Spiky Cascade Biocatalysts as Peroxisome-Mimics for Ultrasound-Augmented Tumor Ablation

Perfluorohexane nanodroplet-assisted mechanical high intensity focused ultrasound cavitation: A strategy for hepatocellular carcinoma treatment

The activation of immune-stimulatory molecules is critical for effective antitumor immunotherapy. Mechanical high-intensity focused ultrasound (mHIFU) sustains this activation in tumor cell debris through cavitation. To enhance cavitation, perfluorohexane nanodroplets (NDs-PFH) were utilized in this study to lower the cavitation threshold during mHIFU ablation. Our results showed that NDs-PFH combined with mHIFU induced 77.2 % Hepa 1-6 tumor cells death, and activated the release of damage-associated molecular patterns (such as HMGB1, CRT, and ATP), enhancing dendritic cell maturation (20.2 %) and T cell activation (1.8 % of TNF-α+ and 2.7 % of IFN-γ+). In vivo, the combination of NDs-PFH and mHIFU effectively suppressed both primary and distant untreated tumors, reducing the tumor volume by 83.3 % (from 657.4 mm3 to 110.0 mm3) and metastatic tumor volume by 76.6 % (from 365.5 mm3 to 85.6 mm3) through enhanced anticancer immune response and a robust abscopal effect. Furthermore, combining NDs-PFH with mHIFU significantly enhanced the efficacy of immune checkpoint inhibitors in liver cancer. When combined with αPD-1 therapy, tumor inhibition improved by 30 % (from 63.6 mm3 to 19.3 mm3) compared to αPD-1 monotherapy. These results highlight the potential of combining mHIFU with a PFH nano-loaded drug delivery system as a promising strategy for advancing antitumor immunotherapy. STATEMENT OF SIGNIFICANCE: Mechanical high-intensity focused ultrasound (mHIFU) can ablate tumors via cavitation effects, however, achieving these effects typically requires an extremely high cavitation threshold. In this study, we utilized widely used perfluorohexane nanodroplets (NDs-PFH) to effectively lower the cavitation threshold. The tumor cell debris generated by the combination of NDs-PFH and mHIFU not only induced immunogenic cells death but also activated antitumor immune responses within the tumor microenvironment. Additionally, our findings demonstrated that this combination elicited a significant abscopal effect and enhanced the efficacy of immunotherapy.

Synergistic Ultrasound-Activable Artificial Enzyme and Precision Gene Therapy to Suppress Redox Homeostasis and Malignant Phenotypes for Controllably Combating Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) remains one of the most lethal malignant tumors. Multimodal therapeutics with synergistic effects for treating HCC have attracted increasing attention, for instance, designing biocompatible porphyrin-based nanomedicines for enzyme-mimetic and ultrasound (US)-activable reactive oxygen species (ROS) generation. Despite the promise, the landscape of such advancements remains sparse. Here, we propose the de novo design of a π-conjugated, osmium (Os)-coordinated polyporphyrin (P-Por-Os) nanovesicle to serve as an ultrasound-activable artificial enzyme for synergistic therapies to suppress redox homeostasis and malignant phenotypes for controllably combating HCC. Our findings reveal that the P-Por-Os with US showed superior, multifaceted, and controllable ROS-generating activities. This system not only subverts the redox balance within HCC cells but also achieves precise and controlled tumor ablation at remarkably low concentrations, as evidenced across cellular assays and animal models. In the liver orthotopic model, US not only activates the artificial enzyme to catalyze ROS but also facilitates remote-controlled ablation of HCC through precise US positioning. Moreover, the P-Por-Os + US can assist the precision gene therapy by knocking down the ROS resistance factor, MT2A, and down-regulating its downstream oncogene IGFBP2 to attenuate ROS resistance, proliferation, and migration of HCC efficiently. We suggest that the design of this ultrasound-activable artificial enzyme presents a promising avenue for the engineering of innovative tumoricidal materials, offering a synergistic therapeutic approach with high biosecurity for HCC treatment.

Progress in application of nanomedicines for enhancing cancer sono-immunotherapy

Cancer immunotherapy has significant potential as a cancer treatment since it boosts the immune system and prevents immune escape to get rid of or fight cancers. However, its clinical applicability is still limited because of the low response rate and immune-related side effects. Recently ultrasound has been shown to alter the tumor immune microenvironment, enhance the effectiveness of other antitumor therapies, and cause tumors to become more sensitive to immunotherapy, thus providing new insights into cancer treatment. Nanomedicines are also anticipated to have a positive impact on improving the immunological effects and enhancing ultrasound effect for cancer therapy. Therefore, designing effective nanomedicines enhanced ultrasound effect for augmenting sono-immunotherapy has been a pivot on anticancer therapy. In this review, the immunological impacts of various ultrasound therapeutic modalities, ultrasound parameters, and their underlying mechanisms are discussed. Moreover, we highlight the recent progress of nanomedicines synergistically enhancing sono-immunotherapy. Finally, we put forward opportunities and challenges on sono-immunotherapy.

Near-infrared and ultrasound triggered Pt/Pd-engineered cluster bombs for the treatment of solid tumors

Owing to the dense extracellular matrix and high interstitial fluid pressure in the tumor microenvironment, methods which enhance the permeation and retention of nano drugs into liver tumors remain unsatisfactory for successful tumor treatment. We designed a near-infrared (NIR)- and ultrasound (US)-triggered Pt/Pd-engineered "cluster bomb" (Pt/Pd-CB) which actively penetrates liver cancer cell membranes and achieves photothermal and sonodynamic therapy (SDT). The physical forces generated by the fast expansion and collapse of perfluoropentane nanodroplets eject "sub bombs" (Pt/Pd nanoalloys) into liver cancer cells upon activation by NIR and US. Pt/Pd nanoalloys can then convert H2O2 into O2 to alleviate hypoxia and boost SDT efficiency while exhibiting a highly efficient photothermal response under NIR irradiation. Our findings might especially be promising for the treatment of solid tumors.

Nanozymes-Mediated Cascade Reaction System for Tumor-Specific Diagnosis and Targeted Therapy

Cascade reactions are described as efficient and versatile tools, and organized catalytic cascades can significantly improve the efficiency of chemical interworking between nanozymes. They have attracted great interest in many fields such as chromogenic detection, biosensing, tumor diagnosis, and therapy. However, how to selectively kill tumor cells by enzymatic reactions without harming normal cells, as well as exploring two or more enzyme-engineered nanoreactors for cascading catalytic reactions, remain great challenges in the field of targeted and specific cancer diagnostics and therapy. The latest research advances in nanozyme-catalyzed cascade processes for cancer diagnosis and therapy are described in this article. Here, various sensing strategies are summarized, for tumor-specific diagnostics. Targeting mechanisms for tumor treatment using cascade nanozymes are classified and analyzed, "elements" and "dimensions" of cascade nanozymes, types, designs of structure, and assembly modes of highly active and specific cascade nanozymes, as well as a variety of new strategies of tumor targeting based on the cascade reaction of nanozymes. Finally, the integrated application of the cascade nanozymes systems in tumor-targeted and specific diagnostic therapy is summarized, which will lay the foundation for the design of more rational, efficient, and specific tumor diagnostic and therapeutic modalities in the future.

[Experimental Study on Biomimetic Curcumin-Mediated Sonodynamic Therapy of Melanoma]

Objective

To study the role of curcumin-mediated sonodynamic therapy in the treatment of malignant melanoma, and to provide a new strategy for the treatment of malignant melanoma.

Methods

The ultrasonic sound and vibration method was applied to coat curcumin with mouse melanoma cell membrane, thereby forming biomimetic curcumin. The morphology of biomimetic curcumin was observed by transmission electron microscope. Flow cytometry was used to analyze the effect of biomimetic curcumin in terms of in vitro targeting, apoptosis, and intracellular reactive oxygen species (ROS) production. The in vivo experiment was divided into control group, US group, turmeric group, imitation turmeric group, and imitation turmeric+US group, with 3 mice in each group. The in vivo safety of biomimetic curcumin was evaluated by HE staining. In addition, HE, CD31, Ki67, and TUNEL stainings were performed to evaluate the in vivo anti-melanoma therapeutic effect of ultrasound combined with biomimetic curcumin.

Results

The biomimetic curcumin had a generally uniform morphology and possessed a core-shell structure. Flow cytometry analysis performed with FlowJo showed that the biomimetic curcumin could be effectively taken up by melanoma cells. The apoptosis rate was (10.30±0.61)% in the control group, (10.41±3.13)% in the ultrasound group, (24.97±1.38)% in the curcumin group, (31.39±3.84)% in the biomimetic curcumin group, and (40.89±0.79)% in the biomimetic curcumin and ultrasound combination group. The apoptosis rate in the biomimetic curcumin and ultrasound combination group was higher than those in the other groups (P<0.05). The results of ROS flow cytometry showed that, compared with the control group, the ultrasound group demonstrated almost no increase in the fluorescence intensity, while the other groups showed an increase in the fluorescence intensity to varying degrees. There was no significant difference in the fluorescence intensity between the biomimetic curcumin group ([1.10±0.38]%) and the curcumin group ([0.73±0.26]%) (P>0.05). The fluorescence intensity of the biomimetic curcumin and ultrasound combination group ([3.35±0.04]%) was higher than those of the other groups (P<0.05). HE staining showed no obvious abnormalities in the morphology of heart, liver, spleen, lung, and kidney tissues in any of the treatment groups. HE staining showed the most significant changes in cell morphology in the biomimetic curcumin and ultrasound combination group, followed by the biomimetic curcumin group and the curcumin group. No obvious abnormalities in tumor cell morphology were observed in the ultrasound group. According to the respective results of CD31 staining, Ki67 staining, and TUNEL staining, the biomimetic curcumin and ultrasound combination group had the largest brown area, the highest number of red fluorescence, and the highest number of green fluorescence, followed by the biomimetic curcumin group and the curcumin group.

Conclusion

The biomimetic curcumin displays uniform morphology, a core-shell structure, and good targeting properties. When it is used in combination with ultrasound, biomimetic curcumin demonstrates a good anti-tumor therapeutic effect both in vivo and in vitro.

Zinc peroxide-based nanotheranostic platform with endogenous hydrogen peroxide/oxygen generation for enhanced photodynamic-chemo therapy of tumors

Nanotheranostic platforms, which can respond to tumor microenvironments (TME, such as low pH and hypoxia), are immensely appealing for photodynamic therapy (PDT). However, hypoxia in solid tumors harms the treatment outcome of PDT which depends on oxygen molecules to generate cytotoxic singlet oxygen (1O2). Herein, we report the design of TME-responsive smart nanotheranostic platform (DOX/ZnO2@Zr-Ce6/Pt/PEG) which can generate endogenously hydrogen peroxide (H2O2) and oxygen (O2) to alleviate hypoxia for improving photodynamic-chemo combination therapy of tumors. DOX/ZnO2@Zr-Ce6/Pt/PEG nanocomposite was prepared by the synthesis of ZnO2 nanoparticles, in-situ assembly of Zr-Ce6 as typical metal-organic framework (MOF) on ZnO2 surface, in-situ reduction of Pt nanozymes, amphiphilic lipids surface coating and then doxorubicin (DOX) loading. DOX/ZnO2@Zr-Ce6/Pt/PEG nanocomposite exhibits average sizes of ∼78 nm and possesses a good loading capacity (48.8 %) for DOX. When DOX/ZnO2@Zr-Ce6/Pt/PEG dispersions are intratumorally injected into mice, the weak acidic TEM induces the decomposition of ZnO2 core to generate endogenously H2O2, then Pt nanozymes catalyze H2O2 to produce O2 for alleviating tumor hypoxia. Upon laser (630 nm) irradiation, the Zr-Ce6 component in DOX/ZnO2@Zr-Ce6/Pt/PEG can produce cytotoxic 1O2, and 1O2 generation rate can be enhanced by 2.94 times due to the cascaded generation of endogenous H2O2/O2. Furthermore, the generated O2 can suppress the expression of hypoxia-inducible factor α, and further enable tumor cells to become more sensitive to chemotherapy, thereby leading to an increased effectiveness of chemotherapy treatment. The photodynamic-chemo combination therapy from DOX/ZnO2@Zr-Ce6/Pt/PEG nanoplatform exhibits remarkable tumor growth inhibition compared to chemotherapy or PDT. Thus, the present study is a good demonstration of a TME-responsive nanoplatform in a multimodal approach for cancer therapy.

Polymerized Network-Based Artificial Peroxisome Reprogramming Macrophages for Photoacoustic Imaging-Guided Treatment of Rheumatoid Arthritis

Artificial peroxisomes (AP) with enzyme-mimetic catalytic activity and recruitment ability have drawn a great deal of attention in fabricating protocell systems for scavenging reactive oxygen species (ROS), modulating the inflammatory microenvironment, and reprogramming macrophages, which is of great potential in treating inflammatory diseases such as rheumatoid arthritis (RA). Herein, a macrophage membrane-cloaked Cu-coordinated polyphthalocyanine-based AP (CuAP) is prepared with a macrocyclic conjugated polymerized network and embedded Cu-single atomic active center, which mimics the catalytic activity and coordination environment of natural superoxide dismutase and catalase, possesses the inflammatory recruitment ability of macrophages, and performs photoacoustic imaging (PAI)-guided treatment. The results of both in vitro cellular and in vivo animal experiments demonstrated that the CuAP under ultrasound and microbubbles could efficiently scavenge excess ROS in cells and tissues, modulate microenvironmental inflammatory cytokines such as interleukin-1β, tumor necrosis factor-α, and arginase-1, and reprogram macrophages by polarization of M1 (proinflammatory phenotype) to M2 (anti-inflammatory phenotype). We believe this study offers a proof of concept for engineering multifaceted AP and a promising approach for a PAI-guided treatment platform for RA.

Transition-Metal-Based Nanozymes: Synthesis, Mechanisms of Therapeutic Action, and Applications in Cancer Treatment

Cancer, as one of the leading causes of death worldwide, drives the advancement of cutting-edge technologies for cancer treatment. Transition-metal-based nanozymes emerge as promising therapeutic nanodrugs that provide a reference for cancer therapy. In this review, we present recent breakthrough nanozymes for cancer treatment. First, we comprehensively outline the preparation strategies involved in creating transition-metal-based nanozymes, including hydrothermal method, solvothermal method, chemical reduction method, biomimetic mineralization method, and sol-gel method. Subsequently, we elucidate the catalytic mechanisms (catalase (CAT)-like activities), peroxidase (POD)-like activities), oxidase (OXD)-like activities) and superoxide dismutase (SOD)-like activities) of transition-metal-based nanozymes along with their activity regulation strategies such as morphology control, size manipulation, modulation, composition adjustment and surface modification under environmental stimulation. Furthermore, we elaborate on the diverse applications of transition-metal-based nanozymes in anticancer therapies encompassing radiotherapy (RT), chemodynamic therapy (CDT), photodynamic therapy (PDT), photothermal therapy (PTT), sonodynamic therapy (SDT), immunotherapy, and synergistic therapy. Finally, the challenges faced by transition-metal-based nanozymes are discussed alongside future research directions. The purpose of this review is to offer scientific guidance that will enhance the clinical applications of nanozymes based on transition metals.

Spiky Artificial Peroxidases with V-O-Fe Pair Sites for Combating Antibiotic-Resistant Pathogens

With the sharp rise of antibiotic-resistant pathogens worldwide, it is of enormous importance to create new strategies for combating pathogenic bacteria. Here, we create an iron oxide-based spiky artificial peroxidase (POD) with V-O-Fe pair sites (V-Fe2 O3 ) for combating methicillin-resistant Staphylococcus aureus (MRSA). The experimental studies and theoretical calculations demonstrate that the V-Fe2 O3 can achieve the localized "capture and killing" bifunction from the spiky morphology and massive reactive oxygen species (ROS) production. The V-Fe2 O3 can reach nearly 100 % bacterial inhibition over a long period by efficiently oxidizing the lipid membrane. Our wound disinfection results identify that the V-Fe2 O3 can not only efficiently eliminate MRSA and their biofilm but also accelerate wound recovery without causing noticeable inflammation and toxicity. This work offers essential insights into the critical roles of V-O-Fe pair sites and localized "capture and killing" in biocatalytic disinfection and provides a promising pathway for the de novo design of efficient artificial peroxidases.

Inorganic nanoparticle agents for enhanced chemodynamic therapy of tumours

With the recent interest in the role of oxidative species/radicals in diseases, inorganic nanomaterials with redox activities have been extensively investigated for their potential use in nanomedicine. While many studies focusing on relieving oxidative stress to prevent pathogenesis and to suppress the progression of diseases have shown considerable success, another approach for increasing oxidative stress using nanomaterials to kill malignant cells has suffered from low efficiency despite its wide applicability to various targets. Chemodynamic therapy (CDT) is an emerging technique that can resolve such a problem by exploiting the characteristic tumour microenvironment to achieve high selectivity. In this review, we summarize the recent strategies and underlying mechanisms that have been used to improve the CDT performance using inorganic nanoparticles. In addition to the design of CDT agents, the effects of contributing factors, such as the acidity and the levels of hydrogen peroxide and antioxidants in the tumour microenvironment, together with their modulation and application in combination therapy, are presented. The challenges lying ahead of future clinical translation of this rapidly advancing technology are also discussed.

Engineering Cell Membrane-Cloaked Catalysts as Multifaceted Artificial Peroxisomes for Biomedical Applications

Artificial peroxisomes (APEXs) or peroxisome mimics have caught a lot of attention in nanomedicine and biomaterial science in the last decade, which have great potential in clinically diagnosing and treating diseases. APEXs are typically constructed from a semipermeable membrane that encloses natural enzymes or enzyme-mimetic catalysts to perform peroxisome-/enzyme-mimetic activities. The recent rapid progress regarding their biocatalytic stability, adjustable activity, and surface functionality has significantly promoted APEXs systems in real-life applications. In addition, developing a facile and versatile system that can simulate multiple biocatalytic tasks is advantageous. Here, the recent advances in engineering cell membrane-cloaked catalysts as multifaceted APEXs for diverse biomedical applications are highlighted and commented. First, various catalysts with single or multiple enzyme activities have been introduced as cores of APEXs. Subsequently, the extraction and function of cell membranes that are used as the shell are summarized. After that, the applications of these APEXs are discussed in detail, such as cancer therapy, antioxidant, anti-inflammation, and neuron protection. Finally, the future perspectives and challenges of APEXs are proposed and outlined. This progress review is anticipated to provide new and unique insights into cell membrane-cloaked catalysts and to offer significant new inspiration for designing future artificial organelles.

Piezoelectric Metal-Organic Frameworks Based Sonosensitizer for Enhanced Nanozyme Catalytic and Sonodynamic Therapies

The regulation of electrostatic electric fields through electrical stimulation is an efficient method to increase the catalytic activity of nanozymes and improve the therapeutic effect of nanozyme catalytic therapy. Piezoelectric materials, which are capable of generating a built-in electric field under ultrasound (US), not only improve the activity of nanozymes but also enable piezoelectric sonodynamic therapy (SDT). In this study, a sonosensitizer based on a Hf-based metal-organic framework (UIO-66) and Au nanoparticles (NPs) was produced. Under US irradiation, UIO-66 can generate a built-in electric field inside the materials, which promotes electron-hole separation and produces reactive oxygen species (ROS). The introduction of Au NPs facilitated the electron transfer, which inhibited the recombination of the electron-hole pairs and improved the piezoelectric properties of UIO-66. The value of the piezoelectric constant (d₃₃) increased from 71 to 122 pmV^-1 after the deposition of Au NPs. In addition, the intrinsic catalase and peroxidase activities of the Au NPs were increased 2-fold after the stimulation from the built-in electric field induced through US exposure. In vivo and in vitro experiments revealed that the proposed sonosensitizer can kill cancer cells and inhibit tumor growth in mice through the enhanced piezoelectric SDT and nanozyme catalytic therapy. The piezoelectric sensitizer proposed in this work proved to be an efficient candidate that can be used for multiple therapeutic modalities in tumor therapy.

Advances in the Application of Nanomaterials to the Treatment of Melanoma

Melanoma can be divided into cutaneous melanoma, uveal melanoma, mucosal melanoma, etc. It is a very aggressive tumor that is prone to metastasis. Patients with metastatic melanoma have a poor prognosis and shorter survival. Although current melanoma treatments have been dramatically improved, there are still many problems such as systemic toxicity and the off-target effects of drugs. The use of nanoparticles may overcome some inadequacies of current melanoma treatments. In this review, we summarize the limitations of current therapies for cutaneous melanoma, uveal melanoma, and mucosal melanoma, as well as the adjunct role of nanoparticles in different treatment modalities. We suggest that nanomaterials may have an effective intervention in melanoma treatment in the future.

Ultrasensitive and preprocessing-free electrochemical biosensing platform for the detection of cancer-derived exosomes based on spiky-shaped aptamer-magnetic beads

Cancer-derived exosomes, as liquid biopsy markers, have been shown to play an important role in the early screening, diagnosis, and prognosis of cancer. However, existing detection methods have shortcomings such as long-time consumption and low sensitivity. Herein, a sandwich-type electrochemical sensing platform based on Prussian blue/graphene oxide (GO/PB) and spiky Au@Fe₃O₄ nanoparticles was successfully designed and constructed to detect tumor-derived exosomes with high sensitivity and no preprocessing. In this strategy, nanospike structures were introduced on magnetic beads to form spiky Au@Fe₃O₄, which was used to enrich exosomes from serum, avoiding the extraction and purification processes of previous detections. The enrichment and signal amplification of spiky Au@Fe₃O₄ could also greatly improve the detection sensitivity of the sensing platform. Consequently, the concentration of exosomes could be directly quantified by monitoring the electroactive molecules of PB. Therefore, the limit of detection (LOD) of the proposed biosensor was 80 particles·μL^-1. Furthermore, this proposed biosensor could realize the high sensitivity analysis of exosomes and effectively save detection time, and provide an effective assistant diagnostic tool for the early diagnosis of cancer.