Tumor-selective catalytic nanomedicine by nanocatalyst delivery

Beyond External Light: On-Spot Light Generation or Light Delivery for Highly Penetrated Photodynamic Therapy

External light sources, such as lasers, light emitting diodes (LEDs) and lamps, are widely applied in photodynamic therapy (PDT); however, their use is severely limited by the nature of shallow tissue penetration depth. The recent exploration of light delivery or local generation on tumor sites has attracted much attention, owing to the fact that these systems are significantly endowed with high tissue penetration. In this review, we briefly introduced the principle of "on-spot light generation or delivery systems" in PDT. These systems are divided into different categories: (1) implantable luminescence, (2) mechanoluminescence, (3) electrochemiluminescence, (4) Cerenkov luminescence, (5) chemiluminescence, and (6) bioluminescence. Finally, their applications, advantages, and disadvantages in PDT will be appropriately summarized and further discussed in detail. We believe that this review will provide general guidance for the further design of light generation or delivery systems and clinical studies for PDT-mediated cancer treatments with unparalleled merits.

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.

Hybrid nanogels by direct mixing of chitosan, tannic acid and magnetite nanoparticles: processes involved in their formation and potential catalytic properties

Magnetite (Fe3O4) nanoparticles (MNPs) as nanocatalysts have drawn considerable attention because of their unique properties such as peroxidase-like activity. However, their biodistribution and availability for specific treatments still need to be improved. In this study, a simple and convenient strategy for the synthesis of hybrid nanogels (NGs) is described, which involves direct mixing of biomaterials such as chitosan (Ch) and tannic acid (TA), with the incorporation of MNPs, under oxidising conditions, using the inverse nanoemulsion method. The different processes involved in the formation of these hybrid nanosystems as well as their morphological and chemical structure are investigated using optical, spectroscopic, and electron microscopic techniques (DLS, UV-VIS, FT-IR, XPS, TEM, and SEM-EDS). It is demonstrated that ∼11 nm synthesized MNPs, post-functionalized with oxidised TA, act as covalent crosslinkers. As a proof of concept, the potential use of these materials in nanocatalytic medicine was evaluated using a colorimetric method based on the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in hydrogen peroxide. The results show that these hybrid nanogels have the same peroxidase-like activity as bare MNPs, indicating that the organic nanostructure stabilises the inorganic nanoparticles without any significant change in the catalytic properties. Therefore, this kind of nanomaterial has promising potential for use in nanocatalytic medicine with improved biocompatibility and biodistribution.

Construction of a Dual-Mode Immune Platform Based on the Photothermal Effect of AgCo@NC NPs for the Detection of α-Fetoprotein

Compared with the accuracy of a single signal and the limitation of environmental applicability, the application value of dual-mode detection is gradually increasing. To this end, based on the photothermal effect of Ag/Co embedded N-rich mesoporous carbon nanomaterials (AgCo@NC NPs), we designed a dual-mode signal response system for the detection of α-fetoprotein (AFP). First, AgCo@NC NPs act as a photothermal immunoprobe that converts light energy into heat driven by a near-infrared (NIR) laser and obtains temperature changes corresponding to the analyte concentration on a hand-held thermal imager. In addition, this temperature recognition system can significantly improve the efficiency of Fenton-like reactions. AgCo@NC NPs act as peroxidase mimics to initiate the generation of poly N-isopropylacrylamide (PNIPAM, resistance enhancer) by cascade catalysis and the degradation of methylene blue (MB), thus enabling electrochemical testing. The dual-mode assay ranges from 0.01 to 100 and 0.001-10 ng/mL, with lower limits of detection (LOD) of 3.2 and 0.089 pg/mL, respectively, and combines visualization, portability, and high efficiency, opening new avenues for future clinical diagnostics and inhibitor studies.

X-ray-controllable release of carbon monoxide potentiates radiotherapy by ultrastable hybrid nanoreservoirs

Carbon monoxide (CO) exhibits unique abilities in sensitizing cancer radiotherapy (RT). However, the development of a highly stable CO-delivery nanosystem with sustained CO release in tumor tissues and the prevention of CO leakage into normal tissues remains a challenge. Herein, an organic-inorganic hybrid strategy is proposed to create ultrastable CO nanoreservoirs by locking an unstable iron carbonyl (FeCO) prodrug in a stable mesoporous silica matrix. Different from traditional FeCO-loading nanoplatforms, FeCO-bridged nanoreservoirs not only tethered labile FeCO in the framework to prevent unwanted FeCO leakage, but also achieved sustained CO release in response to X-ray and endogenous H2O2. Importantly, FeCO-bridged nanoreservoirs exhibited the sequential release of CO and Fe2+, thereby performing highly efficient chemodynamic therapy. Such a powerful combination of RT, gas therapy, and chemodynamic therapy boosts robust immunogenic cell death, thus enabling the elimination of deeply metastatic colon tumors with minimal side effects. The proposed organic-inorganic hybrid strategy opens a new window for the development of stable nanoreservoirs for the on-demand delivery of unstable gases and provides a feasible approach for the sequential release of CO and metal ions from metal carbonyl complexes.

Liquid Nanoparticles for Nanocatalytic Cancer Therapy

Nanotechnology is revolutionizing cancer therapy, and catalyzes the emerging of ion-involved cancer-therapeutic modality, which unfortunately suffers from undesirable nanocarriers for efficient intracellular ion delivery. To radically extricate from this critical issue, the glutathione (GSH)-responsive organosilica network is employed to lock the liquid drops at the nanoscale via a general bottom-up strategy to achieve the systemic delivery of "ion drugs". In this work, a sulfate radical generation donor (Na2 S2 O8 ), as a paradigm "ion drug", is entrapped into this liquid nanoparticle for efficiently delivering to the tumor region. After further surface engineering with pH-responsive tannic acid-Fe2+ framework, these liquid nanoparticles achieve tumor-microenvironmental pH/GSH-dual responsive ion release (Fe2+ /Na+ /S2 O8 2- ) after reaching the tumor sites, where the Fe2+ further triggers S2 O8 2- to generate toxic •SO4 - and •OH, effectively executing cancer cell ferroptosis (Fe2+ , reactive oxygen species-ROS) and pyroptosis (Na+ , ROS). Such a tumor-responsive/specific liquid nanoplatform is highly instructive for further ion-mediated nanomedicine and disease treatment.

Co-Delivery of Metabolic Modulators Leads to Simultaneous Lactate Metabolism Inhibition and Intracellular Acidification for Synergistic Cancer Therapy

Simultaneous lactate metabolism inhibition and intracellular acidification (LIIA) is a promising approach for inducing tumor regression by depleting ATP. However, given the limited efficacy of individual metabolic modulators, a combination of various modulators is required for highly efficient LIIA. Herein, a co-delivery system that combines lactate transporter inhibitor, glucose oxidase, and O2 -evolving nanoparticles is proposed. As a vehicle, a facile room-temperature synthetic method for large-pore mesoporous silica nanoparticles (L-MSNs) is developed. O2 -evolving nanoparticles are then conjugated onto L-MSNs, followed by immobilizing the lactate transporter inhibitor and glucose oxidase inside the pores of L-MSNs. To load the lactate transporter inhibitor, which is too small to be directly loaded into the large pores, it is encapsulated in albumin by controlling the albumin conformation before being loaded into L-MSNs. Notably, inhibiting lactate efflux shifts the glucose consumption mechanism from lactate metabolism to glucose oxidase reaction, which eliminates glucose and produces acid. This leads to synergistic LIIA and subsequent ATP depletion in cancer cells. Consequently, L-MSN-based co-delivery of modulators for LIIA shows high anticancer efficacy in several mouse tumor models without toxicity in normal tissues. This study provides new insights into co-delivery of small-molecule drugs, proteins, and nanoparticles for synergistic metabolic modulation in tumors.

Activation of autophagy by in situ Zn2+ chelation reaction for enhanced tumor chemoimmunotherapy

Chemotherapy can induce a robust T cell antitumor immune response by triggering immunogenic cell death (ICD), a process in which tumor cells convert from nonimmunogenic to immunogenic forms. However, the antitumor immune response of ICD remains limited due to the low immunogenicity of tumor cells and the immunosuppressive tumor microenvironment. Although autophagy is involved in activating tumor immunity, the synergistic role of autophagy in ICD remains elusive and challenging. Herein, we report an autophagy amplification strategy using an ion-chelation reaction to augment chemoimmunotherapy in cancer treatments based on zinc ion (Zn²⁺)-doped, disulfiram (DSF)-loaded mesoporous silica nanoparticles (DSF@Zn-DMSNs). Upon pH-sensitive biodegradation of DSF@Zn-DMSNs, Zn²⁺ and DSF are coreleased in the mildly acidic tumor microenvironment, leading to the formation of toxic Zn²⁺ chelate through an in situ chelation reaction. Consequently, this chelate not only significantly stimulates cellular apoptosis and generates damage-associated molecular patterns (DAMPs) but also activates autophagy, which mediates the amplified release of DAMPs to enhance ICD. In vivo results demonstrated that DSF@Zn-DMSNs exhibit strong therapeutic efficacy via in situ ion chelation and possess the ability to activate autophagy, thus enhancing immunotherapy by promoting the infiltration of T cells. This study provides a smart in situ chelation strategy with tumor microenvironment-responsive autophagy amplification to achieve high tumor chemoimmunotherapy efficacy and biosafety.

NIR-switchable local hydrogen generation by tandem bimetallic MOFs nanocomposites for enhanced chemodynamic therapy

The inadequate quantity of hydrogen peroxide (H2O2) in cancer cells promptly results in the constrained success of chemodynamic therapy (CDT). Significant efforts made throughout the years; nevertheless, researchers are still facing the great challenge of designing a CDT agent and securing H2O2 supply within the tumor cell. In this study, taking advantage of H2O2 level maintenance mechanism in cancer cells, a nanozyme-based bimetallic metal-organic frameworks (MOFs) tandem reactor is fabricated to elevate intracellular H2O2 levels, thereby enhancing CDT. In addition, under near-infrared excitation, the upconversion nanoparticles (UCNPs) loaded into the MOFs can perform photocatalysis and generate hydrogen, which increases cellular susceptibility to radicals induced from H2O2, inhibits cancer cell energy, causes DNA damages and induces tumor cell apoptosis, thus improving CDT therapeutic efficacy synergistically. The proposed nanozyme-based bimetallic MOFs-mediated CDT and UCNPs-mediated hydrogen therapy act as combined therapy with high efficacy and low toxicity.

Glucose oxidase and metal catalysts combined tumor synergistic therapy: mechanism, advance and nanodelivery system

Cancer has always posed a significant threat to human health, prompting extensive research into new treatment strategies due to the limitations of traditional therapies. Starvation therapy (ST) has garnered considerable attention by targeting the primary energy source, glucose, utilized by cancer cells for proliferation. Glucose oxidase (GOx), a catalyst facilitating glucose consumption, has emerged as a critical therapeutic agent for ST. However, mono ST alone struggles to completely suppress tumor growth, necessitating the development of synergistic therapy approaches. Metal catalysts possess enzyme-like functions and can serve as carriers, capable of combining with GOx to achieve diverse tumor treatments. However, ensuring enzyme activity preservation in normal tissue and activation specifically within tumors presents a crucial challenge. Nanodelivery systems offer the potential to enhance therapy effectiveness by improving the stability of therapeutic agents and enabling controlled release. This review primarily focuses on recent advances in the mechanism of GOx combined with metal catalysts for synergistic tumor therapy. Furthermore, it discusses various nanoparticles (NPs) constructs designed for synergistic therapy in different carrier categories. Finally, this review provides a summary of GOx-metal catalyst-based NPs (G-M) and offers insights into the challenges associated with G-M therapy, delivery design, and oxygen (O2) supply.

Emerging enzyme-based nanocomposites for catalytic biomedicine

With the promising advances in nanomedicine, numerous strategies have emerged for the diagnosis and treatment of diseases. Among them, enzyme-based multifunctional nanocomposites have attracted a great deal of attention in the field of catalytic biomedicine. These nanocomposites with high catalytic activity are capable of converting low/non-toxic substances into therapeutic ones, thus realizing highly efficient, site-specific therapy with minimal side effects. Enzyme-based nanocomposites for catalytic biomedicine are mainly divided into three types: (i) natural-enzyme based nanocomposites; (ii) artificial-nanozyme based nanocomposites; and (iii) nanocomposites of natural-enzymes and nanozymes. In this review, we discuss key aspects of enzyme-based catalytic biomedicine, including the construction of enzyme-based nanocomposites, their unique properties and applications in catalytic biomedicine. We also highlight the main challenges faced in this field, and provide relevant guidelines for the rational design and extensive application of enzyme-based nanocomposites from our point of view.

Cascade strategy for glucose oxidase-based synergistic cancer therapy using nanomaterials

Nanomaterial-based cancer therapy faces significant limitations due to the complex nature of the tumor microenvironment (TME). Starvation therapy is an emerging therapeutic approach that targets tumor cell metabolism using glucose oxidase (GOx). Importantly, it can provide a material or environmental foundation for other diverse therapeutic methods by manipulating the properties of the TME, such as acidity, hydrogen peroxide (H2O2) levels, and hypoxia degree. In recent years, this cascade strategy has been extensively applied in nanoplatforms for ongoing synergetic therapy and still holds undeniable potential. However, only a few review articles comprehensively elucidate the rational designs of nanoplatforms for synergetic therapeutic regimens revolving around the conception of the cascade strategy. Therefore, this review focuses on innovative cascade strategies for GOx-based synergetic therapy from representative paradigms to state-of-the-art reports to provide an instructive, comprehensive, and insightful reference for readers. Thereafter, we discuss the remaining challenges and offer a critical perspective on the further advancement of GOx-facilitated cancer treatment toward clinical translation.

Dual antibody-aided mesoporous nanoreactor for H2O2 self-supplying chemodynamic therapy and checkpoint blockade immunotherapy in triple-negative breast cancer

Triple-negative breast cancer (TNBC) represents a formidable challenge due to the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression, rendering it unresponsive to conventional hormonal and targeted therapies. This study introduces the development of mesoporous nanoreactors (NRs), specifically mPDA@CuO2 NRs, as acid-triggered agents capable of self-supplying H2O2 for chemodynamic therapy (CDT). To enhance therapeutic efficacy, these NRs were further modified with immune checkpoint antagonists, specifically anti-PD-L1 and anti-CD24 antibodies, resulting in the formation of dual antibody-aided mesoporous nanoreactors (dAbPD-L1/CD24-mPDA@CuO2 NRs). These NRs were designed to combine CDT and checkpoint blockade immunotherapy (CBIT) for precise targeting of 4T1 TNBC cells. Remarkably, dAbPD-L1/CD24-mPDA@CuO2 NRs exhibited tumor-targeted CDT triggered by H2O2 and successfully activated immune cells including T cells and macrophages. This integrated approach led to a remarkable inhibition of tumor growth by leveraging the collaborative effects of the therapies. The findings of this study introduce a novel and promising strategy for the integrative and collaborative treatment of refractory cancers, providing valuable insights into addressing the challenges posed by aggressive breast cancer, particularly TNBC.

Reactive X (where X = O, N, S, C, Cl, Br, and I) species nanomedicine

Reactive oxygen, nitrogen, sulfur, carbonyl, chlorine, bromine, and iodine species (RXS, where X = O, N, S, C, Cl, Br, and I) have important roles in various normal physiological processes and act as essential regulators of cell metabolism; their inherent biological activities govern cell signaling, immune balance, and tissue homeostasis. However, an imbalance between RXS production and consumption will induce the occurrence and development of various diseases. Due to the considerable progress of nanomedicine, a variety of nanosystems that can regulate RXS has been rationally designed and engineered for restoring RXS balance to halt the pathological processes of different diseases. The invention of radical-regulating nanomaterials creates the possibility of intriguing projects for disease treatment and promotes advances in nanomedicine. In this comprehensive review, we summarize, discuss, and highlight very-recent advances in RXS-based nanomedicine for versatile disease treatments. This review particularly focuses on the types and pathological effects of these reactive species and explores the biological effects of RXS-based nanomaterials, accompanied by a discussion and the outlook of the challenges faced and future clinical translations of RXS nanomedicines.

Dual ligand-assisted assembly of metal-organic frameworks on upconversion nanoparticles for NIR photodynamic therapy against hypoxic tumors

The hypoxic nature of tumor microenvironments significantly impedes the effectiveness of photodynamic therapy (PDT). To address this challenge, we constructed a pioneering nanohybrid by integrating upconversion nanoparticles (UCNPs) and metal-organic frameworks (MOFs) through a dual-ligand-assisted assembly approach. We functionalized UCNPs with polyvinyl pyrrolidone (PVP) and branched polyethylenimine (PEI), enabling the in situ growth of MOFs on multiple UCNP-conjugates. This nanohybrid, termed UCM, possesses a unique heterogeneous structure that facilitates effective energy transfer from UCNPs to MOFs, enhancing NIR-activated PDT. A distinguishing feature of UCMs is biocatalytically active MOFs, which provide them with a peroxidase-like capability. This characteristic allows UCMs to utilize the excess H2O2 in the tumor microenvironment, ensuring continuous oxygen production essential for type II PDT. Our research indicates that UCMs not only amplify the efficacy of PDT but also address the therapeutic challenges in hypoxic tumor microenvironments by supplying in situ oxygen.

Glucose oxidase virus-based nanoreactors for smart breast cancer therapy

BACKGROUND

Breast cancer is the most common malignant tumor disease and the leading cause of female mortality. The evolution of nanomaterials science opens the opportunity to improve traditional cancer therapies, enhancing therapy efficiency and reducing side effects.

METHODS AND MAJOR RESULTS

Herein, protein cages conceived as enzymatic nanoreactors were designed and produced by using virus-like nanoparticles (VLPs) from Brome mosaic virus (BMV) and containing the catalytic activity of glucose oxidase (GOx) enzyme. The GOx enzyme was encapsulated into the BMV capsid (VLP-GOx), and the resulting enzymatic nanoreactors were coated with human serum albumin (VLP-GOx@HSA) for breast tumor cell targeting. The effect of the synthesized GOx nanoreactors on breast tumor cell lines was studied in vitro. Both nanoreactor preparations VLP-GOx and VLP-GOx@HSA showed to be highly cytotoxic for breast tumor cell cultures. Cytotoxicity for human embryonic kidney cells was also found. The monitoring of nanoreactor treatment on triple-negative breast cancer cells showed an evident production of oxygen by the catalase antioxidant enzyme induced by the high production of hydrogen peroxide from GOx activity.

CONCLUSIONS AND IMPLICATIONS

The nanoreactors containing GOx activity are entirely suitable for cytotoxicity generation in tumor cells. The HSA functionalization of the VLP-GOx nanoreactors, a strategy designed for selective cancer targeting, showed no improvement in the cytotoxic effect. The GOx containing enzymatic nanoreactors seems to be an interesting alternative to improve the current cancer therapy. In vivo studies are ongoing to reinforce the effectiveness of this treatment strategy.

Bisphosphonate-incorporated coatings for orthopedic implants functionalization

Bisphosphonates (BPs), the stable analogs of pyrophosphate, are well-known inhibitors of osteoclastogenesis to prevent osteoporotic bone loss and improve implant osseointegration in patients suffering from osteoporosis. Compared to systemic administration, BPs-incorporated coatings enable the direct delivery of BPs to the local area, which will precisely enhance osseointegration and bone repair without the systemic side effects. However, an elaborate and comprehensive review of BP coatings of implants is lacking. Herein, the cellular level (e.g., osteoclasts, osteocytes, osteoblasts, osteoclast precursors, and bone mesenchymal stem cells) and molecular biological regulatory mechanism of BPs in regulating bone homeostasis are overviewed systematically. Moreover, the currently available methods (e.g., chemical reaction, porous carriers, and organic material films) of BP coatings construction are outlined and summarized in detail. As one of the key directions, the latest advances of BP-coated implants to enhance bone repair and osseointegration in basic experiments and clinical trials are presented and critically evaluated. Finally, the challenges and prospects of BP coatings are also purposed, and it will open a new chapter in clinical translation for BP-coated implants.

Cobalt ferrite nanoparticle for the elimination of CD133+CD44+ and CD44+CD24-, in breast and skin cancer stem cells, using non-ionizing treatments

Background

Cancer stem cells (CSCs) are the most challenging issue in cancer treatment, because of their high resistance mechanisms, that can cause tumor recurrence after common cancer treatments such as drug and radiation based therapies, and the insufficient efficiency of common treatments in CSCs removal and the recurrence of tumors after these treatments, it is essential to consider other methods, including non-ionizing treatments likes light-based treatments and magnetic hyperthermia (MHT).

Method and material

After synthesis, characterization and investigation, the toxicity of novel on A375 and MAD-MB-231 cell lines, magnetic hyperthermia and light-based treatments were applied. MTT assay and flow cytometry was employed to determine cell survival. the influence of combination therapy on CD44 + CD24-and CD133 + CD44+ cell population, Comparison and evaluation of combination treatments was done respectively using Combination Indices (CIs).

Result

The final nanoparticle has a high efficiency in producing hydroxyl radicals and generating heat in MHT. According to CIs, we can conclude that combined using of light-based treatment and MHT in the presence of final synthesized nanoparticle have synergistic effect and a high ability to reduce the population of stem cells in both cell lines compared to single treatments.

Conclusion

In this study a novel multi-functional nanoplatform acted well in dual and triple combined treatments, and showed a good performance in the eradication of CSCs, in A375 and MAD-MB-231 cell lines.

Smart Nanozymes for Cancer Therapy: The Next Frontier in Oncology

Nanomaterials that mimic the catalytic activity of natural enzymes in the complex biological environment of the human body are called nanozymes. Recently, nanozyme systems have been reported with diagnostic, imaging, and/or therapeutic capabilities. Smart nanozymes strategically exploit the tumor microenvironment (TME) by the in situ generation of reactive species or by the modulation of the TME itself to result in effective cancer therapy. This topical review focuses on such smart nanozymes for cancer diagnosis, and therapy modalities with enhanced therapeutic effects. The dominant factors that guide the rational design and synthesis of nanozymes for cancer therapy include an understanding of the dynamic TME, structure-activity relationships, surface chemistry for imparting selectivity, and site-specific therapy, and stimulus-responsive modulation of nanozyme activity. This article presents a comprehensive analysis of the subject including the diverse catalytic mechanisms of different types of nanozyme systems, an overview of the TME, cancer diagnosis, and synergistic cancer therapies. The strategic application of nanozymes in cancer treatment can well be a game changer in future oncology. Moreover, recent developments may pave the way for the deployment of nanozyme therapy into other complex healthcare challenges, such as genetic diseases, immune disorders, and ageing.

Recent progress in tannic acid based approaches as a natural polyphenolic biomaterial for cancer therapy: A review

Significant advancements have been noticed in cancer therapy for decades. Despite this, there are still many critical challenges ahead, including multidrug resistance, drug instability, and side effects. To overcome obstacles of these problems, various types of materials in biomedical research have been explored. Chief among them, the applications of natural compounds have grown rapidly due to their superb biological activities. Natural compounds, especially polyphenolic compounds, play a positive and great role in cancer therapy. Tannic acid (TA), one of the most famous polyphenols, has attracted widespread attention in the field of cancer treatment with unique structural, physicochemical, pharmaceutical, anticancer, antiviral, antioxidant and other strong biological features. This review concentrated on the basic structure along with the important role of TA in tuning oncological signal pathways firstly, and then focused on the use of TA in chemotherapy and preparation of delivery systems including nanoparticles and hydrogels for cancer therapy. Besides, the application of TA/Fe3+ complex coating in photothermal therapy, chemodynamic therapy, combined therapy and theranostics is discussed.

A hyperthermia-enhanced nanocatalyst based on asymmetric Au@polypyrrole for synergistic cancer Fenton/photothermal therapy

The specific tumor microenvironment is a conducive breeding ground for malignant tumors, favoring their survival, rapid proliferation, and metastasis, which is also an inevitable obstacle to tumor treatment, particularly for catalytic therapy. To address this issue, a hyperthermia-enhanced nanocatalyst (AuP@MnO2) consisting of an asymmetric Au@polypyrrole core and a MnO2 shell is constructed for synergistic cancer Fenton/photothermal therapy. In an ultra-short reaction time (15 min), the innovative introduction of a new oxidizer, tetrachloroauric acid trihydrate, not only successfully initiates the oxidative polymerization of pyrrole monomer while reducing itself to cubic Au, but also accelerates the polymerization process by supplying protic acid. After MnO2 coating, AuP@MnO2 catalyzes the conversion of antioxidant GSH and excess H2O2 into GSSG and ˙OH through Mn2+/Mn4+ ion couples, leading to oxidative damage of tumor cells. More importantly, after 1064 nm laser irradiation, more extreme oxidative imbalance and cell death are demonstrated in this work under the combined effect of photothermal and catalytic therapy, with insignificant toxicity to normal cells. This work develops an efficient one-step synthesis method of asymmetric Au@polypyrrole and provides constructive insight into its oxidative stress-based antitumor treatment.

Targeting ferroptosis opens new avenues for the development of novel therapeutics

Ferroptosis is an iron-dependent form of regulated cell death with distinct characteristics, including altered iron homeostasis, reduced defense against oxidative stress, and abnormal lipid peroxidation. Recent studies have provided compelling evidence supporting the notion that ferroptosis plays a key pathogenic role in many diseases such as various cancer types, neurodegenerative disease, diseases involving tissue and/or organ injury, and inflammatory and infectious diseases. Although the precise regulatory networks that underlie ferroptosis are largely unknown, particularly with respect to the initiation and progression of various diseases, ferroptosis is recognized as a bona fide target for the further development of treatment and prevention strategies. Over the past decade, considerable progress has been made in developing pharmacological agonists and antagonists for the treatment of these ferroptosis-related conditions. Here, we provide a detailed overview of our current knowledge regarding ferroptosis, its pathological roles, and its regulation during disease progression. Focusing on the use of chemical tools that target ferroptosis in preclinical studies, we also summarize recent advances in targeting ferroptosis across the growing spectrum of ferroptosis-associated pathogenic conditions. Finally, we discuss new challenges and opportunities for targeting ferroptosis as a potential strategy for treating ferroptosis-related diseases.

AuPt-Loaded Cu-Doped Polydopamine Nanocomposites with Multienzyme-Mimic Activities for Dual-Modal Imaging-Guided and Cuproptosis-Enhanced Photothermal/Nanocatalytic Therapy

Nanocatalytic therapy (NCT) has made great achievements in tumor treatments due to its remarkable enzyme-like activities and high specificity. Nevertheless, the limited types of nanozymes and undesirable tumor microenvironments (TME) greatly weaken the therapeutic efficiency. Developing a combination therapy integrating NCT and other strategies is of great significance for optimal treatment outcomes. Herein, a AuPt-loaded Cu-doped polydopamine nanocomposite (AuPt@Cu-PDA) with multiple enzyme-like activities was rationally designed, which integrated photothermal therapy (PTT) and NCT. The peroxidase (POD)-like activity of AuPt@Cu-PDA can catalyze hydrogen peroxide (H2O2) into ·OH, and the catalase (CAT)-mimic activity can decompose H2O2 into O2 to alleviate hypoxia of TME, and O2 can be further converted into toxic ·O2- by its oxidase (OXD)-mimic activity. In addition, Cu2+ in AuPt@Cu-PDA can effectively consume GSH overexpressed in tumor cells. The boosting of reactive oxygen species (ROS) and glutathione (GSH) depletion can lead to severe oxidative stress, which can be enhanced by its excellent photothermal performance. Most importantly, the accumulation of Cu2+ can disrupt copper homeostasis, promote the aggregation of lipoylated dihydrolipoamide S-acetyltransferase (DLAT), disrupt the mitochondrial tricarboxylic acid (TCA) cycle, and finally result in cuproptosis. Collectively, photothermal and photoacoustic imaging (PTI/PAI)-guided cuproptosis-enhanced NCT/PTT can be achieved. This work may expand the application of nanozymes in synergistic therapy and provide new insights into cuproptosis-related therapeutic strategies.

Recent Advancements in the Formulation of Nanomaterials-Based Nanozymes, Their Catalytic Activity, and Biomedical Applications

Nanozymes are nanoparticles with intrinsic enzyme-mimicking properties that have become more prevalent because of their ability to outperform conventional enzymes by overcoming their drawbacks related to stability, cost, and storage. Nanozymes have the potential to manipulate active sites of natural enzymes, which is why they are considered promising candidates to function as enzyme mimetics. Several microscopy- and spectroscopy-based techniques have been used for the characterization of nanozymes. To date, a wide range of nanozymes, including catalase, oxidase, peroxidase, and superoxide dismutase, have been designed to effectively mimic natural enzymes. The activity of nanozymes can be controlled by regulating the structural and morphological aspects of the nanozymes. Nanozymes have multifaceted benefits, which is why they are exploited on a large scale for their application in the biomedical sector. The versatility of nanozymes aids in monitoring and treating cancer, other neurodegenerative diseases, and metabolic disorders. Due to the compelling advantages of nanozymes, significant research advancements have been made in this area. Although a wide range of nanozymes act as potent mimetics of natural enzymes, their activity and specificities are suboptimal, and there is still room for their diversification for analytical purposes. Designing diverse nanozyme systems that are sensitive to one or more substrates through specialized techniques has been the subject of an in-depth study. Hence, we believe that stimuli-responsive nanozymes may open avenues for diagnosis and treatment by fusing the catalytic activity and intrinsic nanomaterial properties of nanozyme systems.

Comprehensively Optimizing Fenton Reaction Factors for Antitumor Chemodynamic Therapy by Charge-Reversal Theranostics

Chemodynamic therapy (CDT) is a highly tumor-specific treatment, while its efficacy is compromised by the intratumoral Fenton reaction efficiency, which is determined by the following reaction factors, including the availability of Fenton ions (e.g., Fe2+), the amount of H2O2, and the degree of acidity. Synchronous optimization of these factors is a big challenge for efficient CDT. Herein, a strategy of comprehensively optimizing Fenton reaction factors was developed for traceable multistage augmented CDT by charge-reversal theranostics. The customized pH-responsive poly(ethylene)glycol-poly(β-amino esters) (PEG-PAE) micelle (PM) was prepared as the carrier. Glucose oxidase (GOx), Fe2+, and pH-responsive second near-infrared (NIR-II) LET-1052 probe were coloaded by PM to obtain the final theranostics. The activity of metastable Fe2+ remained by the unsaturated coordination with PEG-PAE. Then tumor accumulation and exposure of Fe2+ were achieved by charge-reversal cationization of PEG-PAE, which was further enhanced by a GOx catalysis-triggered pH decrease. Together with the abundant H2O2 generation and pH decrease through GOx catalysis, the limiting factors of the Fenton reaction were comprehensively optimized, achieving the enhanced CDT both in vitro and in vivo. These findings provide a strategy for comprehensively optimizing intratumoral Fenton reaction factors to overcome the intrinsic drawbacks of current CDT.

Bifunctional Cascading Nanozymes Based on Carbon Dots Promotes Photodynamic Therapy by Regulating Hypoxia and Glycolysis

Photodynamic therapy (PDT) still faces great challenges with suitable photosensitizers, oxygen supply, and reactive oxygen species (ROS) accumulation, especially in the tumor microenvironment, feathering hypoxia, and high glucose metabolism. Herein, a carbon dots (CDs)-based bifunctional nanosystem (MnZ@Au), acting as photosensitizer and nanozyme with cascading glucose oxidase (GOx)- and catalase (CAT)-like reactivity, was developed for improving hypoxia and regulating glucose metabolism to enhance PDT. The MnZ@Au was constructed using Mn-doped CDs (Mn-CDs) as a core and zeolitic imidazolate framework-8 (ZIF-8) as a shell to form a hybrid (MnZ), followed by anchoring ultrasmall Au nanoparticles (AuNPs) onto the surface of MnZ through the ion exchange and in situ reduction methods. MnZ@Au catalyzed glucose consumption and oxygen generation by cascading GOx- and CAT-like nanozyme reactions, which was further enhanced by its own photothermal properties. In vitro and in vivo studies also confirmed that MnZ@Au greatly improved CDs penetration, promoted ROS accumulation, and enhanced PDT efficacy, leading to efficient tumor growth inhibition in the breast tumor model. Besides, MnZ@Au enabled photoacoustic (PA) imaging to provide a mapping of Mn-CDs distribution and oxygen saturation, showing the real-time catalytic process of MnZ@Au in vivo. 18F-Fluorodeoxyglucose positron emission tomography (18F-FDG PET) imaging also validated the decreased glucose uptake in tumors treated by MnZ@Au. Therefore, the integrated design provided a promising strategy to utilize and regulate the tumor microenvironment, promote penetration, enhance PDT, and finally prevent tumor deterioration.

Shikonin-Loaded Hollow Fe-MOF Nanoparticles for Enhanced Microwave Thermal Therapy

Microwave (MW) thermal therapy has been widely used for the treatment of cancer in clinics, but it still shows limited efficacy and a high recurrence rate owing to non-selective heat delivery and thermo-resistance. Regulating glycolysis shows great promise to improve MW thermal therapy since glycolysis plays an important role in thermo-resistance, progression, metabolism, and recurrence. Herein, we developed a delivery nanosystem of shikonin (SK)-loaded and hyaluronic acid (HA)-modified hollow Fe-MOF (HFM), HFM@SK@HA, as an efficient glycolysis-meditated agent to improve the efficacy of MW thermal therapy. The HFM@SK@HA nanosystem shows a high SK loading capacity of 31.7 wt %. The loaded SK can be effectively released from the HFM@SK@HA under the stimulation of an acidic tumor microenvironment and MW irradiation, overcoming the intrinsically low solubility and severe toxicity of SK. We also find that the HFM@SK@HA can not only greatly improve the heating effect of MW in the tumor site but also mediate MW-enhancing dynamic therapy efficiency by catalyzing the endogenous H2O2 to generate reactive oxygen species (ROS). As such, the MW irradiation treatment in the presence of HFM@SK@HA in vitro enables a highly improved anti-tumor efficacy due to the combined effect of released SK and generated ROS on inhibiting glycolysis in cancer cells. Our in vivo experiments show that the tumor inhibition rate is up to 94.75% ± 3.63% with no obvious recurrence during the 2 weeks after treatment. This work provides a new strategy for improving the efficacy of MW thermal therapy.

Advances in immunotherapy for triple-negative breast cancer

BACKGROUND

Immunotherapy has recently emerged as a treatment strategy which stimulates the human immune system to kill tumor cells. Tumor immunotherapy is based on immune editing, which enhances the antigenicity of tumor cells and increases the tumoricidal effect of immune cells. It also suppresses immunosuppressive molecules, activates or restores immune system function, enhances anti-tumor immune responses, and inhibits the growth f tumor cell. This offers the possibility of reducing mortality in triple-negative breast cancer (TNBC).

MAIN BODY

Immunotherapy approaches for TNBC have been diversified in recent years, with breakthroughs in the treatment of this entity. Research on immune checkpoint inhibitors (ICIs) has made it possible to identify different molecular subtypes and formulate individualized immunotherapy schedules. This review highlights the unique tumor microenvironment of TNBC and integrates and analyzes the advances in ICI therapy. It also discusses strategies for the combination of ICIs with chemotherapy, radiation therapy, targeted therapy, and emerging treatment methods such as nanotechnology, ribonucleic acid vaccines, and gene therapy. Currently, numerous ongoing or completed clinical trials are exploring the utilization of immunotherapy in conjunction with existing treatment modalities for TNBC. The objective of these investigations is to assess the effectiveness of various combined immunotherapy approaches and determine the most effective treatment regimens for patients with TNBC.

CONCLUSION

This review provides insights into the approaches used to overcome drug resistance in immunotherapy, and explores the directions of immunotherapy development in the treatment of TNBC.

Engineering a gold nanoparticles-carbon dots nanocomposite with pH-flexibility for monitoring hydrogen peroxide released from living cells

Constructing nanozymes with satisfactory catalytic efficiency under physiological conditions is still in great demand for facilitating the advancement of biocatalysts. We herein present a gold nanoparticles-carbon dots nanocomposite (Au-CDs) as an efficient photo-activated nanozyme for monitoring H2O2 released from living cells. The integration of CDs with AuNPs remarkably accelerates the catalytic activity at neutral pH via engaging Mn3+ ions as the mediators. Meanwhile, the reserved cyclodextrin cavities also enhance the adsorption capacity towards chromogenic substrates through host-guest interactions. Moreover, taking advantage of the inhibitory effect of H2O2 on the photo-oxidation ability of the Au-CDs nanocomposite, the Au-CDs based colorimetric method was able to realize in situ assessment of the hydrogen peroxide (H2O2) released from living cells. This method paves a new way to establish a promising biosensing platform for unraveling biological events.

Supramolecular Nanozyme System Based on Polydopamine and Polyoxometalate for Photothermal-Enhanced Multienzyme Cascade Catalytic Tumor Therapy

The advent of enzyme-facilitated cascade events in which endogenous substrates within the human body are used to generate reactive oxygen species (ROS) has spawned novel cancer treatment possibilities. In this study, a supramolecular cascade catalytic nanozyme system was successfully developed, exhibiting photothermal-enhanced multienzyme cascade catalytic and glutathione (GSH) depletion activities and ultimately triggering the apoptosis-ferroptosis synergistic tumor therapy. The nanozyme system was fabricated using β-cyclodextrin-functionalized polydopamine (PDA) as the substrate, which was then entangled with polyoxometalate (POM) via electrostatic forces and assembled with adamantane-grafted hyaluronic acid and glucose oxidase (GOx) via host-guest supramolecular interaction for tumor targeting and GOx loading. The catalytic function of GOx facilitates the conversion of glucose to H2O2 and gluconic acid. In turn, this process affirms the propitious generation of hydroxyl radical (•OH) through the POM-mediated cascade catalysis. Additionally, the POM species actively deplete the intracellular GSH pool, initiating a cascade catalytic tumor therapy. In addition, the PDA-POM-mediated photothermal hyperthermia boosted the cascade catalytic effect and increased ROS production. This confers considerable promise for photothermal therapy (PTT)/nanocatalytic cancer therapy on supramolecular nanozyme systems. The in vitro and in vivo antitumor efficacy studies demonstrated that the supramolecular cascade catalytic nanozyme system was effective at reducing tumor development while maintaining an acceptable level of biocompatibility. Henceforth, this study is to widen the scope of cascade catalytic nanoenzyme production using supramolecular techniques, as well as endeavor to delineate a prospective pathway for the application of PTT-enhanced nanocatalytic tumor 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.

Renal Clearable Magnetic Nanoreporter for Colorimetric Urinalysis of Tumor

The convenience and availability are of great significance for the early screening of cancer. Herein, a magnetic nanoreporter with renal clearable capability and activatable catalytic activity was developed for colorimetric urinalysis of tumors. The magnetic nanoreporters were prepared by loading 3.2 nm Fe3O4 nanoparticles (NPs) and glucose oxidase (GOD) into macrophage cell-derived microvesicles (MVs) through electroporation, and these compositions serve as renal clearable catalytic reporters, synergistic catalysts, and targeted delivery carriers, respectively. The magnetic nanoreporters can convert the H2O2 in the mildly acidic tumor microenvironment into hydroxyl radicals through the synergistic catalysis of Fe3O4 NPs and GOD. Then the MVs can be disintegrated by the radicals, and ultrasmall Fe3O4 NPs will be released from the MVs at the tumor site, enabling rapid clearance of the Fe3O4 NPs into urine and a direct colorimetric urinalysis of the tumor within 4 h. The magnetic nanoreporters had good biocompatibility, and the released Fe3O4 NPs were rapidly excreted from the body, avoiding the potential toxicity. We envision that the magnetic nanoreporters can be used for convenient and rapid cancer screening.

Antioxidant and Prooxidant Nanozymes: From Cellular Redox Regulation to Next-Generation Therapeutics

Nanozymes, nanomaterials with enzyme-mimicking activity, have attracted tremendous interest in recent years owing to their ability to replace natural enzymes in various biomedical applications, such as biosensing, therapeutics, drug delivery, and bioimaging. In particular, the nanozymes capable of regulating the cellular redox status by mimicking the antioxidant enzymes in mammalian cells are of great therapeutic significance in oxidative-stress-mediated disorders. As the distinction of physiological oxidative stress (oxidative eustress) and pathological oxidative stress (oxidative distress) occurs at a fine borderline, it is a great challenge to design nanozymes that can differentially sense the two extremes in cells, tissues and organs and mediate appropriate redox chemical reactions. In this Review, we summarize the advances in the development of redox-active nanozymes and their biomedical applications. We primarily highlight the therapeutic significance of the antioxidant and prooxidant nanozymes in various disease model systems, such as cancer, neurodegeneration, and cardiovascular diseases. The future perspectives of this emerging area of research and the challenges associated with the biomedical applications of nanozymes are described.

Precisely Amplifying Intracellular Oxidative Storm by Metal-Organic Coordination Polymers to Augment Anticancer Immunity

Oxidative stress accompanying the reactive oxygen species (ROS) burst governs immunocyte infiltration, activation, and differentiation in tumor microenvironments and thus can elicit robust antitumor immunity. Here, we identify a photoactive metal-organic coordination polymer (MOCP), composed of an organometallic core formed by cytotoxic mitoxantrone (MTX) acylates and photosensitive Ru(BIQ)-HDBB [BIQ = 2,2'-biquinoline, HDBB = 4,4'-di(4-benzoato)-2,2'-bipyridine] linked by Fe(II) ions via coordinate covalent bonds and an amphipathic shell encapsulating cholesterol-modified siRNA against GPX4 (siGPX4) via hydrophobic force, to precisely amplify intracellular oxidative storm. MOCPs simultaneously encapsulated MTX, Ru, and siGPX4 with efficiencies >98% and loaded Fe with efficiencies of ∼0.49%. With longer blood circulation and higher tumor accumulation, MOCPs with a 670 nm LED irradiation generate abundant ROS to induce biomembrane dysfunction and subsequently contribute to ferroptotic and immunogenic cell death, which drive tumor-associated antigen-specific immunity. MTX analogs contributed to Type I immunogenic cell death (ICD), while oxidative storm served as a damager for endo/lysosomal escape, an initiator for ferroptosis, and an inducer for type II ICD. Moreover, the blockade of CD73 that reduces extoATP catabolism unleashes immunosuppression, finally enhancing antitumor immune stimulation of MOCPs to promote orthotopic mammary cancer regression and prevent postoperative advanced cancer from recurrence and metastasis. MOCPs by exposing sufficient antigenicity thus provide a platform to synergize immune checkpoint inhibitors for the treatment of immunologically cold tumors.

PD-L1 Blockade Peptide-Modified Polymeric Nanoparticles for Oxygen-Independent-Based Hypoxic Tumor Photo/Thermodynamic Immunotherapy

Distant metastasis of malignant tumors is considered to be the main culprit for the failure of current antitumor treatments. Conventional single treatments often exhibit limited efficacy in inhibiting tumor metastasis. Therefore, there is a growing interest in developing collaborative antitumor strategies based on photothermal therapy (PTT) and free-radical-generated photodynamic therapy (PDT), especially utilizing oxygen-independent nanoplatforms, to address this challenge. Such antitumor strategies can enhance the therapeutic outcomes by ensuring the cytotoxicity of free radicals even in the hypoxic tumor microenvironment, thereby improving the effective suppression of primary tumors. Additionally, these approaches can stimulate the production of tumor-associated antigens and amplify the immunogenic cell death (ICD) effects, potentially feasible for enhancing the therapeutic outcomes of immunotherapy. Herein, we fabricated a functional nanosystem that co-loads IR780 and 2,2'-azobis[2-(2-imidazolin-2-yl)propane]-dihydrochloride (AIPH) to realize PTT-triggered thermodynamic combination therapy via the oxygen-independent pathway for the elimination of primary tumors. Furthermore, the nanocomposites were surface-decorated with a predesigned complex peptide (PLGVRGC-anti-PD-L1 peptide, MMP-sensitive), which facilitated the immunotherapy targeting distant tumors. Through the specific recognition of matrix metalloproteinase (MMP), the sensitive segment on the obtained aNC@IR780A was cleaved. As a result, the freed anti-PD-L1 peptide effectively blocked immune checkpoints, leading to the infiltration and activation of T cells (CTLs). This nanosystem was proven to be effective at inhibiting both primary tumors and distant tumors, providing a promising combination strategy for tumor PTT/TDT/immunotherapy.

Prussian blue analog with separated active sites to catalyze water driven enhanced catalytic treatments

Chemodynamic therapy (CDT) uses the Fenton or Fenton-like reaction to yield toxic ‧OH following H2O2 → ‧OH for tumoral therapy. Unfortunately, H2O2 is often taken from the limited endogenous supply of H2O2 in cancer cells. A water oxidation CoFe Prussian blue (CFPB) nanoframes is presented to provide sustained, external energy-free self-supply of ‧OH from H2O to process CDT and/or photothermal therapy (PTT). Unexpectedly, the as-prepared CFPB nanocubes with no near-infrared (NIR) absorption is transformed into CFPB nanoframes with NIR absorption due to the increased Fe3+-N ≡ C-Fe2+ composition through the proposed proton-induced metal replacement reactions. Surprisingly, both the CFPB nanocubes and nanoframes provide for the self-supply of O2, H2O2, and ‧OH from H2O, with the nanoframe outperforming in the production of ‧OH. Simulation analysis indicates separated active sites in catalyzation of water oxidation, oxygen reduction, and Fenton-like reactions from CFPB. The liposome-covered CFPB nanoframes prepared for controllable water-driven CDT for male tumoral mice treatments.

Constructing Spatiotemporally Controllable Biocatalytic Cascade in RBC Nanovesicles for Precise Tumor Therapy Based on Reversibly Induced Glucose Oxidase-Magnetoferritin Dimers

Chemodynamic therapy is a promising tumor treatment strategy. However, it remains a great challenge to overcome the unavoidable off-target damage to normal tissues. In this work, it is discovered that magnetoferritin (M-HFn, biomimic peroxidase) can form nanocomplexes with glucose oxidase (GOD) in the presence of glucose, thus inhibiting the enzyme activity of GOD. Interestingly, GOD&M-HFn (G-M) nanocomplexes can dissociate under near-infrared (NIR) laser, reactivating the enzyme cascade. Based on this new finding, a spatiotemporally controllable biocatalytic cascade in red blood cell (RBC) nanovesicles (G-M@RBC-A) is fabricated for precise tumor therapy, which in situ inhibits enzyme cascade between GOD and M-HFn during blood circulation and reactivates the cascade activity in tumor site by NIR laser irradiation. In RBC nanovesicles, GOD is grabbed by M-HFn to form G-M nanocomplexes in the presence of glucose, thus inhibiting the Fenton reaction and reducing side effects. However, after NIR laser irradiation, G-M nanocomplexes are spatiotemporally dissociated and the cascade activity is reactivated in the tumor site, initiating reactive oxygen species damage to cancer cells in vivo. Therefore, this work provides new insight into the fabrication of spatiotemporally controllable biocatalytic cascade for precise cancer therapy in the future.

Multistage-Responsive Dual-Enzyme Nanocascades for Synergistic Radiosensitization-Starvation Cancer Therapy

Radiotherapy is a common cancer treatment approach in clinical practice, yet its efficacy has been restricted by tumor hypoxia. Nanomaterials-mediated systemic delivery of glucose oxidase (GOx) and catalase (CAT) or CAT-like nanoenzymes holds the potential to enhance tumor oxygenation. However, they face the challenge of intermediate (hydrogen peroxide [H2 O2 ]) escape during systemic circulation if the enzyme pair is not closely placed to largely decompose H2 O2 , leading to oxidative stress on normal tissues. In the present study, a oxygen-generating nanocascade, n(GOx-CAT)C7A , constructed by strategically placing an enzymatic cascade (GOx and CAT) within a polymeric coating rich in hexamethyleneimine (C7A) moieties, is reported. During blood circulation, C7A remains predominantly non-protonated , achieving prolonged blood circulation due to its low-fouling surface. Once n(GOx-CAT)C7A reaches the tumor site, the acidic tumor microenvironment (TME) induces protonation of C7A moieties, resulting in a positively charged surface for enhanced tumor transcytosis. Moreover, GOx and CAT are covalently conjugated into close spatial proximity (<10 nm) for effective H2 O2  elimination. As demonstrated by the in vivo results, n(GOx-CAT)C7A achieves effective tumor retention and oxygenation, potent radiosensitization and antitumor effects. Such a dual-enzyme nanocascade for smart O2  delivery holds great potential for enhancing the hypoxia-compromised cancer therapies.

Spontaneous formation of MXene-oxidized sono/chemo-dynamic sonosensitizer/nanocatalyst for antibacteria and bone-tissue regeneration

Prolonged and incurable bacterial infections in soft tissue and bone are currently causing large challenges in the clinic. Two-dimensional (2D) materials have been designed to address these issues, but materials with satisfying therapeutic effects are still needed. Herein, CaO₂-loaded 2D titanium carbide nanosheets (CaO₂-TiO_x@Ti₃C₂, C-T@Ti₃C₂) were developed. Surprisingly, this nanosheet exhibited sonodynamic ability, in which CaO₂ caused the in situ oxidation of Ti₃C₂ MXene to produce acoustic sensitiser TiO₂ on its surface. In addition, this nanosheet displayed chemodynamic features, which promoted a Fenton reaction triggered by self-supplied H₂O₂. We detected that C-T@Ti₃C₂ nanosheets increased reactive oxygen species (ROS) production in response to sonodynamic therapy, which displayed an ideal antibacterial effect. Furthermore, these nanoreactors facilitated the deposition of Ca²⁺, which promoted osteogenic transformation and enhanced bone quality in osteomyelitis models. Herein, a wound healing model and prosthetic joint infection (PJI) model were established, and the C-T@Ti₃C₂ nanosheets played a protective role in these models. Taken together, the results indicated that the C-T@Ti₃C₂ nanosheets function as a multifunctional instrument with sonodynamic features, which might reveal information regarding the treatment of bacterial infections during wound healing.

Nanozymes with Peroxidase-like Activity for Ferroptosis-Driven Biocatalytic Nanotherapeutics of Glioblastoma Cancer: 2D and 3D Spheroids Models

Glioblastoma (GBM) is the most common primary brain cancer in adults. Despite the remarkable advancements in recent years in the realm of cancer diagnosis and therapy, regrettably, GBM remains the most lethal form of brain cancer. In this view, the fascinating area of nanotechnology has emerged as an innovative strategy for developing novel nanomaterials for cancer nanomedicine, such as artificial enzymes, termed nanozymes, with intrinsic enzyme-like activities. Therefore, this study reports for the first time the design, synthesis, and extensive characterization of innovative colloidal nanostructures made of cobalt-doped iron oxide nanoparticles chemically stabilized by a carboxymethylcellulose capping ligand (i.e., Co-MION), creating a peroxidase-like (POD) nanozyme for biocatalytically killing GBM cancer cells. These nanoconjugates were produced using a strictly green aqueous process under mild conditions to create non-toxic bioengineered nanotherapeutics against GBM cells. The nanozyme (Co-MION) showed a magnetite inorganic crystalline core with a uniform spherical morphology (diameter, 2R = 6-7 nm) stabilized by the CMC biopolymer, producing a hydrodynamic diameter (H_D) of 41-52 nm and a negatively charged surface (ZP~-50 mV). Thus, we created supramolecular water-dispersible colloidal nanostructures composed of an inorganic core (Cox-MION) and a surrounding biopolymer shell (CMC). The nanozymes confirmed the cytotoxicity evaluated by an MTT bioassay using a 2D culture in vitro of U87 brain cancer cells, which was concentration-dependent and boosted by increasing the cobalt-doping content in the nanosystems. Additionally, the results confirmed that the lethality of U87 brain cancer cells was predominantly caused by the production of toxic cell-damaging reactive oxygen species (ROS) through the in situ generation of hydroxyl radicals (·OH) by the peroxidase-like activity displayed by nanozymes. Thus, the nanozymes induced apoptosis (i.e., programmed cell death) and ferroptosis (i.e., lipid peroxidation) pathways by intracellular biocatalytic enzyme-like activity. More importantly, based on the 3D spheroids model, these nanozymes inhibited tumor growth and remarkably reduced the malignant tumor volume after the nanotherapeutic treatment (ΔV~40%). The kinetics of the anticancer activity of these novel nanotherapeutic agents decreased with the time of incubation of the GBM 3D models, indicating a similar trend commonly observed in tumor microenvironments (TMEs). Furthermore, the results demonstrated that the 2D in vitro model overestimated the relative efficiency of the anticancer agents (i.e., nanozymes and the DOX drug) compared to the 3D spheroid models. These findings are notable as they evidenced that the 3D spheroid model resembles more precisely the TME of "real" brain cancer tumors in patients than 2D cell cultures. Thus, based on our groundwork, 3D tumor spheroid models might be able to offer transitional systems between conventional 2D cell cultures and complex biological in vivo models for evaluating anticancer agents more precisely. These nanotherapeutics offer a wide avenue of opportunities to develop innovative nanomedicines for fighting against cancerous tumors and reducing the frequency of severe side effects in conventionally applied chemotherapy-based treatments.

Dual-infinite coordination polymer-engineered nanomedicines for dual-ion interference-mediated oxidative stress-dependent tumor suppression

Recently, nanomedicine design has shifted from simple nanocarriers to nanodrugs with intrinsic antineoplastic activities for therapeutic performance optimization. In this regard, degradable nanomedicines containing functional inorganic ions have blazed a highly efficient and relatively safe ion interference paradigm for cancer theranostics. Herein, given the potential superiorities of infinite coordination polymers (ICPs) in degradation peculiarity and functional integration, a state-of-the-art dual-ICP-engineered nanomedicine is elaborately fabricated via integrating ferrocene (Fc) ICPs and calcium-tannic acid (Ca-TA) ICPs. Thereinto, Fc ICPs, and Ca-TA ICPs respectively serve as suppliers of ferrous iron ions (Fe²⁺) and calcium ions (Ca²⁺). After the acid-responsive degradation of ICPs, released TA from Ca-TA ICPs facilitated the conversion of released ferric iron (Fe³⁺) from Fc ICPs into highly active Fe²⁺. Owing to the dual-path oxidative stress and neighboring effect mediated by Fe²⁺ and Ca²⁺, such a dual-ICP-engineered nanomedicine effectively induces dual-ion interference against triple-negative breast cancer (TNBC). Therefore, this work provides a novel antineoplastic attempt to establish ICP-engineered nanomedicines and implement ion interference-mediated synergistic therapy.

Degradable iron-rich mesoporous dopamine as a dual-glutathione depletion nanoplatform for photothermal-enhanced ferroptosis and chemodynamic therapy

Glutathione (GSH) is a crucial factor in limiting the effects of chemodynamic therapy (CDT) and ferroptosis, an iron-based cell death pathway. Based on this, we constructed iron-rich mesoporous dopamine (MPDA@Fe) nanovehicles with a dual-GSH depletion function by combining MPDA and Fe. Poly (ethylene glycol) (PEG) was further modified to provide desirable stability (PM@Fe) and glucose oxidase (GOx) was grafted onto PM@Fe (GPM@Fe) to address the limitation of hydrogen peroxide (H₂O₂). After the nanoparticles reached the tumor site, the weakly acidic microenvironment promoted the release of Fe. Then Fe^II reacted with H₂O₂ to generate hydroxyl radical (OH) and Fe^III. The generated Fe^III was reduced to Fe^II by GSH, which circularly participated in the Fenton reaction and continuously produced tumor inhibitory free radicals. Meanwhile, GOx consumed glucose to provide H₂O₂ for the reaction. MPDA had also been reported to deplete GSH. Therefore, dual consumption of GSH led to the destruction of intracellular redox balance and inhibition of glutathione-dependent peroxidase 4 (GPX4) expression, resulting in an increase in lipid peroxides (LPO) and further induction of ferroptosis. Additionally, MPDA-mediated photothermal therapy (PTT) raised the temperature of tumor area and produced photothermal-enhanced cascade effects. Hence, the synergistic strategy that combined dual-GSH depletion-induced ferroptosis, enhanced CDT and photothermal cascade enhancement based on MPDA@Fe could provide more directions for designing nanomedicines for cancer treatment.

Emulsion-oriented assembly for Janus double-spherical mesoporous nanoparticles as biological logic gates

The ability of Janus nanoparticles to establish biological logic systems has been widely exploited, yet conventional non/uni-porous Janus nanoparticles are unable to fully mimic biological communications. Here we demonstrate an emulsion-oriented assembly approach for the fabrication of highly uniform Janus double-spherical MSN&mPDA (MSN, mesoporous silica nanoparticle; mPDA, mesoporous polydopamine) nanoparticles. The delicate Janus nanoparticle possesses a spherical MSN with a diameter of ~150 nm and an mPDA hemisphere with a diameter of ~120 nm. In addition, the mesopore size in the MSN compartment is tunable from ~3 to ~25 nm, while those in the mPDA compartments range from ~5 to ~50 nm. Due to the different chemical properties and mesopore sizes in the two compartments, we achieve selective loading of guests in different compartments, and successfully establish single-particle-level biological logic gates. The dual-mesoporous structure enables consecutive valve-opening and matter-releasing reactions within one single nanoparticle, facilitating the design of single-particle-level logic systems.

Enzyme/inorganic nanoparticle dual-loaded animal protein/plant protein composite nanospheres and their synergistic effect in cancer therapy

It is a viable strategy to develop a safer and tumor-specific method by considering the tumor microenvironment to optimize the curative effect and reduce the side effects in cancer treatment. In this study, glucose oxidase (GOx) and Fe₃O₄ nanoparticles were successfully loaded inside regenerated silk fibroin/zein (RSF/zein) nanospheres to obtain dual-loaded Fe₃O₄/GOx@RSF/zein nanospheres. The unique structure of the RSF/zein nanospheres reported in our previous work was favorable to loading sufficient amounts of GOx and Fe₃O₄ nanoparticles in the nanospheres. For Fe₃O₄/GOx@RSF/zein nanospheres, GOx depletes endogenous glucose via an enzyme-catalyzed bioreaction, simultaneously generating plenty of H₂O₂in situ. It was further catalyzed through a Fe₃O₄-mediated Fenton reaction to form highly toxic hydroxyl free radicals (˙OH) in the acidic tumor microenvironment. These two successive reactions made up the combination of starvation therapy and chemodynamic therapy during cancer treatment. The catalytic activity of GOx loaded in the RSF/zein nanospheres is similar to that of the pristine enzyme. It was maintained for more than one month due to the protection of the RSF/zein nanospheres. The methylene blue degradation results confirmed the sequential reaction by GOx and Fe₃O₄ from Fe₃O₄/GOx@RSF/zein nanospheres. The in vitro experiments demonstrated that the Fe₃O₄/GOx@RSF/zein nanospheres entered MCF-7 cells and generated ˙OH free radicals. Therefore, these Fe₃O₄/GOx@RSF/zein nanospheres exhibited a considerable synergistic therapeutic effect. They showed more efficient suppression in cancer cell growth than either single-loaded GOx@RSF/zein or Fe₃O₄@RSF/zein nanospheres, achieving the design goal for the nanospheres. Therefore, the Fe₃O₄/GOx@RSF/zein nanospheres cut off the nutrient supply due to the strong glucose dependence of tumor cells and generated highly toxic ˙OH free radicals in tumor cells, effectively enhancing the anticancer effect and minimizing side effects. Therefore, in future clinical applications, the Fe₃O₄/GOx@RSF/zein nanospheres developed in this study have significant potential for combining starvation and chemodynamic therapy.

Dual-inhibition of lactate metabolism and Prussian blue-mediated radical generation for enhanced chemodynamic therapy and antimetastatic effect

Numerous research studies have proved that lactate is pivotal in tumor proliferation, metastasis, and recurrence, so disrupting the lactate metabolism in the tumor microenvironment (TME) has become one of the effective methods of tumor treatment. Herein, we have developed a versatile nanoparticle (HCLP NP) based on hollow Prussian blue (HPB) as the functional carrier for loading α-cyano-4-hydroxycinnamate (CHC), and lactate oxidase (LOD), followed by coating with polyethylene glycol to enhance chemodynamic therapy (CDT) and the antimetastatic effect of cancer. The obtained HCLP NPs would be degraded under endogenous mild acidity within the TME to simultaneously release CHC and LOD. CHC inhibits the expression of monocarboxylate transporter 1 in tumors, thereby interrupting the uptake of lactate from the outside and alleviating tumor hypoxia by reducing lactate aerobic respiration. Meanwhile, the released LOD can catalyze the decomposition of lactate into hydrogen peroxide, further enhancing the efficacy of CDT by generating plenty of toxic reactive oxygen species through the Fenton reaction. The strong absorbance at about 800 nm endows HCLP NPs with excellent photoacoustic imaging properties. Both in vitro and in vivo studies have demonstrated that HCLP NPs can inhibit tumor growth and metastasis, providing a new possibility for tumor therapy.

Intelligent Pd1.7Bi@CeO2 Nanosystem with Dual-Enzyme-Mimetic Activities for Cancer Hypoxia Relief and Synergistic Photothermal/Photodynamic/Chemodynamic Therapy

Reactive oxygen species-mediated therapeutic strategies, including chemodynamic therapy (CDT) and photodynamic therapy (PDT), have exhibited translational promise for effective cancer management. However, monotherapy often ends up with the incomplete elimination of the entire tumor due to inherent limitations. Herein, we report a core-shell-structured Pd_1.7Bi@CeO₂-ICG (PBCI) nanoplatform constructed by a facile and effective strategy for synergistic CDT, PDT, and photothermal therapy. In the system, both Pd_1.7Bi and CeO₂ constituents exhibit peroxidase- and catalase-like characteristics, which not only generate cytotoxic hydroxyl radicals (^•OH) for CDT but also produce O₂ in situ and relieve tumor hypoxia for enhanced PDT. Furthermore, upon 808 nm laser irradiation, Pd_1.7Bi@CeO₂ and indocyanine green (ICG) coordinately prompt favorable photothermia, resulting in thermodynamically amplified catalytic activities. Meanwhile, PBCI is a contrast agent for near-infrared fluorescence imaging to determine the optimal laser therapeutic window in vivo. Consequently, effective tumor elimination was realized through the above-combined functions. The as-synthesized unitary PBCI theranostic nanoplatform represents a potential one-size-fits-all approach in multimodal synergistic therapy of hypoxic tumors.

Recent Advances of Fe(III)/Fe(II)-MPNs in Biomedical Applications

Metal-phenolic networks (MPNs) are a new type of nanomaterial self-assembled by metal ions and polyphenols that have been developed rapidly in recent decades. They have been widely investigated, in the biomedical field, for their environmental friendliness, high quality, good bio-adhesiveness, and bio-compatibility, playing a crucial role in tumor treatment. As the most common subclass of the MPNs family, Fe-based MPNs are most frequently used in chemodynamic therapy (CDT) and phototherapy (PTT), where they are often used as nanocoatings to encapsulate drugs, as well as good Fenton reagents and photosensitizers to improve tumor therapeutic efficiency substantially. In this review, strategies for preparing various types of Fe-based MPNs are first summarized. We highlight the advantages of Fe-based MPNs under the different species of polyphenol ligands for their application in tumor treatments. Finally, some current problems and challenges of Fe-based MPNs, along with a future perspective on biomedical applications, are discussed.

Dual Nanozyme-Driven PtSn Bimetallic Nanoclusters for Metal-Enhanced Tumor Photothermal and Catalytic Therapy

Specific generation of reactive oxygen species (ROS) within tumors in situ catalyzed by nanozymes is a promising strategy for cancer therapeutics. However, it remains a significant challenge to fabricate highly efficient nanozymes acting in the tumor microenvironment. Herein, we develop a bimetallic nanozyme (Pt₅₀Sn₅₀) with the photothermal enhancement of dual enzymatic activities for tumor catalytic therapy. The structures and activities of PtSn bimetallic nanoclusters (BNCs) with different Sn content are explored and evaluated systematically. Experimental comparisons show that the Pt₅₀Sn₅₀ BNCs exhibit the highest activities among all those investigated, including enzymatic activity and photothermal property, due to the generation of SnO_2-x with oxygen vacancy (O_vac) sites on the surface of Pt₅₀Sn₅₀ BNCs. Specifically, the Pt₅₀Sn₅₀ BNCs exhibit photothermal-enhanced peroxidase-like and catalase-like activities, as well as a significantly enhanced anticancer efficacy in both multicellular tumor spheroids and in vivo experiments. Due to the high X-ray attenuation coefficient and excellent light absorption property, the Pt₅₀Sn₅₀ BNCs also show dual-mode imaging capacity of computed tomography and photoacoustic imaging, which could achieve in vivo real-time monitoring of the therapeutic process. Therefore, this work will advance the development of noble-metal nanozymes with optimal composition for efficient tumor catalytic therapy.

NIR-II Light-Activated Gold Nanorods for Synergistic Thermodynamic and Photothermal Therapy of Tumor

There are tricky challenges in tumor therapy due to the hypoxic tumor microenvironment, inevitably inhibiting the treatment efficacy of the traditional photodynamic therapy (PDT), radiation therapy (RT), and sonodynamic therapy (SDT). Herein, to overcome tumor hypoxia limitation, we constructed a near-infrared II (NIR-II) light-triggered thermodynamic therapy (TDT) nanoplatform of Au@mSiO₂-AIPH@PCM/PEG (ASAPP) by integrating the Au nanorods (Au NRs) and thermally activated alkyl free radical-releasing molecules (AIPH). Au NRs@mSiO₂ was used as a photothermally responsive material and AIPH carrier, and the hot-melt phase-change material (PCM) was used as a capping agent to prevent leakage of AIPH during blood circulation. Upon NIR-II light irradiation, heat-triggered free radical release from AIPH was successfully achieved for killing cancer cells in vitro and in vivo without oxygen dependence, leading to synergistically enhanced antitumor therapy.