Design and Challenges of Sonodynamic Therapy System for Cancer Theranostics: From Equipment to Sensitizers

Cancer metastasis: molecular mechanisms and therapeutic interventions

The metastatic cascade is a complicated process where cancer cells travel across multiple organs distant from their primary site of onset. Despite the wide acceptance of the 'seed and soil' theory, mechanisms driving metastasis organotropism remain mystery. Using breast cancer of different subtypes as the disease model, we characterized the 'metastatic profile of cancer cells' and the 'redox status of the organ microenvironment' as the primary determinants of cancer metastasis organotropism. Mechanically, we identified a positive correlation between cancer metabolic plasticity and stemness, and proposed oxidative stress as the selection power of cancer cells succeeding the metastasis cascade. Therapeutically, we proposed the use of pro-oxidative therapeutics in ablating cancer cells taking advantages of this fragile moment during metastasis. We comprehensively reviewed current pro-oxidative strategies for treating cancers that cover the first line chemo- and radio-therapies, approaches relying on naturally existing power including magnetic field, electric field, light and sound, nanoparticle-based anti-cancer composites obtained through artificial design, as well as cold atmospheric plasma as an innovative pro-oxidative multi-modal modality. We discussed possible combinations of pro-oxidative approaches with existing therapeutics in oncology prior to the forecast of future research directions. This paper identified the fundamental mechanics driving metastasis organotropism and proposed intervention strategies accordingly. Insights provided here may offer clues for the design of innovative solutions that may open a new paradigm for cancer treatment.

Understanding the interplay between pH and charges for theranostic nanomaterials

Nanotechnology has emerged as a highly promising platform for theranostics, offering dual capabilities in targeted imaging and therapy. Interactions between the nanomaterial and biological components determine the in vivo fate of these materials which makes the control of their surface properties of utmost importance. Nanoparticles with neutral or negative surface charge have a longer circulation time while positively charged nanoparticles have higher affinity to cells and better cellular uptake. This trade-off presents a key challenge in optimizing surface charge for theranostic applications. A sophisticated solution is an on-demand switch of surface charge, enabled by leveraging the distinct pH conditions at the target site. In this review, we explore the intricate relationship between pH and charge modulation, summarizing recent advances in pH-induced charge-switchable nanomaterials for theranostics over the past five years. Additionally, we discuss how these innovations enhance targeted drug delivery and imaging contrast and provide perspectives on future directions for this transformative field.

Ultrasound and glutathione dual-responsive biomimetic nanoplatform for ultrasound/magnetic resonance imaging and sonodynamic therapy of ovarian cancer

Sonodynamic therapy (SDT) has emerged as a promising treatment method for unresectable ovarian cancer (OC) due to its deeper permeability and absence of phototoxicity. However, the low targeting efficiency of sonosensitizers and the hypoxic tumor environment limit the efficacy of SDT, posing significant challenges to tumor treatment. Herein, an ultrasound (US) and glutathione (GSH) dual-responsive SDT nanoplatform, AIPH-MSTN@BSA-MnO2@CCM (AMBC) was prepared by loading O2 generator MnO2 nanoparticles (NPs) and alkyl radical generator 2,2-azobis [2-(2-imidazoline-2-yl) propane] dihydrochloride (AIPH) into porous SiO2 grown with TiO2 NPs (MSTN), followed by coating with OC cell membrane (CCM). The MnO2 not only can be reduced by GSH to Mn2+ for T1-weighted magnetic resonance (MR) imaging but also catalyzes the decomposition of endogenous H2O2, providing sufficient O2 for the production of reactive oxygen species (ROS) induced by TiO2. Under the action of US, AIPH decomposes to produce alkyl radicals and N2, which further enhances the acoustic cavitation effect of TiO2 and promotes the production of ROS and enhances US imaging. In addition, CCM, with its homologous targeting and immune escape properties, enables AMBC to be targeted and delivered to tumor cells. Together, this work constructs a novel sonodynamic nanoplatform with homologous targeting and superior hypoxia-overcoming ability for efficient SDT of OC, guided by US/MR dual-mode imaging.

Sono-Piezo Dynamic Therapy: Utilizing Piezoelectric Materials as Sonosensitizer for Sonodynamic Therapy

Sonodynamic therapy (SDT) represents a promising approach for cancer treatment. Compared to photodynamic therapy, SDT offers increased penetration depth and higher precision. However, the practical application of SDT is constrained by the low water solubility, poor tumor specificity, and metabolic susceptibility of most sonosensitizers. Recent research has explored the use of piezoelectric materials as sonosensitizers in cancer treatment and inhibition of bacterial growth. Upon ultrasound excitation, the separation of electron-hole (e--h+) pairs occurs within the piezoelectric material. By improving the crystal structure of the material or incorporating other nanoparticles to prevent rapid recombination of e--h+ pairs, the piezoelectric material accumulates charges in the conduction band and valence band, achieving the redox potential of O2/·O2 -. This enables the piezoelectric material to serve as a sonosensitizer, leading to the concept termed Sono-Piezo Dynamic Therapy (SPDT). This review aims to define the concept of SPDT, provide a systematic overview of the historical development of piezoelectric materials in the application of SDT, and elucidate the potential mechanisms by which piezoelectric materials act as sonosensitizers. Importantly, various piezoelectric materials will be discussed in terms of their feasibility, advantages, and disadvantages as sonosensitizers, offering new perspectives for identifying potential sonosensitizers.

Chemical Design of Magnetic Nanomaterials for Imaging and Ferroptosis-Based Cancer Therapy

Ferroptosis, an iron-dependent form of regulatory cell death, has garnered significant interest as a therapeutic target in cancer treatment due to its distinct characteristics, including lipid peroxide generation and redox imbalance. However, its clinical application in oncology is currently limited by issues such as suboptimal efficacy and potential off-target effects. The advent of nanotechnology has provided a new way for overcoming these challenges through the development of activatable magnetic nanoparticles (MNPs). These innovative MNPs are designed to improve the specificity and efficacy of ferroptosis induction. This Review delves into the chemical and biological principles guiding the design of MNPs for ferroptosis-based cancer therapies and imaging-guided therapies. It discusses the regulatory mechanisms and biological attributes of ferroptosis, the chemical composition of MNPs, their mechanism of action as ferroptosis inducers, and their integration with advanced imaging techniques for therapeutic monitoring. Additionally, we examine the convergence of ferroptosis with other therapeutic strategies, including chemodynamic therapy, photothermal therapy, photodynamic therapy, sonodynamic therapy, and immunotherapy, within the context of nanomedicine strategies utilizing MNPs. This Review highlights the potential of these multifunctional MNPs to surpass the limitations of conventional treatments, envisioning a future of drug-resistance-free, precision diagnostics and ferroptosis-based therapies for treating recalcitrant cancers.

Nanomaterials Enhanced Sonodynamic Therapy for Multiple Tumor Treatment

Sonodynamic therapy (SDT) as an emerging modality for malignant tumors mainly involves in sonosensitizers and low-intensity ultrasound (US), which can safely penetrate the tissue without significant attenuation. SDT not only has the advantages including high precision, non-invasiveness, and minimal side effects, but also overcomes the limitation of low penetration of light to deep tumors. The cytotoxic reactive oxygen species can be produced by the utilization of sonosensitizers combined with US and kill tumor cells. However, the underlying mechanism of SDT has not been elucidated, and its unsatisfactory efficiency retards its further clinical application. Herein, we shed light on the main mechanisms of SDT and the types of sonosensitizers, including organic sonosensitizers and inorganic sonosensitizers. Due to the development of nanotechnology, many novel nanoplatforms are utilized in this arisen field to solve the barriers of sonosensitizers and enable continuous innovation. This review also highlights the potential advantages of nanosonosensitizers and focus on the enhanced efficiency of SDT based on nanosonosensitizers with monotherapy or synergistic therapy for deep tumors that are difficult to reach by traditional treatment, especially orthotopic cancers.

Nanobiohybrid Oncolytic Bacteria with Optimized Intratumoral Distribution for Combined Sono-Photodynamic/Immunotherapy

"Living therapeutic carriers" present a promising avenue for cancer research, but it is still challenging to achieve uniform and durable distribution of payloads throughout the solid tumor owing to the tumor microenvironment heterogeneity. Herein, a living drug sprinkle biohybrid (YB1-HCNs) was constructed by hitching acid/enzyme-triggered detachable nanoparticles (HCNs) backpack on the surface of metabolic oligosaccharide-engineered oncolytic bacteria YB1. Along with the process of tumor penetration by bacterial hypoxia navigation, YB1-HCNs responsively and continuously release HCNs, achieving a uniform distribution of loaded agents throughout the tumor. Upon successive irradiation of laser and ultrasound (US), the HCNs can separately generate type II and type I ROS for superior sono-photodynamic therapy (SPDT), which enables HCNs to synergize with YB1 for a satisfactory therapeutic effect in both superficial normoxic and deep hypoxic regions of the tumor. After a single dose, this efficient combination realized 98.3% primary tumor inhibition rate and prolonged survival of mice for 90 days with no recurrence, further inducing a powerful immunological memory effect to completely suppress tumor rechallenge in cured mice. Such a bacterial hybridization vector enables optimization of the spatial distribution of YB1 and HCNs, providing an innovative strategy to maximize therapeutic outcomes and evoke durable antitumor immunity.

A nanodrug loading indocyanine green and metformin dually alleviating tumor hypoxia for enhanced chemodynamic/sonodynamic therapy

As an emerging therapeutic method, the application of sonodynamic therapy (SDT) is hindered by its intrinsic unsatisfactory efficiency, the tumor hypoxia and low tumor specificity. Here, we reported the design of a tumor-targeting multifunctional nanodrug for O2-generation/O2-economization dually enhanced SDT/chemodynamic therapy (CDT) combination therapy. After the co-encapsulation of sonosensitizer indocyanine green (ICG) and oxidative phosphorylation inhibitor metformin (Met) into hollow MnO2 (H-MnO2) nanoparticles, ICG/Met@H-MnO2@MPN-FA (IMMMF) was conveniently prepared through the formation of metal-phenolic networks (MPNs) between Fe3+ and folic acid (FA) immobilized tannic acid (TA, TA-FA) onto its surface. In vitro experiments indicated its selective uptake by 4T1 cells via the specific folate receptors-FA interactions. Responding to glutathione (GSH) and the acidic environment, the decomposition of IMMMF led to the release of Mn2+ and Fe2+ for enhanced CDT, and ICG for SDT. Furthermore, Met was continuously released to reduce O2 consumption for enhanced SDT. More importantly, IMMMF catalyzed the endogenous H2O2 into O2 for further enhanced SDT. Expectedly, both in vitro and in vivo antitumor assays confirmed its satisfactory therapeutic efficiency via CDT/SDT synergistic therapy. Hence, this intelligent sonocatalytic nanoagent emerges as a promising candidate for CDT-enhanced SDT, which also provides a novel strategy for dually alleviating tumor hypoxia with better therapy.

A glutathione-activated bismuth-gallic acid metal-organic framework nano-prodrug for enhanced sonodynamic therapy of breast tumor

Sonodynamic therapy is a promising, noninvasive, and precise tumor treatment that leverages sonosensitizers to generate cytotoxic reactive oxygen species during ultrasound stimulation. Gallic acid (GA), a natural polyphenol, possesses certain anti-tumor properties, but exhibits significant toxicity toward normal cells, limiting its application in cancer treatment. To overcome this issue, we synthesized a bismuth-gallic acid (BGA), coordinated metal-organic framework (MOF) nano-prodrug. Upon encountering glutathione (GSH), BGA gradually dissociated and depleted GSH, releasing GA, which had anti-tumor effects. As an MOF with semiconductor properties, BGA primarily produced superoxide anion radical upon ultrasound excitation. After the release of GA, GA generated superoxide anion radical and further produced high toxic singlet oxygen under ultrasound stimulation, while further oxidizing and consuming GSH, enhancing sonocatalytic performance. Additionally, the released GA induced cell cycle arrest, ultimately leading to apoptosis. Our results revealed that BGA, as a GSH-activated, metal-polyphenol MOF nano-prodrug, showed potential for use in breast tumor sonodynamic therapy, providing a novel strategy for precise tumor treatment.

Phytochlorin-Based Sonosensitizers Combined with Free-Field Ultrasound for Immune-Sonodynamic Cancer Therapy

Phytochlorins, a class of plant-derived tetrapyrroles, show great potential as sonosensitizers in sonodynamic therapy (SDT). The development of new phytochlorin-based sonosensitizers has significantly improved SDT, yet the absence of specialized sonodynamic systems limits their clinical translation. Herein, a dedicated ultrasound system along with a detailed step-by-step sonodynamic process from in vitro to in vivo is developed to activate phytochlorin-based sonosensitizers. Compared to standing-wave ultrasound, free-field ultrasound maintains stable acoustic pressure amplitudes and minimizes mechanical damage to cell membranes. In vitro experiments demonstrate that free-field ultrasound effectively activates naturally occurring phytochlorin, reducing the cavitation threshold for reactive oxygen species production and triggering immunogenic cell death. Furthermore, the intravenously injectable phytochlorin-based sonosensitizer (C34) enhances sonodynamic efficiency by reducing interfacial tension. Driven by in vivo free-field ultrasound, C34 effectively inhibits tumor growth in an orthotopic murine breast cancer model and elicits an immune response, preventing tumor metastasis. The reliable protocol provided by the free-field ultrasound system facilitates the activation of phytochlorin-based sonosensitizers while simultaneously stimulating the immune system, highlighting the potential of immune-sonodynamic therapy.

Versatile Bi2MoO6/Prussian Blue-Au nanoplatform for oxygen-self-produced and GSH-depleted enhanced sonodynamic efficacy

Deprivation of oxygen and scavenging of reactive oxygen species (ROS) severely restrict the antitumor efficiency of sonodynamic therapy (SDT). To address these challs, we report the Bi2MoO6/Prussian Blue-Au (BMO/PB-Au) nanosystem as piezoelectric sonosensitiser for highly efficient ROS production under ultrasonic irradiation. In this system, the nanosystem has catalase-like (CAT) and glutathione oxidase (GSHOD) catalytic activity, which can enhance SDT effectively by producing reactive oxygen species and consuming glutathione (GSH). While the narrow bandgap and heterojunctions contribute to the improved charge separation and charge recombination suppression of the piezoelectric semiconductor BMO, accelerating ROS generation. Packaging MCF-7 cancer cell membranes (CM) on the surface of BMO/PB-Au will effectively improve the enrichment of nanoparticles in tumor tissue. The in vivo results showed that the BMO/PB-Au@CM nanoplatform can effectively inhibit tumor growth through the enhanced SDT effect. Our findings provide a paradigm to rationally design hypoxia-relieve and GSH-depleted SDT platform to for promoting cancer therapy efficiency.

ROS Regulation in CNS Disorder Therapy: Unveiling the Dual Roles of Nanomedicine

The treatment of brain diseases has always been the focus of attention. Due to the presence of the blood-brain barrier (BBB), most small molecule drugs are difficult to reach the brain, leading to undesirable therapeutic outcomes. Recently, nanomedicines that can cross the BBB and precisely target lesion sites have emerged as thrilling tools to enhance the early diagnosis and treat various intractable brain disorders. Extensive research has shown that reactive oxygen species (ROS) play a crucial role in the occurrence and progression of brain diseases, including brain tumors and neurodegenerative diseases (NDDs) such as Alzheimer's disease, Parkinson's disease, stroke, or traumatic brain injury, making ROS a potential therapeutic target. In this review, on the structure and function of BBB as well as the mechanisms are first elaborated through which nanomedicine traverses it. Then, recent studies on ROS production are summarized through photodynamic therapy (PDT), chemodynamic therapy (CDT), and sonodynamic therapy (SDT) for treating brain tumors, and ROS depletion for treating NDDs. This provides valuable guidance for the future design of ROS-targeted nanomedicines for brain disease treatment. The ongoing challenges and future perspectives in developing nanomedicine-based ROS management for brain diseases are also discussed and outlined.

A pH responsive nanocomposite for combination sonodynamic-immunotherapy with ferroptosis and calcium ion overload via SLC7A11/ACSL4/LPCAT3 pathway

Sonodynamic therapy offers a non-invasive approach to induce the death of tumor cells. By harnessing ultrasound waves in tandem with sonosensitizers, this method produces reactive oxygen species (ROS) that inflict oxidative damage upon tumor cells, subsequently causing their demise. Ferroptosis is a regulatory form of cell death that differs from other forms, characterized by iron accumulation, ROS accumulation, and lipid peroxidation. In the presented research, a nanoparticle formulation, parthenolide/ICG-CaCO3@lipid (PTL/ICG-CaCO3@Lip), has been engineered to amplify ferroptosis in tumor cells, positioning it as a potent agent for sonodynamic cancer immunotherapy. This nanoparticle significantly augments ROS levels within tumor cells, inducing oxidative stress that leads to cell death. The therapeutic potential of PTL/ICG-CaCO3@Lip, both in vivo and in vitro, has been convincingly demonstrated. Furthermore, RNA-seq analysis insights revealed that PTL/ICG-CaCO3@Lip facilitates tumor cell ferroptosis by regulating P53 to downregulate SLC7A11 protein expression, thereby inhibiting the glutamate-cystine antiporter system Xc- and stimulating ACSL4/LPCAT3 pathways. This pioneering work uncovers an innovative strategy for combatting tumors, leveraging enhanced oxidative stress to promote cell ferroptosis, and paves the way for groundbreaking cancer immunotherapeutic interventions.

Antimony Component Schottky Nanoheterojunctions as Ultrasound-Heightened Pyroptosis Initiators for Sonocatalytic Immunotherapy

Pyroptosis, an inflammatory modality of programmed cell death associated with the immune response, can be initiated by bioactive ions and reactive oxygen species (ROS). However, bioactive ion-induced pyroptosis lacks specificity, and further exploration of other ions that can induce pyroptosis in cancer cells is needed. Sonocatalytic therapy (SCT) holds promise due to its exceptional penetration depth; however, the rapid recombination of electron-hole (e--h+) pairs and the complex tumor microenvironment (TME) impede its broader application. Herein, we discovered that antimony (Sb)-based nanomaterials induced pyroptosis in cancer cells. Therefore, Schottky heterojunctions containing Sb component (Sb2Se3@Pt) were effectively designed and constructed via in situ growth of platinum (Pt) nanoparticles (NPs) on Sb2Se3 semiconductor with narrow band gaps, which were utilized as US-heightened pyroptosis initiators to induce highly effective pyroptosis in cancer cells to boost SCT-immunotherapy. Under US irradiation, excited electrons were transferred from Sb2Se3 nanorods (NRs) to the co-catalyst Pt via Schottky junctions, and band bending effectively prevented electron backflow and achieved efficient ROS generation. Moreover, the pores oxidized and depleted the overexpressed GSH in the TME, potentially amplifying ROS generation. The biological effects of the Sb2Se3@Pt nanoheterojunction itself combined with the sonocatalytic amplification of oxidative stress significantly induced Caspase-1/GSDMD-dependent pyroptosis in cancer cells. Therefore, SCT treatment with Sb2Se3@Pt not only effectively restrained tumor proliferation but also induced potent immune memory responses and suppressed tumor recurrence. Furthermore, the integration of this innovative strategy with immune checkpoint blockade (ICB) treatment elicited a systemic immune response, effectively augmenting therapeutic effects and impeding the growth of abscopal tumors. Overall, this study provides further opportunities to explore pyroptosis-mediated SCT-immunotherapy.

A metal-phenolic nanotuner induces cancer pyroptosis for sono-immunotherapy

Although ultrasound therapy is efficacious and safe in clinical oncology, its capacity to elicit an anti-tumor immune response is constrained by ultrasound-induced apoptosis. Pyroptosis, which releases immunogenic damage-associated molecular patterns (DAMPs), can significantly enhance immune activation. It necessitates robust Gasdermin E (GSDME) expression in cancer cells for caspase-3-mediated pyroptosis. An epigenetic strategy is introduced to induce cancer pyroptosis during sonotherapy using a nanocoordinator (HTA) constructed through metal-phenolic coordination involving Aza (a DNA methyltransferase inhibitor), TiO2 nanoparticles, and polyphenol-modified hyaluronic acid. While Aza restores GSDME expression, TiO2 generates reactive oxygen species (ROS) under ultrasound stimulation, activating caspase-3 and inducing pyroptosis via GSDME cleavage. In an orthotopic breast cancer model, HTA enhanced anti-tumor immunity and improved the efficacy of sonodynamic therapy (SDT). This approach presents a novel strategy for augmenting SDT through epigenetically induced pyroptosis.

Bacterial carrier-mediated drug delivery systems: a promising strategy in cancer therapy

Cancer is a major killer threatening modern human health and a leading cause of death worldwide. Due to the heterogeneity and complexity of cancer, traditional treatments have limited effectiveness. To address this problem, an increasing number of researchers and medical professionals are working to develop new ways to treat cancer. Bacteria have chemotaxis that can target and colonize tumor tissue, as well as activate anti-tumor immune responses, which makes them ideal for biomedical applications. With the rapid development of nanomedicine and synthetic biology technologies, bacteria are extensively used as carriers for drug delivery to treat tumors, which holds the promise of overcoming the limitations of conventional cancer treatment regimens. This paper summarizes examples of anti-cancer drugs delivered by bacterial carriers, and their strengths and weaknesses. Further, we emphasize the promise of bacterial carrier delivery systems in clinical translation.

Hybrid Cell Membrane-Coated Nanoparticles for Synergizing Sonodynamic Therapy and Immunotherapy against Triple-Negative Breast Cancer

Tumor immunotherapy represents a highly promising modality for the treatment of triple-negative breast cancer (TNBC). Nevertheless, its therapeutic efficacy has been profoundly impacted by challenges such as low drug uptake, hypoxia, and immunosuppression. To address these problems, the study develops a strategy combining sonodynamic therapy (SDT) and immunotherapy using biomimetic nanoparticles coated with hybrid membranes. The nanoparticles are loaded with semiconducting polymers (PFODBT), Atovaquone (ATO), and TMP195 to enhance biocompatibility, targeting ability, and drug uptake and retention at the tumor site. In in vitro experiments, the biomimetic nanoparticles alleviate hypoxia, induce immunogenic cell death (ICD), and prompt reprogramming of tumor-associated macrophages (TAMs) from M2 type to M1 type. In in vivo experiments, the synergistic effects of enhanced SDT-mediated ICD and TAMs repolarization significantly inhibit the proliferation of primary and distant tumor in the 4T1 subcutaneous tumor model, and effectively attenuated metastasis of lung and liver. Moreover, the in vivo immune responses are further activated by improving the maturation of dendritic cells, filtration of CD8+ T cells, and depletion of regulatory T cells. This study offers a novel strategy for TNBC therapy by converting the tumor microenvironment from the "cold" into "hot" tumor through multiple synergistic therapies.

Recent Advances and Future Directions in Sonodynamic Therapy for Cancer Treatment

Deep-tissue solid cancer treatment has a poor prognosis, resulting in a very low 5-year patient survival rate. The primary challenges facing solid tumor therapies are accessibility, incomplete surgical removal of tumor tissue, the resistance of the hypoxic and heterogeneous tumor microenvironment to chemotherapy and radiation, and suffering caused by off-target toxicities. Here, sonodynamic therapy (SDT) is an evolving therapeutic approach that uses low-intensity ultrasound to target deep-tissue solid tumors. The ability of ultrasound to deliver energy safely and precisely into small deep-tissue (>10 cm) volumes makes SDT more effective than conventional photodynamic therapy. While SDT is currently in phase 1/2 clinical trials for glioblastoma multiforme, its use for other solid cancer treatments, such as breast, pancreatic, liver, and prostate cancer, is still in the preclinical stage, with further investigation required to improve its therapeutic efficacy. This review, therefore, focuses on recent advances in SDT cancer treatments. We describe the interaction between ultrasound and sonosensitizer molecules and the associated energy transfer mechanism to malignant cells, which plays a central role in SDT-mediated cell death. Different sensitizers used in clinical and preclinical trials of various cancer treatments are listed, and the critical ultrasound parameters for SDT are reviewed. We also discuss approaches to improve the efficacies of these sonosensitizers, the role of the 3-dimensional spheroid in vitro investigations, ultrasound-controlled CAR-T cell and SDT-based multimodal therapy, and machine learning for sonosensitizer optimization, which could facilitate clinical translation of SDT.

Nanomedicines harnessing cGAS-STING pathway: sparking immune revitalization to transform 'cold' tumors into 'hot' tumors

cGAS-STING pathway stands at the forefront of innate immunity and plays a critical role in regulating adaptive immune responses, making it as a key orchestrator of anti-tumor immunity. Despite the great potential, clinical outcomes with cGAS-STING activators have been disappointing due to their unfavorable in vivo fate, signaling an urgent need for innovative solutions to bridge the gap in clinical translation. Recent advancements in nanotechnology have propelled cGAS-STING-targeting nanomedicines to the cutting-edge of cancer therapy, leveraging precise drug delivery systems and multifunctional platforms to achieve remarkable region-specific biodistribution and potent therapeutic efficacy. In this review, we provide an in-depth exploration of the molecular mechanisms that govern cGAS-STING signaling and its potential to dynamically modulate the anti-tumor immune cycle. We subsequently introduced several investigational cGAS-STING-dependent anti-tumor agents and summarized their clinical trial progress. Additionally, we provided a comprehensive review of the unique advantages of cGAS-STING-targeted nanomedicines, highlighting the transformative potential of nanotechnology in this field. Furthermore, we comprehensively reviewed and comparatively analyzed the latest breakthroughs cGAS-STING-targeting nanomedicine, focusing on strategies that induce cytosolic DNA generation via exogenous DNA delivery, chemotherapy, radiotherapy, or dynamic therapies, as well as the nanodelivery of STING agonists. Lastly, we discuss the future prospects and challenges in cGAS-STING-targeting nanomedicine development, offering new insights to bridge the gap between mechanistic research and drug development, thereby opening new pathways in cancer treatment.

Acid-responsive liposomal nanodrug with promoted tumor penetration for photoacoustic imaging-guided sonodynamic therapy

Herein, an acid-responsive liposomal nanodrug was developed for photoacoustic (PA) imaging-guided oxygen (O2)-independent sonodynamic therapy (SDT). This liposomal nanodrug offers several advantages: (i) it facilitates O2-independent alkyl radical generation upon ultrasound irradiation, (ii) it exhibits acid-responsive charge reversion that enhances tumor penetration, and (iii) it enables activated PA imaging for therapeutic feedback.

Electronic band structure modulation for sonodynamic therapy

Sonodynamic therapy (SDT) is a burgeoning and newfangled therapy modality with great application potential. Sonosensitizers are essential factors used to ensure the effectiveness of SDT. For the past few years, a lot of scientists have discovered many valid ways to refine and improve the performance of SDT. Among these methods, modulating the electronic band structure of sonosensitizers is one of the eminent measures to improve SDT, but relevant research studies on this are still unsatisfactory for actual transformation. Herein, this review provides a brief and comprehensive introduction of common ways to modulate electronic band structure, such as forming defects, doping, piezoelectric effect and heterostructure. Then, some nanomaterials with excellent properties that can be used as a sonosensitizer to enhance the SDT effect by modulating electronic band structure are overviewed, such as Ti-based, Zn-based, Bi-based, noble metal-based and MOF-based nanomaterials. At the same time, this paper also discusses the problems and challenges that may be encountered in the future application progress of SDT. In conclusion, the strategy of enhancing SDT through modulating electronic band structure will promote the rapid development of nanomedicine and provide a great research direction for SDT.

Trends of mapping knowledge structure and themes of cancer sonodynamic therapy: a text-mining study

Background

Sonodynamic therapy (SDT) is a non-invasive cancer treatment technique stemming from photodynamic therapy (PDT) and has garnered escalated interest among researchers in recent years. Numerous aspects of cancer SDT remain contentious, and the global research trajectory within this domain remains insufficiently explored. This study seeks to delineate the comprehensive knowledge framework, developmental trends, and pivotal research focal points concerning cancer SDT.

Methods

The study retrieved documents on cancer SDT from the Web of Science Core Collection (WoSCC) database spanning from 1 January 2000 to 7 December 2023. Bibliometric visualization was carried out through the utilization of CiteSpace 6.2 R6, VOSviewer 1.6.20, and an online analytical platform. Several bibliometric techniques including co-authorship, co-citation, co-occurrence, cluster, as well as burst analysis were used.

Results

A total of 672 publications including 603 articles and 69 reviews were included. The annual publication count exhibited a steady increase over time, notably experiencing a surge, particularly in recent years. In terms of contributors, China has maintained its prominent position with the highest outputs and the most financial support. Chinese Academy of Sciences contributed the most articles. Materials Science was the most investigated research areas. Breast cancer emerged as the most extensively studied tumor, succeeded by sarcoma, hepatocellular carcinoma, melanoma, pancreatic cancer, glioma. According to co-cited references, "harnessing nanomaterial", "sonodynamic precision tumor therapy" and "metal-organic framework" denote the current and emerging research focuses within the field. In tandem with the results from keywords co-occurrence and burst, we identified the following research topics including mechanism of induced cell death (ferroptosis, immunogenic cell death), nano-related research (nanoplatform, nanozymes, nanomaterials, nanosheets, metal-organic frameworks (MOFs), nanocomposites, nanoparticles, nanosonosensitizers, liposomes, nanocarriers), combination therapies (chemodynamic therapy, immunotherapy, radiotherapy, photothermal therapy), and tumor microenvironment (hypoxia, singlet oxygen, oxidative stress), that may remain the research hotspots and receive sustained attention in the near future.

Conclusions

For the first time, this bibliometric analysis not only presents a comprehensive portrayal of the knowledge framework, but also delineates shifts in research focal points related to cancer SDT within the last two decades. This systematic summarization offers a comprehensive and lucid comprehension of cancer SDT, providing valuable insights for further investigations in this domain.

An update on the role of focused ultrasound in neuro-oncology

PURPOSE OF REVIEW

Brain tumor treatment presents challenges for patients and clinicians, with prognosis for many of the most common brain tumors being poor. Focused ultrasound (FUS) can be deployed in several ways to circumvent these challenges, including the need to penetrate the blood-brain barrier and spare healthy brain tissue. This article reviews current FUS applications within neuro-oncology, emphasizing ongoing or recently completed clinical trials.

RECENT FINDINGS

Most clinical interest in FUS for neuro-oncology remains focused on exploring BBB disruption to enhance the delivery of standard-of-care therapeutics. More recently, the application of FUS for radiosensitization, liquid biopsy, and sonodynamic therapy is garnering increased clinical attention to assist in tumor ablation, early detection, and phenotypic diagnosis. Preclinical studies show encouraging data for the immunomodulatory effects of FUS, but these findings have yet to be tested clinically.

SUMMARY

FUS is a burgeoning area of neuro-oncology research. Data from several forthcoming large clinical trials should help clarify its role in neuro-oncology care.

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.

In vitro and in vivo investigation of the inhibitory effects of Sinoporphyrin sodium-mediated Sonodynamic therapy on human oral squamous cell carcinoma

OBJECTIVE

Sonodynamic therapy (SDT) is an innovative, non-invasive approach to cancer treatment, by using low-intensity ultrasound to trigger the activation of sonosensitizers localized within cancerous cells. This current study aimed to explore the therapeutic efficacy of a new sonosensitizer, Sinoporphyrin Sodium (DVDMS), under ultrasound irradiation, against oral squamous cell carcinoma (OSCC)-derived SCC-154 cells, both in vitro and in vivo.

METHODS

Fluorescence spectra, cytotoxicity assessments, uptake mechanisms, and subcellular distributions of DVDMS within the SCC-154 cell line were detected. Additionally, the study comprehensively assessed the antitumor effect, oxidative stress responses, apoptosis, apoptosis-related proteins, autophagic processes, and ultrastructural changes in SCC-154 cells, both in vitro and in vivo, subsequent to treatment with low-intensity ultrasound (at 1.0 MHz, 1 W/cm2 in vitro and 3 W/cm2 in vivo) in conjunction with DVDMS also being examined.

RESULTS

The findings indicate that SCC-154 cells exhibit heightened sensitivity to DVDMS compared to SAS and HSC-3 cell lines. Within SCC-154 cells, DVDMS primarily localizes within the mitochondria and lysosomes. DVDMS-based SDT significantly increased the intracellular levels of reactive oxygen species (ROS), induced morphological changes such as mitochondrial swelling and formation of autolysosomes, and exhibited a notable dose-dependent reduction in cell viability in vitro. Also, DVDMS-SDT demonstrated significant inhibition of xenograft growth without discernible adverse effects. Mechanistically, DVDMS-SDT upregulated Bax expression while downregulating Bcl-2 expression, which led to the Bax/Bcl-2 ratio and induced autophagy.

CONCLUSION

DVDMS-SDT triggers mitochondrial-dependent apoptosis in SCC-154 cells, unlike 5-ALA and protoporphyrin IX (PpIX). Also, the combination of DVDMS with ultrasound stimulation induces autophagy, with the onset of autophagic processes preceding apoptosis.

Biodegradable persistent ROS-generating nanosonosensitizers for enhanced synergistic cancer therapy by inducing cascaded oxidative stress

Sonodynamic therapy (SDT) is gaining popularity in cancer treatment due to its superior controllability and high tissue permeability. Nonetheless, the efficacy of SDT is severely diminished by the transient generation of limited reactive oxygen species (ROS). Herein, we introduce an acid-activated nanosonosensitizer, CaO2@PCN, by the controllable coating of porphyrinic metal-organic frameworks (PCN-224) on CaO2 to induce cascaded oxidative stress in tumors. The PCN-224 doping can generate ROS during SDT to induce intracellular oxidative stress and abnormal calcium channels. Meanwhile, the ultrasound also promotes extracellular calcium influx. In addition, CaO2@PCN sequentially degrades in the tumor cell lysosomes, releasing Ca2+ and H2O2 to induce further abnormal calcium channels and elevate the levels of Ca2+. Insufficient catalase (CAT) in tumor cells promotes intracellular calcium overload, which can induce persistent ROS generation and mitochondrial dysfunction through ion interference therapy (IIT). More importantly, PCN-224 also protects CaO2 against significant degradation under neutral conditions. Hence, the well-designed CaO2@PCN produces synergistic SDT/IIT effects and persistent ROS against cancer. More notably, the acidity-responsive biodegradability endows CaO2@PCN with excellent biosafety and promising clinical potential.

AQ4N nanocomposites for hypoxia-associated tumor combination therapy

Hypoxia in solid tumors increases their invasiveness and resistance to therapy, presenting a formidable obstacle in tumor therapy. The hypoxia prodrug banoxantrone (AQ4N) undergoes conversion into its topoisomerase II inhibitor form AQ4 under hypoxic conditions, which inhibits tumor cells while leaving normal cells unharmed. Numerous studies have found that AQ4N significantly enhances the tumor effect while minimizing toxicity to normal tissues when combined with other drugs or therapeutic approaches. Thus, to maximize AQ4N's effectiveness, co-delivery of AQ4N with other therapeutic agents to the tumor site is paramount, leading to the development of multifunctional multicomponent AQ4N nanocomposites thereby emerging as promising candidates for combination therapy in tumor treatment. However, currently there is a lack of systematic analysis and reviews focusing on AQ4N. Herein, this review provides a comprehensive retrospect and analysis of the recent advancements in AQ4N nanocomposites. Specifically, we discuss the synergistic effects observed when AQ4N is combined with chemotherapeutic drugs, radiotherapy, phototherapy, starvation, sonodynamic therapy and immunotherapy in preclinical models. Moreover, the advantages, limitations, and future perspectives of different AQ4N nanocomposites are highlighted, providing researchers from diverse fields with novel insights into tumor treatment.

Nucleus-Targeted Sonosensitizer Activates the cGAS-STING Pathway for Tumor Sonodynamic Immunotherapy

A nucleus is crucial for both sonodynamic therapy (SDT) and antitumor immunity. However, how to burst ROS generation in situ, accurately damage a nucleus, and meanwhile activate a cGAS-STING pathway-induced innate immune response are still a great challenge. Here, we present TBzT-CPi, a small molecule with a D-A-π-A1 structure that simultaneously amplifies nucleus-targeted SDT and cGAS-STING pathway-dependent immune stimulation. TBzT-CPi could accumulate in the nucleus upon ultrasound irradiation and generate ROS in situ, which damages DNA and simultaneously triggers immunogenic cell death (ICD). Stirringly, nucleus-targeting SDT not only efficiently induces apoptosis in tumor cells but also modifies the immunosuppressive tumor microenvironment by activating cytotoxic T lymphocytes, maturing dendritic cells, and secreting cytokines. These findings pave the way for developing nucleus-targeting sonosensitizers for sonodynamic immunotherapy of cancer.

Ultrasound-Responsive Lipid Nanoplatform with Nitric Oxide and Carbon Monoxide Release for Cancer Sono-Gaso-Therapy

Local gas therapy is emerging as a potential cancer treatment approach due to its specificity as gas-containing molecules can be packed into a nanodelivery system to release the corresponding gaseous molecules around the tumor site upon a suitable stimulus. Single-gas therapy has been reported, while synergistic dual-gas therapy has rarely been reported. Herein, we report a dual-gas-containing nanoplatform for synergistic cancer gasotherapy upon ultrasound irradiation. First, a robust ultrasound-responsive lipid-coated nanosystem was prepared with suitable particle size and characteristics. A low-intensity ultrasound (1.25 W/cm2) was found to simultaneously modulate carbon monoxide (CO) and nitric oxide (NO) release from the nanosystem in media and CT26 colon cancer cells for efficient therapeutic effect. The intracellular release promoted the overgeneration of reactive oxygen species (ROS) and triggered cancer cell apoptosis synergistically. The in vivo test demonstrated that the optimal dual-gas-containing formulation efficiently inhibited tumor growth (by ∼87%) at relatively low doses upon ultrasound irradiation (1.25 W/cm2, 5 min). This therapeutic efficacy shows that the current responsive lipid-coated delivery system has potential for ultrasound-triggered dual-gas therapy of both superficially and deeply seated cancers.

Sonodynamic and Acoustically Responsive Nanodrug Delivery System: Cancer Application

The advent of acoustically responsive nanodrugs that are specifically optimized for sonodynamic therapy (SDT) is a novel approach for clinical applications. Examining the therapeutic applications of sono-responsive drug delivery systems, understanding their dynamic response to acoustic stimuli, and their crucial role in enhancing targeted drug delivery are intriguing issues for current cancer treatment. Specifically, the suggested review covers SDT, a modality that enhances the cytotoxic activity of specific compounds (sonosensitizers) using ultrasound (US). Notably, SDT offers significant advantages in cancer treatment by utilizing US energy to precisely target and activate sonosensitizers toward deep-seated malignant sites. The potential mechanisms underlying SDT involve the generation of radicals from sonosensitizers, physical disruption of cell membranes, and enhanced drug transport into cells via US-assisted sonoporation. In particular, SDT is emerging as a promising modality for noninvasive, site-directed elimination of solid tumors. Given the complexity and diversity of tumors, many studies have explored the integration of SDT with other treatments to enhance the overall efficacy. This trend has paved the way for SDT-based multimodal synergistic cancer therapies, including sonophototherapy, sonoimmunotherapy, and sonochemotherapy. Representative studies of these multimodal approaches are comprehensively presented, with a detailed discussion of their underlying mechanisms. Additionally, the application of audible sound waves in biological systems is explored, highlighting their potential to influence cellular processes and enhance therapeutic outcomes. Audible sound waves can modulate enzyme activities and affect cell behavior, providing novel avenues for the use of sound-based techniques in medical applications. This review highlights the current challenges and prospects in the development of SDT-based nanomedicines in this rapidly evolving research field. The anticipated growth of this SDT-based therapeutic approach promises to significantly improve the precision of cancer treatment.

The advance of ultrasound-enabled diagnostics and therapeutics

Point-of-care ultrasound demonstrates significant potential in biomedical research due to its noninvasive, real-time visualization, cost-effectiveness, and other biological benefits. Ultrasound irradiation can precisely control the mechanical and physicochemical effects on pathogenic lesions, enabling real-time visualization, tunable tissue penetration depth, and therapeutic applications. This review summarizes recent advancements in ultrasound-enabled diagnostics and therapeutics, focusing on mechanochemical effects that can be directly integrated into biomedical applications. Additionally, the structure-functionality relationships of sonotheranostic nanoplatforms are systematically discussed, providing insights into the underlying biological effects. Finally, the limitations of current ultrasonic medicine are discussed, along with potential expansions to facilitate patient-centered translations.

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.

Precise Clearance of Intracellular MRSA via Internally and Externally Mediated Bioorthogonal Activation of Micro/Nano Hydrogel Microspheres

Traditional high-dose antibiotic treatments of intracellular methicillin-resistant staphylococcus aureus (MRSA) are highly inefficient and associated with a high rate of infection relapse. As an effective antibacterial technology, sonodynamic therapy (SDT) may be able to break the dilemma. However, indiscriminate reactive oxygen species (ROS) release leads to potential side effects. This study incorporates Staphylococcal Protein A antibody-modified Cu2+/tetracarboxyphenylporphyrin nanoparticles (Cu(II)NS-SPA) into hydrogel microspheres (HAMA@Cu(II)NS-SPA) to achieve precise eradication of intracellular bacteria. This eradication is under bioorthogonal activation mediated by bacillithiol (BSH) (internally) and ultrasound (US) (externally). To specify, the US responsiveness of Cu(II)NS-SPA is restored when it is reduced to Cu(I)NS-SPA by the BSH secreted characteristically by intracellular MRSA, thus forming a bioorthogonal activation with the external US, which confines ROS production within the infected MΦ. Under external US activation at 2 W cm-2, over 95% of intracellular MRSA can be cleared. In vivo, a single injection of HAMA@Cu(II)NS-SPA achieves up to two weeks of antibacterial sonodynamic therapy, reducing pro-inflammatory factor expression by 90%, and peri-implant bone trabeculae numbers exceed the control group by five times. In summary, these micro/nano hydrogel microspheres mediated by internal and external bioorthogonal activation can precisely eliminate intracellular MRSA, effectively treating multi-drug resistant intracellular bacterial infections.

Titanium boride nanosheets with photo-enhanced sonodynamic efficiency for glioblastoma treatment

Sonodynamic therapy (SDT) has garnered significant attention in cancer treatment, however, the low-yield reactive oxygen species (ROS) generation from sonosensitizers remains a major challenge. In this study, titanium boride nanosheets (TiB2 NSs) with photo-enhanced sonodynamic efficiency was fabricated for SDT of glioblastoma (GBM). Compared with commonly-used TiO2 nanoparticles, the obtained TiB2 NSs exhibited much higher ROS generation efficiency under ultrasound (US) irradiation due to their narrower band gap (2.50 eV). Importantly, TiB2 NSs displayed strong localized surface plasmon resonance (LSPR) effect in the second near-infrared (NIR II) window, which facilitated charge transfer rate and improved the separation efficiency of US-triggered electron-hole pairs, leading to photo-enhanced ROS generation efficiency. Furthermore, TiB2 NSs were encapsulated with macrophage cell membranes (CM) and then modified with RGD peptide to construct biomimetic nanoagents (TiB2@CM-RGD) for efficient blood-brain barrier (BBB) penetrating and GBM targeting. After intravenous injection into the tumor-bearing mouse, TiB2@CM-RGD can efficiently cross BBB and accumulate in the tumor sites. The tumor growth was significantly inhibited under simultaneous NIR II laser and US irradiation without causing appreciable long-term toxicity. Our work highlighted a new type of multifunctional titanium-based sonosensitizer with photo-enhanced sonodynamic efficiency for GBM treatment. STATEMENT OF SIGNIFICANCE: Titanium boride nanosheets (TiB2 NSs) with photo-enhanced sonodynamic efficiency was fabricated for SDT of glioblastoma (GBM). The obtained TiB2 NSs displayed strong localized surface plasmon resonance (LSPR) effect in the second near-infrared (NIR II) window, which facilitated charge transfer rate and improved the separation efficiency of US-triggered electron-hole pairs, leading to photo-enhanced ROS generation efficiency. Furthermore, TiB2 NSs were encapsulated with macrophage cell membranes (CM) and then modified with RGD peptide to construct biomimetic nanoagents (TiB2@CM-RGD) for efficient blood-brain barrier (BBB) penetrating and GBM targeting. After intravenous injection into the tumor-bearing mouse, TiB2@CM-RGD can efficiently cross BBB and accumulate in the tumor sites. The tumor growth was significantly inhibited under simultaneous NIR II laser and US irradiation without causing appreciable long-term toxicity.

Regulating Manganese-Site Electronic Structure via Reconstituting Nitrogen Coordination for Efficient Non-Oxygen-Dependent Sonocatalytic Therapy against Orthotopic Breast Cancer

Sonocatalytic therapy (SCT) has emerged as a promising noninvasive modality for tumor treatment but is hindered by the insufficient generation of ultrasound-induced reactive oxygen species (ROS) and the hypoxic tumor microenvironments. Herein, we fabricated a carbon nanoframe-confined N-coordinated manganese single-atom sonocatalyst with a five-coordinated structure (MnN5 SA/CNF) using a phthalocyanine-mediated pyrolysis strategy. The precise coordination structure was identified by synchrotron X-ray absorption fine structure analyses. The MnN5 SA/CNF exhibits superior and nonoxygen-dependent sonocatalytic activity owing to the optimized coordination structure and cavitation effect enhanced by defects. Additionally, density functional theory studies reveal that the five-coordination structure downshifts the d-band center of Mn from -0.547 to -0.829 eV and enhances the desorption capacity for oxygen-containing intermediates, thus accelerating the catalytic process. Finally, the as-synthesized MnN5 SA/CNF demonstrates a significantly enhanced antitumor effect through mitochondrial apoptosis in an orthotopic breast cancer mouse model. This work explores the potential of SAzymes-supported biomedical interventions by leveraging enzymatic activity with sonocatalytic properties.

Sonodynamic Therapy for HER2+ Breast Cancer with Iodinated Heptamethine Cyanine-Trastuzumab Conjugate

The first example of sonodynamic therapy (SDT) with a cyanine dye-antibody conjugate is reported. The aim of this study was to evaluate the sonodynamic efficacy of a trastuzumab-guided diiodinated heptamethine cyanine-based sensitizer, 2ICy7-Ab, versus its non-iodinated counterpart, Cy7-Ab, in a human epidermal growth factor receptor 2-positive (HER2+) xenograft model. In addition, the combined sonodynamic and photodynamic (PDT) effects were investigated. A single intravenous injection of 2ICy7-Ab followed by sonication or combined sonication and photoirradiation in mice resulted in complete tumor growth suppression compared with the nontreated control and showed no detectable toxicity to off-target tissues. In contrast, Cy7-Ab provided only a moderate therapeutic effect (~1.4-1.6-fold suppression). SDT with 2ICy7-Ab resulted in a 3.5-fold reduction in tumor volume within 45 days and exhibited 13-fold greater tumor suppression than PDT alone. In addition, 2ICy7-Ab showed more durable sonostability than photostability. The sonotoxicity of the iodinated versus noniodinated counterparts is attributed to the increased generation of hydroxyl radicals, superoxide, and singlet oxygen. We observed no significant contribution of PDT to the efficacy of the combined SDT and PDT, indicating that SDT with 2ICy7-Ab is superior to PDT alone. These new findings set the stage for the application of cyanine-antibody conjugates for fluorescently monitored targeted sonodynamic treatment of cancer.

What Is the Magical Cavitation Bubble: A Holistic Perspective to Trigger Advanced Bubbles, Nano-Sonocatalysts, and Cellular Sonosensitizers

Sonodynamic therapy (SDT) has emerged as a novel and highly researched advancement in the medical field. Traditional ultrasound contrast agents and novel bubble-shaped agents are used to stimulate cavitation and enhance SDT efficiency. However, the impact of artificially modified shell structures on the acoustic properties of microbubbles remains to be explored. Alternatively, in the absence of bubble-shaped agents, some clinically available organic sonosensitizers and advanced inorganic materials are also used to enhance the efficacy of SDT. Diagnostic and therapeutic ultrasound can also activate cavitation bubbles, which supply energy to sonosensitive agents, leading to the production of cytotoxic free radicals to achieve therapeutic effects. While inorganic materials often spark controversy in clinical applications, their relatively simple structure enables researchers to gain insight into the mechanism by which SDT produces various free radicals. Some organic-inorganic hybrid sonosensitive systems have also been reported, combining the benefits of inorganic and organic sonosensitive agents. Alternatively, by employing cell surface modification engineering to enable cells to perform functions such as immune escape, drug loading, gas loading, and sonosensitivity, cellular sonosensitizers have also been developed. However, further exploration is needed on the acoustic properties, ability to generate reactive oxygen species (ROS), and potential clinical application of this cellular sonosensitizer. This review offers a comprehensive analysis of vesical microbubbles and nanoscale sonocatalysts, including organic, inorganic, combined organic-inorganic sonosensitizers, and cellular sonosensitizers. This analysis will enhance our understanding of SDT and demonstrate its important potential in transforming medical applications.

Novel 131-iodine labeled and ultrasound-responsive nitric oxide and reactive oxygen species controlled released nanoplatform for synergistic sonodynamic/nitric oxide/chemodynamic/radionuclide therapy

Nitric oxide (NO) and reactive oxygen species (ROS) embody excellent potential in cancer therapy. However, as a small molecule, their targeted delivery and precise, controllable release are urgently needed to achieve accurate cancer therapy. In this paper, a novel US-responsive bifunctional molecule (SD) and hyaluronic acid-modified MnO2 nanocarrier was developed, and a US-responsive NO and ROS controlled released nanoplatform was constructed. US can trigger SD to release ROS and NO simultaneously at the tumor site. Thus, SD served as acoustic sensitizer for sonodynamic therapy and NO donor for gas therapy. In the tumor microenvironment, the MnO2 nanocarrier can effectively deplete the highly expressed GSH, and the released Mn2+ can make H2O2 to produce .OH by Fenton-like reaction, which exhibited a strong chemodynamic effect. The high concentration of ROS and NO in cancer cell can induce cancer cell apoptosis ultimately. In addition, toxic ONOO-, which was generated by the reaction of NO and ROS, can effectively cause mitochondrial dysfunction, which induced the apoptosis of tumor cells. The 131I was labeled on the nanoplatform, which exhibited internal radiation therapy for tumor therapy. In -vitro and -vivo experiments showed that the nanoplatform has enhanced biocompatibility, and efficient anti-tumor potential, and it achieves synergistic sonodynamic/NO/chemodynamic/radionuclide therapy for cancer.

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.

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.

Integrated organosilica nanomedicine enables sonoimaging, sonochemistry and antitumor sonodynamic therapy

Sonography with its non-invasive and deep tissue-penetrating characteristics, not only contributes to promising developments in clinical disease diagnosis but also obtains acknowledgments as a prospective therapeutic approach in the field of tumor treatment. However, it remains a challenge for sonography simultaneously to achieve efficient imaging and therapeutic functionality. Here, we present an innovative integrated diagnosis and treatment paradigm by developing the nanomedicine of percarbamide-bromide-mesoporous organosilica spheres (MOS) with RGD peptide modification (PBMR) by loading percarbamide and bromide in MOS which were prepared by a one-step O/W microemulsion method. The PBMR nanomedicine effectively modifies the tumor acoustic environment to improve sonoimaging efficacy and induces sonochemical reactions to enhance the production of reactive oxygen species (ROS) for tumor treatment efficiency under sonography. The combination of PBMR nanomedicine and SDT achieved multiple ROS generation through the controlled sonochemical reactions and significantly boosted the potency of sonodynamic therapy and induced significant tumor regression with non-invasive tissue penetrability and minimizing damage to healthy tissues. Simultaneously, the generation of oxygen gas in the sonochemical process augments ultrasound reflection, resulting in a 4.9-fold increase in imaging grayscale. Our research establishes an effective platform for the synergistic integration of sonoimaging and sonodynamic antitumor therapy, offering a novel approach for precise antitumor treatment in the potential clinical applications.

Gold Nanodots-Anchored Cobalt Ferrite Nanoflowers as Versatile Tumor Microenvironment Modulators for Reinforced Redox Dyshomeostasis

Given that tumor microenvironment (TME) exerts adverse impact on the therapeutic response and clinical outcome, robust TME modulators may significantly improve the curative effect and increase survival benefits of cancer patients. Here, Au nanodots-anchored CoFe2O4 nanoflowers with PEGylation (CFAP) are developed to respond to TME cues, aiming to exacerbate redox dyshomeostasis for efficacious antineoplastic therapy under ultrasound (US) irradiation. After uptake by tumor cells, CFAP with glucose oxidase (GOx)-like activity can facilitate glucose depletion and promote the production of H2O2. Multivalent elements of Co(II)/Co(III) and Fe(II)/Fe(III) in CFAP display strong Fenton-like activity for·OH production from H2O2. On the other hand, energy band structure CFAP is superior for US-actuated 1O2 generation, relying on the enhanced separation and retarded recombination of e-/h+ pairs. In addition, catalase-mimic CFAP can react with cytosolic H2O2 to generate molecular oxygen, which may increase the product yields from O2-consuming reactions, such as glucose oxidation and sonosensitization processes. Besides the massive production of reactive oxygen species, CFAP is also capable of exhausting glutathione to devastate intracellular redox balance. Severe immunogenic cell death and effective inhibition of solid tumor by CFAP demonstrates the clinical potency of such heterogeneous structure and may inspire more relevant designs for disease therapy.

Investigation into the Sonodynamic Activity of Three Newly Synthesized Derivatives of Ciprofloxacin

Sonosensitizers play a crucial role in the efficacy of sonodynamic antitumor therapy (SDT) and sonodynamic antimicrobial chemotherapy (SACT), highlighting the necessity for the development of new compounds with good sonodynamic activity. In this study, three novel 3-substituted ciprofloxacin derivatives (CIPD1, CIPD2, and CIPD3) were designed and synthesized. Their sonodynamic activities were evaluated by assessing the damage to bovine serum albumin (BSA) and Escherichia coli (E. coli). Furthermore, the potential mechanism underlying their sonodynamic damage activities was investigated by detecting reactive oxygen species (ROS) under ultrasound irradiation (US). The results demonstrated that all three derivatives exhibited enhanced sonodynamic damage to BSA and E. coli under US, with CIPD1 and CIPD2 showing superior effectiveness compared to CIP. Both the concentrations of derivatives and the duration of ultrasound irradiation were found to significantly impact their sonodynamic effects. All three CIP derivates could be activated to produce ROS following ultrasound irradiation, primarily consisting of 1O2 and ·OH. The levels of ROS production were positively correlated with their sonodynamic activities, potentially explaining the mechanism underlying their sonodynamic damage activities.

Ultrasound-Responsive Nanodelivery System of GPC3-Targeting and Sonosensitizer for Visualized Hepatocellular Carcinoma Therapy

Purpose

The incidence of hepatocellular carcinoma (HCC) is continuously increasing, and the mortality rate remains high. Thus, more effective strategies are needed to improve the treatment of HCC.

Methods

In this study, we report the use of a visualized glypican-3 (GPC3)-targeting nanodelivery system (named GC-NBs) in combination with sonodynamic therapy (SDT) to enhance the therapeutic efficacy for treating HCC. The obtained nanodelivery system could actively target hepatocellular carcinoma cells and achieve ultrasound imaging through phase changes into nanobubbles under low-intensity ultrasound irradiation. Meanwhile, the released chlorine e6 (Ce6) after the nanobubbles collapse could lead to the generation of reactive oxygen species (ROS) under ultrasound irradiation to induce SDT.

Results

Both in vitro and in vivo experiments have shown that GC-NBs can accumulate in tumour areas and achieve sonodynamic antitumour therapy under the navigation action of glypican-3-antibody (GPC3-Ab). Furthermore, in vitro and in vivo experiments did not show significant biological toxicity of the nanodelivery system. Moreover, GC-NBs can be imaged with ultrasound, providing personalized treatment monitoring.

Conclusion

GC-NBs enable a visualized antitumour strategy from a targeted sonodynamic perspective by combining tumour-specific targeting and stimuli-responsive controlled release into a single system.

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.

A functionalized cell membrane biomimetic nanoformulation based on layered double hydroxide for combined tumor chemotherapy and sonodynamic therapy

The development of nanoformulations with simple compositions that can exert targeted combination therapy still remains a great challenge in the area of precision cancer nanomedicine. Herein, we report the design of a multifunctional nanoplatform based on methotrexate (MTX)-loaded layered double hydroxide (LDH) coated with chlorin e6 (Ce6)-modified MCF-7 cell membranes (CMM) for combined chemo/sonodynamic therapy of breast cancer. LDH nanoparticles were in situ loaded with MTX via coprecipitation, and coated with CMM that were finally functionalized with phospholipid-modified Ce6. The created nanoformulation of LDH-MTX@CMM-Ce6 displays good colloidal stability under physiological conditions and can release MTX in a pH-dependent manner. We show that the formulation can homologously target breast cancer cells, and induce their significant apoptosis through arresting the cell cycle via cooperative MTX-based chemotherapy and ultrasound (US)-activated sonodynamic therapy. The assistance of US can not only trigger sonosensitizer Ce6 to produce reactive oxygen species, but also enhance the cellular uptake of LDH-MTX@CMM-Ce6 via an acoustic cavitation effect. Upon intravenous injection and US irradiation, LDH-MTX@CMM-Ce6 displays an admirable antitumor performance towards a xenografted breast tumor mouse model. Furthermore, the modification of Ce6 on the CMM endows the LDH-based nanoplatform with fluorescence imaging capability. The developed LDH-based nanoformulation here provides a general intelligent cancer nanomedicine platform with simple composition and homologous targeting specificity for combined chemo/sonodynamic therapy and fluorescence imaging of tumors.

Advances in antitumor application of ROS enzyme-mimetic catalysts

The rapid growth of research on enzyme-mimetic catalysts (Enz-Cats) is expected to promote further advances in nanomedicine for biological detection, diagnosis and treatment of disease, especially tumors. ROS-based nanomedicines present fascinating potential in antitumor therapy owing to the rapid development of nanotechnology. In this review, we focus on the applications of Enz-Cats based on ROS in antitumor therapy. Firstly, the definition and category of ROS are introduced, and the key factors enhancing ROS levels are carefully elucidated. Then, the rationally engineered Enz-Cats via different synthetic approaches with high ROS-producing efficiencies are comprehensively discussed. Subsequently, oncotherapy application of Enz-Cats is comprehensively discussed, which integrates diverse synergistic treatment modalities and exhibits high efficiency in ROS generation. Finally, the challenges and future research direction of this field are presented. This review is dedicated to unraveling the enigmas surrounding the interplay of nanomedicine and organisms.

Oxygen Vacancy Piezoelectric Nanosheets Constructed by a Photoetching Strategy for Ultrasound "Unlocked" Tumor Synergistic Therapy

Piezoelectric dynamic therapy (PzDT) is an effective method of tumor treatment by using piezoelectric polarization to generate reactive oxygen species. In this paper, two-dimensional Cu-doped BiOCl nanosheets with surface vacancies are produced by the photoetching strategy. Under ultrasound, a built-in electric field is generated to promote the electron and hole separation. The separated carriers achieve O2 reduction and GSH oxidation, inducing oxidative stress. The bandgap of BiOCl is narrowed by introducing surface oxygen vacancies, which act as charge traps and facilitate the electron and hole separation. Meanwhile, Cu doping induces chemodynamic therapy and depletes GSH via the transformation from Cu(II) to Cu(I). Both in vivo and in vitro results confirmed that oxidative stress can be enhanced by exogenous ultrasound stimulation, which can cause severe damage to tumor cells. This work emphasizes the efficient strategy of doping engineering and defect engineering for US-activated PzDT under exogenous stimulation.

Porphyrin overdrive rewires cancer cell metabolism

All cancer cells reprogram metabolism to support aberrant growth. Here, we report that cancer cells employ and depend on imbalanced and dynamic heme metabolic pathways, to accumulate heme intermediates, that is, porphyrins. We coined this essential metabolic rewiring "porphyrin overdrive" and determined that it is cancer-essential and cancer-specific. Among the major drivers are genes encoding mid-step enzymes governing the production of heme intermediates. CRISPR/Cas9 editing to engineer leukemia cell lines with impaired heme biosynthetic steps confirmed our whole-genome data analyses that porphyrin overdrive is linked to oncogenic states and cellular differentiation. Although porphyrin overdrive is absent in differentiated cells or somatic stem cells, it is present in patient-derived tumor progenitor cells, demonstrated by single-cell RNAseq, and in early embryogenesis. In conclusion, we identified a dependence of cancer cells on non-homeostatic heme metabolism, and we targeted this cancer metabolic vulnerability with a novel "bait-and-kill" strategy to eradicate malignant cells.

PAD4 Inhibitor-Functionalized Layered Double Hydroxide Nanosheets for Synergistic Sonodynamic Therapy/Immunotherapy Of Tumor Metastasis

Sonodynamic therapy (SDT) is demonstrated to trigger the systemic immune response of the organism and facilitate the treatment of metastatic tumors. However, SDT-mediated neutrophil extracellular traps (NETs) formation can promote tumor cell spread, thus weakening the therapeutic effectiveness of metastatic tumors. Herein, the amorphous CoW-layered double hydroxide (a-CoW-LDH) nanosheets are functionalized with a peptidyl arginine deiminase 4 (PAD4) inhibitor, i.e., YW3-56, to construct a multifunctional nanoagent (a-LDH@356) for synergistic SDT/immunotherapy. Specifically, a-CoW-LDH nanosheets can act as a sonosensitizer to generate abundant reactive oxygen species (ROS) under US irradiation. After loading with YW3-56, a-LDH@356 plus US irradiation not only effectively induces ROS generation and immunogenic cell death, but also inhibits the elevation of citrullinated histone H3 (H3cit) and the release of NETs, enabling a synergistic enhancement of anti-tumor metastasis effect. Using 4T1 tumor model, it is demonstrated that combining a-CoW-LDH with YW3-56 stimulates an anti-tumor response by upregulating the proportion of immune-activated cells and inducing polarization of M1 macrophages, and inhibits immune escape by downregulating the expression of PD-1 on immune cells under US irradiation, which not only arrests primary tumor progression with a tumor inhibition rate of 69.5% but also prevents tumor metastasis with the least number of lung metastatic nodules.