Etching Bulk Covalent Organic Frameworks into Nanoparticles of Uniform and Controllable Size by the Molecular Exchange Etching Method for Sonodynamic and Immune Combination Antitumor Therapy

Metallized hollow-COF nanobowls with dual-mode ROS generation for cancer sonodynamic therapy

Sonodynamic therapy (SDT) has emerged as an encouraging route in tumor treatment, due to its exceptional tissue penetration depth and favorable safety profile. Nevertheless, the clinical translation of conventional organic sonosensitizers is hindered by intrinsic limitations, including pronounced hydrophobicity, insufficient chemical stability, and low reactive oxygen species (ROS) production. In contrast, hollow covalent organic frameworks (HCOFs) exhibit exceptional cargo-loading capabilities, structural robustness, and biocompatibility, positioning them as ideal nanoplatforms for advanced therapeutic applications. Herein, we engineered a bowl-shaped HCOF architecture designed to amplify ultrasonic cavitation effects. This nanostructure was subsequently functionalized with the sonosensitizer (Hemin) and subjected to strategic metallization via metal ion incorporation, culminating in the development of a high-efficiency antitumor nanosystem (FeHHCA). FeHHCA can achieve dual-mode ROS generation, namely, sonodynamic synergistically generating 1O2 and being specifically activated by a tumor microenvironment (TME) to generate ˙OH through a Fenton-like reaction, achieving an 78.7% tumor inhibition rate in vivo. These findings offer innovative approaches and strategies for the design of hollow COFs and offer great potential for the application of SDT in cancer treatment.

Reprogramming Lung Redox Homeostasis by NIR Driven Ultra-Small Pd Loaded Covalent Organic Framework Inhibits NF-κB Pathway for Acute Lung Injury Immunotherapy

Acute lung injury (ALI) refers to damage to lung related cells, typically caused by an uncontrollable inflammatory response, and over-generated reactive oxygen species (ROS). Increasing evidence suggests that reprogramming lung redox homeostasis holds significant potentials for the clinical treatment of ALI. Herein, the simple synthesis of ultra-small Pd loaded covalent organic framework (COF) (TP@Pd) is reported, which, when combined with near infrared (NIR) irradiation, exhibits nanozyme functionalities, including multiple enzyme mimicking activities and broad spectrum ROS scavenging, thereby promoting tissue repair for ALI immunotherapy. Mechanistically, through the therapeutic strategy of TP@Pd+NIR, the damaged cells and tissues are ameliorated by decreasing intracellular ROS levels (total ROS, ·OH and ·O2 -), downregulating inflammatory cytokines levels (IL-6, TNF-α and IL-1β), upregulating antioxidant factor level (SOD2), inducing macrophage M2 directional polarization (downregulation of iNOS and CD86, and upregulation of IL-10 and CD206), activating immunoregulation (CD4+/CD8+ ratio increase), promoting tissue repair factor levels (upregulation of HSP70 and CD31), and suppressing the NF-κB signaling pathway (downregulation of phosphorylated p65 and IκBα). Furthermore, following intravenous (IV) injection in rats, TP@Pd accumulated in lung tissue for 6 h, indicating the promising therapeutic efficacy via this administration route. Notably, the TP@Pd+NIR strategy demonstrated the excellent synergistic effects in alleviating lung inflammation storms, reducing diffuse alveolar damage, and accelerating lung tissue repair. Summarily, this work has designed a novel TP@Pd+NIR strategy for the synergistic enhancement of ALI amelioration, which may serve as a promising therapeutic approach for other ROS related diseases.

Editing Benzotrithiophene-Based Covalent Organic Frameworks for Developing New Sonosensitizers

Recent insights into covalent organic frameworks (COFs) provide an opportunity for developing new sonosensitizers with the advantages of both small molecules and inorganic nanoagents. Herein, we synthesize two benzotrithiophene-based imine-linked COFs (BTT-DPh-COF and BTT-DPy-COF) through density-functional-theory-guided structure editing. The tailored donor-acceptor (D-A) structures optimize the band position of the COFs and endow them with good intrinsic sonodynamic activity, which can efficiently kill cancer cells, showing excellent sonodynamic therapeutic effect. Particularly, because of the enhanced D-A effect that promotes charge separation and transfer behavior, BTT-DPy-COF exhibits superior ultrasound-triggered reactive oxygen species (ROS) generation capability than BTT-DPh-COF. Therefore, these studies highlight the great potential of elaborate editing COFs with D-A configurations as suitable candidates for advanced sonosensitizers.

Covalent organic frameworks in cancer theranostics: advancing biomarker detection and tumor-targeted therapy

In recent years, covalent organic frameworks (COFs) have garnered considerable attention in the field of onco-nanotechnology as a new type of nanoporous construct due to their promising physicochemical properties, ease of modification, and ability to be coupled with several moieties and therapeutic molecules. They can not only be used as biocompatible nanocarriers to deliver therapeutic payloads to the tumor zone selectively but can also be combined with a variety of therapeutic modalities to achieve the desired treatments. This review comprehensively presented recent achievements and progress in COF-based cancer diagnosis, detection, and cancer therapy to provide a better prospect for further research. Herein our primary emphasis lies on exploring the application of COFs as potential sensors for cancer-derived biomarkers that have received comparatively less attention in previous discussions. While the utilization of COFs in solid tumor therapy has faced significant challenges in scientific research and clinical applications, we reviewed the most promising features that underscore their potential in cancer theranostics.

A Covalent Organic Framework as Photocatalyst for Smart Conversion Between Photooxidation and Photoreduction and H2O2 Production in Full pH Environment

Developing multifunctional photocatalysts with intelligent self-adjusting is of great significance in the photocatalytic process. Herein, a smart covalent organic framework (Por-HQ-COF) with a phenol-quinone conversion structure with pH changes is constructed for photooxidation, photoreduction, and H2O2 production. As a smart photocatalyst, Por-HQ-COF can convert into Por-BQ-COF intelligently with a trigger including solution pH, and vice versa. The reconstruction of phenol-quinone conversion not only significantly alters the morphologies and the specific surface areas of the COF, but also leads to an entirely change in the band energy and charge distribution to influence photoelectric properties. As a result, under acidic conditions, Por-BQ-COF converts into Por-HQ-COF automatically and can photoreduce high concentration Cr(VI) to Cr(III) efficiently. Under neutral conditions, the superoxide anions (·O2 -) initiate the Por-HQ-COF reconstruction into Por-BQ-COF to accelerate photooxidation to degrade high-concentration TC. Under alkaline conditions, Por-HQ-COF converts into Por-BQ-COF, can effectively photosynthesize H2O2 (1525 µmol h-1 g-1 at λ > 420 nm) in the absence of any sacrificial reagents, and reveal the strong alkalinity lower the energy barrier of hydrogen extraction from H2O and clarify active sites for H2O2 production. This work provides a new strategy for developing smart photocatalysts and fulfill the application across the full pH environment.

Controlling crystallization in covalent organic frameworks to facilitate photocatalytic hydrogen production

The catalytic performance, depending on the surface nature, is ubiquitous in photocatalysis. However, surface engineering for organic photocatalysts through structural modulation has long been neglected. Here, we propose a zone crystallization strategy for covalent organic frameworks (COFs) that enhances surface ordering through regulator-induced amorphous-to-crystalline transformation. Dynamic simulations show that attaching monofunctional regulators to the surface of spherical amorphous precursor improves surface dynamic reversibility, increasing crystallinity from the inside out. The resulting COF microspheres display surface-enhanced crystallinity and uniform spherical morphology. The visible photocatalytic hydrogen evolution rate reaches 126 mmol g-1 h-1 for the simplest β-ketoenamine-linked COF and 350 mmol gCOF-1 h-1 for SiO2@COF with minimal Pt cocatalysts. Mechanism studies indicate that surface crystalline domains build the surface electrical fields to accumulate photogenerated electrons and diminish electron transfer barriers between the COF and Pt interface. This work bridges the gap between microscopic molecules and macroscopic properties, allowing tailored design of crystalline organic photocatalysts.

Ultrasound-Activated Copper Matrix Nanosonosensitizer for Cuproptosis-Based Synergy Therapy

Cuproptosis exhibits enormous application prospects in treatment. However, cuproptosis-based therapy is impeded by the limited intracellular copper ions, the nonspecific delivery, uncontrollable release, and chelation of endogenous overproduced glutathione (GSH). In this work, an ultrasound-triggered nanosonosensitizer (p-TiO2-Cu(I)) was constructed for Cu(I) delivery, on-demand release, GSH consumption, and deeper tissue response. When the nanomedicine was internalized into the tumor cells, ultrasound (US) induced the nanosonosensitizer to produce reactive oxygen species (ROS) to achieve sonodynamic therapy (SDT). GSH, acting as a hole trapping agent, improved the efficiency of SDT. Meanwhile, the downgrade of GSH was beneficial to cuproptosis and oxidative damage-based SDT in return. What is more, the US could regulate the release behavior of Cu(I). Cu(I) bonded to mitochondrial proteins and then aggregated the lipoylated protein, bringing about the turbulence of the tricarboxylic acid cycle. The combination of SDT and cuproptosis showed high matching to induce efficient cuproptosis and may inspire other cuproptosis-based nanosonosensitizer designs.

Size-Tunable Covalent Organic Framework Nanoparticles for Assembling One-Dimensional Photonic Crystals With Visual Sensing

One-dimensional photonic crystals (1D PCs) emerged as superb sensing platforms due to their high sensitivity to environmental changes. However, effectively translating the microscopic interactions between covalent organic frameworks (COFs) and analytes into macroscopic optical responses via 1D PCs for intuitive detection presents a significant challenge. Here, we propose a stepwise-induced synthesis strategy that for the first time achieves a size-controlled synthesis of uniform nanoscale COFs (60-80 nm), leading to a high-quality COF layer. This advancement enables COF-based 1D PCs to exhibit diverse color variations and controllable saturation. Notably, the excellent compatibility of the COF layer with inorganic oxides, organic polymers, and metal-organic frameworks (MOFs) results in these 1D PCs exhibiting bright colors. Crucially, introducing the mesoporous materials enables 1D PCs to achieve deep integration of adsorption and recognition functions for volatile organic compounds (VOCs). The fabricated COF/MOF 1D PC allows differentiation of 12 VOCs and visually detects VOCs at different concentrations (0-80 g m- 3) through color changes, with a response time under 1 s. In particular, COF-based 1D PCs can be transferred to flexible substrates while retaining VOC visual sensing. These attributes highlight the potential of COF-based 1D PCs for real-time VOC monitoring in industrial environments.

β-Ketoenamine covalent organic framework nanoplatform combined with immune checkpoint blockade via photodynamic immunotherapy inhibit glioblastoma progression

The synergistic approach of combining photodynamic immunotherapy with endogenous clearance of PD-L1 immune checkpoint blockade therapy holds promise for enhancing survival outcomes in glioblastoma (GBM) patients. The observed upregulation of O-GlcNAc glycolysis in tumors may contribute to the stabilization of endogenous PD-L1 protein, facilitating tumor immune evasion. This study presents a pH-adapted excited state intramolecular proton transfer (ESIPT)-isomerized β-ketoamide-based covalent organic framework (COF) nanoplatform (denoted as OT@COF-RVG). Temozolomide (TMZ) and OSMI-4 (O-GlcNAc transferase inhibitor) were integrated into COF cavities, then modified on the surface with polyethylene glycol and the rabies virus peptide RVG-29, showing potential for sensitizing TMZ chemotherapy and initiating photodynamic therapy (PDT). By inhibiting O-GlcNAc and promoting lysosomal degradation of PD-L1, OT@COF-RVG enhanced the effectiveness of immune checkpoint blockade (ICB) therapy. Additionally, treatment with OT@COF-RVG led to a notable elevation in reactive oxygen species (ROS) levels, thereby re-establishing an immunostimulatory state, inducing immunogenic cell death (ICD). In summary, our research unveiled a correlation between O-GlcNAc in GBM and the evasion of immune responses by tumors, while showcasing the potential of OT@COF-RVG in reshaping the immunosuppressive microenvironment of GBM and offering a more effective approach to immunotherapy in clinical settings.

Tumor-Targeted Catalytic Immunotherapy

Cancer immunotherapy holds significant promise for improving cancer treatment efficacy; however, the low response rate remains a considerable challenge. To overcome this limitation, advanced catalytic materials offer potential in augmenting catalytic immunotherapy by modulating the immunosuppressive tumor microenvironment (TME) through precise biochemical reactions. Achieving optimal targeting precision and therapeutic efficacy necessitates a thorough understanding of the properties and underlying mechanisms of tumor-targeted catalytic materials. This review provides a comprehensive and systematic overview of recent advancements in tumor-targeted catalytic materials and their critical role in enhancing catalytic immunotherapy. It highlights the types of catalytic reactions, the construction strategies of catalytic materials, and their fundamental mechanisms for tumor targeting, including passive, bioactive, stimuli-responsive, and biomimetic targeting approaches. Furthermore, this review outlines various tumor-specific targeting strategies, encompassing tumor tissue, tumor cell, exogenous stimuli-responsive, TME-responsive, and cellular TME targeting strategies. Finally, the discussion addresses the challenges and future perspectives for transitioning catalytic materials into clinical applications, offering insights that pave the way for next-generation cancer therapies and provide substantial benefits to patients in clinical settings.

Modulating Pore Wall Chemistry Empowers Sonodynamic Activity of Two-Dimensional Covalent Organic Framework Heterojunctions for Pro-Oxidative Nanotherapy

Covalent organic frameworks (COFs) have garnered growing interest in the field of biomedicine; however, their application in sonodynamic therapy remains underexplored due to limited understanding of their intrinsic activity and structure-property relationships. Here, we present a pore wall chemistry modulation strategy for empowering sonodynamic activity to two-dimensional (2D) COF heterojunctions through in situ growth of COFs on bismuth oxycarbonate nanosheets (B NSs). Compared to the negligible sonodynamic effects observed in the pristine B NSs, the 2D heterojunction with vinyl-decorated COF pore walls demonstrates a 3.6-fold enhancement in sonocatalytic singlet oxygen generation. This performance also significantly outperforms that of isoreticular COFs functionalized with methoxy or non-substituted groups. Mechanistic studies reveal that the vinyl groups in the B@COF (BC) heterojunction facilitate the separation and transfer of charge carriers while also enhancing the adsorption of oxygen molecules. Furthermore, peroxymonosulfate (PMS) loading into the porous COFs boosts the therapeutic efficacy of antitumor nanotherapy via sonocatalytic dual oxidative species generation. These findings underscore the critical role of pore wall chemistry in modulating the sonocatalytic properties of COFs, and advance the development of COF-based sonosensitizers for pro-oxidative applications.

Liquid-nano-liquid interface-oriented anisotropic encapsulation

Emulsion interface engineering has been widely employed for the synthesis of nanomaterials with various morphologies. However, the instability of the liquid-liquid interface and uncertain interfacial interactions impose significant limitations on controllable fabrications. Here, we developed a liquid-nano-liquid interface-oriented anisotropic encapsulation strategy for fabricating asymmetric nanohybrids. Specifically, functional nanoparticles such as magnetic nanoparticles, lanthanide fluorescent nanoparticles, and Au nanorods were anisotropically encapsulated by mesoporous polydopamine (mPDA). In this emulsion system, the wetting behavior of functional nanoparticles at the water/oil interface could be manipulated by the stabilizer of the emulsion (surfactant), leading to the anisotropic assembly of mPDA shell and resulting in various nanostructures, including core-shell, yolk-shell with small opening, ball-in-bowl, and multipetal structures. Due to their structural asymmetry, inherent magnetic properties, and photothermal properties, the ball-in-bowl structured Fe3O4@SiO2&mPDA nanohybrids, serving as proof of concept for nanomotors, demonstrated effective penetration of bacterial biofilm and promotion of infected wound healing. Overall, our approach offers a different perspective for designing morphologically controllable asymmetric structures based on liquid-nano-liquid interface in microemulsion systems that hold great potential for establishing innovative functional nanomaterials.

Trigger inducible tertiary lymphoid structure formation using covalent organic frameworks for cancer immunotherapy

The discovery of tertiary lymphoid structures (TLS) within tumor tissues provides a promising avenue to promote the efficacy of cancer immunotherapy. Yet, the lack of effective strategies to induce TLS formation poses a substantial obstacle. Thus, the exploration of potential inducers for TLS formation is of great interest but remains challenging. Here, inspired by the mechanism of artificially cultivated pearls, a covalent organic framework (COF) is employed to induce TLS formation. Single-cell sequencing analysis reveals that this is achieved by promotion of cytokine hypersecretion, which facilitates the maturation, proliferation, and migration of T and B cells, critical for triggering TLS formation. Furthermore, the efficacy of COF-mediated phototherapy in inducing TLS formation is validated in both the MC38 and 4MOSC1 female tumor models. Notably, a strong synergistic effect between COF-mediated phototherapy and αCTLA-4 is observed, resulting in the effective eradication of both primary and distant tumors, while also inhibiting tumor recurrence.

Metal-based smart nanosystems in cancer immunotherapy

Metals are an emerging topic in cancer immunotherapy that have shown great potential in modulating cancer immunity cycle and promoting antitumor immunity by activating the intrinsic immunostimulatory mechanisms which have been identified in recent years. The main challenge of metal-assisted immunotherapy lies in the fact that the free metals as ion forms are easily cleared during circulation, and even cause systemic metal toxicity due to the off-target effects. With the rapid development of nanomedicine, metal-based smart nanosystems (MSNs) with unique controllable structure become one of the most promising delivery carriers to solve the issue, owing to their various endogenous/external stimuli-responsiveness to release free metal ions for metalloimmunotherapy. In this review, the state-of-the-art research progress in metal-related immunotherapy is comprehensively summarized. First, the mainstream mechanisms of MSNs-assisted immunotherapy will be delineated. The immunological effects of certain metals and categorization of MSNs with different characters and compositions are then provided, followed by the representative exemplar applications of MSNs in cancer treatment, and synergistic combination immunotherapy. Finally, we conclude this review with a summary of the remaining challenges associated with MSNs and provide the authors' perspective on their further advances.

NIR-II Fluorescent Nanotheranostics with a Switchable Irradiation Mode for Immunogenic Sonodynamic Therapy

Nanotheranostics, which integrate diagnostic and therapeutic functionalities, offer significant potential for tumor treatment. However, current nanotheranostic systems typically involve multiple molecules, each providing a singular diagnostic or therapeutic function, leading to challenges such as complex structural composition, poor targeting efficiency, lack of spatiotemporal control, and dependence on a single therapeutic modality. This study introduces NPRBOXA, a nanoparticle functionalized with surface-bound cRGD for targeted delivery to αvβ3/αvβ5 receptors on tumor cells, achieving theranostic integration by sequentially switching its irradiation modes. Under 808 nm laser irradiation, NPRBOXA emits NIR-II fluorescence, which aids in identifying the nanoparticle's location and fluorescence intensity, thereby determining the optimal treatment window. Following this, the irradiation mode switches to ultrasound irradiation at the optimal treatment window. Ultrasound irradiation induces NPRBOXA to generate reactive oxygen species, promoting the reduction of OXA-IV to OXA-II, which in turn triggers immunogenic cell death. This mechanism enables a combination of sonodynamic therapy, chemotherapy, and immunotherapy for tumor treatment. The versatile design of NPRBOXA holds promise for advancing precision oncology through enhanced therapeutic efficacy and real-time imaging guidance.

PAFerroptosis Combined with Metabolic Disturbance of Mito by p52-ZER6 for Enhanced Cancer Immunotherapy induced by Nano-Bacilliform-Enzyme

The confused gene expressions and molecular mechanisms for mitochondrial dysfunction of traditional nanoenzymes is a challenge for tumor therapy. Herein, a nano-bacilliform-enzyme obtains the ability to inhibit p52-ZER6 signal pathway, regulate the genes related to mitochondrial metabolism, and possess the GOx/CAT/POD-like property. NBE acquires catalytic activity from the electronic energy transition. The tannin of NBE as a mitochondrial (Mito)-targeting guide overloads MitoROS, and then metabolic disorder and lipid peroxidation of Mito membrane occurs, thus leading to a novel death pathway called PAFerroptosis (pyroptosis, apoptosis, and Ferroptosis). Simultaneously, in order to refrain from mitophagy, hydroxychloroquine is mixed with NBE to form a combo with strength pyroptosis. As a result, NBE/combo improves the PAFerroptosis obviously by activation of CD8+T cells and inactivation of MDSC cells, up-regulating expression of caspase-3 signal pathway, intercepting DHODH pathway to arrive excellent antitumor effect (93%). Therefore, this study establishes a rational nanoenzyme for mitochondrial dysfunction without mitophagy for effective antitumor therapy.

pH-Responsive injectable self-healing hydrogels loading Au nanoparticles-decorated bimetallic organic frameworks for synergistic sonodynamic-chemodynamic-starvation-chemo therapy of cancer

A novel and efficient cancer therapy was developed using a smart hydrogel containing multifunctional bimetallic organic frameworks and anticancer drugs. The injectable self-healing hydrogel with pH-responsiveness was constructed through borate ester and imine bonds among dopamine-grafted sodium alginate (SADA), hydroxypropyl chitosan (HPCS) and 2-formylphenylboronic acid (2-FPBA). The Au nanoparticles-decorated Ti/Fe bimetallic organic framework tetragonal nanosheets (Au/TF-MOF TNS) were synthesized and incorporated into the hydrogel with the anticancer drugs doxorubicin (DOX). Upon intratumoral injection of nanocomposite hydrogel, the acidic tumor microenvironment triggered the cleavage of borate ester and imine bonds, causing the hydrogel to break down and accelerating the release of both Au/TF-MOF TNS and DOX. These Au/TF-MOF TNS functioned as nanozymes, producing hydroxyl radicals (·OH) for chemodynamic therapy (CDT), generating oxygen (O2) to support sonodynamic therapy (SDT), and depleting glucose for starvation therapy (ST). Additionally, the Au/TF-MOF TNS served as sonosensitizers, capable of converting O2 into singlet oxygen (1O2) upon ultrasound irradiation to achieve SDT. Therefore, this nanocomposite hydrogel system enabled synergistic sonodynamic-chemodynamic-starvation-chemo therapy (SDT-CDT-ST-CT) of cancer, presenting a promising platform for advanced cancer therapy strategies.

Bacteria-Mediated Tumor-Targeting Delivery of Multienzyme-Mimicking Covalent Organic Frameworks Promoting Pyroptosis for Combinatorial Sono-Catalytic Immunotherapy

Pyroptosis, an inflammatory cell death, has attracted great attention for potentiating a strong immune response against tumor cells. However, developing powerful pyroptosis inducers and then activating specific pyroptosis still remains challenging. Herein, a PEG-CuP-COF@∆St nanosystem is rationally designed, consisting of PEG-CuP-COF nanozyme pyroptosis inducers and tumor-targeting bacteria of the Salmonella Typhimurium strain VNP20009 (ΔSt), with an affinity for the tumor hypoxic microenvironment. The PEG-CuP-COF nanozymes possessed excellent sonodynamic performance and multienzyme-mimicking activities to generate reactive oxygen species (ROS) and then induce potent pyroptosis. The superoxide dismutase- and peroxidase-mimicking activities of PEG-CuP-COF catalytically produced hydrogen peroxide (H2O2) and hydroxyl radicals (•OH) which have important value in triggering acute inflammatory responses and pyroptosis. Moreover, PEG-CuP-COF showed outstanding glutathione peroxidase-mimicking activities, impairing the antioxidant defense in tumor cells and enhancing sonodynamic efficiency by making them more vulnerable to ROS-induced damage. During in vivo studies, PEG-CuP-COF@∆St nanosystem with its self-driven property exhibited impressive tumor-targeting capability and activated Caspase-3/gasdermin E-dependent pyroptosis to inhibit tumor growth. More importantly, it induced a powerful immune memory effect to prevent bone metastasis. In summary, this study introduces an innovative approach for combinatorial sono-catalytic immunotherapy using bacteria-mediated tumor-targeting delivery of nanozymes as specific pyroptosis inducers.

Photons, Excitons, and Electrons in Covalent Organic Frameworks

Covalent organic frameworks (COFs) are created by the condensation of molecular building blocks and nodes to form two-dimensional (2D) or three-dimensional (3D) crystalline frameworks. The diversity of molecular building blocks with different properties and functionalities and the large number of possible framework topologies open a vast space of possible well-defined porous architectures. Besides more classical applications of porous materials such as molecular absorption, separation, and catalytic conversions, interest in the optoelectronic properties of COFs has recently increased considerably. The electronic properties of both the molecular building blocks and their linkage chemistry can be controlled to tune photon absorption and emission, to create excitons and charge carriers, and to use these charge carriers in different applications such as photocatalysis, luminescence, chemical sensing, and photovoltaics. In this Perspective, we will discuss the relationship between the structural features of COFs and their optoelectronic properties, starting with the building blocks and their chemical connectivity, layer stacking in 2D COFs, control over defects and morphology including thin film synthesis, exploring the theoretical modeling of structural, electronic, and dynamic features of COFs, and discussing recent intriguing applications with a focus on photocatalysis and photoelectrochemistry. We conclude with some remarks about present challenges and future prospects of this powerful architectural paradigm.

Ultrasound-triggered nano delivery of lenvatinib for selective immunotherapy treatment against hepatocellular carcinoma

Although there have been remarkable advances in the treatment of hepatocellular carcinoma (HCC), the prognosis remains poor in those with advanced stage and more effective therapeutic options are urgently needed. Lenvatinib (Len), a multiple receptor tyrosine kinase inhibitor, is an emerging molecular targeted agent for HCC, whose immunomodulatory activities have been investigated. However, Len utilization is limited because of its low metabolic stability, poor bioavailability and dose-dependent toxicity, rendering its direct use insufficient for immune modulation. Stimuli-responsive nanoparticles, which are drug-targeted delivery platforms for on-demand drug release, facilitate deeper and uniform tumour penetration, providing alternative solutions to overcome current limitations. Ultrasound (US) exhibits superior tissue penetration abilities and can produce reactive oxygen species (ROS) at the tumour site to treat deeper tumours. In addition, US serves as an excellent and selective drug delivery mediator for tumour treatment. Herein, we designed US-triggered lenvatinib nanoparticles (Len-RNPs) for selective drug delivery that utilize US-triggered ROS to induce in situ oxidation reactions, resulting in nanoparticle disintegration. Len-RNPs mitigate the toxicity of Len and effectively trigger robust systemic anti-tumour immune responses in a H22 tumour model, resulting in a tumour suppression rate of 95.7%, with 60% of mice being cured. Our study elucidates a novel and precise strategy of combining Len and US therapy for enhanced HCC immunotherapy.

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.

Nanosonosensitizer Optimization for Enhanced Sonodynamic Disease Treatment

Low-intensity ultrasound-mediated sonodynamic therapy (SDT), which, by design, integrates sonosensitizers and molecular oxygen to generate therapeutic substances (e.g., toxic hydroxyl radicals, superoxide anions, or singlet oxygen) at disease sites, has shown enormous potential for the effective treatment of a variety of diseases. Nanoscale sonosensitizers play a crucial role in the SDT process because their structural, compositional, physicochemical, and biological characteristics are key determinants of therapeutic efficacy. In particular, advances in materials science and nanotechnology have invigorated a series of optimization strategies for augmenting the therapeutic efficacy of nanosonosensitizers. This comprehensive review systematically summarizes, discusses, and highlights state-of-the-art studies on the current achievements of nanosonosensitizer optimization in enhanced sonodynamic disease treatment, with an emphasis on the general design principles of nanosonosensitizers and their optimization strategies, mainly including organic and inorganic nanosonosensitizers. Additionally, recent advancements in optimized nanosonosensitizers for therapeutic applications aimed at treating various diseases, such as cancer, bacterial infections, atherosclerosis, and autoimmune diseases, are clarified in detail. Furthermore, the biological effects of the improved nanosonosensitizers for versatile SDT applications are thoroughly discussed. The review concludes by highlighting the current challenges and future opportunities in this rapidly evolving research field to expedite its practical clinical translation and application.

CuPc-Fe@BSA nanocomposite: Intracellular acid-sensitive aggregation for enhanced sonodynamic and chemo-therapy

Due to their rigid π-conjugated macrocyclic structure, organic sonosensitizers face significant aggregation in physiological conditions, hindering the production of reactive oxygen species (ROS). An acid-sensitive nanoassembly was developed to address this issue and enhance sonodynamic therapy (SDT) and emission. Initially, copper phthalocyanine (CuPc) was activated using a H2SO4-assisted hydrothermal method to introduce multiple functional groups (-COOH, -OH, and -SO3H), disrupting strong π-π stacking and promoting ROS generation and emission. Subsequently, negatively charged CuPc-SO4 was incorporated into bovine serum albumin (BSA) to form CuPc-Fe@BSA nanoparticles (10 nm) with Fe3+ ions serving as linkers. In acidic conditions, protonation of CuPc-SO4 and BSA weakened the interactions, leading to Fe3+ release and nanostructure dissociation. Protonated CuPc-SO4 tended to self-aggregate into nanorods. This acidity-sensitive aggregation is vital for achieving specific accumulation within the tumor microenvironment (TME), thereby enhancing retention and SDT efficacy. Prior to this, the nanocomposites demonstrated cycling stability under neutral conditions. Additionally, the released Fe ions exhibited mimicry of glutathione peroxidase and peroxidase activity for chemotherapy (CDT). The synergistic effect of SDT and CDT increased intracellular oxidative stress, causing mitochondrial injury and ferroptosis. Furthermore, the combined therapy induced immunogenic cell death (ICD), effectively activating anticancer immune responses and suppressing metastasis and recurrence.

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.

Rationally Designed Benzobisthiadiazole-Based Covalent Organic Framework for High-Performance NIR-II Fluorescence Imaging-Guided Photodynamic Therapy

Although being applied as photosensitizers for photodynamic therapy, covalent organic frameworks (COFs) fail the precise fluorescence imaging in vivo and phototherapy in deep-tissue, due to short excitation/emission wavelengths. Herein, this work proposes the first example of NIR-II emissive and benzobisthiadiazole-based COF-980. Comparing to its ligands, the structure of COF-980 can more efficiently reducing the energy gap (ΔES1-T1) between the excited state and the triplet state to enhance photodynamic therapy efficiency. Importantly, COF-980 demonstrates high photostability, good anti-diffusion property, superior reactive oxygen species (ROS) generation efficiency, promising imaging ability, and ROS production in deep tissue (≈8 mm). Surprisingly, COF-980 combined with laser irradiation could trigger larger amount of intracellular ROS to high efficiently induce cancer cell death. Notably, COF-980 NPs precisely enable PDT guided by NIR-II fluorescence imaging that effectively inhibit the 4T1 tumor growth with negligible adverse effects. This study provides a universal approach to developing long-wavelength emissive COFs and exploits its applications for biomedicine.

Advancing nanotechnology for neoantigen-based cancer theranostics

Neoantigens play a pivotal role in the field of tumour therapy, encompassing the stimulation of anti-tumour immune response and the enhancement of tumour targeting capability. Nonetheless, numerous factors directly influence the effectiveness of neoantigens in bolstering anti-tumour immune responses, including neoantigen quantity and specificity, uptake rates by antigen-presenting cells (APCs), residence duration within the tumour microenvironment (TME), and their ability to facilitate the maturation of APCs for immune response activation. Nanotechnology assumes a significant role in several aspects, including facilitating neoantigen release, promoting neoantigen delivery to antigen-presenting cells, augmenting neoantigen uptake by dendritic cells, shielding neoantigens from protease degradation, and optimizing interactions between neoantigens and the immune system. Consequently, the development of nanotechnology synergistically enhances the efficacy of neoantigens in cancer theranostics. In this review, we provide an overview of neoantigen sources, the mechanisms of neoantigen-induced immune responses, and the evolution of precision neoantigen-based nanomedicine. This encompasses various therapeutic modalities, such as neoantigen-based immunotherapy, phototherapy, radiotherapy, chemotherapy, chemodynamic therapy, and other strategies tailored to augment precision in cancer therapeutics. We also discuss the current challenges and prospects in the application of neoantigen-based precision nanomedicine, aiming to expedite its clinical translation.

Ultrasound Activated Nanobowls with Deep Penetration for Enhancing Sonodynamic Therapy of Orthotopic Liver Cancer

Owing to the high penetration ability and the safety of ultrasound (US) of sonodynamic therapy (SDT), it has gained significant attention in tumor treatment. However, its therapeutic efficiency depends on the performance of the sonosensitizers. The hypoxic microenvironment and abnormal stromal matrix restrict the full potential of sonosensitizers. In this study, a US-activated bowl-shaped nanobomb (APBN) is designed as a novel sonosensitizer to enhance the SDT effect through various means. This enhancement strategy combines three major characteristics: relieving tumor hypoxia, amplifying bubble cavitation damage, and US-movement-enhanced permeation. The unique bowl-shaped structure of APBN provides more favorable attachment sites for the generated oxygen gas bubbles. Thus, when catalase-like APBN catalyzes endogenous hydrogen peroxide to produce oxygen, bubbles accumulate at the groove, preventing the dissipation of oxygen and increasing the number of cavitation nuclei to improve the acoustic cavitation effect. This approach differs from traditional SDT strategies because it couples the sonodynamic effect with reactive oxygen species generation and bubble cavitation damage rather than a single action. Additionally, the asymmetric bowl-shaped structure generates a driving force under the US field, improving the distribution of sonosensitizers in the tumors. Using US and photoacoustic imaging for dual localization, these sonosensitizers can improve the accuracy of orthotopic liver tumor treatment, which presents a promising avenue for the treatment of deep tumors.

Strategies for utilizing covalent organic frameworks as host materials for the integration and delivery of bioactives

Covalent organic frameworks (COFs), a new and developing class of porous framework materials, are considered a type of promising carrier for the integration and delivery of bioactives, which have diverse fascinating merits, such as a large specific surface area, designable and specific porosity, stable and orderly framework structure, and various active sites. However, owing to the significant differences among bioactives (including drugs, proteins, nucleic acid, and exosomes), such as size, structure, and physicochemical properties, the interaction between COFs and bioactives also varies. In this review, we firstly summarize three strategies for the construction of single or hybrid COF-based matrices for the delivery of cargos, including encapsulation, covalent binding, and coordination bonding. Besides, their smart response release behaviors are also categorized. Subsequently, the applications of cargo@COF biocomposites in biomedicine are comprehensively summarized, including tumor therapy, central nervous system (CNS) modulation, biomarker analysis, bioimaging, and anti-bacterial therapy. Finally, the challenges and opportunities in this field are briefly discussed.

Covalent Organic Frameworks: Opportunities for Rational Materials Design in Cancer Therapy

Nanomedicines are extensively used in cancer therapy. Covalent organic frameworks (COFs) are crystalline organic porous materials with several benefits for cancer therapy, including porosity, design flexibility, functionalizability, and biocompatibility. This review examines the use of COFs in cancer therapy from the perspective of reticular chemistry and function-oriented materials design. First, the modification sites and functionalization methods of COFs are discussed, followed by their potential as multifunctional nanoplatforms for tumor targeting, imaging, and therapy by integrating functional components. Finally, some challenges in the clinical translation of COFs are presented with the hope of promoting the development of COF-based anticancer nanomedicines and bringing COFs closer to clinical trials.

A PD-L1-targeting Regulator for Metabolic Reprogramming to Enhance Glutamine Inhibition-Mediated Synergistic Antitumor Metabolic and Immune Therapy

Inhibition of glutamine metabolism in tumor cells can cause metabolic compensation-mediated glycolysis enhancement and PD-L1 upregulation-induced immune evasion, significantly limiting the therapeutic efficacy of glutamine inhibitors. Here, inspired by the specific binding of receptor and ligand, a PD-L1-targeting metabolism and immune regulator (PMIR) are constructed by decorating the glutaminase inhibitor (BPTES)-loading zeolitic imidazolate framework (ZIF) with PD-L1-targeting peptides for regulating the metabolism within the tumor microenvironment (TME) to improve immunotherapy. At tumor sites, PMIR inhibits glutamine metabolism of tumor cells for elevating glutamine levels within the TME to improve the function of immune cells. Ingeniously, the accompanying PD-L1 upregulation on tumor cells causes self-amplifying accumulation of PMIR through PD-L1 targeting, while also blocking PD-L1, which has the effects of converting enemies into friends. Meanwhile, PMIR exactly offsets the compensatory glycolysis, while disrupting the redox homeostasis in tumor cells via the cooperation of components of the ZIF and BPTES. These together cause immunogenic cell death of tumor cells and relieve PD-L1-mediated immune evasion, further reshaping the immunosuppressive TME and evoking robust immune responses to effectively suppress bilateral tumor progression and metastasis. This work proposes a rational strategy to surmount the obstacles in glutamine inhibition for boosting existing clinical treatments.

Ultrasound technology assisted colloidal nanocrystal synthesis and biomedical applications

Non-invasive and high spatiotemporal resolution mythologies for the diagnosis and treatment of disease in clinical medicine promote the development of modern medicine. Ultrasound (US) technology provides a non-invasive, real-time, and cost-effective clinical imaging modality, which plays a significant role in chemical synthesis and clinical translation, especially in in vivo imaging and cancer therapy. On the one hand, the US treatment is usually accompanied by cavitation, leading to high temperature and pressure, so-called "hot spot", playing a significant role in sonochemical-based colloidal synthesis. Compared with the classical nucleation synthetic method, the sonochemical synthesis strategy presents high efficiency for the fabrication of colloidal nanocrystals due to its fast nucleation and growth procedure. On the other hand, the US is attractive for in vivo and medical treatment, with applications increasing with the development of novel contrast agents, such as the micro and nano bubbles, which are widely used in neuromodulation, with which the US can breach the blood-brain barrier temporarily and safely, opening a new door to neuromodulation and therapy. In terms of cancer treatment, sonodynamic therapy and US-assisted synergetic therapy show great effects against cancer and sonodynamic immunotherapy present unparalleled potentiality compared with other synergetic therapies. Further development of ultrasound technology can revolutionize both chemical synthesis and clinical translation by improving efficiency, precision, and accessibility while reducing environmental impact and enhancing patient care. In this paper, we review the US-assisted sonochemical synthesis and biological applications, to promote the next generation US technology-assisted applications.

Ultrasound activated probe for disease imaging and therapy In-Vivo

Sonodynamic therapy (SDT) is the use of ultrasound (US) to excite sonosensitizers to produce reactive oxygen species (ROS) to induce tumor cell death, thereby achieving therapeutic purposes. Based on the strong tissue penetration ability of ultrasound, SDT can realize the treatment of deeper tumors, and it is targeted, can be specifically concentrated at the tumor site, and has little impact on surrounding normal tissues. It has broad clinical transformation prospects. Therefore, sonosensitizers are the key to SDT, and the exploration of sonosensitizers with excellent therapeutic performance has received great attention. We reviewed the development of ultrasound-inspired sound sensitizers for imaging and treatment. First, different types of sonosensitizers are introduced, the construction and performance of inorganic, organic and hybrid types of sonosensitizers are evaluated, followed by a review of different image-guided SDT, and finally the key problems and solutions in this field are discussed in detail.

Nanomaterials augmented bioeffects of ultrasound in cancer immunotherapy

Immunotherapy as a milestone in cancer treatment has made great strides in the past decade, but it is still limited by low immune response rates and immune-related adverse events. Utilizing bioeffects of ultrasound to enhance tumor immunotherapy has attracted more and more attention, including sonothermal, sonomechanical, sonodynamic and sonopiezoelectric immunotherapy. Moreover, the emergence of nanomaterials has further improved the efficacy of ultrasound mediated immunotherapy. However, most of the summaries in this field are about a single aspect of the biological effects of ultrasound, which is not comprehensive and complete currently. This review proposes the recent progress of nanomaterials augmented bioeffects of ultrasound in cancer immunotherapy. The concept of immunotherapy and the application of bioeffects of ultrasound in cancer immunotherapy are initially introduced. Then, according to different bioeffects of ultrasound, the representative paradigms of nanomaterial augmented sono-immunotherapy are described, and their mechanisms are discussed. Finally, the challenges and application prospects of nanomaterial augmented ultrasound mediated cancer immunotherapy are discussed in depth, hoping to pave the way for cancer immunotherapy and promote the clinical translation of ultrasound mediated cancer immunotherapy through the reasonable combination of nanomaterials augmented ultrasonic bioeffects.

Sonocatalytic cancer therapy: theories, advanced catalysts and system design

Treating cancer remains one of the most formidable challenges in modern medicine, with traditional treatment options often being limited by poor therapeutic outcomes and unacceptable side effects. Nanocatalytic therapy activates tumor-localized catalytic reactions in situ via nontoxic or minimally toxic nanocatalysts responding to unique cues from the tumor microenvironment or external stimuli. In particular, sonocatalytic cancer therapy is a promising approach that has emerged as a potential solution to this problem through the combination of ultrasound waves and catalytic materials to selectively target and destroy cancer cells. Compared to light, ultrasound exhibits higher spatial precision, lower energy attenuation, and superior tissue penetrability, furnishing more energy to catalysts. Multidimensional modulation of nanocatalyst structures and properties is pivotal to maximizing catalytic efficiency given constraints in external stimulative energy as well as substrate types and levels. In this review, we discuss the various theories and mechanisms underlying sonocatalytic cancer therapy, as well as advanced catalysts that have been developed for this application. Additionally, we explore the design of sonocatalytic cancer therapy systems, including the use of heterojunction catalysts and the optimal conditions for achieving maximum therapeutic effects. Finally, we highlight the potential benefits of sonocatalytic cancer therapy over traditional cancer treatments, including its noninvasive nature and lower toxicity.

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.

Adoptive macrophage directed photodynamic therapy of multidrug-resistant bacterial infection

Multidrug-resistant (MDR) bacteria cause severe clinical infections and a high mortality rate of over 40% in patients with immunodeficiencies. Therefore, more effective, broad-spectrum, and accurate treatment for severe cases of infection is urgently needed. Here, we present an adoptive transfer of macrophages loaded with a near-infrared photosensitizer (Lyso700D) in lysosomes to boost innate immunity and capture and eliminate bacteria through a photodynamic effect. In this design, the macrophages can track and capture bacteria into the lysosomes through innate immunity, thereby delivering the photosensitizer to the bacteria within a single lysosome, maximizing the photodynamic effect and minimizing the side effects. Our results demonstrate that this therapeutic strategy eliminated MDR Staphylococcus aureus (MRSA) and Acinetobacter baumannii (AB) efficiently and cured infected mice in both two models with 100% survival compared to 10% in the control groups. Promisingly, in a rat model of central nervous system bacterial infection, we performed the therapy using bone marrow-divided macrophages and implanted glass fiber to conduct light irradiation through the lumbar cistern. 100% of infected rats survived while none of the control group survived. Our work proposes an efaficient and safe strategy to cure MDR bacterial infections, which may benefit the future clinical treatment of infection.

An acid-responsive MOF nanomedicine for augmented anti-tumor immunotherapy via a metal ion interference-mediated pyroptotic pathway

Pyroptosis is an inflammatory form of programmed cell death (PCD) that is regulated by the Gasdermin protein family in response to various stimuli, playing a critical role in the development of tumor therapy strategies. However, cancers are generally known to escape from PCD via immunosuppressive pathways or other resistant mechanisms. In this study, an acid-responsive Fe/Mn bimetal-organic framework nanosystem carrying metal ions and immune adjuvant R848 (FeMn@R@H) was designed for combining pyroptosis and augmented immunotherapy. The FeMn@R@H would be triggered to disintegrate and release Fe3+ and Mn2+ ions in response to the acidic tumor microenvironment (TME), thereby initiating Fenton-like reactions for ROS-mediated pyroptosis. On the one hand, the pyroptosis-caused cell rupture would induce the release of proinflammatory cytokines and immunogenic constituents from tumor cells, further resulting in immunogenic cell death (ICD) to promote antitumor immune responses. On the other hand, the co-delivered R848 could reverse suppressive tumor immune microenvironment (TIME) and induce inflammatory responses by activating the TLR7/8 pathway. In conclusion, this tumor-specific therapy system can co-deliver metal ions and R848 to tumor tissues to perform pyroptosis-mediated PCD and augmented anti-tumor immunotherapy.

Covalent organic frameworks: linkage types, synthetic methods and bio-related applications

Covalent organic frameworks (COFs) are composed of small organic molecules linked via covalent bonds, which have tunable mesoporous structure, good biocompatibility and functional diversities. These excellent properties make COFs a promising candidate for constructing biomedical nanoplatforms and provide ample opportunities for nanomedicine development. A systematic review of the linkage types and synthesis methods of COFs is of indispensable value for their biomedical applications. In this review, we first summarize the types of various linkages of COFs and their corresponding properties. Then, we highlight the reaction temperature, solvent and reaction time required by different synthesis methods and show the most suitable synthesis method by comparing the merits and demerits of various methods. To appreciate the cutting-edge research on COFs in bioscience technology, we also summarize the bio-related applications of COFs, including drug delivery, tumor therapy, bioimaging, biosensing and antimicrobial applications. We hope to provide insight into the interdisciplinary research on COFs and promote the development of COF nanomaterials for biomedical applications and their future clinical translations.

Peptide-Appended Nanosonosensitizers Targeting Tumor Glycolysis for Synergistic Sonodynamic-Immunometabolic Therapy of Spinal-Metastasized Tumors

Despite recent advancements in cancer immunotherapy, challenges have yet to be surmounted to achieve two major goals of magnifying antitumor immunity and remodeling the immunosuppressive tumor microenvironment. Here, a nanosystem (ODM-R) that integrates oxygen-deficient molybdenum oxide (ODM) nanosonosensitizers and R7 peptides with tumor metabolism regulation effects is designed and fabricated for synergistic sonodynamic-immunometabolic therapy of spinal-metastasized tumors. The ODM generates reactive oxygen species upon ultrasound irradiation to implement sonodynamic therapy (SDT), inducing cancer cell apoptosis and immunogenic cell death. The R7 attached on ODM markedly inhibits the uptake of glucose and excretion of lactic acid in cancer cells by perturbing the glycolysis process. The combination of SDT and tumor glycolysis obstruction by ODM-R guarantees satisfactory efficacy in synergizing with PD-L1 antibody to eradicate spinal-metastasized tumors, achieving concurrent sonodynamic-triggered immune activation and immunosuppressive tumor microenvironment remodeling. This work provides a proof-of-concept of nanosonosensitizers for boosting cancer immunotherapy by SDT and tumor metabolic regulation.

Sonocatalytic In Situ Induced Oxygen Storm Precision Enhanced Reactive Oxygen Therapy for Pancreatic Cancer

Deep‐buried tissue, extremely hypoxic blood supply, and complex tumor microenvironment are considered to be the hardest difficult barriers to the accurate treatment of pancreatic cancer. Herein, a novel Au@Co3O4 (AC)‐polyvinylpyrrolidone (AC‐PVP) sonocatalytic agent and radiation sensitizer with a multicore–shell structure are synthesized by a mild reduction method for reshaping the special physiological environment of pancreatic cancer. Oxygen storms can be generated under ultrasonic activation by in situ catalyzed H2O2 in tumor tissue. The oxygen storm improves the ability to produce superoxide anions by sonodynamic therapy as well as rapidly supplements the oxygen‐dependent on active oxygen such as auger electrons produced by high‐energy ray ionization during radiotherapy (RT), further enhancing the efficiency of RT. Interestingly, AC‐PVP can reduce the intracellular glutathione (GSH) level, thus preventing the generated reactive oxygen species from being consumed by GSH. More importantly, the glucose oxidase‐like of AC‐PVP can catalyze glucose in tumor tissue to produce H2O2, and continuously provide substrates for sonocatalytic to form self‐cycling oxygen production. This study offers a novel paradigm for achieving in situ precise self‐oxygenation to overcome the special physiological barrier of pancreatic cancer and efficient sonodynamic synergistic radiotherapy.

Biodegradable covalent organic frameworks achieving tumor micro-environment responsive drug release and antitumor treatment

The emergence of nanocarriers has greatly improved the therapeutic efficacy of chemotherapeutic drugs. As emerging nanocarriers, covalent organic frameworks (COFs) have been increasingly used in biomedicine in recent years. However, due to their inherent chemical stability, existing COF nanocarriers hardly undergo in vivo degradation, which brings potential safety hazards to further applications. In this work, we introduce the azo bond into COFs. When the nanocarrier enters the cell, ˙OH generated by the coordinated Fe response to the H2O2 in the cell will break the azo bond and cause the degradation of the framework structure, accelerating the release of internally loaded DOX to effectively realize tumor treatment. We verified the degradation ability of the materials by constructing model compounds, in vitro drug release, MTT assay and antitumor experiments. Compared with the control groups, the degradable COF accelerates the release of DOX and shows a stronger killing effect on 4T1 cells. Serum biochemical analysis and H&E sections of organs show good biocompatibility for both COFs and degradation products. This work provides a new idea for the design of biodegradable COFs in vivo, and greatly explores the potential application of COF materials in the biomedical field.

Harnessing Nanomaterials for Cancer Sonodynamic Immunotherapy

Immunotherapy has made remarkable strides in cancer therapy over the past decade. However, such emerging therapy still suffers from the low response rates and immune-related adverse events. Various strategies have been developed to overcome these serious challenges. Therein, sonodynamic therapy (SDT), as a non-invasive treatment, has received ever-increasing attention especially in the treatment of deep-seated tumors. Significantly, SDT can effectively induce immunogenic cell death to trigger systemic anti-tumor immune response, termed sonodynamic immunotherapy. The rapid development of nanotechnology has revolutionized SDT effects with robust immune response induction. As a result, more and more innovative nanosonosensitizers and synergistic treatment modalities are established with superior efficacy and safe profile. In this review, the recent advances in cancer sonodynamic immunotherapy are summarized with a particular emphasis on how nanotechnology can be explored to harness SDT for amplifying anti-tumor immune response. Moreover, the current challenges in this field and the prospects for its clinical translation are also presented. It is anticipated that this review can provide rational guidance and facilitate the development of nanomaterials-assisted sonodynamic immunotherapy, helping to pave the way for next-generation cancer therapy and eventually achieve a durable response in patients.

Covalent Organic Framework Nanocages with Enhanced Carrier Utilization and Cavitation Effect for Cancer Sonodynamic Therapy

Ultrasound (US)-triggered sonodynamic therapy (SDT) is an emerging method for treating cancer due to its non-invasive nature and high-depth tissue penetration ability. However, current sonosensitizers commonly have unsatisfactory quantum yields of free radicals. In this work, we have developed unique organic semiconductor π-conjugated covalent organic framework nanocages (COFNs) as highly efficient sonosensitizers to boost free radical (¹O₂ and ^•OH) production and cancer therapy. With the hollow and porous structure and band transport behavior, COFNs displayed remarkably improved SDT performance through enhanced electron utilization and cavitation effect, with a 1.8-fold increase in US pressure and a 64.8% increase in ¹O₂ production relative to the core-shell-structured COF under US irradiation. The in vitro and in vivo experimental results verified the elevated SDT performance, showing a high tumor suppression of 91.4% against refractory breast cancer in mice. This work provides a promising strategy to develop high-performance sonosensitizers for cancer therapy.

Intelligent delivery system targeting PD-1/PD-L1 pathway for cancer immunotherapy

The drugs targeting the PD-1/PD-L1 pathway have gained abundant clinical applications for cancer immunotherapy. However, only a part of patients benefit from such immunotherapy. Thus, brilliant novel tactic to increase the response rate of patients is on the agenda. Nanocarriers, particularly the rationally designed intelligent delivery systems with controllable therapeutic agent release ability and improved tumor targeting capacity, are firmly recommended. In light of this, state-of-the-art nanocarriers that are responsive to tumor-specific microenvironments (internal stimuli, including tumor acidic microenvironment, high level of GSH and ROS, specifically upregulated enzymes) or external stimuli (e.g., light, ultrasound, radiation) and release the target immunomodulators at tumor sites feature the advantages of increased anti-tumor potency but decreased off-target toxicity. Given the fantastic past achievements and the rapid developments in this field, the future is promising. In this review, intelligent delivery platforms targeting the PD-1/PD-L1 axis are attentively appraised. Specifically, mechanisms of the action of these stimuli-responsive drug release platforms are summarized to raise some guidelines for prior PD-1/PD-L1-based nanocarrier designs. Finally, the conclusion and outlook in intelligent delivery system targeting PD-1/PD-L1 pathway for cancer immunotherapy are outlined.

An iodide-containing covalent organic framework for enhanced radiotherapy

Metal-free radiosensitizers, particularly iodine, have shown promise in enhancing radiotherapy due to their suitable X-ray absorption capacities and negligible biotoxicities. However, conventional iodine compounds have very short circulating half-lives and are not retained in tumors very well, which significantly limits their applications. Covalent organic frameworks (COFs) are highly biocompatible crystalline organic porous materials that are flourishing in nanomedicine but have not been developed for radiosensitization applications. Herein, we report the room-temperature synthesis of an iodide-containing cationic COF by the three-component one-pot reaction. The obtained TDI-COF can be a tumor radiosensitizer for enhanced radiotherapy by radiation-induced DNA double-strand breakage and lipid peroxidation and inhibits colorectal tumor growth by inducing ferroptosis. Our results highlight the excellent potential of metal-free COFs as radiotherapy sensitizers.

Defect-Rich Ni-CoO@PEG Porous Hexagonal Nanosheets: Multi-enzyme and Ultrasound Catalysis for Synergistic Anticancer Treatment

Given the similarity with photocatalysis, sonodynamic therapy (SDT) can be defined as ultrasonic (US) catalysis. Encouraged by the principles of photocatalysis and defect chemistry, defect-rich nickel (Ni)-doped cobaltous oxide (Ni-CoO@PEG) porous hexagonal nanosheets have been synthesized as a sonosensitizer. The doping of Ni decreases the band gap that is testified by density functional theory to increase the US-generated charges. Under US irradiation, Ni-CoO@PEG nanosheets produce ¹O₂ as an active species that is determined by dissolved O₂ and electrons. Moreover, the doping also brings abundant oxygen vacancies (O_V) that not only are in favor of efficient separation of electron-hole but also enhance the interaction toward O₂, boosting ¹O₂ generation. In addition, Ni-CoO@PEG shows robust mimic catalase (CAT) and peroxidase characterization to effectively improve the intratumor O₂ content and oxidation stress. What is more, the nanosheets also possess glucose oxidase activity that can consume glucose to elevate the H₂O₂/acid level and to block the intracellular energy supply. The tandem nanozyme behaviors would further regulate the tumor microenvironment for assisting anticancer treatment. It is noted that Ni-CoO@PEG reveals a novel half-metallic feature endowing great magnetism and magnetic resonance imaging capacity. The above synergistic treatments exhibit outstanding anticancer performance that also evokes antitumor immunity to suppress metastasis and recurrence, efficiently.