Cascade catalysis nanozyme for interfacial functionalization in combating implant infections associated with diabetes via sonodynamic therapy and adaptive immune activation

Innovative solutions are required for the intervention of implant associated infections (IAIs), especially for bone defect patients with chronic inflammatory diseases like diabetes mellitus (DM). The complex immune microenvironment of infections renders implants with direct antibacterial ability inadequate for the prolonged against of bacterial infections. Herein, a synergistic treatment strategy was presented that combined sonodynamic therapy (SDT) with adaptive immune modulation to treat IAIs in diabetes patients. A multifunctional coating was created on the surface of titanium (Ti) implants, consisting of manganese dioxide nanoflakes (MnO2 NFs) with cascade catalytic enzyme activity and a responsive degradable hydrogel containing a sonosensitizer. The reactive oxygen species (ROS) generated by glucose-hydrogen peroxide (H2O2) cascade catalysis and ultrasound (US) activation sonosensitizer helped kill bacteria and release bacterial antigens. Meanwhile, Mn2+ facilitated dendritic cells (DCs) maturation, enhancing antigen presentation to activate both cellular and humoral adaptive immunity against bacterial infections. This approach effectively eliminated bacteria in established diabetic IAIs model and activated systemic antibacterial immunity, providing long-term antibacterial protection. This study presents a non-antibiotic immunotherapeutic strategy for fighting IAIs in chronic diseases.

Reactive oxygen species responsive chitooligosaccharides based nanoplatform for sonodynamic therapy in mammary cancer

Sonodynamic therapy (SDT) has been extensively studied as a new type of non-invasive treatment for mammary cancer. However, the poor water solubility and defective biocompatibility of sonosensitizers during SDT hinder the sonodynamic efficacy. Herein, a nanoplatform has been developed to achieve high efficient SDT against mammary cancer through the host-guest interaction of β-cyclodextrin/5-(4-hydroxyphenyl)-10,15,20-triphenylporphyrin (β-CD-TPP) and ferrocenecarboxylic acid/chitooligosaccharides (FC-COS). Moreover, the glucose oxidase (GOx) was loaded through electrostatic adsorption, which efficiently restricts the energy supply in tumor tissues, thus enhancing the therapeutic efficacy of SDT for tumors. Under optimal conditions, the entire system exhibited favorable water solubility, suitable particle size and viable biocompatibility. This facilitated the integration of the characteristics of starvation therapy and sonodynamic therapy, resulting in efficient inhibition of tumor growth with minimal side effects in vivo. This work may provide new insights into the application of natural oligosaccharides for construct multifunctional nanocarrier systems, which could optimize the design and development of sonodynamic therapy strategies and even combination therapy strategies.

Four Birds with One Stone: A Bandgap-Regulated Multifunctional Schottky Heterojunction for Robust Synergistic Antitumor Therapy upon Endo-/Exogenous Stimuli

Considering the profound impact of structure on heterojunction catalysts, the rational design of emerging catalysts with optimized energy band structures is required for antitumor efficiency. Herein, we select titanium nitride (TiN) and Pt to develop a multifunctional Schottky heterojunction named Pt/H-TiN&SRF (PHTS) nanoparticles (NPs) with a narrowed bandgap to accomplish "four birds with one stone" involving enzyo/sono/photo three modals and additional ferroptosis. The in situ-grown Pt NPs acted as electron traps that can cause the energy band to bend upward and form a Schottky barrier, thereby facilitating the separation of electron/hole pairs in exogenous stimulation catalytic therapy. In addition, endogenous catalytic reactions based on peroxidase (POD)- and catalase (CAT)-mimicking activities can also be amplified, triggering intense oxidative stress, in which CAT-like activity decomposes endogenous H2O2 into O2 alleviating hypoxia and provides reactants for sonodynamic therapy. Moreover, PHTS NPs can elicit mild photothermal therapy with boosted photothermal properties as well as ferroptosis with loaded ferroptosis inducer sorafenib for effective tumor ablation and apoptosis-ferroptosis synergistic tumor inhibitory effect. In summary, this paper proposes an attractive design for antitumor strategies and highlights findings for heterojunction catalytic therapy with potential in tumor theranostics.

Stimuli-Responsive Polymersomes: Reshaping the Immunosuppressive Tumor Microenvironment

The progression of cancer involves mutations in normal cells, leading to uncontrolled division and tissue destruction, highlighting the complexity of tumor microenvironments (TMEs). Immunotherapy has emerged as a transformative approach, yet the balance between efficacy and safety remains a challenge. Nanoparticles such as polymersomes offer the possibility to precisely target tumors, deliver drugs in a controlled way, effectively modulate the antitumor immunity, and notably reduce side effects. Herein, stimuli-responsive polymersomes, with capabilities for carrying multiple therapeutics, are highlighted for their potential in enhancing antitumor immunity through mechanisms like inducing immunogenic cell death and activating STING (stimulator of interferon genes), etc. The recent progress of utilizing stimuli-responsive polymersomes to reshape the TME is reviewed here. The advantages and limitations to applied stimuli-responsive polymersomes are outlined. Additionally, challenges and future prospects in leveraging polymersomes for cancer therapy are discussed, emphasizing the need for future research and clinical translation.

Strategies to enhance the therapeutic efficacy of anti-PD-1 antibody, anti-PD-L1 antibody and anti-CTLA-4 antibody in cancer therapy

Although immune checkpoint inhibitors (anti-PD-1 antibody, anti-PD-L1 antibody, and anti-CTLA-4 antibody) have displayed considerable success in the treatment of malignant tumors, the therapeutic effect is still unsatisfactory for a portion of patients. Therefore, it is imperative to develop strategies to enhance the effect of these ICIs. Increasing evidence strongly suggests that the key to this issue is to transform the tumor immune microenvironment from a state of no or low immune infiltration to a state of high immune infiltration and enhance the tumor cell-killing effect of T cells. Therefore, some combination strategies have been proposed and this review appraise a summary of 39 strategies aiming at enhancing the effectiveness of ICIs, which comprise combining 10 clinical approaches and 29 foundational research strategies. Moreover, this review improves the comprehensive understanding of combination therapy with ICIs and inspires novel ideas for tumor immunotherapy.

Mitochondria-targeted sonodynamic modulation of neuroinflammation to protect against myocardial ischemia‒reperfusion injury

Sympathetic hyperactivation and inflammatory responses are the main causes of myocardial ischemia‒reperfusion (I/R) injury and myocardial I/R-related ventricular arrhythmias (VAs). Previous studies have demonstrated that light-emitting diodes (LEDs) could modulate post-I/R neuroinflammation, thus providing protection against myocardial I/R injury. Nevertheless, further applications of LEDs are constrained due to the low penetration depth (<1 cm) and potential phototoxicity. Low-intensity focused ultrasound (LIFU), an emerging noninvasive neuromodulation strategy with deeper penetration depth (∼10 cm), has been confirmed to modulate sympathetic nerve activity and inflammatory responses. Sonodynamic therapy (SDT), which combines LIFU with sonosensitizers, confers additional advantages, including superior therapeutic efficacy, precise localization of neuronal modulation and negligible side effects. Herein, LIFU and SDT were introduced to modulate post-myocardial I/R neuroinflammation to protect against myocardial I/R injury. The results indicated that LIFU and SDT inhibited sympathetic neural activity, suppressed the activation of astrocytes and microglia, and promoted microglial polarization towards the M2 phenotype, thereby attenuating myocardial I/R injury and preventing I/R-related malignant VAs. These insights suggest that LIFU and SDT inspire a noninvasive and efficient neuroinflammatory modulation strategy with great clinical translation potential thus benefiting more patients with myocardial I/R in the future. STATEMENT OF SIGNIFICANCE: Myocardial ischemia-reperfusion (I/R) may cause I/R injury and I/R-induced ventricular arrhythmias. Sympathetic hyperactivation and inflammatory response play an adverse effect in myocardial I/R injury. Previous studies have shown that light emitting diode (LED) can regulate I/R-induced neuroinflammation, thus playing a myocardial protective role. However, due to the low penetration depth and potential phototoxicity of LED, it is difficult to achieve clinical translation. Herein, we introduced sonodynamic modulation of neuroinflammation to protect against myocardial I/R injury, based on mitochondria-targeted nanosonosensitizers (CCNU980 NPs). We demonstrated that sonodynamic modulation could promote microglial autophagy, thereby preventing myocardial I/R injury and I/R-induced ventricular arrhythmias. This is the first example of sonodynamic modulation of myocardial I/R-induced neuroinflammation, providing a novel strategy for clinical translation.

In-Situ Grown Nanocrystal TiO2 on 2D Ti3C2 Nanosheets with Anti-Tumor Activity from Photo-Sonodynamic Treatment and Immunology

Introduction

Traditional cancer treatment strategies often have severe toxic side effects and poor therapeutic efficacy. To address the long-standing problems related to overcoming the complexity of tumors, we develop a novel nanozyme based on the in situ oxidation of 2D Ti3C2 structure to perform simultaneous phototherapy and sonodynamic therapy on tumors. Ti3C2 nanozymes exhibit multi-enzyme activity, including intrinsic peroxidase (POD) activities, which can react with H2O2 in the tumor microenvironment. This new material can construct Ti3C2/TiO2 heterostructures in vivo.

Methods

Photothermal (PTT), sonodynamic (SDT) effects, and photoacoustic (PA) image-guided synergy therapy can be achieved. Finally, anticancer immune responses occur with this nanozyme. In vivo experiments revealed that the Ti3C2/TiO2 heterostructure inhibited tumor growth.

Results

Complementarily, our results showed that the Ti3C2/TiO2 heterostructure enhanced the immunogenic activity of tumors by recruiting cytotoxic T cells, thereby enhancing the tumor ablation effect. Mechanistic studies consistently indicated that Reactive Oxygen Species (ROS) regulates apoptosis of HCC cells by modulating NRF2/OSGIN1 signaling both in vitro and in vivo. As a result, Ti3C2 nanozyme effectively inhibited tumor through its synergistic ability to modulate ROS and enhance immune infiltration of cytotoxic T cells in the tumor microenvironment.

Discussion

These findings open up new avenues for enhancing 2D Ti3C2 nanosheets and suggest a new way to develop more effective sonosensitizers for the treatment of cancer.

A Fully Integrated Conformal Wearable Ultrasound Patch for Continuous Sonodynamic Therapy

Cancer treatment is a continuous process, that the current therapy cannot meet the requirement well, including radiotherapy and chemotherapy. Wearable ultrasound device has the potential for continuous sonodynamic therapy due to its portability. However, the miniaturization of ultrasonic probe, system integration of device, and the strategy of continuous treatment are still urgent issues to be addressed. Herein, a portable wearable antitumor system is introduced, which utilizes a custom-developed multiplexed ultrasonic patch array (CWUS Patch) to accurately focus ultrasound on the lesion site and controllably stimulate sonosensitizer to produce a large amount of toxic reactive oxygen species (ROS). The system enables dynamic control of the ultrasound patches and allows real-time adjustments to optimize their performance in various applications, providing greater flexibility and precision in healthcare technology. Furthermore, the excellent penetration property of ultrasound into tumor tissues that induce synchronous apoptosis of tumor cells from the inside out is verified through a mouse model of breast cancer. This fully integrated conformal wearable ultrasound system provides a promising approach to noninvasively, continuously, and efficiently treat deep tumors.

Recent Progress in Photothermal, Photodynamic and Sonodynamic Cancer Therapy: Through the cGAS-STING Pathway to Efficacy-Enhancing Strategies

Photothermal, photodynamic and sonodynamic cancer therapies offer opportunities for precise tumor ablation and reduce side effects. The cyclic guanylate adenylate synthase-stimulator of interferon genes (cGAS-STING) pathway has been considered a potential target to stimulate the immune system in patients and achieve a sustained immune response. Combining photothermal, photodynamic and sonodynamic therapies with cGAS-STING agonists represents a newly developed cancer treatment demonstrating noticeable innovation in its impact on the immune system. Recent reviews have concentrated on diverse materials and their function in cancer therapy. In this review, we focus on the molecular mechanism of photothermal, photodynamic and sonodynamic cancer therapies and the connected role of cGAS-STING agonists in treating cancer.

Biomaterials with cancer cell-specific cytotoxicity: challenges and perspectives

Significant advances have been made in materials for biomedical applications, including tissue engineering, bioimaging, cancer treatment, etc. In the past few decades, nanostructure-mediated therapeutic strategies have been developed to improve drug delivery, targeted therapy, and diagnosis, maximizing therapeutic effectiveness while reducing systemic toxicity and side effects by exploiting the complicated interactions between the materials and the cell and tissue microenvironments. This review briefly introduces the differences between the cells and tissues of tumour or normal cells. We summarize recent advances in tumour microenvironment-mediated therapeutic strategies using nanostructured materials. We then comprehensively discuss strategies for fabricating nanostructures with cancer cell-specific cytotoxicity by precisely controlling their composition, particle size, shape, structure, surface functionalization, and external energy stimulation. Finally, we present perspectives on the challenges and future opportunities of nanotechnology-based toxicity strategies in tumour therapy.

Turning Waste into Wealth: A Potent Sono-Immune Strategy Based on Microcystis

Currently, sonodynamic therapy (SDT) has limited therapeutic outcomes and immune responses, highlighting the urgent need for enhanced strategies that can stimulate robust and long-lasting antitumor effects. Microcystis, a notorious microalga, reveals the possibility of mediating SDT owing to the presence of gas vesicles (GVs) and phycocyanin (PC). Herein, a nontoxic strain of Microcystis elabens (labeled Me) is developed as a novel agent for SDT because it generates O2 under red light (RL) illumination, while GVs and PC act as cavitation nuclei and sonosensitizers, respectively. Moreover, algal debris is released after ultrasound (US) irradiation, which primes the Toll-like receptor pathway to initiate a cascade of immune responses. This sono-immune strategy inhibits CT26 colon tumor growth largely by promoting dendritic cell (DC) maturation and cytotoxic T-cell activation. After combination with the immune checkpoint blockade (ICB), the therapeutic outcome is further amplified, accompanied by satisfactory abscopal and immune memory effects; the similar potency is proven in the "cold" 4T1 triple-negative breast tumor. In addition, Me exhibits good biosafety without significant acute or chronic toxicity. Briefly, this study turns waste into wealth by introducing sono-immunotherapy based on Microcystis that achieved encouraging therapeutic effects on cancer, which is expected to be translated into the clinic.

Engineering macrophages and their derivatives: A new hope for antitumor therapy

Macrophages are central to the immune system and are found in nearly all tissues. Recently, the development of therapies based on macrophages has attracted significant interest. These therapies utilize macrophages' key roles in immunity, their ability to navigate biological barriers, and their tendency to accumulate in tumors. This review explores the advancement of macrophage-based treatments. We discuss the bioengineering of macrophages for improved anti-tumor effects, the use of CAR macrophage therapy for targeting cancer cells, and macrophages as vehicles for therapeutic delivery. Additionally, we examine engineered macrophage products, like extracellular vesicles and membrane-coated nanoparticles, for their potential in precise and less toxic tumor therapy. Challenges in moving these therapies from research to clinical practice are also highlighted. The aim is to succinctly summarize the current status, challenges, and future directions of engineered macrophages in cancer therapy.

Mucus and Biofilm Penetrating Nanoplatform as an Ultrasound-Induced Free Radical Initiator for Targeted Treatment of Helicobacter pylori Infection

Helicobacter pylori (H. pylori) infection is closely associated with the development of various gastric diseases. The effectiveness of current clinical antibiotic therapy is hampered by the rise of drug-resistant strains and the formation of H. pylori biofilm. This paper reports a sonodynamic nanocomposite PtCu3-PDA@AIPH@Fucoidan (PPAF), which consists of dopamine-modified inorganic sonosensitizers PtCu3, alkyl radicals (R•) generator AIPH and fucoidan, can penetrate the mucus layer, target H. pylori, disrupt biofilms, and exhibit excellent bactericidal ability. In vitro experiments demonstrate that PPAF exhibits excellent acoustic kinetic properties, generating a significant amount of reactive oxygen species and oxygen-independent R• for sterilization under ultrasound stimulation. Simultaneously, the produced N2 can enhance the cavitation effect, aiding PPAF nanoparticles in penetrating the gastric mucus layer and disrupting biofilm integrity. This disruption allows more PPAF nanoparticles to bind to biofilm bacteria, facilitating the eradication of H. pylori. In vivo experiments demonstrate that ultrasound-stimulated PPAF exhibited significant antibacterial efficacy against H. pylori. Moreover, it effectively modulated the expression levels of inflammatory factors and maintained gastrointestinal microbiota stability when compared to the antibiotic treatment group. In summary, PPAF nanoparticles present a potential alternative to antibiotics, offering an effective and healthy option for treating H. pylori infection.

MOF-Derived Nanoparticles with Enhanced Acoustical Performance for Efficient Mechano-Sonodynamic Therapy

Ultrasound (US) generates toxic reactive oxygen species (ROS) by acting on sonosensitizers for cancer treatment, and the mechanical damage induced by cavitation effects under US is equally significant. Therefore, designing a novel sonosensitizer that simultaneously possesses efficient ROS generation and enhanced mechanical effects is promising. In this study, carbon-doped zinc oxide nanoparticles (C-ZnO) are constructed for mechano-sonodynamic cancer therapy. The presence of carbon (C) doping optimizes the electronic structure, thereby enhancing the ROS generation triggered by US, efficiently inducing tumor cell death. On the other hand, the high specific surface area and porous structure brought about by C doping enable C-ZnO to enhance the mechanical stress induced by cavitation bubbles under US irradiation, causing severe mechanical damage to tumor cells. Under the dual effects of sonodynamic therapy (SDT) and mechanical therapy mediated by C-ZnO, excellent anti-tumor efficacy is demonstrated both in vitro and in vivo, along with a high level of biological safety. This is the first instance of utilizing an inorganic nanomaterial to achieve simultaneous enhancement of ROS production and US-induced mechanical effects for cancer therapy. This holds significant importance for the future development of novel sonosensitizers and advancing the applications of US in cancer treatment.

A rat model of cerebral small vascular disease induced by ultrasound and protoporphyrin

Cerebral small vascular disease (CSVD) has a high incidence worldwide, but its pathological mechanisms remain poorly understood due to the lack of proper animal models. The current animal models of CSVD have several limitations such as high mortality rates and large-sized lesions, and thus it is urgent to develop new animal models of CSVD. Ultrasound can activate protoporphyrin to produce reactive oxygen species in a liquid environment. Here we delivered protoporphyrin into cerebral small vessels of rat brain through polystyrene microspheres with a diameter of 15 μm, and then performed transcranial ultrasound stimulation (TUS) on the model rats. We found that TUS did not affect the large vessels or cause large infarctions in the brain of model rats. The mortality rates were also comparable between the sham and model rats. Strikingly, TUS induced several CSVD-like phenotypes such as cerebral microinfarction, white matter injuries and impaired integrity of endothelial cells in the model rats. Additionally, these effects could be alleviated by antioxidant treatment with N-acetylcysteine (NAC). As control experiments, TUS did not lead to cerebral microinfarction in the rat brain when injected with the polystyrene microspheres not conjugated with protoporphyrin. In sum, we generated a rat model of CSVD that may be useful for the mechanistic study and drug development for CSVD.

Charge-reversal polymeric nanomodulators for ferroptosis-enhanced photodynamic therapy

The clinical application of photodynamic therapy (PDT) has some limitations including poor tumor targeting properties, a high reductive tumor microenvironment, and inefficient activation of single cell death machinery. We herein report pH-sensitive polymeric nanomodulators (NBS-PDMC NPs) for ferroptosis-enhanced photodynamic therapy. NBS-PDMC NPs were constructed using a positively charged type-I photosensitizer (NBS) coordinated with a demethylcantharidin (DMC)-decorated block copolymer via electrostatic interactions. NBS-PDMC NPs had a negative surface charge, which ensures their high stability in bloodstream circulation, while exposure to lysosomal acidic environments reverses their surface charge to positive for tumor penetration and the release of DMC and NBS. Under NIR light irradiation, NBS generated ROS to induce cell damage; in the meantime, DMC inhibited the expression of the GPX4 protein in tumor cells and promoted ferroptosis of tumor cells. This polymer design concept provides some novel insights into smart drug delivery and combinational action to amplify the antitumor effect.

Smart Molecular Imaging and Theranostic Probes by Enzymatic Molecular In Situ Self-Assembly

Enzymatic molecular in situ self-assembly (E-MISA) that enables the synthesis of high-order nanostructures from synthetic small molecules inside a living subject has emerged as a promising strategy for molecular imaging and theranostics. This strategy leverages the catalytic activity of an enzyme to trigger probe substrate conversion and assembly in situ, permitting prolonging retention and congregating many molecules of probes in the targeted cells or tissues. Enhanced imaging signals or therapeutic functions can be achieved by responding to a specific enzyme. This E-MISA strategy has been successfully applied for the development of enzyme-activated smart molecular imaging or theranostic probes for in vivo applications. In this Perspective, we discuss the general principle of controlling in situ self-assembly of synthetic small molecules by an enzyme and then discuss the applications for the construction of "smart" imaging and theranostic probes against cancers and bacteria. Finally, we discuss the current challenges and perspectives in utilizing the E-MISA strategy for disease diagnoses and therapies, particularly for clinical translation.

Dual-Drug Loaded Nanobubbles Combined with Sonodynamic and Chemotherapy for Hepatocellular Carcinoma Therapy

Purpose

Chemotherapy remains the primary therapeutic approach for advanced Hepatocellular Carcinoma (HCC). The therapeutic effect of chemotherapy is limited and the toxic side effects are serious. The aim of this study is to develop a nanobubble that is ultrasonically responsive to reduce the toxic side effects of direct chemotherapy.

Methods

We developed curcumin/doxorubicin-cis-aconitic anhydride-polyethylene glycol nanobubble (C/DCNB) surface modified with acid-sensitive polyethylene glycol (PEG). And it is loaded with curcumin (CUR) and doxorubicin (DOX), as liposomes at the nanoscale for diagnosis and therapy of tumors.

Results

In this study, the acid-sensitive PEG on the surface layer of nanobubbles serves to stabilize them in the blood circulatory system and in normal tissues, while peeling off in the acidic tumor microenvironment (pH 6.8). C/DCNB can identify tumor sites through contrast-enhanced ultrasound (CEUS). And ultrasound-mediated nanobubbles promote permeability of the tumor vascular, thus improving the enhanced permeability and retention (EPR) effects in the tumor, leading to the accumulation of nanobubbles in the tumor. After endocytosis of nanobubbles, drugs are released and curcumin generates reactive oxygen species (ROS) under ultrasound conditions. CUR can enhance the sensitivity of tumor cells to DOX by inhibiting the expression of P-glycoprotein. In vitro and vivo experiments demonstrate that C/DCNB can facilitate contrast-enhanced ultrasound imaging while simultaneously delivering drugs, enabling both imaging and treatment.

Conclusion

The combination of C/DCNB and ultrasound provides an effective strategy for improving the efficiency of HCC therapy and imaging.

Naphthalene Diimide-Based Polycyclic Conjugated Molecule Composite CoFe2O4 Nanohybrids for Photoacoustic Imaging-Mediated Photo-/Sonic Therapy

The complex and harsh tumor microenvironment imped the efficacy of single-modality tumor therapy. With the advantages of biosafety, organic/inorganic nanohybrids have attracted more and more interest of researchers, and it is critical to investigate the development of highly efficient nanohybrids for multimodality combination therapy of cancers. Herein, a naphthalene diimide-based polycyclic conjugated molecule (NDI-S) is designed and synthesized, which has broader light absorption in the near infrared (NIR) region, outstanding photothermal conversion ability, and excellent photostability. Inorganic CoFe2O4 is synthesized via a solvothermal technique, which can produce much more reactive oxygen species (ROS) as a sonosensitizer when activated by ultrasonic (US). NDI-S and CoFe2O4 are then nanoprecipitated to create the organic/inorganic nanohybrids, NDI-S@CoFe2O4. According to the results of in vitro and in vivo experiments, NDI-S@CoFe2O4 can serve as a multifunctional nanoplatform for multimodal treatment of tumors in combination with photothermal/photodynamic/sonodynamic- therapy under the guidance of photoacoustic imaging, which provides a new vision of the development of organic/inorganic nanohybrids for cancer theranostics.

Endogenous and exogeneous stimuli-triggered reactive oxygen species evoke long-lived carbon monoxide to fight against lung cancer

Reactive oxygen species (ROS)-associated anticancer approaches usually suffer from two limitations, i.e., insufficient ROS level and short ROS half-life. Nevertheless, no report has synchronously addressed both concerns yet. Herein, a multichannel actions-enabled nanotherapeutic platform using hollow manganese dioxide (H-MnO2) carriers to load chlorin e6 (Ce6) sonosensitizer and CO donor (e.g., Mn2(CO)10) has been constructed to maximumly elevate ROS level and trigger cascade catalysis to produce CO. Therein, intratumoral H2O2 and ultrasound as endogenous and exogeneous triggers stimulate H-MnO2 and Ce6 to produce •OH and 1O2, respectively. The further cascade reaction between ROS and Mn2(CO)10 proceeds to release CO, converting short-lived ROS into long-lived CO. Contributed by them, such a maximumly-elevated ROS accumulation and long-lived CO release successfully suppresses the progression, recurrence and metastasis of lung cancer with a prolonged survival rate. More significantly, proteomic and genomic investigations uncover that the CO-induced activation of AKT signaling pathway, NRF-2 phosphorylation and HMOX-1 overexpression induce mitochondrial dysfunction to boost anti-tumor consequences. Thus, this cascade catalysis strategy can behave as a general means to enrich ROS and trigger CO release against refractory cancers.

Fluorinated Titanium Oxide (TiO2-xFx) Nanospindles as Ultrasound-Triggered Pyroptosis Inducers to Boost Sonodynamic Immunotherapy

Pyroptosis is an inflammatory form of programmed cell death associated with the immune system that can be induced by reactive oxygen species (ROS). As a therapeutic strategy with better penetration depth, sonodynamic therapy (SDT) is expected to induce pyroptosis of cancer cells and boost the immune response. However, it is still a limited problem to precisely adjust the structure of sonosensitizers to exhibit satisfactory sono-catalytic properties. Herein, fluorinated titanium oxide (TiO2-xFx) sonosensitizers were developed to induce pyroptosis under ultrasound (US) to boost antitumor immune responses, enabling highly effective SDT. On the one hand, the introduction of F atoms significantly reduced the adsorption energy of TiO2-xFx for oxygen and water, which is conducive to the occurrence of sono-catalytic reactions. On the other hand, the process of F replacing O increased the oxygen vacancies of the sonosensitizer and shortened the band gap, which enabled powerful ROS generation ability under US stimulation. In this case, large amounts of ROS could effectively kill cancer cells by inducing mitochondrial damage and disrupting oxidative homeostasis, leading to significant cell pyroptosis. Moreover, SDT treatment with TiO2-xFx not only suppressed tumor proliferation but also elicited robust immune memory effects and hindered tumor recurrence. This work highlighted the importance of precisely regulating the structure of sonosensitizers to achieve efficient ROS generation for inducing pyroptosis, which sets the stage for the further development of SDT-immunotherapy.

Reactive oxygen species of tumor microenvironment: Harnessing for immunogenic cell death

The tumor microenvironment (TME) is a dynamic and complex system that undergoes continuous changes in its network architecture, notably affecting redox homeostasis. These alterations collectively shape a diverse ecosystem actively supporting tumor progression by influencing the cellular and molecular components of the TME. Despite the remarkable clinical advancements in cancer immunotherapy, its spectrum of clinical utility is limited by the altered TME and inadequate tumor immunogenicity. Recent studies have revealed that some conventional and targeted therapy strategies can augment the efficacy of immunotherapy even in patients with less immunogenic solid tumors. These strategies provoke immunogenic cell death (ICD) through the ROS-dependent liberation of damage-associated molecular patterns (DAMPs). These DAMPs recognize and bind with Pattern Recognition Receptors (PRRs) on immune cells, activating and maturing defense cells, ultimately leading to a robust antitumor immune response. The present review underscores the pivotal role of redox homeostasis in orchestrating the transition of TME from a cold to a hot phenotype and the ROS-ICD axis in immune response induction. Additionally, it provides up-to-date insights into strategies that leverage ROS generation to induce ICD. The comprehensive analysis aims to develop ROS-based effective cancer immunotherapies for less immunogenic tumors.

Russell Mechanism-Mediated Cancer Therapy: A Minireview

The Russell mechanism, proposed by Russell, is a cyclic mechanism for the formation of linear tetroxide intermediates, which can spontaneously produce cytotoxic singlet oxygen (1O2) independent of oxygen, suggesting its anticancer potential. Compared with other mainstream anticancer strategies, the Russell mechanism employed for killing cancer cells does not require external energy input, harsh pH condition, and sufficient oxygen. However, up till now, the applications of Russell mechanism in antitumor therapy have been relatively rare, and there is almost no summary of the Russell mechanism in the cancer therapy field. This minireview introduces the different metal elements-based Russell mechanisms and the relevant research progress in Russell mechanism-based cancer therapy in recent years. At the same time, we briefly discussed the current challenges and future development regarding the applications of Russell mechanism. It is hoped that this review can further expand the research of Russell Mechanism in the biomedical field, and inspire researchers to extend its application fields to antibacterial, antiinflammatory, and wound healing uses.

Ultrasound-Based Micro-/Nanosystems for Biomedical Applications

Due to the intrinsic non-invasive nature, cost-effectiveness, high safety, and real-time capabilities, besides diagnostic imaging, ultrasound as a typical mechanical wave has been extensively developed as a physical tool for versatile biomedical applications. Especially, the prosperity of nanotechnology and nanomedicine invigorates the landscape of ultrasound-based medicine. The unprecedented surge in research enthusiasm and dedicated efforts have led to a mass of multifunctional micro-/nanosystems being applied in ultrasound biomedicine, facilitating precise diagnosis, effective treatment, and personalized theranostics. The effective deployment of versatile ultrasound-based micro-/nanosystems in biomedical applications is rooted in a profound understanding of the relationship among composition, structure, property, bioactivity, application, and performance. In this comprehensive review, we elaborate on the general principles regarding the design, synthesis, functionalization, and optimization of ultrasound-based micro-/nanosystems for abundant biomedical applications. In particular, recent advancements in ultrasound-based micro-/nanosystems for diagnostic imaging are meticulously summarized. Furthermore, we systematically elucidate state-of-the-art studies concerning recent progress in ultrasound-based micro-/nanosystems for therapeutic applications targeting various pathological abnormalities including cancer, bacterial infection, brain diseases, cardiovascular diseases, and metabolic diseases. Finally, we conclude and provide an outlook on this research field with an in-depth discussion of the challenges faced and future developments for further extensive clinical translation and application.

Engineering Sonosensitizer-Derived Nanotheranostics for Augmented Sonodynamic Therapy

Sonodynamic therapy (SDT), featuring noninvasive, deeper penetration, low cost, and repeatability, is a promising therapy approach for deep-seated tumors. However, the general or only utilization of SDT shows low efficiency and unsatisfactory treatment outcomes due to the complicated tumor microenvironment (TME) and SDT process. To circumvent the issues, three feasible approaches for enhancing SDT-based therapeutic effects, including sonosensitizer optimization, strategies for conquering hypoxia TME, and combinational therapy are summarized, with a particular focus on the combination therapy of SDT with other therapy modalities, including chemodynamic therapy, photodynamic therapy, photothermal therapy, chemotherapy, starvation therapy, gas therapy, and immunotherapy. In the end, the current challenges in SDT-based therapy on tumors are discussed and feasible approaches for enhanced therapeutic effects are provided. It is envisioned that this review will provide new insight into the strategic design of high-efficiency sonosensitizer-derived nanotheranostics, thereby augmenting SDT and accelerating the potential clinical transformation.

The Convergence of Sonodynamic Therapy and Cuproptosis in the Dual-Responsive Biomimetic CytoNano for Precision Mitochondrial Intervention in Cancer Treatment

The integration of sonodynamic therapy (SDT) with cuproptosis for targeted cancer treatment epitomizes a significant advancement in oncology. Herein, we present a dual-responsive therapeutic system, "CytoNano", which combines a cationic liposome infused with copper-nitride nanoparticles and oxygen-rich perfluorocarbon (Lip@Cu3N/PFC-O2), all enveloped in a biomimetic coating of neutrophil membrane and acid-responsive carboxymethylcellulose. CytoNano leverages the cellular mimicry of neutrophils and acid-responsive materials, enabling precise targeting of tumors and their acidic microenvironment. This strategic design facilitates the targeted release of Lip@Cu3N/PFC-O2 within the tumor, enhancing cancer cell uptake and mitochondrial localization. Consequently, it amplifies the therapeutic efficacy of both Cu3N-driven SDT and cuproptosis while preserving healthy tissues. Additionally, CytoNano's ultrasound responsiveness enhances intratumoral oxygenation, overcoming physiological barriers and initiating a combined sonodynamic-cuproptotic effect that induces multiple cell death pathways. Thus, we pioneer a biomimetic approach in precise sonodynamic cuproptosis, revolutionizing cancer therapy.

Facile synthesis of a hydrazone-based zinc(ii) complex for ferroptosis-augmented sonodynamic therapy

Sonodynamic therapy (SDT), as a novel non-invasive cancer treatment modality derived from photodynamic therapy (PDT), has drawn much attention due to its unique advantages for the treatment of deep tumors. Zinc-based complexes have shown great clinical prospect in PDT due to their excellent photodynamic activity and biosafety. However, their application in SDT has lagged seriously behind. Exploring efficient zinc-based complexes as sono-sensitizers remains an appealing but significantly challenging task. Herein, we develop a hydrazone ligand-based zinc complex (ZnAMTC) for SDT of tumors in vitro and in vivo. ZnAMTC was facilely synthesized via a two-step reaction from low-cost raw materials without tedious purification. It shows negligible dark toxicity and can produce singlet oxygen (1O2) under ultrasound (US) irradiation, exhibiting high sono-cytotoxicity to various cancer cells. Mechanism studies show that ZnAMTC can effectively reduce the levels of glutathione (GSH) and glutathione peroxidase 4 (GPX4) under US irradiation and later cause ferroptosis of cancer cells. In vivo studies further demonstrate that ZnAMTC exhibits efficient tumor growth inhibition under US irradiation and has good biosafety. This work provides useful insights into the design of first-row transition metal complexes for SDT application.

Sono-promoted piezocatalysis and low-dose drug penetration for personalized therapy via tumor organoids

Chemotherapy is a widely used cancer treatment, however, it can have notable side effects owing to the high-doses of drugs administered. Sonodynamic therapy (SDT) induced by sonosensitizers has emerged as a promising approach to treat cancer, however, there is limited research evaluating its therapeutic effects on human tumors. In this study, we introduced a dual therapy that combines low-dose chemotherapeutic drugs with enhanced sonodynamic therapy, utilizing barium titanate (BaTiO3, BTO) nanoparticles (NPs) as sonosensitizers to treat tumor organoids. We demonstrated that ultrasound could improve the cellular uptake of chemotherapy drugs, while the chemotherapeutic effect of the drugs made it easier for BTO NPs to enter tumor cells, and the dual therapy synergistically inhibited tumor cell viability. Moreover, different patient-derived tumor organoids exhibited different sensitivities to this therapy, highlighting the potential to evaluate individual responses to combination therapies prior to clinical intervention. Furthermore, this dual therapy exhibited therapeutic effects equivalent to those of high-dose chemotherapy drugs on drug-resistant tumor organoids and showed the potential to enhance the efficacy of killing drug-resistant tumors. In addition, the biosafety of the BTO NPs was successfully verified in live mice via oral administration. This evidence confirms the reliable and safe nature of the dual therapy approach, making it a feasible option for precise and personalized therapy in clinical applications.

Sequential dual-locking strategy using photoactivated Pt(IV)-based metallo-nano prodrug for enhanced chemotherapy and photodynamic efficacy by triggering ferroptosis and macrophage polarization

Selective activation of Pt(IV) prodrugs within tumors has emerged as a promising strategy in tumor treatment. Although progress has been made with photo- and ultrasound-activated Pt(IV) prodrugs, concerns remain over the non-specific activation of photosensitizers (PS) and the potential for phototoxicity and chemical toxicity. In this study, a sequential dual-locked Pt(IV) nano-prodrug that can be activated by both the acidic tumor microenvironment and light was developed. The Pt(IV) prodrug was prepared by conjugating PS-locked Pt(IV) to a polymeric core, which was then chelated with metallo iron to lock its photoactivity and form a metallo-nano prodrug. Under acidic tumor microenvironment conditions, the metallo-nano prodrug undergoes dissociation of iron, triggering a reduction process in oxaliplatin under light irradiation, resulting in the activation of both chemotherapy and photodynamic therapy (PDT). Additionally, the prodrug could induce metallo-triggered ferroptosis and polarization of tumor-associated macrophages (TAM), thereby enhancing tumor inhibition. The dual-lock strategy employed in a nanoparticle delivery system represents an expansion in the application of platinum-based anticancer drugs, making it a promising new direction in cancer treatment.

"Multi-in-One" Yolk-Shell Structured Nanoplatform Inducing Pyroptosis and Antitumor Immune Response Through Cascade Reactions

Pyroptosis, a new mode of regulatory cell death, holds a promising prospect in tumor therapy. The occurrence of pyroptosis can trigger the release of damage-associated molecular patterns (DAMPs) and activate the antitumor immune response. Moreover, enhancing intracellular reactive oxygen species (ROS) generation can effectively induce pyroptosis. Herein, an integrated nanoplatform (hCZAG) based on zeolitic imidazolate framework-8 (ZIF-8) with Cu2+ and Zn2+ as active nodes and glucose oxidase (GOx) loading is constructed to evoke pyroptosis. GOx can effectively elevate intracellular hydrogen peroxide (H2O2) levels to regulate the unfavorable tumor microenvironment (TME). Cu2+ can be reduced to Cu+ by endogenous overexpressed GSH and both Cu2+ and Cu+ can exert Fenton-like activity to promote ROS generation and amplify oxidative stress. In addition, the accumulation of Cu2+ leads to the aggregation of lipoylated dihydrolipoamide S-acetyltransferase (DLAT), thus resulting in cuproptosis. Notably, the outburst of ROS induced by hCZAG activates Caspase-1 proteins, leads to the cleavage of gasdermin D (GSDMD), and induces pyroptosis. Pyroptosis further elicits an adaptive immune response, leading to immunogenic cell death (ICD). This study provides effective strategies for triggering pyroptosis-mediated immunotherapy and achieving improved therapeutic effects.

Progression in low-intensity ultrasound-induced tumor radiosensitization

BACKGROUND

Radiotherapy (RT) is a widely utilized tumor treatment approach, while a significant obstacle in this treatment modality is the radioresistance exhibited by tumor cells. To enhance the effectiveness of RT, scientists have explored radiosensitization approaches, including the use of radiosensitizers and physical stimuli. Nevertheless, several approaches have exhibited disappointing results including adverse effects and limited efficacy. A safer and more effective method of radiosensitization involves low-intensity ultrasound (LIUS), which selectively targets tumor tissue and enhances the efficacy of radiation therapy.

METHODS

This review summarized the tumor radioresistance reasons and explored LIUS potential radiosensitization mechanisms. Moreover, it covered diverse LIUS application strategies in radiosensitization, including the use of LIUS alone, ultrasound-targeted intravascular microbubble destruction, ultrasound-mediated targeted radiosensitizers delivery, and sonodynamic therapy. Lastly, the review presented the limitations and prospects of employing LIUS-RT combined therapy in clinical settings, emphasizing the need to connect research findings with practical applications.

RESULTS AND CONCLUSION

LIUS employs cost-effective equipment to foster tumor radiosensitization, curtail radiation exposure, and elevate the quality of life for patients. This efficacy is attributed to LIUS's ability to utilize thermal, cavitation, and mechanical effects to overcome tumor cell resistance to RT. Multiple experimental analyses have underscored the effectiveness of LIUS in inducing tumor radiosensitization using diverse strategies. While initial studies have shown promising results, conducting more comprehensive clinical trials is crucial to confirm its safety and effectiveness in real-world situations.

Axial O Atom-Modulated Fe(III)-N4 Sites for Enhanced Cascade Catalytic 1O2-Induced Tumor Therapy

The rational construction of efficient hypoxia-tolerant nanocatalysts capable of generating singlet oxygen (1O2) without external stimuli is of great importance for tumor therapy. Herein, uniformly dispersed and favorable biosafety profile graphitic carbon nitride quantum dots immobilized with Fe-N4 moieties modulated by axial O atom (denoted as O-Fe-N4) are developed for converting H2O2 into 1O2 via Russell reaction, without introducing external energy. Notably, O-Fe-N4 performs two interconnected catalytic properties: glutathione oxidase-mimic activity to provide substrate for subsequent 1O2 generation, avoiding the blunting anticancer efficacy by glutathione. The O-Fe-N4 catalyst demonstrates a specific activity of 79.58 U mg-1 at pH 6.2, outperforming the most reported Fe-N4 catalysts. Density functional theory calculations demonstrate that the axial O atom can effectively modulate the relative position and electron affinity between Fe and N, lowering the activation energy, strengthening the selectivity, and thus facilitating the Russell-type reaction. The gratifying enzymatic activity stemming from the well-defined Fe-N/O structure can inhibit tumor proliferation by efficiently downregulating glutathione peroxidase 4 activity and inducing lipid peroxidation. Altogether, the O-Fe-N4 catalyst not only represents an efficient platform for self-cascaded catalysis to address the limitations of 1O2-involved cancer treatment but also provides a paradigm to enhance the performance of the Fe-N4 catalyst.

The emergence of cancer sono-immunotherapy

Owing to its remarkable ease of use, ultrasound has recently been explored for stimulating or amplifying immune responses during cancer therapy, termed 'sono-immunotherapy'. Ultrasound can cause immunogenic cell death in cancer cells via thermal and nonthermal effects to regulate the tumor microenvironment, thereby priming anticancer immunity; by integrating well-designed biomaterials, novel sono-immunotherapy approaches with augmented efficacy can also be developed. Here, we review the advances in sono-immunotherapy for cancer treatment and summarize existing limitations along with potential trends. We offer emerging insights into this realm, which might prompt breakthroughs and expand its potential applications to other diseases.

Ultrasonic-responsive piezoelectric stimulation enhances sonodynamic therapy for HER2-positive breast cancer

INTRODUCTION

Breast cancer ranks second as the most common malignancy globally, after lung cancer. Among the various subtypes of breast cancer, HER2 positive breast cancer (HER2 BC)poses a particularly challenging prognosis due to its heightened invasiveness and metastatic potential. The objective of this study was to construct a composite piezoelectric nanoparticle based on poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) for imaging and treatment of HER2 BC.

METHOD

By reshaping the crystal structure of P(VDF-TrFE) piezoelectric nanoparticles, improving hydrophilicity, and incorporating imaging capabilities, we developed piezoelectric composite nanoparticles (PGd@tNBs) that integrate imaging and therapeutic functions. The in vitro characterization encompassed the assessment of piezoelectric properties, hydrophilicity, imaging performance, and therapeutic efficacy of these particles. The targeting and therapeutic effectiveness of PGd@tNBs particles were further validated in the SK-BR3 cell line and subsequently confirmed in HER2-positive tumor-bearing mice.

RESULTS

The nanoparticle demonstrated excellent biocompatibility and impressive multimodal imaging performance. Magnetic resonance imaging (MRI) observations revealed significant accumulation of PGd@tNBs particles in the HER2 positive tumor, exhibiting superior contrast-enhanced ultrasound performance compared to traditional ultrasound contrast agents, and small animal in vivo imaging showed that PGd@tNBs particles were primarily excreted through respiration and urinary metabolism. Piezoforce Microscopy characterization highlighted the outstanding piezoelectric properties of PGd@tNBs particles. Upon targeted binding to HER2-BC, ultrasound stimulation influenced the cell membrane potential, leading to reversible electroporation. This, in turn, affected the balance of calcium ions inside and outside the cells and the mitochondrial membrane potential. Following ingestion by cells, PGd@tNBs, when exposed to ultrasound, triggered the generation of reactive oxygen species (ROS), resulting in the consumption of glutathione and superoxide dismutase and achieving sonodynamic therapy. Notably, repeated ultrasound stimulation, post PGd@tNBs particles binding and entry into cells, increased ROS production and elevated the apoptosis rate by approximately 45%.

CONCLUSION

In conclusion, the PGd@tNBs particles developed exhibit outstanding imaging and therapeutic efficacy, holding potential for precise diagnosis and personalized treatment of HER2 BC.

MXene/Carbon Dots Nanozyme Composites for Glutathione Detection and Tumor Therapy

Co-N-CDs-based MXene nanocomposites (MXene@PDA/Co-N-CDs) were constructed by decorating Co-N-CDs on polydopamine-functionalized MXene nanosheets. Both Co-N-CDs and MXene nanosheets have peroxidase-like activity; when the two materials are combined to form MXene@PDA/Co-N-CDs nanocomposites, the peroxide-like activity can be further enhanced. MXene@PDA/Co-N-CDs could oxidize the substrate 3,3'5,5'-tetramethylbenziline (TMB) to form ox-TMB, as confirmed by detecting the absorption of the blue products. A highly selective colorimetric biosensor was developed for the determination of glutathione (GSH) in the concentration range of 0.3 to 20 µM with a lower detection limit (LOD) of 0.12 µM, which realized the accurate detection of GSH in human serum and urine samples. Moreover, in the tumor microenvironment, MXene@PDA/Co-N-CDs could catalyze hydrogen peroxide to produce hydroxyl free radicals and produce a photothermal effect under the exposure of NIR-I irradiation. The catalytic activity of MXene@PDA/Co-N-CD nanocomposites was fully achieved for the death of cancer cells through photothermal/photodynamic synergistic therapy. The MXene@PDA/Co-N-CDs nanozyme offers multiple applications in GSH detection and tumor therapy.

Transition Metal Oxide Nanomaterials: New Weapons to Boost Anti-Tumor Immunity Cycle

Semiconductor nanomaterials have emerged as a significant factor in the advancement of tumor immunotherapy. This review discusses the potential of transition metal oxide (TMO) nanomaterials in the realm of anti-tumor immune modulation. These binary inorganic semiconductor compounds possess high electron mobility, extended ductility, and strong stability. Apart from being primary thermistor materials, they also serve as potent agents in enhancing the anti-tumor immunity cycle. The diverse metal oxidation states of TMOs result in a range of electronic properties, from metallicity to wide-bandgap insulating behavior. Notably, titanium oxide, manganese oxide, iron oxide, zinc oxide, and copper oxide have garnered interest due to their presence in tumor tissues and potential therapeutic implications. These nanoparticles (NPs) kickstart the tumor immunity cycle by inducing immunogenic cell death (ICD), prompting the release of ICD and tumor-associated antigens (TAAs) and working in conjunction with various therapies to trigger dendritic cell (DC) maturation, T cell response, and infiltration. Furthermore, they can alter the tumor microenvironment (TME) by reprogramming immunosuppressive tumor-associated macrophages into an inflammatory state, thereby impeding tumor growth. This review aims to bring attention to the research community regarding the diversity and significance of TMOs in the tumor immunity cycle, while also underscoring the potential and challenges associated with using TMOs in tumor immunotherapy.

Glutathione and acid dual-responsive bismuth-based nanosensitizer for chemo-mediated cancer sonodynamic therapy

Chemotherapeutic agents hold significant clinical potential in combating tumors. However, delivering these drugs to the tumor site for controlled release remains a crucial challenge. In this study, we synthesize and construct a glutathione (GSH) and acid dual-responsive bismuth-based nano-delivery platform (BOD), aiming for sonodynamic enhancement of docetaxel (DTX)-mediated tumor therapy. The bismuth nanomaterial can generate multiple reactive oxygen species under ultrasound stimulation. Furthermore, the loading of DTX to form BOD effectively reduces the toxicity of DTX in the bloodstream, ensuring its cytotoxic effect is predominantly exerted at the tumor site. DTX can be well released in high expression of GSH and acidic tumor microenvironment. Meanwhile, ultrasound can also promote the release of DTX. Results from bothin vitroandin vivoexperiments substantiate that the synergistic therapy involving chemotherapy and sonodynamic therapy significantly inhibits the growth and proliferation of tumor cells. This study provides a favorable paradigm for developing a synergistic tumor treatment platform for tumor microenvironment response and ultrasound-promoted drug release.

Oral Heterojunction Coupling Interventional Optical Fiber Mediates Synergistic Therapy for Orthotopic Rectal Cancer

Catalytic therapy has shown great potential for clinical application. However, conventional catalytic therapies rely on reactive oxygen species (ROS) as "therapeutic drugs," which have limitations in effectively inhibiting tumor recurrence and metastasis. Here, a biomimetic heterojunction catalyst is developed that can actively target orthotopic rectal cancer after oral administration. The heterojunction catalyst is composed of quatrefoil star-shaped BiVO4 (BVO) and ZnIn2S4 (ZIS) nanosheets through an in situ direct growth technique. Poly-norepinephrine and macrophage membrane coatings afford the biomimetic heterojunction catalyst (BVO/ZIS@M), which has high rectal cancer targeting and retention abilities. The coupled optical fiber intervention technology activates the multicenter coordination of five catalytic reactions of heterojunction catalysts, including two reduction reactions (O2→·O2 - and CO2→CO) and three oxidation reactions (H2O→·OH, GSH→GSSG, and LA→PA). These catalytic reactions not only induce immunogenic death in tumor cells through the efficient generation of ROS/CO and the consumption of GSH but also specifically lead to the use of lactic acid (LA) as an electron donor to improve catalytic activity and disrupt the LA-mediated immunosuppressive microenvironment, mediating synergistic catalysis and immunotherapy for orthotopic rectal cancer. Therefore, this optical fiber intervention triggered the combination of heterojunction catalytic therapy and immunotherapy, which exhibits prominent antitumor effects.

Photoactivated Gas-Generating Nanocontrast Agents for Long-Term Ultrasonic Imaging-Guided Combined Therapy of Tumors

To date, long-term and continuous ultrasonic imaging for guiding the puncture biopsy remains a challenge. In order to address this issue, a multimodality imaging and therapeutic method was developed in the present study to facilitate long-term ultrasonic and fluorescence imaging-guided precision diagnosis and combined therapy of tumors. In this regard, certain types of photoactivated gas-generating nanocontrast agents (PGNAs), capable of exhibiting both ultrasonic and fluorescence imaging ability along with photothermal and sonodynamic function, were designed and fabricated. The advantages of these fabricated PGNAs were then utilized against tumors in vivo, and high therapeutic efficacy was achieved through long-term ultrasonic imaging-guided treatment. In particular, the as-prepared multifunctional PGNAs were applied successfully for the fluorescence-based determination of patient tumor samples collected through puncture biopsy in clinics, and superior performance was observed compared to the clinically used SonoVue contrast agents that are incapable of specifically distinguishing the tumor in ex vivo tissues.

A comprehensive review of miR-21 in liver disease: Big impact of little things

microRNAs (miRNAs), a class of non-coding RNA with 20-24 nucleotides, are defined as the powerful regulators for gene expression. miR-21 is a multifunctional miRNA enriched in the circulatory system and multiple organs, which not only serves as a non-invasive biomarker in disease diagnosis, but also participates in many cellular activities. In various chronic liver diseases, the increase of miR-21 affects glycolipid metabolism, viral infection, inflammatory and immune cell activation, hepatic stellate cells activation and tissue fibrosis, and autophagy. Moreover, miR-21 is also a liaison in the deterioration of chronic liver disease to hepatocellular carcinoma (HCC), and it impacts on cell proliferation, apoptosis, migration, invasion, angiogenesis, immune escape, and epithelial-mesenchymal transformation by regulating target genes expression in different signaling pathways. In current research on miRNA therapy, some natural products can exert the hepatoprotective effects depending on the inhibition of miR-21 expression. In addition, miR-21-based therapeutic also play a role in regulating intracellular miR-21 levels and enhancing the efficacy of chemotherapy drugs. Herein, we systemically summarized the recent progress of miR-21 on biosynthesis, biomarker function, molecular mechanism and miRNA therapy in chronic liver disease and HCC, and looked forward to outputting some information to enable it from bench to bedside.

Metainterface Heterostructure Enhances Sonodynamic Therapy for Disrupting Secondary Biofilms

Implant-related secondary infections are a challenging clinical problem. Sonodynamic therapy (SDT) strategies are promising for secondary biofilm infections by nonsurgical therapy. However, the inefficiency of SDT in existing acoustic sensitization systems limits its application. Therefore, we take inspiration from popular metamaterials and propose the design idea of a metainterface heterostructure to improve SDT efficiency. The metainterfacial heterostructure is defined as a periodic arrangement of heterointerface monoclonal cells that amplify the intrinsic properties of the heterointerface. Herein, we develop a TiO2/Ti2O3/vertical graphene metainterface heterostructure film on titanium implants. This metainterface heterostructure exhibits extraordinary sonodynamic and acoustic-to-thermal conversion effects under low-intensity ultrasound. The modulation mechanisms of the metainterface for electron accumulation and separation are revealed. The synergistic sonodynamic/mild sonothermal therapy disrupts biofilm infections (antibacterial rates: 99.99% for Staphylococcus aureus, 99.54% for Escherichia coli), and the osseointegration ability of implants is significantly improved in in vivo tests. Such a metainterface heterostructure film lays the foundation for the metainterface of manipulating electron transport to enhance the catalytic performance and holding promise for addressing secondary biofilm infections.

Facile Synthesis of a Multifunctional Porous Organic Polymer Nanosonosensitizer (mHM@HMME) for Enhanced Cancer Sonodynamic Therapy

Sonodynamic therapy (SDT), which involves the activation of sonosensitizers to generate cytotoxic reactive oxygen species under ultrasound irradiation, is a promising noninvasive modality for cancer treatment. However, the clinical translational application of SDT is impeded by the lack of efficient sonosensitizers, the inefficient accumulation of sonosensitizers at tumor sites, and the complicated immunosuppressive tumor microenvironment. Herein, we developed a facilely synthesized multifunctional porous organic polymer nanosonosensitizer (mHM@HMME) for enhanced SDT. Specifically, mHM@HMME nanosonosensitizers were prepared by incorporating chemotherapeutic mitoxantrone into the one-step synthesis process of disulfide bond containing porous organic polymers, followed by loading with organic sonosensitizer (HMME) and camouflaging with a cancer cell membrane. Due to the cancer cell membrane camouflage, this multifunctional mHM@HMME nanosonosensitizer showed prolonged blood circulation and tumor targeting aggregation. Under ultrasound irradiation, the mHM@HMME nanosonosensitizer exhibited a satisfactory SDT performance both in vitro and in vivo. Moreover, the potent SDT combined with glutathione-responsive drug release in tumor cells induced robust immunogenic cell death to enhance the antitumor effect of SDT in turn. Overall, this facilely synthesized multifunctional mHM@HMME nanosonosensitizer shows great potential application in enhanced SDT.

Boosting Checkpoint Immunotherapy with Biomimetic Nanodrug Delivery Systems

Immune checkpoint blockade (ICB) has achieved unprecedented progress in tumor immunotherapy by blocking specific immune checkpoint molecules. However, the high biodistribution of the drug prevents it from specifically targeting tumor tissues, leading to immune-related adverse events. Biomimetic nanodrug delivery systems (BNDSs) readily applicable to ICB therapy have been widely developed at the preclinical stage to avoid immune-related adverse events. By exploiting or mimicking complex biological structures, the constructed BNDS as a novel drug delivery system has good biocompatibility and certain tumor-targeting properties. Herein, the latest findings regarding the aforementioned therapies associated with ICB therapy are highlighted. Simultaneously, prospective bioinspired engineering strategies can be designed to overcome the four-level barriers to drug entry into lesion sites. In future clinical translation, BNDS-based ICB combination therapy represents a promising avenue for cancer treatment.

Nanotherapeutics targeting autophagy regulation for improved cancer therapy

The clinical efficacy of current cancer therapies falls short, and there is a pressing demand to integrate new targets with conventional therapies. Autophagy, a highly conserved self-degradation process, has received considerable attention as an emerging therapeutic target for cancer. With the rapid development of nanomedicine, nanomaterials have been widely utilized in cancer therapy due to their unrivaled delivery performance. Hence, considering the potential benefits of integrating autophagy and nanotechnology in cancer therapy, we outline the latest advances in autophagy-based nanotherapeutics. Based on a brief background related to autophagy and nanotherapeutics and their impact on tumor progression, the feasibility of autophagy-based nanotherapeutics for cancer treatment is demonstrated. Further, emerging nanotherapeutics developed to modulate autophagy are reviewed from the perspective of cell signaling pathways, including modulation of the mammalian target of rapamycin (mTOR) pathway, autophagy-related (ATG) and its complex expression, reactive oxygen species (ROS) and mitophagy, interference with autophagosome-lysosome fusion, and inhibition of hypoxia-mediated autophagy. In addition, combination therapies in which nano-autophagy modulation is combined with chemotherapy, phototherapy, and immunotherapy are also described. Finally, the prospects and challenges of autophagy-based nanotherapeutics for efficient cancer treatment are envisioned.

Metal-organic framework-mediated siRNA delivery and sonodynamic therapy for precisely triggering ferroptosis and augmenting ICD in osteosarcoma

The complex genomics, immunosuppressive tumor microenvironment (TME), and chemotherapeutic resistance of osteosarcoma (OS) have resulted in limited therapeutic effects in the clinic. Ferroptosis is involved in tumor progression and is regulated mainly by glutathione peroxidase 4 (GPX4). Small interfering RNA (siRNA)-based RNA interference (RNAi) can precisely target any gene. However, achieving effective siRNA delivery is highly challenging. Here, we fabricated a TME-responsive metal-organic framework (MOF)-based biomimetic nanosystem (mFeP@si) with siGPX4 delivery and sonodynamic therapy (SDT) to treat OS by targeting ferroptosis. Under ultrasound (US) irradiation, mFeP@si achieves lysosomal escape via singlet oxygen (1O2)-mediated lysosomal membrane disruption and then accelerates ROS generation and glutathione (GSH) depletion. Meanwhile, siGPX4 silences GPX4 expression by binding to GPX4 mRNA and leads to the accumulation of toxic phospholipid hydroperoxides (PL-OOH), further magnifying the ROS storm and triggering ferroptosis. Notably, synergistic therapy remarkably enhances antitumor effects, improves the immunosuppressive TME by inducing potent immunogenic cell death (ICD), and increases the sensitivity of chemotherapy-resistant OS cells to cisplatin. Overall, this novel nanosystem, which targets ferroptosis by integrating RNAi and SDT, exhibits strong antitumor effects both in vitro and in vivo, providing new insights for treating OS.

Metal-organic frameworks as candidates for tumor sonodynamic therapy: Designable structures for targeted multifunctional transformation

Sonodynamic therapy (SDT), utilizing ultrasound (US) as the trigger, has gained popularity recently as a therapeutic approach with significant potential for treating various diseases. Metal-organic frameworks (MOFs), characterized by structural flexibility, are prominently emerging in the SDT realm as an innovative type of sonosensitizer, offering functional tunability and biocompatibility. However, due to the inherent limitations of MOFs, such as low reactivity to reactive oxygen species and challenges posed by the complex tumor microenvironment, MOF-based sonosensitizers with singular functions are unable to demonstrate the desired therapeutic efficacy and may pose risks of toxicity, limiting their biological applications to superficial tissues. MOFs generally possess distinctive crystalline structures and properties, and their controlled coordination environments provide a flexible platform for exploring structure-effect relationships and guiding the design and development of MOF-based nanomaterials to unlock their broader potential in biological fields. The primary focus of this paper is to summarize cases involving the modification of different MOF materials and the innovative strategies developed for various complex conditions. The paper outlines the diverse application areas of functionalized MOF-based sonosensitizers in tumor synergistic therapies, highlighting the extensive prospects of SDT. Additionally, challenges confronting SDT are briefly summarized to stimulate increased scientific interest in the practical application of MOFs and the successful clinical translation of SDT. Through these discussions, we strive to foster advancements that lead to early-stage clinical benefits for patients. STATEMENT OF SIGNIFICANCE: 1. An overview for the progresses in SDT explored from a novel and fundamental perspective. 2. Different modification strategies to improve the MOFs-mediated SDT efficacy are provided. 3. Guidelines for the design of multifunctional MOFs-based sonosensitizers are offered. 4. Powerful tumor ablation potential is reflected in SDT-led synergistic therapies. 5. Future challenges in the field of MOFs-based SDT in clinical translation are suggested.

Recent Progress in Anti-Tumor Nanodrugs Based on Tumor Microenvironment Redox Regulation

The growth state of tumor cells is strictly affected by the specific abnormal redox status of the tumor microenvironment (TME). Moreover, redox reactions at the biological level are also central and fundamental to essential energy metabolism reactions in tumors. Accordingly, anti-tumor nanodrugs targeting the disruption of this abnormal redox homeostasis have become one of the hot spots in the field of nanodrugs research due to the effectiveness of TME modulation and anti-tumor efficiency mediated by redox interference. This review discusses the latest research results of nanodrugs in anti-tumor therapy, which regulate the levels of oxidants or reductants in TME through a variety of therapeutic strategies, ultimately breaking the original "stable" redox state of the TME and promoting tumor cell death. With the gradual deepening of study on the redox state of TME and the vigorous development of nanomaterials, it is expected that more anti-tumor nano drugs based on tumor redox microenvironment regulation will be designed and even applied clinically.

The H2O2 Self-Sufficient 3D Printed β-TCP Scaffolds with Synergistic Anti-Tumor Effect and Reinforced Osseointegration

Tumor recurrence and massive bone defects are two critical challenges for postoperative treatment of oral and maxillofacial tumor, posing serious threats to the health of patients. Herein, in order to eliminate residual tumor cells and promote osteogenesis simultaneously, the hydrogen peroxide (H2O2) self-sufficient TCP-PDA-CaO2-CeO2 (TPCC) scaffolds are designed by preparing CaO2 or/and CeO2 nanoparticles (NPs)/chitosan solution and modifying the NPs into polydopamine (PDA)-modified 3D printed TCP scaffolds by rotary coating method. CaO2 NPs loaded on the scaffolds can release Ca2+ and sufficient H2O2 in the acidic tumor microenvironment (TME). The generated H2O2 can further produce hydroxyl radicals (·OH) under catalysis effect by peroxidase (POD) activity of CeO2 NPs, in which the photothermal effect of the PDA coating enhances its POD catalytic effect. Overall, NPs loaded on the scaffold chemically achieve a cascade reaction of H2O2 self-sufficiency and ·OH production, while functionally achieving synergistic effects on anti-tumor and bone promotion. In vitro and in vivo studies show that the scaffolds exhibit effective osteo-inductivity, induced osteoblast differentiation and promote osseointegration. Therefore, the multifunctional composite scaffolds not only validate the concept of chemo-dynamic therapy (CDT) cascade therapy, but also provide a promising clinical strategy for postoperative treatment of oral and maxillofacial tumor.

Single Atom Catalysts Remodel Tumor Microenvironment for Augmented Sonodynamic Immunotherapy

The immunosuppressive tumor microenvironment (TME) is a huge hurdle in immunotherapy. Sono-immunotherapy is a new treatment modality that can reverse immunosuppressive TME, but the sonodynamic effects are compromised by overexpressed glutathione (GSH) and hypoxia in the TME. Herein, this work reports a new sono-immunotherapy strategy using Pdδ+ single atom catalysts to enhance positive sonodynamic responses to the immunosuppressive and sono-suppressive TME. To demonstrate this technique, this work employs rich and reductive Ti vacancies in Ti3-xC2Ty nanosheets to construct the atomically dispersed Pd-C3 single atom catalysts (SAC) with Pd content up to 2.5 wt% (PdSA/Ti3-xC2Ty). Compared with Pd nanoparticle loaded Ti3-xC2Ty, PdSA/Ti3-xC2Ty single-atom enzyme showed augmented sonodynamic effects that are ascribed to SAC facilitated electron-hole separation, rapid depletion of overexpressed GSH by ultrasound (US) excited holes, and catalytic decomposition of endogenous H2O2 for relieving hypoxia. Importantly, the sono-immunotherapy strategy can boost abscopal antitumor immune responses by driving maturation of dendritic cells and polarization of tumor-associated macrophages into the antitumoral M1 phenotype. Bilateral tumor models demonstrate the complete eradication of localized tumors and enhance metastatic regression. Th strategy highlights the potential of single-atom catalysts for robust sono-immunotherapy by remodeling the tumor microenvironment.

Targeting regulated cell death (RCD) in hematological malignancies: Recent advances and therapeutic potential

Regulated cell death (RCD) is a form of cell death that can be regulated by numerous biomacromolecules. Accumulating evidence suggests that dysregulated expression and altered localization of related proteins in RCD promote the development of cancer. Targeting subroutines of RCD with pharmacological small-molecule compounds is becoming a promising therapeutic avenue for anti-tumor treatment, especially in hematological malignancies. Herein, we summarize the aberrant mechanisms of apoptosis, necroptosis, pyroptosis, PANoptosis, and ferroptosis in hematological malignancies. In particular, we focus on the relationship between cell death and tumorigenesis, anti-tumor immunotherapy, and drug resistance in hematological malignancies. Furthermore, we discuss the emerging therapeutic strategies targeting different RCD subroutines. This review aims to summarize the significance and potential mechanisms of RCD in hematological malignancies, along with the development and utilization of pertinent therapeutic strategies.