dots as carriers. In addition, there is currently no related research in the single-atom field in the context of oral cancer, especially head and neck squamous cell carcinoma. This research developed a lipid surface-coated nanozyme combined with CDs, single-atomic gold, and modified lipid ligands (DSPE-PEG) with transferrin (Tf) to treat oral squamous cell carcinoma. The study results have demonstrated that surface-modified single-atom carbon quantum dots (m-SACDs) exhibit excellent therapeutic effects and enable in situ image tracking for diagnosing and treating head and neck squamous carcinoma (HNSCC).

Gd/hafnium oxide@gold@chitosan core-shell nanoparticles as a platform for multimodal theranostics in oncology research

In the current study, we synthesized thiolated chitosan-stabilized gold-coated, gadolinium-doped hafnium oxide nanoparticles (CAuGH NPs) with the capability of acting as a multifunctional system to deliver anticancer drug doxorubicin (DOX), to enhance radiosensitization by ROS generation, and to provide magnetic resonance (MR) imaging contrast for biomedical applications.

Reactive oxygen nanobiocatalysts: activity-mechanism disclosures, catalytic center evolutions, and changing states

Benefiting from low costs, structural diversities, tunable catalytic activities, feasible modifications, and high stability compared to the natural enzymes, reactive oxygen nanobiocatalysts (RONBCs) have become dominant materials in catalyzing and mediating reactive oxygen species (ROS) for diverse biomedical and biological applications. Decoding the catalytic mechanism and structure-reactivity relationship of RONBCs is critical to guide their future developments. Here, this timely review comprehensively summarizes the recent breakthroughs and future trends in creating and decoding RONBCs. First, the fundamental classification, activity, detection method, and reaction mechanism for biocatalytic ROS generation and elimination have been systematically disclosed. Then, the merits, modulation strategies, structure evolutions, and state-of-art characterisation techniques for designing RONBCs have been briefly outlined. Thereafter, we thoroughly discuss different RONBCs based on the reported major material species, including metal compounds, carbon nanostructures, and organic networks. In particular, we offer particular insights into the coordination microenvironments, bond interactions, reaction pathways, and performance comparisons to disclose the structure-reactivity relationships and mechanisms. In the end, the future challenge and perspectives for RONBCs are also carefully summarised. We envision that this review will provide a comprehensive understanding and guidance for designing ROS-catalytic materials and stimulate the wide utilisation of RONBCs in diverse biomedical and biological applications.

Burst of hopping trafficking correlated reversible dynamic interactions between lipid droplets and mitochondria under starvation

Dynamic membrane contacts between lipid droplets (LDs) and mitochondria play key roles in lipid metabolism and energy homeostasis. Understanding the dynamics of LDs under energy stimulation is thereby crucial to disclosing the metabolic mechanism. Here, the reversible interactions between LDs and mitochondria are tracked in real-time using a robust LDs-specific fluorescent probe (LDs-Tags). Through tracking the dynamics of LDs at the single-particle level, spatiotemporal heterogeneity is revealed. LDs in starved cells communicate and integrate their activities (i.e., lipid exchange) through a membrane contact site-mediated mechanism. Thus the diffusion is intermittently alternated between active and confined states. Statistical analysis shows that the translocation of LDs in response to starvation stress is non-Gaussian, and obeys nonergodic-like behavior. These results provide deep understanding of the anomalous diffusion of LDs in living cells, and also afford guidance for rationally designing efficient transporter.

Biological interactions of polystyrene nanoplastics: Their cytotoxic and immunotoxic effects on the hepatic and enteric systems

As emerging pollutants in the environment, nanoplastics (NPs) can cross biological barriers and be enriched in organisms, posing a greatest threat to the health of livestock and humans. However, the size-dependent toxic effects of NPs in higher mammals remain largely unknown. To determine the size-dependent potential toxicities of NPs, we exposed mouse (AML-12) and human (L02) liver cell lines in vitro, and 6-week-old C57BL/6 mice (well-known preclinical model) in vivo to five different sizes of polystyrene NPs (PS-NPs) (20, 50, 100, 200 and 500 nm). We found that ultra-small NPs (20 nm) induced the highest cytotoxicity in mouse and human liver cell lines, causing oxidative stress and mitochondrial membrane potential loss on AML-12 cells. Unexpectedly in vivo, after long-term oral exposure to PS-NPs (75 mg/kg), medium NPs (200 nm) and large NPs (500 nm) induced significant hepatotoxicity, evidenced by increased oxidative stress, liver dysfunction, and lipid metabolism disorders. Most importantly, medium or large NPs generated local immunotoxic effects via recruiting and activating more numbers of neutrophils and monocytes in the liver or intestine, which potentially resulted in increased proinflammatory cytokine secretion and the tissue damage. The discrepancy in in vitro-in vivo toxic results might be attributed to the different properties of biodistribution and tissue accumulation of different sized NPs in vivo. Our study provides new insights regarding the hepatotoxicity and immunotoxicity of NPs on human and livestock health, warranting us to take immense measures to prevent these NPs-associated health damage.

Low-Temperature Photothermal Therapy Platform Based on Pd Nanozyme-Modified Hydrogenated TiO2

In photothermal treatments (PTTs), normal tissues around cancerous tumors get injured by excessive heat, whereas damaged cancer cells are easily restored by stress-induced heat shock proteins (HSPs) at low temperatures. Therefore, to achieve a unique tumor microenvironment (TME), it is imperative to increase PTT efficiency and reduce normal tissue injury by adopting appropriate reactive oxygen species (ROS) and lipid peroxides (LPO) cross-linked with HSPs. In the present research, a potential strategy for mild photothermal treatments (mPTTs) was proposed by initiating localized catalytic chemical reactions in TME based on Pd nanozyme-modified hydrogenated TiO2 (H-TiO2@Pd). In vitro and in vivo evaluations demonstrated that H-TiO2@Pd had good peroxidase-like activities (POD), glutathione oxidase-like activities (GSHOx), and photodynamic properties and also satisfactory biocompatibility for 4T1 cells. Localized catalytic chemical reactions in H-TiO2@Pd significantly depleted GSH to downregulate the protein expression of GPX4 and promoted the accumulation of LPO and ROS, which consumed HSP70 or inhibited its function in 4T1 cells. Hence, the as-constructed low-temperature photothermal therapeutic platform based on Pd nanozyme-modified H-TiO2 can be a promising candidate to develop a safe and effective mPTT for cancer treatments.

Smart Nanoplatform for Visualizing Hydrogen Sulfide and Amplifying Oxidative Stress to Tumor Apoptosis

Oxidative stress is involved in various signaling pathways and serves a key role in inducing cell apoptosis. Therefore, it is significant to monitor oxidative stress upon drug release for the assessment of therapeutic effects in cancer cells. Herein, a glutathione (GSH)-responsive surface-enhanced Raman scattering (SERS) nanoplatform is proposed for ultra-sensitively monitoring the substance related with oxidative stress (hydrogen sulfide, H2S), depleting reactive sulfur species and releasing anticancer drugs to amplify oxidative stress for tumor apoptosis. The Au@Raman reporter@Ag (Au@M@Ag) nanoparticles, where a 4-mercaptobenzonitrile molecule as a Raman reporter was embedded between layers of gold and silver to obtain sensitive SERS response, were coated with a covalent organic framework (COF) shell to form a core-shell structure (Au@M@Ag@COFs) as the SERS nanoplatform. The COF shell loading doxorubicin (DOX) of Au@M@Ag@COFs exhibited the GSH-responsive degradation capacity to release DOX, and its Ag layer as the sensing agent was oxidized to Ag2S by H2S to result in its prominent changes in SERS signals with a low detection limit of 0.33 nM. Moreover, the releasing DOX can inhibit the generation of H2S to promote the production of reactive oxygen species, and the depletion of reactive sulfur species (GSH and H2S) in cancer cells can further enhance the oxidative stress to induce tumor apoptosis. Overall, the SERS strategy could provide a powerful tool to monitor the dynamic changes of oxidative stress during therapeutic processes in a tumor microenvironment.

Glutathione-sensitive mesoporous nanoparticles loaded with cinnamaldehyde for chemodynamic and immunological therapy of cancer

Chemodynamic therapy as a novel type of chemotherapy can damage the DNA structures and induce cell apoptosis and immunogenic cell death (ICD) through generating reactive oxygen species (ROS) to aggravate oxidative stress. Nonetheless, as an intrinsic antioxidative response of tumor cells, the expression of glutathione (GSH) can be upregulated to maintain the cellular redox balance and protect the tumor cells from ROS-mediated damage. In this context, it is feasible to simultaneously boost ROS generation and GSH depletion in tumor cells; however, the precise delivery and release of GSH scavengers at specific subcellular sites is of great importance. Herein, we propose a GSH-responsive mesoporous organosilica nanoparticle (MON)-based nanomedicine MON-CA-TPP@HA through sequentially covalently attaching triphenylphosphine (TPP) and electrostatically coating hyaluronic acid (HA) onto the surface of cinnamaldehyde (CA)-loaded MONs, known as MON-CA-TPP@HA, which has been demonstrated to be an extremely effective therapeutic strategy for cancer treatment through inducing ICD and apoptosis of breast cancer cells. Systematic in vitro experimental results clearly revealed that the nanomedicine can actively target the tumor cells with the help of HA, subsequently enter the tumor cells, and precisely bind with the mitochondria through TPP residues. Upon cleavaging the disulfide bond in the MONs triggered by over-expressed GSH within tumors, the CA molecules can be released inducing the excessive ROS in situ surrounding the mitochondria to activate oxidative stress to induce apoptosis and ICD of breast cancer cells. The results of the in vivo experiments confirm that the MON-CA-TPP@HA nanomedicine can effectively promote dendritic cell (DC) maturation and CD 8+ T cell activation and regulate the ratio of M1/M2 macrophages, which improve tumor immunosuppressive microenvironment. It is thus believed that the current nanomedicine has paved a new way for future cancer therapy.

Metal-Organic Frameworks@Au Nanoreactor as an Oxidative Stress Amplifier for Enhanced Tumor Photodynamic Therapy through the Alleviation of Hypoxemia and the Depletion of Glutathione

Recently, photodynamic therapy (PDT) based on the generation of cytotoxic reactive oxygen species (ROS) has drawn great attention in tumor treatment. However, the hypoxia tumor microenvironment (TME) inhibits the generation efficacy of ROS, and the high glutathione (GSH) level in TME could neutralize the generated ROS, both of which strongly reduce the therapeutic efficiency of PDT. In this work, we first constructed the porphyrinic metal-organic framework PCN-224. Then Au nanoparticles were decorated on the PCN-224 to obtain the PCN-224@Au. The decorated Au nanoparticles could not only produce O2 through the decomposition of H2O2 in tumor sites for enhancing the generation of 1O2 in PDT but also deplete glutathione through the strong interactions between Au and sulfhydryl groups on glutathione to weaken the antioxidant ability of tumor cells, thus amplifying the 1O2 damage to cancer cells. The in vitro and in vivo experiments totally exhibited that the as-prepared PCN-224@Au nanoreactor can be used as an oxidative stress amplifier for enhanced PDT, which provides a promising candidate to conquer the limitation of intratumor hypoxia and high GSH level on PDT of cancer.

GPX4 inhibition synergistically boosts mitochondria targeting nanoartemisinin-induced apoptosis/ferroptosis combination cancer therapy

Artemisinin, originally used for its antimalarial activity, has received much attention in recent years for cancer therapy. The anticancer mechanisms of artemisinin are complicated and debatable. Challenges in the delivery of artemisinin also persist because the anticancer effect of artemisinin alone is often not satisfactory when used with traditional nanocarriers. We herein report the mitochondrial delivery of artemisinin with extremely high anticancer capacity. The action mode of artemisinin in the mitochondria of cancer cells includes heme-participating and oxygen-independent conversion of artemisinin into a carbon-centered radical, which is partly converted into ROS in the presence of molecular oxygen. We reveal that artemisinin alone in the mitochondria can induce strong cancer cell apoptosis. In addition, due to the weak inhibition of GPX4 activity by artemisinin, weak ferroptosis is also observed. We further discover that GPX4 activity in MCF-7 cells is greatly inhibited by RSL3 to synergistically enhance the anticancer capacity of artemisinin via enhancing ferroptosis. The synergistic anticancer activity of artemisinin and RSL3 in the mitochondria not only improves cancer cell-killing ability, but also inhibits the re-proliferation of residual cancer cells. This study provides a new insight into developing highly efficient and practical artemisinin nanomedicines for cancer therapy.

Nanophotocatalysts in biomedicine: Cancer therapeutic, tissue engineering, biosensing, and drug delivery applications

Photocatalysis can be considered as a green technology owing to its excellent potential for sustainability and fulfilling several principles of green chemistry. This process uses light radiation as the primary energy source, preventing or reducing the requirement for artificial light sources and exogenous catalytic entities. Photocatalysis has promising applications in biomedicine such as drug delivery, biosensing, tissue engineering, cancer therapeutics, etc. In targeted cancer therapeutics, photocatalysis can be employed in photodynamic therapy to form reactive oxygen species that damage cancerous cells' structure. Nanophotocatalysts can be used in targeted drug delivery, showing potential applications in nuclear-targeted drug delivery along with specific delivery of chemotherapeutics to cancer cells or tumor sites. On the other hand, in tissue engineering, nanophotocatalysts can be employed in designing scaffolds that promote cell growth and tissue regeneration. However, some important challenges pertaining to the performance of photocatalysis, large-scale production of nanophotocatalysts, optimization of reaction/synthesis conditions, long-term biosafety issues, stability, clinical translation, etc. still need further explorations. Herein, the most recent advancements pertaining to the biomedical applications of nanophotocatalysts are reflected, focusing on drug delivery, tissue engineering, biosensing, and cancer therapeutic potentials.

Nanomedicine in cancer therapy

Cancer remains a highly lethal disease in the world. Currently, either conventional cancer therapies or modern immunotherapies are non-tumor-targeted therapeutic approaches that cannot accurately distinguish malignant cells from healthy ones, giving rise to multiple undesired side effects. Recent advances in nanotechnology, accompanied by our growing understanding of cancer biology and nano-bio interactions, have led to the development of a series of nanocarriers, which aim to improve the therapeutic efficacy while reducing off-target toxicity of the encapsulated anticancer agents through tumor tissue-, cell-, or organelle-specific targeting. However, the vast majority of nanocarriers do not possess hierarchical targeting capability, and their therapeutic indices are often compromised by either poor tumor accumulation, inefficient cellular internalization, or inaccurate subcellular localization. This Review outlines current and prospective strategies in the design of tumor tissue-, cell-, and organelle-targeted cancer nanomedicines, and highlights the latest progress in hierarchical targeting technologies that can dynamically integrate these three different stages of static tumor targeting to maximize therapeutic outcomes. Finally, we briefly discuss the current challenges and future opportunities for the clinical translation of cancer nanomedicines.

Self-Assembled Copper-Based Nanoparticles for Glutathione Activated and Enzymatic Cascade-Enhanced Ferroptosis and Immunotherapy in Cancer Treatment

As an emerging cancer treatment strategy, ferroptosis is greatly restricted by excessive glutathione (GSH) in tumor microenvironment (TME) and low reactive oxygen species (ROS) generation efficiency. Here, this work designs self-assembled copper-alanine nanoparticles (CACG) loaded with glucose oxidase (GOx) and cinnamaldehyde (Cin) for in situ glutathione activated and enzymatic cascade-enhanced ferroptosis and immunotherapy. In response to GSH-rich and acidic TME, CACG allows to effectively co-deliver Cu2+ , Cin, and GOx into tumors. Released Cin consumes GSH through Michael addition, accompanying with the reduction of Cu2+ into Cu+ for further GSH depletion. With the cascade of Cu+ -catalyzed Fenton reactions and enzyme-catalyzed reactions by GOx, CACG could get rid of the restriction of insufficient hydrogen peroxide in TME, leading to a robust and constant generation of ROS. With the high efficiency of GSH depletion and ROS production, ferroptosis is significantly enhanced by CACG in vivo. Moreover, elevated oxidative stress triggers robust immune responses by promoting dendritic cells maturation and T cell infiltration. The in vivo results prove that CACG could efficiently inhibit tumor growth in 4T1 tumor-bearing mouse model without causing obvious systemic toxicity, suggesting the great potential of CACG in enhancing ferroptosis and immunotherapy for effective cancer treatment.

Antioxidant hepatic lipid metabolism can be promoted by orally administered inorganic nanoparticles

Accumulation of inorganic nanoparticles in living organisms can cause an increase in cellular reactive oxygen species (ROS) in a dose-dependent manner. Low doses of nanoparticles have shown possibilities to induce moderate ROS increases and lead to adaptive responses of biological systems, but beneficial effects of such responses on metabolic health remain elusive. Here, we report that repeated oral administrations of various inorganic nanoparticles, including TiO₂, Au, and NaYF₄ nanoparticles at low doses, can promote lipid degradation and alleviate steatosis in the liver of male mice. We show that low-level uptake of nanoparticles evokes an unusual antioxidant response in hepatocytes by promoting Ces2h expression and consequently enhancing ester hydrolysis. This process can be implemented to treat specific hepatic metabolic disorders, such as fatty liver in both genetic and high-fat-diet obese mice without causing observed adverse effects. Our results demonstrate that low-dose nanoparticle administration may serve as a promising treatment for metabolic regulation.

Construction of an oxidative stress-related lncRNAs signature to predict prognosis and the immune response in gastric cancer

Oxidative stress, as a characteristic of cellular aerobic metabolism, plays a crucial regulatory role in the development and metastasis of gastric cancer (GC). Long noncoding RNAs (lncRNAs) are important regulators in GC development. However, research on the prognostic patterns of oxidative stress-related lncRNAs (OSRLs) and their functions in the immune microenvironment is currently insufficient. We identified the OSRLs signature (DIP2A-IT1, DUXAP8, TP53TG1, SNHG5, AC091057.1, AL355001.1, ARRDC1-AS1, and COLCA1) from 185 oxidative stress-related genes in The Cancer Genome Atlas (TCGA) cohort via random survival forest and Cox analyses, and the results were subsequently validated in the Gene Expression Omnibus (GEO) dataset. The patients were divided into high- and low-risk groups by the risk score of the OSRLs signature. Longer overall survival was detected in the low-risk group than in the high-risk group in both the TCGA cohort (P < 0. 001, HR = 0.43, 95% CI 0.31-0.62) and the GEO cohort (P = 0.014, HR = 0.67, 95% CI 0.48-0.93). Next, multivariate Cox analysis identified that the risk model was an independent prognostic characteristic (HR > 1, P = 0.005), and time-dependent receiver operating characteristic (ROC) curve analysis and nomogram analysis were utilized to evaluate the predictive ability of the risk model. Next, gene set enrichment analysis revealed that the immune-related pathway, Wnt/[Formula: see text]-catenin signature, mammalian target of rapamycin complex 1 signature, and cytokine‒cytokine receptor interaction was enriched. High-risk patients were more responsive to CD200, TNFSF4, TNFSF9, and BTNL2 immune checkpoint blockade. The results of qRT‒PCR further proved the accuracy of our bioinformatic analysis. Overall, our study identified a novel OSRLs signature that can serve as a promising biomarker and prognostic indicator, which provides a personalized predictive approach for patient prognosis evaluation and treatment.

Microbial synthesis of Prussian blue for potentiating checkpoint blockade immunotherapy

Cancer immunotherapy is revolutionizing oncology. The marriage of nanotechnology and immunotherapy offers a great opportunity to amplify antitumor immune response in a safe and effective manner. Here, electrochemically active Shewanella oneidensis MR-1 can be applied to produce FDA-approved Prussian blue nanoparticles on a large-scale. We present a mitochondria-targeting nanoplatform, MiBaMc, which consists of Prussian blue decorated bacteria membrane fragments having further modifications with chlorin e6 and triphenylphosphine. We find that MiBaMc specifically targets mitochondria and induces amplified photo-damages and immunogenic cell death of tumor cells under light irradiation. The released tumor antigens subsequently promote the maturation of dendritic cells in tumor-draining lymph nodes, eliciting T cell-mediated immune response. In two tumor-bearing mouse models using female mice, MiBaMc triggered phototherapy synergizes with anti-PDL1 blocking antibody for enhanced tumor inhibition. Collectively, the present study demonstrates biological precipitation synthetic strategy of targeted nanoparticles holds great potential for the preparation of microbial membrane-based nanoplatforms to boost antitumor immunity.

Self-Propelled Enzymatic Nanomotors from Prodrug-Skeletal Zeolitic Imidazolate Frameworks for Boosting Multimodel Cancer Therapy Efficiency

Self-propelled nanomotors, which can autonomous propelled by harnessing others type of energy, have shown tremendous potential as drug delivery systems for cancer therapy. However, it remains challenging for nanomotors in tumor theranostics because of their structural complexity and deficient therapeutic model. Herein, glucose-fueled enzymatic nanomotors (GC6@cPt ZIFs) are developed through encapsulation of glucose oxidase (GOx), catalase (CAT), and chlorin e6 (Ce6) using cisplatin-skeletal zeolitic imidazolate frameworks (cPt ZIFs) for synergetic photochemotherapy. The GC6@cPt ZIFs nanomotors can produce O₂ through enzymatic cascade reactions for propelling the self-propulsion. Trans-well chamber and multicellular tumor spheroids experiments demonstrate the deep penetration and high accumulation of GC6@cPt nanomotors. Importantly, the glucose-fueled nanomotor can release the chemotherapeutic cPt and generate reactive oxygen species under laser irradiation, and simultaneously consume intratumoral over-expressed glutathione. Mechanistically, such processes can inhibit cancer cell energy and destroy intratumoral redox balance to synergistically damage DNA and induce tumor cell apoptosis. Collectively, this work demonstrates that the self-propelled prodrug-skeleton nanomotors with oxidative stress activation can highlight a robust therapeutic capability of oxidants amplification and glutathione depletion to boost the synergetic cancer therapy efficiency.

Mitochondria-Targeted Nanosystem Enhances Radio-Radiodynamic-Chemodynamic Therapy on Triple Negative Breast Cancer

Radiodynamic therapy (RDT), which produces ¹O₂ and other reactive oxygen species (ROS) in response to X-rays, can be used in conjunction with radiation therapy (RT) to drastically lower X-ray dosage and reduce radio resistance associated with conventional radiation treatment. However, radiation-radiodynamic therapy (RT-RDT) is still impotent in a hypoxic environment in solid tumors due to its oxygen-dependent nature. Chemodynamic therapy (CDT) can generate reactive oxygen species and O₂ by decomposing H₂O₂ in hypoxic cells and thus potentiate RT-RDT to achieve synergy. Herein, we developed a multifunctional nanosystem, AuCu-Ce6-TPP (ACCT), for RT-RDT-CDT. Ce6 photosensitizers were conjugated to AuCu nanoparticles via Au-S bonds to realize radiodynamic sensitization. Cu can be oxidized by H₂O₂ and catalyze the degradation of H₂O₂ to generate ^•OH through the Fenton-like reaction to realize CDT. Meanwhile, the degradation byproduct oxygen can alleviate hypoxia while Au can consume glutathione to increase the oxidative stress. We then attached mercaptoethyl-triphenylphosphonium (TPP-SH) to the nanosystem, targeting ACCT to mitochondria (colocalization Pearson coefficient 0.98) to directly disrupt mitochondrial membranes and more efficiently induce apoptosis. We confirmed that ACCT efficiently generates ¹O₂ and ^•OH upon X-ray irradiation, resulting in strong anticancer efficacy in both normoxic and hypoxic 4T1 cells. The down-regulation of hypoxia-inducible factor 1α expression and reduction of intracellular H₂O₂ concentrations suggested that ACCT could significantly alleviate hypoxia in 4T1 cells. ACCT-enhanced RT-RDT-CDT can successfully shrink or remove tumors in radioresistant 4T1 tumor-bearing mice upon 4 Gy of X-ray irradiation. Our work thus presents a new strategy to treat radioresistant hypoxic tumors.

Geometric Tuning of Single-Atom FeN4 Sites via Edge-Generation Enhances Multi-Enzymatic Properties

Single-atom nanozymes (SAzymes) are considered promising alternatives to natural enzymes. The catalytic performance of SAzymes featuring homogeneous, well-defined active structures can be enhanced through elucidating structure-activity relationship and tailoring physicochemical properties. However, manipulating enzymatic properties through structural variation is an underdeveloped approach. Herein, the synthesis of edge-rich Fe single-atom nanozymes (FeNC-edge) via an H₂ O₂ -mediated edge generation is reported. By controlling the number of edge sites, the peroxidase (POD)- and oxidase (OXD)-like performance is significantly enhanced. The activity enhancement results from the presence of abundant edges, which provide new anchoring sites to mononuclear Fe. Experimental results combined with density functional theory (DFT) calculations reveal that FeN₄ moieties in the edge sites display high electron density of Fe atoms and open N atoms. Finally, it is demonstrated that FeNC-edge nanozyme effectively inhibits tumor growth both in vitro and in vivo, suggesting that edge-tailoring is an efficient strategy for developing artificial enzymes as novel catalytic therapeutics.

Integrated supramolecular nanovalves for photothermal augmented chemodynamic therapy through strengthened amplification of oxidative stress

The amplified oxidative stress strategy has been emerged as one promising method to enhance the chemodynamic therapy (CDT) efficacy due to the H₂O₂ up-regulation and glutathione (GSH) down-regulation behavior in tumor cells. However, how to further achieve the satisfied CDT efficacy is still a big challenge. In this paper, the supramolecular nanovalves (SNs) with oxidative amplification agents cinnamaldehyde-(phenylboronic acid pinacol ester) conjugates (CA-BE) encapsulated inside were developed to accelerate and amplify the generation of ·OH and consumption of GSH while augmenting the CDT efficacy. SNs were obtained through ferrocene/Au modified mesoporous silica nanoparticles (MSN@Au-Fc) and active targeting β-cyclodextrin modified hyaluromic acid (HA-CD). After CD44 receptor-mediated cellular internalization, the CA-BE were released to elevate H₂O₂ amount and consume GSH for the desired generation of higher cytotoxic hydroxyl radicals (·OH). Moreover, the NIR-activated MSN@Au-Fc can increase the temperature for the accelerated and amplified oxidative stress. As such, the therapeutic efficacy of our synthesized CA-BE and the accompanied hyperthermia were augmented toward synergistically inhibiting tumor growth.

Dual-Emissive Carbon Dots: Exploring Their Fluorescence Properties for Sensitive Turn-Off-On Recognition of Ferric and Pyrophosphate Ions and Its Application in Fluorometric Detection of the Loop-Mediated Isothermal Amplification Reaction

In this study, dual-emissive carbon dots (CDs) were prepared using p-phenylenediamine (pPDA) and phytic acid (PA) precursors via a one-pot-hydrothermal method. The photophysical, morphological, and structural characterization of CDs was carried out using absorption, fluorescence, Fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR), and high-resolution transmission electron microscopy (HR-TEM) analysis. The as-prepared CDs displayed dual-fluorescence peaks at 525 and 620 nm upon excitation at 450 nm. The CDs showed good photostability and exhibited solvent-dependent fluorescence properties. The solvatochromic behavior of CDs was utilized to detect water content in organic solvents. Furthermore, the dual-emissive property of CDs was utilized for the sequential detection of ferric (Fe³⁺) and pyrophosphate ions (PPi) by a fluorescence turn-off-on mechanism. The proposed assay showed appreciable fluorescence response toward Fe³⁺ and PPi with high selectivity and good tolerance for common interfering ions. The potential practical application of the CD probe was ascertained by carrying out the fluorometric detection of PPi to affirm the loop-mediated isothermal amplification (LAMP) reaction specific for Mycobacterium tuberculosis (negative and positive clinical samples).

Engineering Single-Atom Nanozymes for Catalytic Biomedical Applications

Nanomaterials with enzyme-mimicking properties, coined as nanozymes, are a promising alternative to natural enzymes owing to their remarkable advantages, such as high stability, easy preparation, and favorable catalytic performance. Recently, with the rapid development of nanotechnology and characterization techniques, single atom nanozymes (SAzymes) with atomically dispersed active sites, well-defined electronic and geometric structures, tunable coordination environment, and maximum metal atom utilization are developed and exploited. With superior catalytic performance and selectivity, SAzymes have made impressive progress in biomedical applications and are expected to bridge the gap between artificial nanozymes and natural enzymes. Herein, the recent advances in SAzyme preparation methods, catalytic mechanisms, and biomedical applications are systematically summarized. Their biomedical applications in cancer therapy, oxidative stress cytoprotection, antibacterial therapy, and biosensing are discussed in depth. Furthermore, to appreciate these advances, the main challenges, and prospects for the future development of SAzymes are also outlined and highlighted in this review.

Copper Single-Atom Jellyfish-like Nanomotors for Enhanced Tumor Penetration and Nanocatalytic Therapy

Single-atom catalysts with extraordinary catalytic activity have been receiving great attention in tumor therapy. However, most single-atom catalysts lack self-propulsion properties, restricting them from actively approaching cancer cells or penetrating the interior of tumors. Herein, we design N-doped jellyfish-like mesoporous carbon nanomotors coordinated with single-atom copper (Cu-JMCNs). It is a combination of single-atom nanocatalytic medicine and nanomotor self-propulsion for cancer therapy. The Cu single atom can catalyze H₂O₂ into toxic hydroxyl radical (^•OH) for chemodynamic therapy (CDT). Near-infrared light triggers Cu-JMCNs to achieve self-thermophoretic motion because of the jellyfish-like asymmetric structure and photothermal property of carbon, which significantly improves the cellular uptake and the penetration of three-dimensional tumors. In vivo experiments indicate that the combination of single-atom Cu for CDT and near-infrared light propulsion can achieve over 85% tumor inhibition rate. This work sheds light on the development of advanced nanomotors with single-atom catalysts for biomedical applications.

The Key Effect of Carboxyl Group and CuN2 O2 Coordinate Structure for Cu, N Co-Doped Carbon Dots with Peroxidase-Like Property

Carbon dots (CDs) with good water solubility and biocompatibility have become a research hotspot in the nano-enzyme and biomedical field. However, the problems of low catalytic activity and ambiguous catalytic site of CDs as nanozymes still need to be addressed. In this work, CDs loaded with Cu single atoms are obtained through pyrolysis, and the coordination structure and surface functional groups are regulated by adjusting the pyrolysis temperature. CDs obtained at 300 °C (named Cu-CDs-300) have the most carboxyl content and Cu is coordinated in the form of CuN₂ O₂ , which can better decompose H₂ O₂ to produce free radical and is beneficial to catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB). The v_max is 6.56*10^-7  m s^-1 , 6.56 times higher than that of horseradish peroxidase (HRP). Moreover, Cu-CDs-300 can effectively lead to CT26 apoptosis by generating much free radicals. This work demonstrates the synergistic effect of oxygen-containing functional groups and metal coordination structures on peroxide-like activity of CDs and provides new ideas for the design of clear active structure and high efficiency peroxide-like single atom CDs catalyst.

Multifunctional carbon dots for glutathione detection and Golgi imaging

Glutathione (GSH) is present in almost every cell in the body and plays various integral roles in many biological processes. The Golgi apparatus is a eukaryotic organelle for the biosynthesis, intracellular distribution, and secretion of various macromolecules; however, the mechanism of GSH in the Golgi apparatus has not been fully elucidated. Here, specific and sensitive sulfur-nitrogen co-doped carbon dots (SNCDs) with orange-red fluorescence was synthesized for the detection of GSH in the Golgi apparatus. The SNCDs have a Stokes shift of 147 nm and excellent fluorescence stability, and they exhibited excellent selectivity and high sensitivity to GSH. The linear response of the SNCDs to GSH was in the range of 10-460 μM (LOD = 0.25 μΜ). More importantly, we used SNCDs with excellent optical properties and low cytotoxicity as probes, and successfully realized golgi imaging in HeLa cells and GSH detection at the same time.

Activating One/Two-Photon Excited Red Fluorescence on Carbon Dots: Emerging n→π Photon Transition Induced by Amino Protonation

Due to the complicated nature of carbon dots (CDs), fluorescence mechanism of red fluorescent CDs is still unrevealed and features highly controversial. Reliable and effective strategies for manipulating the red fluorescence of CDs are urgently needed. Herein, CDs with one-photon excited (622 nm, QYs ≈ 17%) and two-photon (629 nm) excited red fluorescence are prepared by acidifying o-phenylenediamine-based reaction sediments. Systematic analysis reveals that the protonation of amino groups increases the particle surface potential, disperse the bulk sediments into nano-scale CDs. In the meanwhile, amino protonation of pyridinic nitrogen (-N=) structure inserts numerous n orbital energy levels between the π → π* transition, narrows the gap distance for photon transition, and induces red fluorescence emission on CDs. Present research reveals an effective pathway to activate CDs reaction sediments and trigger red emission, thus may open a new avenue for developing CDs with ideal optical properties and promising application prospects.

Unraveling mitochondria-targeting reactive oxygen species modulation and their implementations in cancer therapy by nanomaterials

Functional subcellular organelle mitochondria are emerging as a crucial player and driver of cancer. For maintaining the sites of cellular respiration, mitochondria experience production, and accumulation of reactive oxygen species (ROS) underlying oxidative damage in electron transport chain carriers. Precision medicine targeting mitochondria can change nutrient availability and redox homeostasis in cancer cells, which might represent a promising strategy for suppressing tumor growth. Herein, this review highlights how the modification capable of manipulating nanomaterials for ROS generation strategies can influence or compensate the state of mitochondrial redox homeostasis. We propose foresight to guide research and innovation with an overview of seminal work and discuss future challenges and our perspective on the commercialization of novel mitochondria-targeting agents.

Renal Clearable Catalytic 2D Au-Porphyrin Coordination Polymer Augmented Photothermal-Gas Synergistic Cancer Therapy

As a gasotransmitter, carbon monoxide (CO) possesses antitumor activity by reversing the Warburg effect at higher concentrations. The targeted delivery of carbon monoxide-releasing molecules (CORMs) using nanomaterials is an appealing option for CO administration, but how to maintain CO above the threshold concentration in tumor tissue remains a challenge. Herein, a nanozyme-catalyzed cascade reaction is proposed to promote CO release for high-efficacy photothermal therapy (PTT)-combined CO therapy of cancer. A gold-based porphyrinic coordination polymer nanosheet (Au⁰ -Por) is synthesized to serve as a carrier for CORM. It also possesses excellent glucose oxygenase-like activity owing to ultrasmall zero-valent gold atoms on the nanosheet. The catalytically generated H₂ O₂ can efficiently catalyze CORM decomposition, which enables in situ generation of sufficient CO for gas therapy. In vivo, the Au⁰ -Por nanosheets-enhanced photoacoustic imaging (PAI) and fluorescence imaging collectively demonstrate high tumor-targeting efficiency and nanomaterial retention. Proven to have augmented therapeutic efficacy, the nanoplatform can also be easily degraded and excreted through the kidney, indicating good biocompatibility. Thus, the application of rational designed Au⁰ -Por nanosheet with facile approach and biodegradable property to PAI-guided synergistic gas therapy can provide a strategy for the development of biocompatible and highly effective gaseous nanomedicine.

Solid-state Fluorescence from Carbon Dots Widely Tunable from Blue to Deep Red through Surface Ligand Modulation

Carbon dots (CDs) find widespread attention due to their remarkable fluorescent and electronic properties. However, aggregation-caused quenching currently limits the application of CDs in colored displays. The construction of CDs with color-tunable solid-state fluorescence (SSF) is rarely reported, since the preparation of SSF CDs is technically challenging. Herein, through surface ligand modulation, SSF CDs with an emission-color span of almost 300 nm (from blue to deep red) were obtained. In-depth structure-property studies reveal that intra- and inter-molecular hydrogen-bonding inside SSF CDs provokes the emission properties in the aggregated state. Photodynamic characterizations demonstrate emission wavelengths can be switched smoothly by deliberately altering conjugation ability between substituent ligands and CDs core. Three-dimensional printing patterning is used to create a range of emissive objects, demonstrating the commercial potential for use in optical lamps.

Vanadium Oxide Nanozymes with Multiple Enzyme-Mimic Activities for Tumor Catalytic Therapy

Using tumors containing high concentrations of hydrogen peroxide to design nanozymes is a new and effective strategy, and vanadium-based nanomaterials receive increasing attention. In this paper, four kinds of vanadium oxide nanozymes with different valences of vanadium are synthesized by a simple method to verify the effect of valence on enzyme activity. Vanadium oxide nanozyme-III (Vnps-III) with a low valence of vanadium (V⁴⁺) exhibits good peroxidase (POD) and oxidase (OXD) activities, which can effectively produce reactive oxygen species (ROS) in the tumor microenvironment for tumor treatment. In addition, Vnps-III can also consume glutathione (GSH) to reduce ROS consumption. Vanadium oxide nanozyme-I (Vnps-I) containing a high valence of vanadium (V⁵⁺) has catalase (CAT) activity, which can catalyze hydrogen peroxide (H₂O₂) into oxygen (O₂), which is beneficial to alleviate the hypoxic environment of solid tumors. Finally, a vanadium oxide nanozyme with both trienzyme simulation activity and GSH consumption ability was screened out by adjusting the ratio of V⁴⁺ to V⁵⁺ in vanadium oxide nanozymes. In cell and animal experiments, we successfully demonstrate that vanadium oxide nanozymes have excellent antitumor ability and high safety, which may bring great potential for clinical cancer treatment.

Anticancer Activity of Bitter Melon-Derived Vesicles Extract against Breast Cancer

Due to their low immunogenicity, high biocompatibility and ready availability in large quantities, plant-derived vesicles extracts have attracted considerable interest as a novel nanomaterial in tumor therapy. Bitter melon, a medicinal and edible plant, has been reported to exhibit excellent antitumor effects. It is well-documented that breast cancer gravely endangers women’s health, and more effective therapeutic agents must be urgently explored. Therefore, we investigated whether bitter melon-derived vesicles extract (BMVE) has antitumor activity against breast cancer. Ultracentrifugation was used to isolate BMVE with a typical “cup-shaped” structure and an average size of approximately 147 nm from bitter melon juice. The experimental outcomes indicate that 4T1 breast cancer cells could efficiently internalize BMVE, which shows apparent anti-proliferative and migration-inhibiting effects. In addition, BMVE also possesses apoptosis-inducing effects on breast cancer cells, which were achieved by stimulating the production of reactive oxygen species (ROS) and disrupting mitochondrial function. Furthermore, BMVE could dramatically inhibit tumor growth in vivo with negligible adverse effects. In conclusion, BMVE exhibits a pronounced antitumor effect on 4T1 breast cancer cells, which has great potential for use in tumor therapy.

Targeted Degradation of PD-L1 and Activation of the STING Pathway by Carbon-Dot-Based PROTACs for Cancer Immunotherapy

Proteolysis targeting chimeras (PROTACs) technology is an emerging approach to degrade disease-associated proteins. Here, we report carbon-dot (CD)-based PROTACs (CDTACs) that degrade membrane proteins via the ubiquitin-proteasome system. CDTACs can bind to programmed cell death ligand 1 (PD-L1), recruit cereblon (CRBN) to induce PD-L1 ubiquitination, and degrade them with proteasomes. Fasting-mimicking diet (FMD) is also used to enhance the cellular uptake and proteasome activity. More than 99 % or 90 % of PD-L1 in CT26 or B16-F10 tumor cells can be degraded by CDTACs, respectively. Furthermore, CDTACs can activate the stimulator of interferon genes (STING) pathway to trigger immune responses. Thus, CDTACs with FMD treatment effectively inhibit the growth of CT26 and B16-F10 tumors. Compared with small-molecule-based PROTACs, CDTACs offer several advantages, such as efficient membrane protein degradation, targeted tumor accumulation, immune system activation, and in vivo detection.

Ligand vacancy channels in pillared inorganic-organic hybrids for electrocatalytic organic oxidation with enzyme-like activities

Simultaneously achieving abundant and well-defined active sites with high selectivity has been one of the ultimate goals for heterogeneous catalysis. Herein, we construct a class of Ni hydroxychloride-based inorganic-organic hybrid electrocatalysts with the inorganic Ni hydroxychloride chains pillared by the bidentate N-N ligands. The precise evacuation of N-N ligands under ultrahigh-vacuum forms ligand vacancies while partially retaining some ligands as structural pillars. The high density of ligand vacancies forms the active vacancy channel with abundant and highly-accessible undercoordinated Ni sites, exhibiting 5-25 fold and 20-400 fold activity enhancement compared to the hybrid pre-catalyst and standard β-Ni(OH)₂ for the electrochemical oxidation of 25 different organic substrates, respectively. The tunable N-N ligand can also tailor the sizes of the vacancy channels to significantly impact the substrate configuration leading to unprecedented substrate-dependent reactivities on hydroxide/oxide catalysts. This approach bridges heterogenous and homogeneous catalysis for creating efficient and functional catalysis with enzyme-like properties.

Fe-Doped Carbon Dots as NIR-II Fluorescence Probe for In Vivo Gastric Imaging and pH Detection

Carbon dots (CDs) with excellent cytocompatibility, tunable optical properties, and simple synthesis routes are highly desirable for use in optical bioimaging. However, the majority of existing CDs are triggered by ultraviolet/blue light, presenting emissions in the visible/first near-infrared (NIR-I) regions, which do not allow deep tissue penetration. Emerging research into CDs with NIR-II emission in the red region has generated limited designs with poor quantum yield, restricting their in vivo imaging applications due to low penetration depth. Developing novel CDs with NIR-II emissions and high quantum yield has significant and far-reaching applications in bioimaging and photodynamic therapy. Here, it is developed for the first time Fe-doped CDs (Fe-CDs) exhibiting the excellent linear relationship between 900-1200 nm fluorescence-emission and pH values, and high quantum yield (QY-1.27%), which can be used as effective probes for in vivo NIR-II bioimaging. These findings demonstrate reliable imaging accuracy in tissue as deep as 4 mm, reflecting real-time pH changes comparable to a standard pH electrode. As an important example application, the Fe-CDs probe can non-invasively monitor in vivo gastric pH changes during the digestion process in mice, illustrating its potential applications in aiding imaging-guided diagnosis of gastric diseases or therapeutic delivery.

High performance carbon dots based prodrug Platform: Image-Guided photodynamic and chemotherapy with On-Demand drug release upon laser irradiation

The design of therapeutic nanoplatforms based on fluorescent carbon dots (CDs) has become a viable strategy because of their aqueous solubility, biocompatibility, and ease of further functionalization. By doping various heteroatoms into pristine CDs structures, we synthesized N-, Cl-, and S-doped CDs (NClS/CDs), as well as Se-, N-, and Cl-doped CDs (NClSe/CDs) with superior optoelectronic properties using rapid and straightforward microwave heating. The quantum efficiencies of these NClS/CDs and NClSe/CDs were enhanced to 30.7 % and 42.9 %, respectively, compared to those of undoped CDs (0.66 %). Owing to their better light absorption properties, NClS/CDs efficiently produced reactive oxygen species (ROS) under 532 nm laser irradiation for photodynamic therapy (PDT). Considering the ROS generation and surface carrier abilities of NClS/CDs, we designed the loading of camptothecin (CPT) drug via a thioketal linker (TL), resulting in h/CDs@CPT nanovesicles (NVs) with a drug-loading efficiency of 46.5 %. Under laser irradiation in an acidic environment, ROS-triggered CPT release was observed, with 50.2 % of CPT released following the breakdown of the ROS-sensitive TL. In vitro cellular studies revealed that h/CDs@CPT NVs possessed minimal cytotoxicity toward HeLa and 4 T1 cancer cells, despite the high clinical efficacy of PDT and ROS-induced chemotherapeutic response under laser treatment. Confocal microscopy of HeLa and 4 T1 cells revealed that h/CDs@CPT NVs produced red-emissive photographs for potential cancer cell detection. Therefore, our study presents an image-guided PDT and chemotherapeutic platform based on h/CDs@CPT NVs, which will be an attractive candidate for future cancer treatment.

Protoporphyrin-sensitized degradable bismuth nanoformulations for enhanced sonodynamic oncotherapy

Decreasing the scavenging capacity of reactive oxygen species (ROS) and enhancing ROS production are the two principal objectives in the development of novel sonosensitizers for sonodynamic therapy (SDT). Herein, we designed a protoporphyrin-sensitized bismuth-based semiconductor (P-NBOF) as a sonosensitizer to generate ROS and synergistically depleted glutathione for enhanced SDT against tumors. The bismuth-based nanomaterial (NBOF) is a wide-bandgap semiconductor. Sensitization by protoporphyrin made it easier to excite electrons under ultrasonic stimulation, and the energy of the lowest unoccupied electron orbital in protoporphyrin was higher than the conduction-band energy of NBOF. Under ultrasound excitation, the excited electrons in the protoporphyrin were injected into the conduction band of the NBOF, increasing its reducing ability leading to the production of more superoxide anion radicals and also helping to increase the charge separation of protoporphyrin leading to the production of more singlet oxygen. Meanwhile, P-NBOF continuously depleted glutathione, which was not only conducive to breaking the redox balance of the tumor microenvironment to enhance the therapeutic efficacy of SDT, but also promoted its degradation and metabolism. The construction of this P-NBOF sonosensitizer thus provided an effective strategy to enhance SDT for tumors. STATEMENT OF SIGNIFICANCE: To enhance the efficacy of sonodynamic tumor therapy, we developed a degradable protoporphyrin-sensitized bismuth-based nano-semiconductor (P-NBOF) by optimizing the band structure and glutathione-depletion ability. Protoporphyrin in P-NBOF under excitation preferentially generates free electrons, which are then injected into the conduction band of NBOF, improving the reducing ability of NBOF and promoting the separation of electron-hole pairs, thereby enhancing the production capacity of reactive oxygen species. Furthermore, P-NBOF can deplete glutathione, reduce the scavenging of reactive oxygen species, and reactivate and amplify the effect of sonodynamic therapy. The construction of the nanotherapeutic platform provides an option for enhancing sonodynamic therapy.

Engineering a synergistic antioxidant inhibition nanoplatform to enhance oxidative damage in tumor treatment

The antioxidant system of tumor cells severely impairs reactive oxygen species (ROS)-mediated tumor therapy. Despite extensive attempts to attenuate the antioxidant capacity by eliminating ROS scavengers such as glutathione (GSH), nicotinamide adenine dinucleotide phosphate (NADPH) over-expressed in the tumor microenvironment can regenerate GSH from glutathione disulfide (GSSG), hence weakening ROS-induced oxidative damage. Therefore, engineering a nanoplatform capable of depleting both NADPH and GSH is extremely significant for improving ROS-mediated tumor treatment. Herein, a synergetic antioxidant inhibition strategy is proposed to attenuate intracellular antioxidant capacity for hypoxic tumor therapy. In this context, both porous Prussian blue nanoparticles (PPB NPs) and cisplatin prodrug [cis-Pt (IV)] in the nanoplatform can oxidize GSH to directly reduce GSH levels, while PPB NPs also enable NADPH depletion by peroxidase-mimicking to impair GSH regeneration. Furthermore, PPB NPs with catalase-mimicking activity catalyze H₂O₂ decomposition to alleviate tumor hypoxia, thus reducing the generation of GSH and boosting singlet oxygen (¹O₂) production by Chlorin e6 (Ce6) for enhancing oxidative damage. Experimental results prove that the nanoplatform, denoted as PPB-Ce6-Pt, can induce remarkable tumor cells apoptosis and ferroptosis. Importantly, a simple loading method and the use of Food Drug Administration (FDA)-approved materials make PPB-Ce6-Pt have great potential for practical applications. STATEMENT OF SIGNIFICANCE: The antioxidant system in tumor cells disables ROS-mediated tumor therapy. Besides, extensive attempts aim at depleting GSH without considering their regeneration. Therefore, we developed a synergetic strategy to attenuate intracellular antioxidant capacity for hypoxic tumor therapy. PPB-Ce6-Pt nanoplatform could not only directly reduce GSH levels but also deplete NADPH by peroxidase-mimicking to impair GSH regeneration. In addition, PPB-Ce6-Pt nanoplatform could catalyze H₂O₂ decomposition to alleviate tumor hypoxia, thus reducing the generation of GSH and boosting ¹O₂ production by Chlorin e6 (Ce6) for increasing oxidative damage. Then, intracellular ROS boost and redox dyshomeostasis induced remarkable tumor cells apoptosis and ferroptosis. Importantly, a simple loading method and the use of biosafety materials made the nanoplatform have great potential for practical applications.

Biodegradable nanomaterials for diagnosis and therapy of tumors

Although degradable nanomaterials have been widely designed and applied for cancer bioimaging and various cancer treatments, few reviews of biodegradable nanomaterials have been reported. Herein, we have summarized the representative research advances of biodegradable nanomaterials with respect to the mechanism of degradation and their application in tumor imaging and therapy. First, four kinds of tumor microenvironment (TME) responsive degradation are presented, including pH, glutathione (GSH), hypoxia and matrix metalloproteinase (MMP) responsive degradation. Second, external stimulation degradation is summarized briefly. Next, we have outlined the applications of nanomaterials in bioimaging. Finally, we have focused on some typical examples of biodegradable nanomaterials in radiotherapy (RT), photothermal therapy (PTT), starvation therapy, photodynamic therapy (PDT), chemotherapy, chemodynamic therapy (CDT), sonodynamic therapy (SDT), gene therapy, immunotherapy and combination therapy.

Photocatalytic Generation of Hydrogen Radical (H⋅) with GSH for Photodynamic Therapy

As a reactive hydrogen species, the hydrogen radical (H⋅) scarcely sees applications in tumor biological therapy due to the very limited bio-friendly sources of H⋅. In this work, we report that TAF can act as an organic photosensitizer as well as an efficient photocatalytic H⋅ generator with reduced glutathione (GSH) as a fuel. The photoactivation of TAF leads to cell death in two ways including triple amplification of oxidative stress via ferroptosis-apoptosis under normoxia and apoptosis through biological reductions under hypoxia. TAF presents excellent biosafety with ultrahigh photocytotoxicity index at an order of magnitude of 10² -10³ on both normoxic and hypoxic cells. The in vitro data suggest that H⋅ therapy is promising to overcome the challenge of tumor hypoxia at low doses of both photocatalyst and light. In addition, the capability of near-infrared two-photon excitation would benefit broad biological applications.

Reactive oxygen species-upregulating nanomedicines towards enhanced cancer therapy

Reactive oxygen species (ROS) play a crucial role in physiological and pathological processes, emerging as a therapeutic target in cancer. Owing to the high concentration of ROS in solid tumor tissues, ROS-based treatments, such as photodynamic therapy and chemodynamic therapy, and ROS-responsive drug delivery systems have been widely explored to powerfully and specifically suppress tumors. However, their anticancer efficacy is still hampered by the heterogeneous ROS levels, and thus comprehensively upregulating the ROS levels in tumor tissues can ensure an enhanced therapeutic effect, which can further sensitize and/or synergize with other therapies to inhibit tumor growth and metastasis. Herein, we review the recently emerging drug delivery strategies and technologies for increasing the H₂O₂, ˙OH, ¹O₂, and ˙O₂^- concentrations in cancer cells, including the efficient delivery of natural enzymes, nanozymes, small molecular biological molecules, and nanoscale Fenton-reagents and semiconductors and neutralization of intracellular antioxidant substances and localized input of mechanical and electromagnetic waves (such as ultrasound, near infrared light, microwaves, and X-rays). The applications of these ROS-upregulating nanosystems in enhancing and synergizing cancer therapies including chemotherapy, chemodynamic therapy, phototherapy, and immunotherapy are surveyed. In addition, we discuss the challenges of ROS-upregulating systems and the prospects for future studies.

Cobalt Single-Atom Nanozyme Co-Administration with Ascorbic Acid Enables Redox Imbalance for Tumor Catalytic Ablation

The elevated antioxidant defense system in cancer cells can lead to resistance to treatments involving ROS. Breaking the redox balance of the cell system through a "open up the source and regulate the flow" strategy can inhibit the growth of cancer cells and thus design a cancer treatment strategy. Here, cobalt single atom-supported N-doped carbon nanozymes (Co SA-N/C) were synthesized via a simple sacrificial template method, which can mimic the properties of ascorbate oxidase and glutathione oxidase effectively. The synthesized Co SA-N/C can induce the generation of active oxygen by accelerating the oxidation of ascorbic acid (AA) and destroy the endogenous active oxygen scavenging system by consuming the main antioxidant, glutathione (GSH). In-depth in vitro and in vivo investigations indicate that compared with solo therapy, Co SA-N/C together with AA can significantly enhance the anti-tumor efficiency by simultaneously elevating oxidative stress and consuming the overexpressed glutathione (GSH) through the redox reaction catalyzed by Co SA-N/C. This work provides a promising route for developing nanozyme-guided and ascorbate-based antitumor agents.