Cascade catalytic nanoplatform for enhanced starvation and sonodynamic therapy

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.

Application of Nanomaterial-Based Sonodynamic Therapy in Tumor Therapy

Sonodynamic therapy (SDT) has attracted significant attention in recent years as it is an innovative approach to tumor treatment. It involves the utilization of sound waves or ultrasound (US) to activate acoustic sensitizers, enabling targeted drug release for precise tumor treatment. This review aims to provide a comprehensive overview of SDT, encompassing its underlying principles and therapeutic mechanisms, the applications of nanomaterials, and potential synergies with combination therapies. The review begins by introducing the fundamental principle of SDT and delving into the intricate mechanisms through which it facilitates tumor treatment. A detailed analysis is presented, outlining how SDT effectively destroys tumor cells by modulating drug release mechanisms. Subsequently, this review explores the diverse range of nanomaterials utilized in SDT applications and highlights their specific contributions to enhancing treatment outcomes. Furthermore, the potential to combine SDT with other therapeutic modalities such as photothermal therapy (PTT) and chemotherapy is discussed. These combined approaches aim to synergistically improve therapeutic efficacy while mitigating side effects. In conclusion, SDT emerges as a promising frontier in tumor treatment that offers personalized and effective treatment options with the potential to revolutionize patient care. As research progresses, SDT is poised to play a pivotal role in shaping the future landscape of oncology by providing patients with a broader spectrum of efficacious and tailored treatment options.

A biomimetic nanocarrier facilitates glucose consumption and reactive oxide species accumulation in enzyme therapy for colorectal cancer

Glucose oxidase (GOx)-based enzyme therapeutics are potential alternatives for colorectal cancer (CRC) treatment via glucose consumption and accumulation of hydrogen peroxide (H2O2). Given that H2O2 can be eliminated by cytoprotective autophagy, autophagy inhibitors that can interrupt autolysosome-induced H2O2 elimination are promising combination drugs of GOx. Here, we developed a multifunctional biomimetic nanocarrier for effective co-delivery of an autophagy inhibitor-chloroquine phosphate (CQP) and GOx to exert their synergistic effect by irreversibly upregulating intracellular reactive oxygen species (ROS) levels. Poly (D, l-lactide-co-glycolide) (PLGA) nanoparticles (NPs) were used to encapsulate both GOx and CQP using a W/O/W multi-emulsion method. Calcium phosphate (CaP) was used to "fix" CQP to GOx in the internal water phase, where it served as a pH-sensitive unit to facilitate intracellular drug release. Folic acid-modified red blood cell membranes (FR) were used to camouflage the GOx/CQP/CaP encapsulated PLGA NPs (referred to as PLGA/GCC@FR). In an AOM/DSS-induced CRC mouse model, PLGA/GCC@FR exhibited improved antitumor effects, in which the number of tumor nodes were only a quarter of that in the free drug combination group. The enhanced therapeutic effects of PLGA/GCC@FR were attributed to the prolonged tumor retention which was verified by both dynamic in vivo imaging and drug biodistribution. This multifunctional biomimetic nanocarrier facilitated combined enzyme therapeutics by depleting glucose and augmenting intracellular ROS levels in tumor cells, which exerted a synergistic inhibitory effect on tumor growth. Therefore, this study proposed a novel strategy for the enhancement of combined enzyme therapeutics, which provided a promising method for effective CRC treatment.

Manganese-Based Nanotheranostics for Magnetic Resonance Imaging-Mediated Precise Cancer Management

Manganese (Mn)-based magnetic resonance imaging (MRI) has become a competitive imaging modality for cancer diagnosis due to its advantages of non-invasiveness, high resolution and excellent biocompatibility. In recent years, a variety of Mn contrast agents based on different material systems have been synthesized, and a series of multi-purpose Mn nanocomposites have also emerged, showing satisfactory relaxation efficiency and MRI performance thus possess the transformation and application value in MRI-synergized cancer diagnosis and treatment. This tutorial review starts from the classification and properties of Mn-based nanomaterials, and then summarizes various preparation and functionalization strategies of nanosized Mn contrast agents, especially focuses on the latest progress of Mn contrast agents in MRI-synergized precise cancer theranostics. In addition, present review also discusses the current clinical transformation obstacles such as unclear molecular mechanisms, potential nanotoxicity, and scale production constraints. This paper provides evidence-based recommendations about the future prospects of multifunctional nanoplatforms, as well as technical guidance and panoramic expectations for the design of clinically meaningful cancer management programs.

Recent advances in glucose oxidase-based nanocarriers for tumor targeting therapy

Glucose oxidase (GOx) can specifically catalyze the conversion of β-d-glucose into gluconic acid and hydrogen peroxide (H2O2) in the presence of oxygen, making it promising for tumor starvation therapy and oxidative therapy. However, GOx's immunogenicity, poor in vivo stability, short half-life, and potential systemic toxicity, limit its application in cancer therapy. Nanocarriers are capable of improving the pharmacological properties of therapeutic drugs (e.g. stability, circulating half-life, and tumor accumulation) and lower toxicity, hence resolving GOx issues and enhancing its efficacy. Although the application of targeted nanocarriers based on GOx has recently flourished, this field has not yet been reviewed and evaluated. Herein, we initially examined the mechanism of GOx-based nanocarriers for enhanced tumor therapy. Also, we present a comprehensive and up-to-date review that highlights GOx-based nanocarriers for tumor targeting therapy. This review expands on GOx-based nano-targeted combination therapies from both passive and active targeting perspectives, meanwhile, active targeting is further classified into ligand-mediated targeting and physical-mediated targeting. Furthermore, this review also emphasizes the present challenges and promising advancements.

Record-High Ultrasound-Sensitive NO Nanogenerators for Cascade Tumor Pyroptosis and Immunotherapy

Pyroptosis is a pro-inflammatory cell death that is associated with innate immunity promotion against tumors. Excess nitric oxide (NO)-triggered nitric stress has potential to induce pyroptosis, but the precise delivery of NO is challenging. Ultrasound (US)-responsive NO production has dominant priority due to its deep penetration, low side effects, noninvasion, and local activation manner. In this work, US-sensitive NO donor N-methyl-N-nitrosoaniline (NMA) with thermodynamically favorable structure is selected and loaded into hyaluronic acid (HA)-modified hollow manganese dioxide nanoparticles (hMnO2 NPs) to fabricate hMnO2 @HA@NMA (MHN) nanogenerators (NGs). The obtained NGs have a record-high NO generation efficiency under US irradiation and can release Mn2+ after targeting the tumor sites. Later on, cascade tumor pyroptosis and cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING)-based immunotherapy is achieved and tumor growth is effectively inhibited.

Research progress on reactive oxygen species production mechanisms in tumor sonodynamic therapy

In recent years, because of the growing desire to improve the noninvasiveness and safety of tumor treatments, sonodynamic therapy has gradually become a popular research topic. However, due to the complexity of the therapeutic process, the relevant mechanisms have not yet been fully elucidated. One of the widely accepted possibilities involves the effect of reactive oxygen species. In this review, the mechanism of reactive oxygen species production by sonodynamic therapy (SDT) and ways to enhance the sonodynamic production of reactive oxygen species are reviewed. Then, the clinical application and limitations of SDT are discussed. In conclusion, current research on sonodynamic therapy should focus on the development of sonosensitizers that efficiently produce active oxygen, exhibit biological safety, and promote the clinical transformation of sonodynamic therapy.

Research progress on reactive oxygen species production mechanisms in tumor sonodynamic therapy

In recent years, because of the growing desire to improve the noninvasiveness and safety of tumor treatments, sonodynamic therapy has gradually become a popular research topic. However, due to the complexity of the therapeutic process, the relevant mechanisms have not yet been fully elucidated. One of the widely accepted possibilities involves the effect of reactive oxygen species. In this review, the mechanism of reactive oxygen species production by sonodynamic therapy (SDT) and ways to enhance the sonodynamic production of reactive oxygen species are reviewed. Then, the clinical application and limitations of SDT are discussed. In conclusion, current research on sonodynamic therapy should focus on the development of sonosensitizers that efficiently produce active oxygen, exhibit biological safety, and promote the clinical transformation of sonodynamic therapy.

Biomimetic liposomal nanozymes improve breast cancer chemotherapy with enhanced penetration and alleviated hypoxia

BACKGROUND

Doxorubicin (Dox) has been recommended in clinical guidelines for the standard-of-care treatment of breast cancer. However, Dox therapy faces challenges such as hypoxia, acidosis, H₂O₂-rich conditions and condensed extracellular matrix in TME as well as low targeted ability.

METHODS

We developed a nanosystem H-MnO₂-Dox-Col NPs based on mesoporous manganese dioxide (H-MnO₂) in which Dox was loaded in the core and collagenase (Col) was wrapped in the surface. Further the H-MnO₂-Dox-Col NPs were covered by a fusion membrane (MP) of inflammation-targeted RAW264.7 cell membrane and pH-sensitive liposomes to form biomimetic MP@H-MnO₂-Dox-Col for in vitro and in vivo study.

RESULTS

Our results shows that MP@H-MnO₂-Dox-Col can increase the Dox effect with low cardiotoxicity based on multi-functions of effective penetration in tumor tissue, alleviating hypoxia in TME, pH sensitive drug release as well as targeted delivery of Dox.

CONCLUSIONS

This multifunctional biomimetic nanodelivery system exhibited antitumor efficacy in vivo and in vitro, thus having potential for the treatment of breast cancer.

Metal-Organic Frameworks (MOF)-Assisted Sonodynamic Therapy in Anticancer Applications

Sonodynamic therapy (SDT) has emerged as a promising therapeutic modality for anticancer treatments and is becoming a cutting-edge interdisciplinary research field. This review starts with the latest developments of SDT and provides a brief comprehensive discussion on ultrasonic cavitation, sonodynamic effect, and sonosensitizers in order to popularize the basic principles and probable mechanisms of SDT. Then the recent progress of MOF-based sonosensitizers is overviewed, and the preparation methods and properties (e.g., morphology, structure, and size) of products are presented in a fundamental perspective. More importantly, many deep observations and understanding toward MOF-assisted SDT strategies were described in anticancer applications, aiming to highlight the advantages and improvements of MOF-augmented SDT and synergistic therapies. Last but not least, the review also pointed out the probable challenges and technological potential of MOF-assisted SDT for the future advance. In all, the discussions and summaries of MOF-based sonosensitizers and SDT strategies will promote the fast development of anticancer nanodrugs and biotechnologies.

Glucose Oxidase-Modified Metal-Organic Framework for Starving-Enhanced Chemodynamic Therapy

Chemodynamic therapy (CDT) has been considered an emerging strategy for cancer treatment. However, the tumor microenvironment (TME) with slight acidity and restricted H₂O₂ limits the efficacy of CDT. Here, we report a Hf-Mn-TCPP (Hf = hafnium; Mn-TCPP = 5, 10, 15, 20-tetrakis (4-carboxyphenyl) porphyrinato-manganese (II) chloride) loaded with glucose oxidase (GOx) to realize starving-enhanced CDT. GOx consumes glucose to produce H₂O₂ and gluconic acid. Gluconic acid increases the acidity of TME and subsequently provides favorable conditions for the Fenton-like reaction based on Hf-Mn-TCPP. The results indicate that GOx-modified Hf-Mn-TCPP provided a great therapeutic effect in starvation-enhanced CDT in vitro and in vivo.

Short-Term Starvation Weakens the Efficacy of Cell Cycle Specific Chemotherapy Drugs through G1 Arrest

Short-term starvation (STS) during chemotherapy can block the nutrient supply to tumors and make tumor cells much more sensitive to chemotherapeutic drugs than normal cells. However, because of the diversity of starvation methods and the heterogeneity of tumors, this method's specific effects and mechanisms for chemotherapy are still poorly understood. In this study, we used HeLa cells as a model for short-term starvation and etoposide (ETO) combined treatment, and we also mimicked the short-term starvation effect by knocking down the glycolytic enzyme GAPDH to explore the exact molecular mechanism. In addition, our study demonstrated that short-term starvation protects cancer cells against the chemotherapeutic agent ETO by reducing DNA damage and apoptosis due to the STS-induced cell cycle G1 phase block and S phase reduction, thereby diminishing the effect of ETO. Furthermore, these results suggest that starvation therapy in combination with cell cycle-specific chemotherapeutic agents must be carefully considered.

Acoustic-Based Theranostic Probes Activated by Tumor Microenvironment for Accurate Tumor Diagnosis and Assisted Tumor Therapy

Acoustic-based imaging techniques, including ultrasonography and photoacoustic imaging, are powerful noninvasive approaches for tumor imaging owing to sound transmission facilitation, deep tissue penetration, and high spatiotemporal resolution. Usually, imaging modes were classified into "always-on" mode and "activatable" mode. Conventional "always-on" acoustic-based probes often have difficulty distinguishing lesion regions of interest from surrounding healthy tissues due to poor target-to-background signal ratios. As compared, activatable probes have attracted attention with improved sensitivity, which can boost or amplify imaging signals only in response to specific biomolecular recognition or interactions. The tumor microenvironment (TME) exhibits abnormal physiological conditions that can be used to identify tumor sections from normal tissues. Various types of organic dyes and biomaterials can react with TME, leading to obvious changes in their optical properties. The TME also affects the self-assembly or aggregation state of nanoparticles, which can be used to design activatable imaging probes. Moreover, acoustic-based imaging probes and therapeutic agents can be coencapsulated into one nanocarrier to develop nanotheranostic probes, achieving tumor imaging and cooperative therapy. Satisfactorily, ultrasound waves not only accelerate the release of encapsulated therapeutic agents but also activate therapeutic agents to exert or enhance their therapeutic performance. Meanwhile, various photoacoustic probes can convert photon energy into heat under irradiation, achieving photoacoustic imaging and cooperative photothermal therapy. In this review, we focus on the recently developed TME-triggered ultrasound and photoacoustic theranostic probes for precise tumor imaging and targeted tumor therapy.

Recent Progress Toward Imaging Application of Multifunction Sonosensitizers in Sonodynamic Therapy

Sonodynamic therapy (SDT) is a rapidly developing non-surgical therapy that initiates sensitizers’ catalytic reaction using ultrasound, showing great potential for cancer treatment due to its high safety and non-invasive nature. In addition, recent research has found that using different diagnostic and therapeutic methods in tandem can lead to better anticancer outcomes. Therefore, as essential components of SDT, sonosensitizers have been extensively explored to optimize their functions and integrate multiple medical fields. The review is based on five years of articles evaluating the combined use of SDT and imaging in treating cancer. By developing multifunctional sonosensitive particles that combine imaging and sonodynamic therapy, we have integrated diagnosis into the treatment of precision medicine applications, improving SDT cell uptake and antitumor efficacy utilizing different tumour models. This paper describes the imaging principle and the results of cellular and animal imaging of the multifunctional sonosensitizers. Efforts are made in this paper to provide data and design references for future SDT combined imaging research and clinical application development and to provide offer suggestions.

Copper peroxide coated upconversion nanoparticle modified with glucose oxidase for H2O2 self-supplying starvation-enhanced chemodynamic therapy in vitro

Chemodynamic therapy (CDT) can convert endogenous hydrogen peroxide (H₂O₂) to highly reactive hydroxyl radical (˙OH) through Fenton or Fenton-like reaction to kill tumor cells, which is a promising anticancer strategy. However, the limited H₂O₂ and overexpressed glutathione (GSH) in tumor cells make CDT ineffective. Here, an efficient nanocomposite, UCN@CuO₂-GOx (UCCuG), was synthesized, realizing both starvation therapy and H₂O₂ self-supplying CDT in vitro. In this case, the glucose oxidase (GOx) of the nanocomposite could consume glucose for starvation therapy after the UCCuG nanocomposite entered tumor cells. In addition, the acidic environment of the lysosome triggered the release of Cu²⁺ and H₂O₂ by the decomposition of UCCu; then, Cu²⁺ was reduced to Cu⁺ by GSH in tumor cells; and finally, Cu⁺ catalyzed the released H₂O₂ to generate ˙OH for CDT. The in vitro experiments demonstrated starvation-enhanced CDT with remarkable results. Meanwhile, under 980 nm laser irradiation, the upconversion luminescence signal of UCN in the UCCuG nanocomposite was reduced due to the CuO₂-GOx coating, while it gradually recovered after the UCCuG nanocomposite reacted with glucose and GSH under the tumor microenvironment (TME). Such a luminescent intensity recovery process is expected to monitor the TME-activated therapeutic effect in real time. This strategy may solve the problem of insufficient CDT efficacy caused by limited endogenous H₂O₂ and overexpressed GSH in tumor cells. This multifunctional nanocomposite demonstrates the promising application of starvation-enhanced CDT in tumor treatment.

Exhausted local lactate accumulation via injectable nanozyme-functionalized hydrogel microsphere for inflammation relief and tissue regeneration

Local lactate accumulation greatly hinders tissue repair and regeneration under ischemic condition. Herein, an injectable microsphere (MS@MCL) for local lactate exhaustion was constructed by grafting manganese dioxide (MnO₂) -lactate oxidase (LOX) composite nanozyme on microfluidic hyaluronic acid methacrylate (HAMA) microspheres via chemical bonds, achieving a long-term oxygen-promoted lactate exhaustion effect and a long half-life in vivo. The uniform and porous microspheres synthesized by microfluidic technology is beneficial to in situ injection therapy and improving encapsulation efficiency. Furthermore, chemical grafting into HAMA microspheres through amide reactions promoted local enzymatic concentration and activity enhancement. It was showed that the MS@MCL eliminated oxidative and inflammatory stress and promoted extracellular matrix metabolism and cell survival when co-cultured with nucleus pulposus cells (NPCs) in vitro. In the rat degenerative intervertebral disc model caused by lactate injection, MS@MCL showed a long-term therapeutic effect in reducing intervertebral height narrowing and preventing extracellular matrix (ECM) degradation as well as inflammatory damage in vivo. Altogether, this study confirms that this nanozyme-functionalized injectable MS@MCL effectively improves the regenerative and reparative effect in ischemic tissues by disposing of enriched lactate in local microenvironment.

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Exhausted local lactate accumulation via injectable hydrogel microsphere.

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Long-acting microfluidic hyaluronic acid microspheres.

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Manganese dioxide-lactate oxidase composited nanozyme via covalent bond.

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Promoted sustained release of nanozyme and maintained enzymatic activity.

Current status of cancer starvation therapy

Conventional therapies for malignant tumors have limitations and disadvantages. In recent years, the cancer starvation therapy has emerged which intends to deprive cancer cells of nutritional supply. There are several approaches to"starve" cancer cells: to intervene tumor angiogenesis by targeted inhibition of angiogenic factors or their receptors and integrins; to block the blood supply of cancer cells by embolizing or compressing blood vessels; to intervene metabolic process of cancer cells by inhibition of the signal pathways of mitochondrial serine-glycine-one earbon metabolism, glycolysis and amino acid metabolism; cancer starvation therapy can be employed with oxidation therapy, chemotherapy, sonodynamic therapy, anti-autophagy therapy or other therapies to achieve synergistic effects. This article reviews the research progress of cancer starvation therapy in recent years and discusses the existing problems.

Hollow Mesoporous Manganese Oxides: Application in Cancer Diagnosis and Therapy

The precision, minimal invasiveness, and integration of diagnosis and treatment are critical factors for tumor treatment at the present. Although nanomedicine has shown the potential in tumor precision treatment, nanocarriers with high efficiency, excellent targeting, controlled release, and good biocompatibility still need to be further explored. Hollow mesoporous manganese oxides nanomaterials (HM-MONs), as an efficient drug delivery carrier, have attracted substantial attention in applications of tumor diagnosis and therapy due to their unique properties, such as tumor microenvironment stimuli-responsiveness, prominent catalytic activity, excellent biodegradation, and outstanding magnetic resonance imaging ability. The HM-MONs can not only enhance the therapeutic efficiency but also realize multimodal diagnosis of tumors. Consequently, it is necessary to introduce applications based on HM-MONs in cancer diagnosis and therapy. In this review, the representative progress of HM-MONs in synthesis is discussed. Then, several promising applications in drug delivery, bio-imaging, and bio-detection are highlighted. Finally, the challenges and perspectives of the anticancer applications are summarized, which is expected to provide meaningful guidance on further research.

Ultrasound-activated nanomaterials for sonodynamic cancer theranostics

Despite intensive efforts to develop diagnostic and therapeutic tools, the successful treatment of cancer is still hampered by the obscure boundary between cancerous cells and normal cells, recurrence of the cancer, and the development of drug resistance during chemotherapy. In recent years, sonodynamic therapy (SDT), employing therapeutic ultrasound with sonosensitizers, has attracted attention as a potentially promising approach for cancer therapy. This review describes the current understanding of the mechanisms and the preclinical and clinical efficacy of SDT-based applications in tumors, providing an insight into the therapeutic potential offered by SDT. The limitations and future directions of this emerging treatment are also discussed.

Application of nanosonosensitizer materials in cancer sono-dynamic therapy

Sonodynamic therapy (SDT) is a novel non-invasive treatment for cancer combining low-intensity ultrasound and sonosensitizers.

Manganese silicate nanospheres-incorporated hydrogels：starvation therapy and tissue regeneration

To prevent postoperative skin tumor recurrence and repair skin wound, a glucose oxidase (GOx)-loaded manganese silicate hollow nanospheres (MS HNSs)-incorporated alginate hydrogel (G/MS-SA) was constructed for starvation-photothermal therapy and skin tissue regeneration. The MS HNSs showed a photothermal conversion efficiency of 38.5%, and endowed composite hydrogels with satisfactory photothermal effect. Taking advantage of the catalytic activity of Mn ions, the composite hydrogels could decompose hydrogen peroxide (H2O2) into oxygen (O2), which can alleviate the problem of tumor hypoxia microenvironment and endow GOx with an ability to consume glucose in the presence of O2 for tumor starvation. Meanwhile, hyperthermia triggered by near infrared (NIR) irradiation could not only accelerate the reaction rate of H2O2 decomposition by MS HNSs and glucose consumption by GOx, but also ablate tumor cells. The anti-tumor results showed that synergistic effect of starvation-photothermal therapy led to the highest death rate of tumor cells among all groups, and its anti-tumor effect was obviously improved as compared with that of single photothermal treatment or starvation treatment. Interestingly, the introduction of MS HNSs into hydrogels could distinctly promote the epithelialization of the wound beds by releasing Mn ions as compared with the hydrogels without MS HNSs. It is expected that such a multifunctional platform with starvation-photothermal therapy will be promising for treating tumor-caused skin defects in combination of its regeneration bioactivity in the future.

The promise of low-intensity ultrasound: A review on sonosensitizers and sonocatalysts by ultrasonic activation for bacterial killing

Antimicrobial resistance has become one of the main public health issues in modern society. Ultrasonicantimicrobial treatment (UAT) is expected to solve the problem of antimicrobial resistance since ultrasonic treatment does not cause drug resistance during inactivation. However, the ultrasonic application is hindered due to the high energy cost. To cast more lights on the ultrasound in tandem with catalysts as a superior strategy for bacterial inactivation, the present review focuses on the UAT with the assistant of continuous development of organic sonosensitizer and inorganic sonocatalyst. With the application of these nanomaterials, the ultrasonic parameters changed from low-frequency and high-power ultrasound to high-frequency and low-power ultrasound. The review also presents the composition of sonosensitizers/sonocatalysts including organic and inorganic nanoparticles and discusses the ultrasonic activation mechanisms triggered by these catalysts. Based on the synergistic effect of ultrasound and catalysts, we discuss the importance of extracellular oxidation and intracellular oxidation in the process of bacterial inactivation. Overall, UAT combined with catalysts appears to be an effective treatment strategy that can be successfully applied in the field of medicine, environmental treatment, and food industry.

A cascaded enzyme-loaded Fe-hemoporfin framework for synergistic sonodynamic-starvation therapy of tumors

Enzyme-loaded nanosystems with multimodal therapeutic functions have received increasing attention in the treatment of malignant tumors. Herein, we designed and prepared cascaded dual-enzyme-augmented Fe-hemoporfin framework nanosonosensitizers for synergistic sonodynamic-starvation therapy of tumors. Amorphous Fe-hemoporfin frameworks (FeHF) with an average size of ∼85 nm were synthesized by assembling the clinical drug hemoporfin with Fe³⁺ ions. Then, FeHF was used to load dual enzymes (glucose oxidase (GOx) and catalase (CAT)) and modified by PEGylated folic acid-conjugated lipids. The dual-enzyme loaded FeHF (FeHF-GOx/CAT) exhibited higher efficiency not only for glucose depletion but also for ultrasound (US)-triggered ¹O₂ generation than that of pure FeHF, resulting from the cascaded catalytic reaction from the dual-enzyme system. As observed by magnetic resonance imaging, the intravenously injected FeHF-GOx/CAT was accumulated within tumors. The FeHF-GOx/CAT + US exhibited the highest inhibition effect compared to the FeHF-CAT + US (only SDT) or FeHF-GOx/CAT (only starvation therapy), due to the synergistic effects of SDT and starvation therapy. Therefore, the cascaded dual-enzyme loading strategy can increase the SDT efficiency of FeHF, which may guide further works in the development of efficient nanosonosensitizers.

Design and application of inorganic nanoparticles for sonodynamic cancer therapy

This review focus on the recent developments in inorganic nanomaterials for tumor SDT.

Recent Advances in Nanomaterial-Assisted Combinational Sonodynamic Cancer Therapy

Ultrasound (US)-triggered sonodynamic therapy (SDT), as a promising noninvasive therapeutic modality, has received ever-increasing attention in recent years. Its specialized chemical agents, named sonosensitizers, are activated by low-intensity US to produce lethal reactive oxygen species (ROS) for oncotherapy. Compared with phototherapeutic strategies, SDT provides many noteworthy opportunities and benefits, such as deeper penetration depth, absence of phototoxicity, and fewer side effects. Nevertheless, previous studies have also demonstrated its intrinsic limitations. Thanks to the facile engineering nature of nanotechnology, numerous novel nanoplatforms are being applied in this emerging field to tackle these intrinsic barriers and achieve continuous innovations. In particular, the combination of SDT with other treatment strategies has demonstrated a superior efficacy in improving anticancer activity relative to that of monotherapies alone. Therefore, it is necessary to summarize the nanomaterial-assisted combinational sonodynamic cancer therapy applications. Herein, the design principles in achieving synergistic therapeutic effects based on nanomaterial engineering methods are highlighted. The ultimate goals are to stimulate the design of better-quality combined sonodynamic treatment schemes and provide innovative ideas for the perspectives of SDT in promoting its future transformation to clinical application.

Nanoplatform-based cascade engineering for cancer therapy

Various therapeutic techniques have been studied for treating cancer precisely and effectively, such as targeted drug delivery, phototherapy, tumor-specific catalytic therapy, and synergistic therapy, which, however, evoke numerous challenges due to the inherent limitations of these therapeutic modalities and intricate biological circumstances as well. With the remarkable advances of nanotechnology, nanoplatform-based cascade engineering, as an efficient and booming strategy, has been tactfully introduced to optimize these cancer therapies. Based on the designed nanoplatforms, pre-supposed cascade processes could be triggered under specific conditions to generate/deliver more therapeutic species or produce stronger tumoricidal effects inside tumors, aiming to achieve cancer therapy with increased anti-tumor efficacy and diminished side effects. In this review, the recent advances in nanoplatform-based cascade engineering for cancer therapy are summarized and discussed, with an emphasis on the design of smart nanoplatforms with unique structures, compositions and properties, and the implementation of specific cascade processes by means of endogenous tumor microenvironment (TME) resources and/or exogenous energy inputs. This fascinating strategy presents unprecedented potential in the enhancement of cancer therapies, and offers better controllability, specificity and effectiveness of therapeutic functions compared to the corresponding single components/functions. In the end, challenges and prospects of such a burgeoning strategy in the field of cancer therapy will be discussed, hopefully to facilitate its further development to meet the personalized treatment demands.

Sonodynamic therapy-derived multimodal synergistic cancer therapy

Sonodynamic therapy (SDT) represents a promising modality that provides the possibility of non-invasively eliminating solid tumors in a site-directed manner. In light of the complexity and heterogeneity of tumors, more and more studies are attempting to combine SDT with other therapeutic methods so as to achieve better tumor treatment effect, which sheds new light on the potential of SDT-based synergistic therapeutics. Herein, the representative studies of SDT-instructed multimodal synergistic cancer therapy are comprehensively presented, such as sono-chemotherapy, sono-radiotherapy, sono-immunotherapy, and sono-chemodynamic therapy, etc., and their incorporate mechanisms are discussed in detail. The current challenges and future prospects to promote the advanced development of SDT-based nanomedicines in this burgeoning research field are highlighted. It is believed that such an emerging synergistic therapeutic modality based on SDT will play a more significant role in the field of tumor precision treatment medicine.

A mitochondria-targeted anticancer nanoplatform with deep penetration for enhanced synergistic sonodynamic and starvation therapy

Sonodynamic therapy (SDT), as an emerging technique, gives rise to reactive oxygen species (ROS)-induced apoptosis of tumor cells. However, nonselective enrichment and unsatisfactory penetration depth of sonosensitizers in tumor tissues limit its application. In this study, we synthesized core/shell (glucose oxidase (GOx) in the core/hematoporphyrin monomethyl ether (HMME) and IR780 in the shell) structured polylactic-co-glycolic acid (PLGA) nanoparticles (NPs) with deep tumor penetration and mitochondrial targeting capability for synergistic sonodynamic and starvation therapy. After passing through the endothelial space of tumor vasculatures, by virtue of IR780, these NPs can selectively accumulate towards cancer cells/sites, especially in mitochondria and diffuse into deep tumour centres. Upon ultrasound (US) exposure, the overproduced ROS cause tumor cell apoptosis. Sonodynamic effects can be amplified by mitochondrial targeting because mitochondria are susceptible to ROS. GOx blocks glucose (energy) supply, further suppressing the growth of malignant tumors. This synergistic therapy exhibited a superb response to treatment (4.7-fold lower tumor growth in volume than the control group). In addition, these NPs also serve as excellent photoacoustic (PA)/fluorescent (FL) imaging contrast agents to simultaneously monitor and guide cancer therapy. This study paves a promising way to achieve an ideal strategy for cancer therapy.

Nanoenzymes in disease diagnosis and therapy

This feature article highlights various nanoenzymes and their bio-applications in disease diagnosis and therapy. Current challenges and future trends of nanoenzymes are also discussed.