Ultrasound-Triggered Nitric Oxide Release Platform Based on Energy Transformation for Targeted Inhibition of Pancreatic Tumor

VISTA antibody-loaded Fe3O4@TiO2 nanoparticles for sonodynamic therapy-synergistic immune checkpoint therapy of pancreatic cancer

Breaking the poor permeability of immune checkpoint inhibitors (ICIs) caused by the stromal barrier and reversing the immunosuppressive microenvironment are significant challenges in pancreatic cancer immunotherapy. In this study, we synthesized core-shell Fe3O4@TiO2 nanoparticles to act as carriers for loading VISTA monoclonal antibodies to form Fe3O4@TiO2@VISTAmAb (FTV). The nanoparticles are designed to target the overexpressed ICIs VISTA in pancreatic cancer, aiming to improve magnetic resonance imaging-guided sonodynamic therapy (SDT)-facilitated immunotherapy. Laser confocal microscopy and flow cytometry results demonstrate that FTV nanoparticles are specifically recognized and phagocytosed by Panc-2 cells. In vivo experiments reveal that ultrasound-triggered TiO2 SDT can induce tumor immunogenic cell death (ICD) and recruit T-cell infiltration within the tumor microenvironment by releasing damage-associated molecular patterns (DAMPs). Furthermore, ultrasound loosens the dense fibrous stroma surrounding the pancreatic tumor and increases vascular density, facilitating immune therapeutic efficiency. In summary, our study demonstrates that FTV nanoparticles hold great promise for synergistic SDT and immunotherapy in pancreatic cancer.

A Distinctive Insight into Inorganic Sonosensitizers: Design Principles and Application Domains

Sonodynamic therapy (SDT) as a promising non-invasive anti-tumor means features the preferable penetration depth, which nevertheless, usually can't work without sonosensitizers. Sonosensitizers produce reactive oxygen species (ROS) in the presence of ultrasound to directly kill tumor cells, and concurrently activate anti-tumor immunity especially after integration with tumor microenvironment (TME)-engineered nanobiotechnologies and combined therapy. Current sonosensitizers are classified into organic and inorganic ones, and current most reviews only cover organic sonosensitizers and highlighted their anti-tumor applications. However, there have few specific reviews that focus on inorganic sonosensitizers including their design principles, microenvironment regulation, etc. In this review, inorganic sonosensitizers are first classified according to their design rationales rather than composition, and the action rationales and underlying chemistry features are highlighted. Afterward, what and how TME is regulated based on the inorganic sonosensitizers-based SDT nanoplatform with an emphasis on the TME targets-engineered nanobiotechnologies are elucidated. Additionally, the combined therapy and their applications in non-cancer diseases are also outlined. Finally, the setbacks and challenges, and proposed the potential solutions and future directions is pointed out. This review provides a comprehensive and detailed horizon on inorganic sonosensitizers, and will arouse more attentions on SDT.

Ultrasound-Controlled Prodrug Activation: Emerging Strategies in Polymer Mechanochemistry and Sonodynamic Therapy

Ultrasound has gained prominence in biomedical applications due to its noninvasive nature and ability to penetrate deep tissue with spatial and temporal resolution. The burgeoning field of ultrasound-responsive prodrug systems exploits the mechanical and chemical effects of ultrasonication for the controlled activation of prodrugs. In polymer mechanochemistry, materials scientists exploit the sonomechanical effect of acoustic cavitation to mechanochemically activate force-sensitive prodrugs. On the other hand, researchers in the field of sonodynamic therapy adopt fundamentally distinct methodologies, utilizing the sonochemical effect (e.g., generation of reactive oxygen species) of ultrasound in the presence of sonosensitizers to induce chemical transformations that activate prodrugs. This cross-disciplinary review comprehensively examines these two divergent yet interrelated approaches, both of which originated from acoustic cavitation. It highlights molecular and materials design strategies and potential applications in diverse therapeutic contexts, from chemotherapy to immunotherapy and gene therapy methods, and discusses future directions in this rapidly advancing domain.

Nanotechnology-enabled sonodynamic therapy against malignant tumors

Sonodynamic therapy (SDT) is an emerging approach for malignant tumor treatment, offering high precision, deep tissue penetration, and minimal side effects. The rapid advancements in nanotechnology, particularly in cancer treatment, have enhanced the efficacy and targeting specificity of SDT. Combining sonodynamic therapy with nanotechnology offers a promising direction for future cancer treatments. In this review, we first systematically discussed the anti-tumor mechanism of SDT and then summarized the common nanotechnology-related sonosensitizers and their recent applications. Subsequently, nanotechnology-related therapies derived using the SDT mechanism were elaborated. Finally, the role of nanomaterials in SDT combined therapy was also introduced.

Application and progress of nanozymes in antitumor therapy

Tumors remain one of the major threats to public health and there is an urgent need to design new pharmaceutical agents for their diagnosis and treatment. In recent years, due to the rapid development of nanotechnology, biotechnology, catalytic science, and theoretical computing, subtlety has gradually made great progress in research related to tumor diagnosis and treatment. Compared to conventional drugs, enzymes can improve drug distribution and enhance drug enrichment at the tumor site, thereby reducing drug side effects and enhancing drug efficacy. Nanozymes can also be used as tumor tracking imaging agents to reshape the tumor microenvironment, providing a versatile platform for the diagnosis and treatment of malignancies. In this paper, we review the current status of research on enzymes in oncology and analyze novel oncology therapeutic approaches and related mechanisms. To date, a large number of nanomaterials, such as noble metal nanomaterials, nonmetallic nanomaterials, and carbon-based nanomaterials, have been shown to be able to function like natural enzymes, particularly with significant advantages in tumor therapy. In light of this, the authors in this review have systematically summarized and evaluated the construction, enzymatic activity, and their characteristics of nanozymes with respect to current modalities of tumor treatment. In addition, the application and research progress of different types of nicknames and their features in recent years are summarized in detail. We conclude with a summary and outlook on the study of nanozymes in tumor diagnosis and treatment. It is hoped that this review will inspire researchers in the fields of nanotechnology, chemistry, biology, materials science and theoretical computing, and contribute to the development of nano-enzymology.

Oxygen-producing and pH-responsive targeted DNA nanoflowers for enhanced chemo-sonodynamic therapy of lung cancer

Lung cancer is the deadliest kind of cancer in the world, and the hypoxic tumor microenvironment can significantly lower the sensitivity of chemotherapeutic drugs and limit the efficacy of different therapeutic approaches. In order to overcome these problems, we have designed a drug-loaded targeted DNA nanoflowers encoding AS1411 aptamer and encapsulating chemotherapeutic drug doxorubicin and oxygen-producing drug horseradish peroxidase (DOX/HRP-DFs). These nanoflowers can release drugs in response to acidic tumor microenvironment and alleviate tumor tissue hypoxia, enhancing the therapeutic effects of chemotherapy synergistic with sonodynamic therapy. Owing to the encoded drug-loading sequence, the doxorubicin loading rate of DNA nanoflowers reached 73.24 ± 3.45%, and the drug could be released quickly by disintegrating in an acidic environment. Furthermore, the AS1411 aptamer endowed DNA nanoflowers with exceptional tumor targeting properties, which increased the concentration of chemotherapeutic drug doxorubicin in tumor cells. It is noteworthy that both in vitro and in vivo experiments demonstrated DNA nanoflowers could considerably improve the hypoxia of tumor cells, which enabled the generation of sufficient reactive oxygen species in combination with ultrasound, significantly enhancing the therapeutic effect of sonodynamic therapy and evidently inhibiting tumor growth and metastasis. Overall, this DNA nanoflowers delivery system offers a promising approach for treating lung cancer.

Recent advances on the development of NO-releasing molecules (NORMs) for biomedical applications

Nitric oxide (NO) is an important biological messenger as well as a signaling molecule that participates in a broad range of physiological events and therapeutic applications in biological systems. However, due to its very short half-life in physiological conditions, its therapeutic applications are restricted. Efforts have been made to develop an enormous number of NO-releasing molecules (NORMs) and motifs for NO delivery to the target tissues. These NORMs involve organic nitrate, nitrite, nitro compounds, transition metal nitrosyls, and several nanomaterials. The controlled release of NO from these NORMs to the specific site requires several external stimuli like light, sound, pH, heat, enzyme, etc. Herein, we have provided a comprehensive review of the biochemistry of nitric oxide, recent advancements in NO-releasing materials with the appropriate stimuli of NO release, and their biomedical applications in cancer and other disease control.

Arginine-Nanoenzyme with Timely Angiogenesis for Promoting Diabetic Wound Healing

The successful treatment of diabetic wounds requires strategies that promote anti-inflammation, angiogenesis, and re-epithelialization of the wound. Excessive oxidative stress in diabetic ulcers (DUs) inhibits cell proliferation and hinders timely vascular formation and macrophage polarization from pro-inflammatory M1 to anti-inflammatory M2, resulting in a persistent inflammatory environment and a nonhealing wound. We designed arginine-nanoenzyme (FTA) with mimic-catalase and arginine-loading. 2,3,4-trihydroxy benzaldehyde and arginine (Arg) were connected by a Schiff base bond, and the nanoassembly of Arg to FTA was driven by the coordination force between a ferric ion and polyphenol and noncovalent bond force such as a hydrogen bond. FTA could remove excess reactive oxygen species at the wound site in situ and convert it to oxygen to improve hypoxia. Meanwhile, Arg was released and catalytically metabolized by NO synthase in M1 to promote vascular repair in the early phase. In the late phase, the metabolite of Arg catalyzed by arginase in M2 was mainly ornithine, which played a vital role in promoting tissue repair, which implemented angiogenesis timely and prevented hypertrophic scars. Mechanistically, FTA activated the cAMP signaling pathway combined with reducing inflammation and ameliorating angiogenesis, which resulted in excellent therapeutic effects on a DU mice model.

Silicon-containing nanomedicine and biomaterials: materials chemistry, multi-dimensional design, and biomedical application

The invention of silica-based bioactive glass in the late 1960s has sparked significant interest in exploring a wide range of silicon-containing biomaterials from the macroscale to the nanoscale. Over the past few decades, these biomaterials have been extensively explored for their potential in diverse biomedical applications, considering their remarkable bioactivity, excellent biocompatibility, facile surface functionalization, controllable synthesis, etc. However, to expedite the clinical translation and the unexpected utilization of silicon-composed nanomedicine and biomaterials, it is highly desirable to achieve a thorough comprehension of their characteristics and biological effects from an overall perspective. In this review, we provide a comprehensive discussion on the state-of-the-art progress of silicon-composed biomaterials, including their classification, characteristics, fabrication methods, and versatile biomedical applications. Additionally, we highlight the multi-dimensional design of both pure and hybrid silicon-composed nanomedicine and biomaterials and their intrinsic biological effects and interactions with biological systems. Their extensive biomedical applications span from drug delivery and bioimaging to therapeutic interventions and regenerative medicine, showcasing the significance of their rational design and fabrication to meet specific requirements and optimize their theranostic performance. Additionally, we offer insights into the future prospects and potential challenges regarding silicon-composed nanomedicine and biomaterials. By shedding light on these exciting research advances, we aspire to foster further progress in the biomedical field and drive the development of innovative silicon-composed nanomedicine and biomaterials with transformative applications in biomedicine.

Current trends in gas-synergized phototherapy for improved antitumor theranostics

Phototherapy, such as photothermal therapy (PTT) and photodynamic therapy (PDT), has been considered an elegant solution to eradicate tumors due to its minimal invasiveness and low systemic toxicity. Nevertheless, it is still challenging for phototherapy to achieve ideal outcomes and clinical translation due to its inherent drawbacks. Owing to the unique biological functions, diverse gases have attracted growing attention in combining with phototherapy to achieve super-additive therapeutic effects. Specifically, gases such as nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H2S) have been proven to kill tumor cells by inducing mitochondrial damage in synergy with phototherapy. Additionally, several gases not only enhance the thermal damage in PTT and the reactive oxygen species (ROS) production in PDT but also improve the tumor accumulation of photoactive agents. The inflammatory responses triggered by hyperthermia in PTT are also suppressed by the combination of gases. Herein, we comprehensively review the latest studies on gas-synergized phototherapy for cancer therapy, including (1) synergistic mechanisms of combining gases with phototherapy; (2) design of nanoplatforms for gas-synergized phototherapy; (3) multimodal therapy based on gas-synergized phototherapy; (4) imaging-guided gas-synergized phototherapy. Finally, the current challenges and future opportunities of gas-synergized phototherapy for tumor treatment are discussed. STATEMENT OF SIGNIFICANCE: 1. The novelty and significance of the work with respect to the existing literature. (1) Strategies to design nanoplatforms for gas-synergized anti-tumor phototherapy have been summarized for the first time. Meanwhile, the integration of various imaging technologies and therapy modalities which endow these nanoplatforms with advanced theranostic capabilities has been summarized. (2) The mechanisms by which gases synergize with phototherapy to eradicate tumors are innovatively and comprehensively summarized. 2. The scientific impact and interest. This review elaborates current trends in gas-synergized anti-tumor phototherapy, with special emphases on synergistic anti-tumor mechanisms and rational design of therapeutic nanoplatforms to achieve this synergistic therapy. It aims to provide valuable guidance for researchers in this field.

Near Infrared Light-Activatable Platelet-Mimicking NIR-II NO Nano-Prodrug for Precise Atherosclerosis Theranostics

Atherosclerosis is a chronic inflammatory disease that affects arteries and is the main cause of cardiovascular disease. Atherosclerotic plaque formation is usually asymptomatic and does not manifest until the occurrence of clinical events. Therefore, early diagnosis and treatment of atherosclerotic plaques is particularly important. Here, a series of NIR-II fluorescent dyes (RBT-NH) are developed for three photoresponsive NO prodrugs (RBT-NO), which can be controllably triggered by 808 nm laser to release NO and turn on the NIR-II emission in the clinical medicine "therapeutic window". Notably, RBT3-NO is selected for its exhibited high NO releasing efficiency and superior fluorescence signal enhancement. Subsequently, a platelet-mimicking nano-prodrug system (RBT3-NO-PEG@PM) is constructed by DSPE-mPEG5k and platelet membrane (PM) for effectively targeted diagnosis and therapy of atherosclerosis in mice. The results indicate that this platelet-mimicking NO nano-prodrug system can reduce the accumulation of lipids at the sites of atherosclerotic plaques, improve the inflammatory response at the lesion sites, and promote endothelial cell migration, thereby slowing the progression of plaques.

Mitochondria-specific near-infrared photoactivation of peroxynitrite upconversion luminescent nanogenerator for precision cancer gas therapy

Gas therapy is emerging as a highly promising therapeutic strategy for cancer treatment. However, there are limitations, including the lack of targeted subcellular organelle accuracy and spatiotemporal release precision, associated with gas therapy. In this study, we developed a series of photoactivatable nitric oxide (NO) donors NRh-R-NO (R = Me, Et, Bn, iPr, and Ph) based on an N-nitrosated upconversion luminescent rhodamine scaffold. Under the irradiation of 808 nm light, only NRh-Ph-NO could effectively release NO and NRh-Ph with a significant turn-on frequency upconversion luminescence (FUCL) signal at 740 nm, ascribed to lower N-N bond dissociation energy. We also investigated the involved multistage near-infrared-controlled cascade release of gas therapy, including the NO released from NRh-Ph-NO along with one NRh-Ph molecule generation, the superoxide anion O2⋅- produced by the photodynamic therapy (PDT) effect of NRh-Ph, and highly toxic peroxynitrite anion (ONOO‒) generated from the co-existence of NO and O2⋅-. After mild nano-modification, the nanogenerator (NRh-Ph-NO NPs) empowered with superior biocompatibility could target mitochondria. Under an 808 nm laser irradiation, NRh-Ph-NO NPs could induce NO/ROS to generate RNS, causing a decrease in the mitochondrial membrane potential and initiating apoptosis by caspase-3 activation, which further induced tumor immunogenic cell death (ICD). In vivo therapeutic results of NRh-Ph-NO NPs showed augmented RNS-potentiated gas therapy, demonstrating excellent biocompatibility and effective tumor inhibition guided by real-time FUCL imaging. Collectively, this versatile strategy defines the targeted RNS-mediated cancer therapy.

Innovative Experimental Ultrasound and US-Related Techniques Using the Murine Model in Pancreatic Ductal Adenocarcinoma: A Systematic Review

Pancreatic ductal adenocarcinoma (PDAC) is a cancer with one of the highest mortality rates in the world. Several studies have been conductedusing preclinical experiments in mice to find new therapeutic strategies. Experimental ultrasound, in expert hands, is a safe, multifaceted, and relatively not-expensive device that helps researchers in several ways. In this systematic review, we propose a summary of the applications of ultrasonography in a preclinical mouse model of PDAC. Eighty-eight studies met our inclusion criteria. The included studies could be divided into seven main topics: ultrasound in pancreatic cancer diagnosis and progression (n: 21); dynamic contrast-enhanced ultrasound (DCE-US) (n: 5); microbubble ultra-sound-mediated drug delivery; focused ultrasound (n: 23); sonodynamic therapy (SDT) (n: 7); harmonic motion elastography (HME) and shear wave elastography (SWE) (n: 6); ultrasound-guided procedures (n: 9). In six cases, the articles fit into two or more sections. In conclusion, ultrasound can be a really useful, eclectic, and ductile tool in different diagnostic areas, not only regarding diagnosis but also in therapy, pharmacological and interventional treatment, and follow-up. All these multiple possibilities of use certainly represent a good starting point for the effective and wide use of murine ultrasonography in the study and comprehensive evaluation of pancreatic cancer.

"Ice and Fire" Supramolecular Cell-Conjugation Drug Delivery Platform for Deep Tumor Ablation and Boosted Antitumor Immunity

Cancer recurrence and metastasis are two major challenges in the current clinical therapy. In this work, a novel diketopyrrolopyrrole-based photothermal reagent (DCN) with unique J-aggregation-induced redshift is synthesized to achieve efficient tumor thermal ablation under safe power (0.33 W cm-2 ). Meanwhile, S-nitroso-N-acetylpenicillamine (SNAP) is co-loaded with near-infrared-absorbing DCN in amphiphilic polymers to realize heat-induced massive release of nitric oxide (NO), which can form oxidant peroxynitrite (ONOO- ) to active matrix metalloproteinases (MMPs), thereby degrading the compact tumor extracellular matrix to improve the ablation depth and infiltration of immune cells. Through a facile supramolecular assembly method, the DCN/SNAP nanoparticles are anchored to liquid-nitrogen-frozen cancer cells, achieving enhanced antitumor immune responses and effective inhibition of distant tumors and pulmonary metastases after only one treatment. The safety and effectiveness of this supramolecular cell-conjugation platform are verified by 2D/3D cellular experiments and bilateral tumor model, confirming the thermal-ablation-gas-permeation-antigen-presentation therapeutic mode has promising anticancer prospects.

Nanoreactor-based catalytic systems for therapeutic applications: Principles, strategies, and challenges

Inspired by natural catalytic compartments, various synthetic compartments that seclude catalytic reactions have been developed to understand complex multistep biosynthetic pathways, bestow therapeutic effects, or extend biosynthetic pathways in living cells. These emerging nanoreactors possessed many advantages over conventional biomedicine, such as good catalytic activity, specificity, and sustainability. In the past decade, a great number of efficient catalytic systems based on diverse nanoreactors (polymer vesicles, liposome, polymer micelles, inorganic-organic hybrid materials, MOFs, etc.) have been designed and employed to initiate in situ catalyzed chemical reactions for therapy. This review aims to present the recent progress in the development of catalytic systems based on nanoreactors for therapeutic applications, with a special emphasis on the principles and design strategies. Besides, the key components of nanoreactor-based catalytic systems, including nanocarriers, triggers or energy inputs, and products, are respectively introduced and discussed in detail. Challenges and prospects in the fabrication of therapeutic catalytic nanoreactors are also discussed as a conclusion to this review. We believe that catalytic nanoreactors will play an increasingly important role in modern biomedicine, with improved therapeutic performance and minimal side effects.

Simultaneous Light-Triggered Release of Nitric Oxide and Carbon Monoxide from a Lipid-Coated Upconversion Nanosystem Inhibits Colon Tumor Growth

Gas therapy has gained noteworthy attention in biomedical research, with the rise of gas-releasing molecules enhancing their therapeutic potential, especially when integrated into nano-based drug delivery systems. Herein, we present a lipid-coated gas delivery system to simultaneously shuttle two gas-releasing molecules carrying nitric oxide (NO) and carbon monoxide (CO), respectively. Upconversion nanoparticles (UCNPs) are designed to generate photons at 360 nm upon 808 nm of near-infrared (NIR) irradiation. These in situ-generated UV photons trigger simultaneous NO and CO release from S-nitrosoglutathione (GSNO) and the CO-releasing molecule (CORM), respectively, which are coloaded into lipid-coated UCNP/GSNO/CORM/FA nanoparticles (LUGCF). LUGCF with a GSNO/CORM mass ratio of 2:1 is determined to be optimal in terms of synergistically instigating apoptosis in HCT116 and CT26 colon cancer cells, where both NO/CO are released and subsequent production of ROS are detected. This CO/NO combination nanoplatform exhibits a very effective inhibition of colon tumor growth in vivo at relatively low doses upon a mild 808 nm irradiation. Overall, we effectively integrated two therapeutic gas-releasing molecules in one NIR-responsive nanosystem, presenting a promising therapeutic strategy for future biomedical applications in dual-gas cancer therapy.

Exploring the redox potential induced by low-intensity focused ultrasound on tumor masses

Cancer is still a major health problem worldwide despite huge efforts being spent on its biomedical research. Beyond the mainstream therapeutic interventions (i.e., surgery, chemotherapy, immunotherapy and radiotherapy), further significant progresses in anticancer therapy could rely on the development of novel treatment paradigms. To this end, one emerging approach consists in the use of non-thermal low-intensity focused ultrasound (LIFU) for conditioning cancer molecules and/or cancer-targeted compounds, thereby leading to cancer cell death with least side-effects. Cellular redox homeostasis manifested as the generation of reactive oxygen species (ROS) during energy metabolism as well as the antioxidant capacity is interwoven to the composition, size and anatomical location of the tumor masses. The higher content of "oxide free radicals" in cancers makes them vulnerable to disruption of redox homeostasis than in the healthy cells and therefore, one of the best options for preferentially eradicating them is increasing their oxidative stress, excessively. A little is known about the modulation of cellular redox homeostasis by LIFU, and so it will be of great interest and utility to understand the effects of LIFU on the energy metabolism of cancer cells. This review is intended to improve our knowledge on the effect of LIFU on cancer cells with particular reference to its redox metabolism for ultrasound-based therapies. Thereby, it could pave the way for exploring novel methodologies and designing combined anti-cancer therapies, especially, for faster and safer eradication of drug resistant and metastasizing solid tumors.

Amplification of oxidative damage using near-infrared II-mediated photothermal/thermocatalytic effects for periodontitis treatment

Periodontitis is a biofilm-related disease characterized by damage to the periodontal tissue and the development of systemic diseases. However, treatment of periodontitis remains unsatisfactory, especially with deep-tissue infections. This study describes rationally designed multifunctional photothermocatalytic agents for near-infrared-II light-mediated synergistic antibiofilm treatment, through modification of Lu-Bi2Te3 with Fe3O4 and poly(ethylene glycol)-b-poly(l-arginine) (PEG-b-PArg). Notably, 1064-nm laser irradiation led to photothermal/thermocatalytic effects, resulting in the synergistic generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) and consequent damage to the biofilm. This treatment was based on the thermoelectric and photothermal conversion properties of Lu-Bi2Te3, the peroxidase-like catalytic capacity of Fe3O4, and the guanidinium polymer, PEG-b-PArg. Oxidative damage to biofilm was further enhanced by H2O2, resulting in the effective elimination of biofilm both in vitro and in vivo. These findings suggest that this synergistic therapeutic strategy is effective for the clinical treatment of periodontitis. STATEMENT OF SIGNIFICANCE: The current treatment for periodontitis involves time-consuming and labor-intensive clinical scaling of the teeth. The present study is the first to assess the efficacy of a photothermal catalyst for periodontitis treatment. This used near-infrared-II light at 1064 nm to induce oxidative damage in the biofilm, resulting in its degradation. The synergistic photothermal/thermoelectric effect produced deep tissue penetration and was well tolerated, and can kill the biofilm formed by periodontitis pathogens up to 5 orders of magnitude, effectively treating the biofilm-induced periodontitis.

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.

Current status of porous coordination networks (PCNs) derived porphyrin spacers for cancer therapy

INTRODUCTION

Porous coordination networks (PCNs) have been widely used in large number of applications such as light harvesting, catalysis, and biomedical applications. Inserting porphyrins into PCNs scaffolds can alleviate the solubility and chemical stability problems associated with porphyrin ligands and add functionality to PCNs. The discovery that some PCNs materials have photosensitizer and acoustic sensitizer properties has attracted significant attention in the field of biomedicine, particularly in cancer therapy. This article describes the latest applications of the porphyrin ligand-based family of PCNs in cancer chemodynamic therapy (CDT), photodynamic therapy (PDT), sonodynamic therapy (SDT), photothermal therapy (PTT), and combination therapies and offers some observations and reflections on them.

AREAS COVERED

This article discusses the use of the PCN family of MOFs in cancer treatment, specifically focusing on chemodynamic therapy, sonodynamic therapy, photodynamic therapy, photothermal therapy, and combination therapy.

EXPERT OPINION

Although a large number of PCNs have been developed for use in novel cancer therapeutic approaches, further improvements are needed to advance the use of PCNs in the clinic. For example, the main mechanism of action of PCNs against cancer and the metabolic processes in organisms, and how to construct PCNs that maintain good stability in the complex environment of organisms.

l-Arginine-Modified CoWO4 /FeWO4 S-Scheme Heterojunction Enhances Ferroptosis against Solid Tumor

Ferroptosis has recently attracted much attention as an anti-tumor therapy. Evidence suggests that ferroptosis can induce oxidative stress and accumulation of lethal lipid peroxides in cancer cells, leading to cell damage. However, unsuitable pH, H2 O2 levels, and high glutathione (GSH) expression in the tumor microenvironment hinder the development of ferroptosis-mediated therapy. In this study, an l-arginine (l-arg)-modified CoWO4 /FeWO4 (CFW) S-scheme heterojunction is strategically designed and constructed for ultrasound (US)-triggered sonodynamic- and gas therapy-induced ferroptosis. CFW not only has excellent Fenton-catalytic activity, outstanding GSH consumption capacity, and excellent ability to overcome tumor hypoxia, but its S-scheme heterostructure can also avoid the rapid combination of electron (e) and hole (h+ ) pairs, thereby enhancing the sonodynamic effects. As a precursor of nitric oxide (NO), l-arg is modified on the surface of CFW (CFW@l-arg) to achieve controlled NO release under US irradiation, thereby enhancing ferroptosis. In addition, poly(allylamine hydrochloride) is further modified on the surface of CFW@l-arg to stabilize l-arg and achieve controllable NO release. Both in vitro and in vivo results demonstrate that such a multifunctional therapeutic nanoplatform can achieve high therapeutic efficacy through sonodynamic and gas therapy-enhanced ferroptosis. This designed oncotherapy nanoplatform provides new inspiration for ferroptosis-mediated therapy.

X-ray-responsive prodrugs and polymeric nanocarriers for multimodal cancer therapy

Radiotherapy as one of the most important cancer treatment modalities has been widely used in the therapy of various cancers. The clinically used radiation (e.g. X-ray) for radiotherapy has the advantages of precise spatiotemporal controllability and deep tissue penetration. However, traditional radiotherapy is frequently limited by the high side effects and tumor hypoxia. The combination of radiotherapy and other cancer treatment modalities may overcome the disadvantages of radiotherapy and improve the final therapeutic efficacy. In recent years, X-ray-activable prodrugs and polymeric nanocarriers have been extensively explored to introduce other treatment modalities in the precise position during radiotherapy, which can reduce the side toxicity of the drugs and improve the combination therapeutic efficacy. In this review, we focus on recent advances in X-ray-activable prodrugs and polymeric nanocarriers to boost X-ray-based multimodal synergistic therapy with reduced toxicity. The design strategies of prodrugs and polymeric nanocarriers are highlighted. Finally, challenges and outlooks of X-ray-activable prodrugs and polymeric nanocarriers are discussed.

Research development of porphyrin-based metal-organic frameworks: targeting modalities and cancer therapeutic applications

Porphyrins are naturally occurring organic molecules that have attracted widespread attention for their potential in the field of biomedical research. Porphyrin-based metal-organic frameworks (MOFs) that utilize porphyrin molecules as organic ligands have gained attention from researchers due to their excellent results as photosensitizers in tumor photodynamic therapy (PDT). Additionally, MOFs hold significant promise and potential for other tumor therapeutic approaches due to their tunable size and pore size, excellent porosity, and ultra-high specific surface area. Active delivery of nanomaterials via targeted molecules for tumor therapy has demonstrated greater accumulation, lower drug doses, higher therapeutic efficacy, and reduced side effects relative to passive targeting through the enhanced permeation and retention effect (EPR). This paper presents a comprehensive review of the targeting methods employed by porphyrin-based MOFs in tumor targeting therapy over the past few years. It further discusses the applications of porphyrin-based MOFs for targeted cancer therapy through various therapeutic methods. The objective of this paper is to provide a valuable reference and source of ideas for targeted therapy using porphyrin-based MOF materials and to inspire further exploration of their potential in the field of cancer therapy.

Multimodal Biofilm Inactivation Using a Photocatalytic Bismuth Perovskite-TiO2-Ru(II)polypyridyl-Based Multisite Heterojunction

Infectious bacterial biofilms are recalcitrant to most antibiotics compared to their planktonic version, and the lack of appropriate therapeutic strategies for mitigating them poses a serious threat to clinical treatment. A ternary heterojunction material derived from a Bi-based perovskite-TiO₂ hybrid and a [Ru(2,2'-bpy)₂(4,4'-dicarboxy-2,2'-bpy)]²⁺ (2,2'-bpy, 2,2'-bipyridyl) as a photosensitizer (RuPS) is developed. This hybrid material is found to be capable of generating reactive oxygen species (ROS)/reactive nitrogen species (RNS) upon solar light irradiation. The aligned band edges and effective exciton dynamics between multisite heterojunctions are established by steady-state/time-resolved optical and other spectroscopic studies. Proposed mechanistic pathways for the photocatalytic generation of ROS/RNS are rationalized based on a cascade-redox processes arising from three catalytic centers. These ROS/RNS are utilized to demonstrate a proof-of-concept in treating two elusive bacterial biofilms while maintaining a high level of biocompatibility (IC₅₀ > 1 mg/mL). The in situ generation of radical species (ROS/RNS) upon photoirradiation is established with EPR spectroscopic measurements and colorimetric assays. Experimental results showed improved efficacy toward biofilm inactivation of the ternary heterojunction material as compared to their individual/binary counterparts under solar light irradiation. The multisite heterojunction formation helped with better exciton delocalization for an efficient catalytic biofilm inactivation. This was rationalized based on the favorable exciton dissociation followed by the onset of multiple oxidation and reduction sites in the ternary heterojunction. This together with exceptional photoelectric features of lead-free halide perovskites outlines a proof-of-principle demonstration in biomedical optoelectronics addressing multimodal antibiofilm/antimicrobial modality.

Advanced Nitric Oxide Generating Nanomedicine for Therapeutic Applications

Nitric oxide (NO), a gaseous transmitter extensively present in the human body, regulates vascular relaxation, immune response, inflammation, neurotransmission, and other crucial functions. Nitrite donors have been used clinically to treat angina, heart failure, pulmonary hypertension, and erectile dysfunction. Based on NO's vast biological functions, it further can treat tumors, bacteria/biofilms and other infections, wound healing, eye diseases, and osteoporosis. However, delivering NO is challenging due to uncontrolled blood circulation release and a half-life of under five seconds. With advanced biotechnology and the development of nanomedicine, NO donors packaged with multifunctional nanocarriers by physically embedding or chemically conjugating have been reported to show improved therapeutic efficacy and reduced side effects. Herein, we review and discuss recent applications of NO nanomedicines, their therapeutic mechanisms, and the challenges of NO nanomedicines for future scientific studies and clinical applications. As NO enables the inhibition of the replication of DNA and RNA in infectious microbes, including COVID-19 coronaviruses and malaria parasites, we highlight the potential of NO nanomedicines for antipandemic efforts. This review aims to provide deep insights and practical hints into design strategies and applications of NO nanomedicines.

Synergistic antibacterial effect of multifunctional TiO2-X-based nanoplatform loading arginine and polydopamine for promoting infected wounds healing

The gas therapy of some endogenous signaling molecules to treat diseases has caused extensive research, among which NO gas has shown great potential in fighting infection with various pathogens, promoting wound healing, etc. Here, we propose a photothermal/photodynamic/NO synergistic antibacterial nanoplatform by loading L-arginine (LA) on mesoporous TiO₂ and then encapsulating it with polydopamine. The obtained TiO_2-x-LA@PDA nanocomposite possesses both the excellent photothermal effect and ROS generation ability of mesoporous TiO₂, and the release of nitric oxide (NO) from L-arginine under near-infrared (NIR) light irradiation, while the sealing layer of PDA could induce NIR-triggered NO controlled release. In vitro antibacterial experiments confirmed that the synergistic effect of TiO_2-x-LA@PDA nanocomposites has excellent antibacterial effects against Gram-negative and Gram-positive bacteria, while in vivo experiments showed that it has lower toxicity. It is worth noting that compared with the pure photothermal effect and ROS, the generated NO showed a better bactericidal effect, and NO had a better ability to promote wound healing. In conclusion, the developed TiO_2-x-LA@PDA nanoplatform can be used as a nanoantibacterial agent, which can be further explored in the related biomedical field of photothermal activation of multimodal combined antibacterial therapy.

Recent Advances in Functional Nanomaterials for Catalytic Generation of Nitric Oxide: A Mini Review

As a gaseous second messenger, nitric oxide (NO) plays an important role in a series of signal pathways. Research on the NO regulation for various disease treatments has aroused wide concern. However, the lack of accurate, controllable, and persistent release of NO has significantly limited the application of NO therapy. Profiting from the booming development of advanced nanotechnology, a mass of nanomaterials with the properties of controllable release have been developed to seek new and effective NO nano-delivery approaches. Nano-delivery systems that generate NO through catalytic reactions exhibit unique superiority in terms of precise and persistent release of NO. Although certain achievements have been made in the catalytically active NO delivery nanomaterials, some basic but critical issues, such as the concept of design, are of low attention. Herein, an overview of the generation of NO through catalytic reactions and the design principles of related nanomaterials are summarized. Then, the nanomaterials that generate NO through catalytic reactions are classified. Finally, the bottlenecks and perspectives are also discussed in depth for the future development of catalytical NO generation nanomaterials.

Chiral Ruthenium Nanozymes with Self-Cascade Reaction Driven the NO Generation Induced Macrophage M1 Polarization Realizing the Lung Cancer "Cocktail Therapy"

Macrophages as the main cause of cancer immunosuppression, how to effectively induce macrophage M1 polarization remain the major challenge in lung cancer therapy. Herein, inspired by endogenous reactions, a strategy is proposed to coactivate macrophage M1 polarization by reactive oxygen species (ROS) and nitric oxide (NO) with self-autocatalytic cascade reaction. To enhance the generation of NO and ROS, NO Precursor-Arginine as capping agents for inducing synthesis two kinds of chiral ruthenium nanozyme (D/L-Arginine@Ru). Under the properties of Ru nanozymes through synchronously mimicking the activity of oxidase and nitric oxide synthase (NOS), chiral Ru nanozyme can rapidly generate ¹ O₂ and O₂ at first stage, and then catalyze Arginine to produce sufficient NO, thus enhance macrophage M1 polarization to reverse tumor immunosuppression. Moreover, combination the antitumor activity of ¹ O₂ , NO, the chiral Ru nanozymes realize the "cocktail therapy" by inducing tumor cell apoptosis as well as ferroptosis. In addition, the chirality influences the bioactivity of Ru nanozymes that L-Arginine@Ru shows the better therapeutic effect with stronger catalytic activity and natural homology. It is hoped the high performance of chiral Ru nanozyme with "cocktail therapy" is an effective therapeutic reagent and can provide a feasible treatment strategy for tumor catalytic therapy.

Recent advances in sonodynamic immunotherapy

Tumor immunotherapy has become an important means of tumor therapy by enhancing the immune response and triggering the activation of immune cells. However, currently, only a small number of patients respond to immunotherapy alone, and patients may experience immune-related adverse events (irAEs) during the course of treatment. Sonodynamic therapy (SDT) can produce cytotoxic substances to tumor tissue, induce apoptosis and enhance immunity. SDT combined with immunotherapy is considered a promising strategy for cancer treatment. In this mini review, we summarize the role of SDT in immunotherapy in recent years, including the application of SDT-triggered immunotherapy and the combination of SDT and immunotherapy.

Recent applications of phase-change materials in tumor therapy and theranostics

Phase-change materials (PCMs) are a type of special material which can store and release a large amount of thermal energy without any significant temperature change. They are emerging in recent years as a promising functional material in tumor therapy and theranostics due to their accurate responses to the temperature variations, biocompatibility and low toxicity. In this review, we will introduce the main types of PCMs and their desirable physiochemical properties for biomedical applications, and highlight the recent progress of PCM's applications in the modulated release of antitumor drugs, with special attentions paid to various ways to initiate temperature-dependent phase change, the concomitant thermal therapy and its combination with or activation of other therapies, particularly unconventional therapies. We will also summarize PCM's recent applications in tumor theranostics, where both drugs and imaging probes are delivered by PCMs for controlled drug release and imaging-guided therapy. Finally, the future perspectives and potential limitations of harnessing PCMs in tumor therapy will be discussed.

Ultrasound-Induced Piezocatalysis Triggered NO Generation for Enhanced Hypoxic Tumor Therapy

Conventional NO gas generation based on l-arginine (l-Arg) is usually dependent on H₂O₂ and O₂, both of which are very limited within the tumor microenvironment, thus greatly limiting l-Arg's therapeutic effect. Herein, a novel nanoplatform for efficiently triggering NO production based on ultrasound-induced piezocatalysis was developed, which was fabricated by coating amphiphilic poly-l-arginine (DSPE-PEG₂₀₀₀-Arg, DPA) on the piezoelectric material of barium titanate (BTO). The resulting BTO@DPA nanoparticles can efficiently generate H₂O₂, ¹O₂, and O₂ via ultrasound-induced piezocatalysis based on BTO and oxidize the surface arginine to produce NO, which can even further interact with the reactive oxygen species (ROS) to produce more reactive peroxynitrite, thus inducing serious tumor cell apoptosis both in hypoxia and normoxia. After intravenous injection, BTO@DPA accumulated well at the tumor tissue at 4 h postinjection; later, ultrasound irradiation on the tumor not only achieved the best tumor inhibition rate of ∼70% but also completely inhibited tumor metastasis to the lungs via the alleviation of tumor hypoxia. Such a strategy was not dependent on the tumor microenvironment and can be well controlled by ultrasound irradiation, providing a simple and efficient therapy paradigm for hypoxic tumor.

A multifunctional nanocomposite coated with a BSA membrane for cascaded nitric oxide therapy

Gas therapy based on nitric oxide (NO) has emerged as a potential therapeutic approach for cancer, and in conjunction with multi-mode combination therapy, offers new possibilities for achieving significant hyperadditive effects. In this study, an integrated AI-MPDA@BSA nanocomposite for diagnosis and treatment was constructed for PDA based photoacoustic imaging (PAI) and cascade NO release. Natural NO donor L-arginine (L-Arg) and photosensitizer (PS) IR780 were loaded into mesoporous polydopamine (MPDA). Bovine serum albumin (BSA) was conjugated to the MPDA to increase the dispersibility and biocompatibility of the nanoparticles, as well as to serve as a gatekeeper controlling IR780 release from the MPDA pores. The AI-MPDA@BSA produced singlet oxygen (¹O₂) and converted it into NO through a chain reaction based on L-Arg, enabling a combination of photodynamic therapy and gas therapy. Moreover, due to the photothermal properties of MPDA, the AI-MPDA@BSA performed good photothermal conversion, which allowed photoacoustic imaging. As expected, both in vitro and in vivo studies have confirmed that the AI-MPDA@BSA nanoplatform has a significant inhibitory effect on cancer cells and tumors, and no apparent systemic toxicity or side effects were detected during the treatment period.

Rational Design of Biomaterials to Potentiate Cancer Thermal Therapy

Cancer thermal therapy, also known as hyperthermia therapy, has long been exploited to eradicate mass lesions that are now defined as cancer. With the development of corresponding technologies and equipment, local hyperthermia therapies such as radiofrequency ablation, microwave ablation, and high-intensity focused ultrasound, have has been validated to effectively ablate tumors in modern clinical practice. However, they still face many shortcomings, including nonspecific damages to adjacent normal tissues and incomplete ablation particularly for large tumors, restricting their wide clinical usage. Attributed to their versatile physiochemical properties, biomaterials have been specially designed to potentiate local hyperthermia treatments according to their unique working principles. Meanwhile, biomaterial-based delivery systems are able to bridge hyperthermia therapies with other types of treatment strategies such as chemotherapy, radiotherapy and immunotherapy. Therefore, in this review, we discuss recent progress in the development of functional biomaterials to reinforce local hyperthermia by functioning as thermal sensitizers to endow more efficient tumor-localized thermal ablation and/or as delivery vehicles to synergize with other therapeutic modalities for combined cancer treatments. Thereafter, we provide a critical perspective on the further development of biomaterial-assisted local hyperthermia toward clinical applications.

Inflammatory Cell-Inspired Cascade Nanozyme Induces Intracellular Radical Storm for Enhanced Anticancer Therapy

Manipulating intracellular levels of reactive oxygen and nitrogen species (RONS) is of great potential for cancer treatment. Inspired by the natural mechanism of a radical storm in inflammatory cells via activated and regulatable biocatalysis, the authors herein report a self-powered nanozyme that can enable RONS production in tumor cells via cascade reactions. The nanozymes are constructed via glucose oxidase (GOx)-templated inverse microemulsion polymerization from acrylamide, arginine-acrylamide, ferrocene-acrylate, and N,N'-bis(acryloyl)cystamine, followed by surface coating with hyaluronic acid. After targeted delivery into cancer cells, the nanozymes are dissociated by intracellular glutathione to release GOx, which decomposed glucose to generate gluconic acid and H₂ O₂ . Under such acidified conditions, H₂ O₂ efficiently oxidized pendant arginine residues to produce nitric oxide , transformed into a highly toxic hydroxyl radical and superoxide anion via ferrocene-mediated Fenton reaction and Haber-Weiss cycle, and simultaneously generated peroxynitrite anion via reaction between NO and ·O₂ ^- , thus provoking the RONS radical storm to effectively eradicate A549 tumor cells both in vitro and in vivo. This nature-inspired enzyme-chemical dynamic therapy may provide a promising modality for anti-cancer treatment.

Achieving Fast Charge Separation by Ferroelectric Ultrasonic Interfacial Engineering for Rapid Sonotherapy of Bacteria-Infected Osteomyelitis

Bacteria-infected osteomyelitis is life-threatening without effective therapeutic methods clinically. Here, a rapid and effective therapeutic strategy to treat osteomyelitis through ferroelectric polarization interfacial engineering of BiFeO₃ /MXene (Ti₃ C₂ ) triggered by ultrasound (US) is reported. Under US, the ferroelectric polarization induces the formation of the piezoelectric field. US cavitation effect induced sonoluminescence stimulates BiFeO₃ /Ti₃ C₂ to produce photogenerated carriers. With synergistic action of the polarization electric field and Schottky junction, BiFeO₃ /Ti₃ C₂ accelerates the separation of electrons and holes and simultaneously inhibits the backflow of electrons, thus improving the utilization of polarized charges and photogenerated charges and consequently enhancing the yield of reactive oxygen species under US. As a result, 99.87 ± 0.05% of Staphylococcus aureus are efficiently killed in 20 min with the assistance of ultrasonic heating. The theory of ferroelectric ultrasonic interfacial engineering is proposed, which brings new insight for developing ferroelectric ultrasonic responsive materials used for the diagnosis and therapy of deep tissue infection and other acoustoelectric devices.

Ultrasound-Triggered Piezocatalysis for Selectively Controlled NO Gas and Chemodrug Release to Enhance Drug Penetration in Pancreatic Cancer

Nitric oxide (NO) is drawing widespread attention in treating pancreatic ductal adenocarcinoma (PDAC) as a safe and therapeutically efficient technique through modulating the dense fibrotic stroma in the tumor microenvironment to enhance drug penetration. Considerable NO nanogenerators and NO releasing molecules have been developed to shield the systemic toxicity caused by free diffusion of NO gas. However, on-demand controlled release of NO and chemotherapy drugs at tumor sites remains a problem limited by the complex and dynamic tumor microenvironment. Herein, we present an ultrasound-responsive nanoprodrug of CPT-t-R-PEG₂₀₀₀@BaTiO₃ (CRB) which encapsulates piezoelectric nanomaterials barium titanate nanoparticle (BaTiO₃) with amphiphilic prodrug molecules that consisted of thioketal bond (t) linked chemotherapy drug camptothecin (CPT) and NO-donor l-arginine (R). Based on ultrasound-triggered piezocatalysis, BaTiO₃ can continuously generate ROS in the hypoxic tumor environment, which induces a cascade of reaction processes to break the thioketal bond to release CPT and oxidize R to release NO, simultaneously delivering CPT and NO to the tumor site. It is revealed that CRB shows a uniform size distribution, prolonged blood circulation time, and excellent tumor targeting ability. Moreover, controlled release of CPT and NO were observed both in vitro and in vivo under the stimulation of ultrasound, which is beneficial to the depletion of dense stroma and subsequently enhanced delivery and efficacy of CPT. Taken together, CRB significantly increased the antitumor efficacy against highly malignant Panc02 tumors in mice through inhibiting chemoresistance, representing a feasible approach for targeted therapies against Panc02 and other PDAC.

Photodynamic therapy: Innovative approaches for antibacterial and anticancer treatments

Photodynamic therapy is an alternative treatment mainly for cancer but also for bacterial infections. This treatment dates back to 1900 when a German medical school graduate Oscar Raab found a photodynamic effect while doing research for his doctoral dissertation with Professor Hermann von Tappeiner. Unexpectedly, Raab revealed that the toxicity of acridine on paramecium depends on the intensity of light in his laboratory. Photodynamic therapy is therefore based on the administration of a photosensitizer with subsequent light irradiation within the absorption maxima of this substance followed by reactive oxygen species formation and finally cell death. Although this treatment is not a novelty, there is an endeavor for various modifications to the therapy. For example, selectivity and efficiency of the photosensitizer, as well as irradiation with various types of light sources are still being modified to improve final results of the photodynamic therapy. The main aim of this review is to summarize anticancer and antibacterial modifications, namely various compounds, approaches, and techniques, to enhance the effectiveness of photodynamic therapy.

Active therapy based on the byproducts of micro/nanomotors

Different from traditional colloidal particles based on Brownian motion, micro/nanomotors are micro/nanoscale devices capable of performing complex tasks in liquid media via transforming various energy sources into mechanical motion or actuation. Such unique self-propulsion endows motors with fantastic capabilities to access and enter the deep layer of targeted diseased tissue, which in turn breaks through the limitation of the poor permeability of traditional pharmaceutical preparations, thus providing giant prospects for active therapy. It is noteworthy that recently several studies, which utilized the byproducts generated in situ by micro/nanomotors to achieve active therapy, in a truly green zero-waste manner, have been carried out. In this minireview, we highlight the recent efforts with respect to active therapy based on the byproducts of micro/nanomotors, expecting to motivate readers to expand the practical biomedical application scope of micro/nanomotors in a broader horizon. Accompanied by ever booming enthusiasm and persevering exploration, micro/nanomotors are on their way to revolutionize conventional fields.

Superiorly Stable Three-Layer Air Microbubbles Generated by Versatile Ethanol-Water Exchange for Contrast-Enhanced Ultrasound Theranostics

Microbubbles have been widely used as ultrasound contrast agents in clinical diagnosis. Moreover, most current preparation methods for microbubbles are uncontrollable, and the as-obtained microbubbles are unstable in aqueous solution or under ultrasound. Here, we report a strategy to prepare superiorly stable microbubbles with three-layer structures by the ethanol-water exchange. This versatile method can also be applied to prepare different kinds of protein microbubbles with various sizes for advanced biomedical applications. To demonstrate this, the protein air microbubbles are created, which is stable in water for several days with intact structures and exhibits excellent contrast-enhanced ultrasound imaging. Moreover, the protein air microbubbles can also deliver a mass of drugs while maintaining their stable structures, making them a platform for ultrasound imaging-guided drug delivery. The versatile protein air microbubbles have great potential for the design and application of theranostic platforms.

Recent progress in nitric oxide-generating nanomedicine for cancer therapy

Nitric oxide (NO) is an endogenous, multipotent biological signaling molecule that participates in several physiological processes. Recently, exogenous supplementation of tumor tissues with NO has emerged as a potential anticancer therapy. In particular, it induces synergistic effects with other conventional therapies (such as chemo-, radio-, and photodynamic therapies) by regulating the activity of P-glycoprotein, acting as a vascular relaxant to relieve tumor hypoxia, and participating in the metabolism of reactive oxygen species. However, NO is highly reactive, and its half-life is relatively short after generation. Meanwhile, NO-induced anticancer activity is dose-dependent. Therefore, the targeted delivery of NO to the tumor is required for better therapeutic effects. In the past decade, NO-generating nanomedicines (NONs), which enable sustained and specific NO release in tumor tissues, have been developed for enhanced cancer therapy. This review describes the recent efforts and preclinical achievements in the development of NON-based cancer therapies. The chemical structures employed in the fabrication of NONs are summarized, and the strategies involved in NON-based cancer therapies are elaborated.

Photothermal/nitric oxide synergistic anti-tumour therapy based on MOF-derived carbon composite nanoparticles

Conventional organic photothermal conversion reagents still face some challenges for their real applications, such as the requirement of carriers for in vivo transport, uncontrolled degradation during use, reduction in photothermal conversion efficiency by repeated exposure to a near-infrared laser, and so on. Herein, uniform ZIF-8 nanoparticles were prepared first, and then carbonized and etched to form porous carbon nanoparticles (CNPs). After loading an NO donor and wrapping with red blood cell membrane, the novel CNP-NO@RBC photothermal agent integrated with in situ imaging ability was obtained. Due to the great photothermal conversion efficiency of the carbon material and the specific release of NO from the loaded NO conformer, the CNP-NO@RBCs show excellent tumour cell killing ability based on light-triggered photothermal/gas therapy at lower doses of CNP-NO@RBCs.

Intraparticle Double-Scattering-Decoded Sonogenetics for Augmenting Immune Checkpoint Blockade and CAR-T Therapy

Genetically arming new chimeric antigen receptors (CARs) on T cells is a prevalent method to fulfill CAR-T immunotherapy. However, this approach fails to completely address the poor infiltration, complex immunosuppressive tumor microenvironment (ITM), and insufficient immune cells, which are recognized as the three dominant hurdles to discouraging the trafficking and persistence of CAR-T and immune checkpoint blockade (ICB) immunotherapies against solid tumors. To address the three hurdles, a sonoimmunity-engineered nanoplatform is designed in which a rattle-type-structured carrier enables intraparticle-double-scattering to generate massive reactive oxygen species (ROS) during the sonodynamic process. Abundant ROS accumulation can directly kill tumor cells, release antigens, and activate systematic immune responses for expanding effector T or CAR-T cells, while alleviating ITM via immunosuppressive macrophage polarization and reduction in pro-tumorigenic cytokine secretion. Furthermore, the co-loaded phosphodiesterase-5 inhibitors release nitric oxide (NO) to impel vascular normalization and open the infiltration barrier (IB) for allowing more T cells to enter into the tumor. Systematic experiments demonstrate the feasibility of such intraparticle-double-scattering-decoded sonogenetics in the sonoimmunity-engineered nanoplatforms for expanding effector T or CAR-T cells, thereby promoting their infiltration into tumors and alleviating ITM. These compelling actions lead to excellent CAR-T and ICB immunotherapies against solid tumors with repressed tumor metastasis.

Recent advances in diverse nanosystems for nitric oxide delivery in cancer therapy

Gas therapy has been proven to be a promising and advantageous treatment option for cancers. Studies have shown that nitric oxide (NO) is one of the smallest structurally significant gas molecules with great potential to suppress cancer. However, there is controversy and concern about its use as it exhibits the opposite physiological effects based on its levels in the tumor. Therefore, the anti-cancer mechanism of NO is the key to cancer treatment, and rationally designed NO delivery systems are crucial to the success of NO biomedical applications. This review summarizes the endogenous production of NO, its physiological mechanisms of action, the application of NO in cancer treatment, and nano-delivery systems for delivering NO donors. Moreover, it briefly reviews challenges in delivering NO from different nanoparticles and the issues associated with its combination treatment strategies. The advantages and challenges of various NO delivery platforms are recapitulated for possible transformation into clinical applications.

Rational Nanomedicine Design Enhances Clinically Physical Treatment-Inspired or Combined Immunotherapy

Independent of tumor type and non-invasive or minimally-invasive feature, current physical treatments including ultrasound therapy, microwave ablation (MWA), and radiofrequency ablation (RFA) are widely used as the local treatment methods in clinics for directly killing tumors and activating systematic immune responses. However, the activated immune responses are inadequate and incompetent for tumor recession, and the incomplete thermal ablation even aggravates the immunosuppressive tumor microenvironment (ITM), resulting in the intractable tumor recurrence and metastasis. Intriguingly, nanomedicine provides a powerful platform as they can elevate energy utilization efficiency and augment oncolytic effects for mitigating ITM and potentiating the systematic immune responses. Especially after combining with clinical immunotherapy, the anti-tumor killing effect by activating or enhancing the human anti-tumor immune system is reached, enabling the effective prevention against tumor recurrence and metastasis. This review systematically introduces the cutting-edge progress and direction of nanobiotechnologies and their corresponding nanomaterials. Moreover, the enhanced physical treatment efficiency against tumor progression, relapse, and metastasis via activating or potentiating the autologous immunity or combining with exogenous immunotherapeutic agents is exemplified, and their rationales are analyzed. This review offers general guidance or directions to enhance clinical physical treatment from the perspectives of immunity activation or magnification.

Therapeutic gas-releasing nanomedicines with controlled release: Advances and perspectives

Nanoparticle-based drug delivery has become one of the most popular approaches for maximising drug therapeutic potentials. With the notable improvements, a greater challenge hinges on the formulation of gasotransmitters with unique challenges that are not met in liquid and solid active ingredients. Gas molecules upon release from formulations for therapeutic purposes have not really been discussed extensively. Herein, we take a critical look at four key gasotransmitters, that is, carbon monoxide (CO), nitric oxide (NO), hydrogen sulphide (H2S) and sulphur dioxide (SO2), their possible modification into prodrugs known as gas-releasing molecules (GRMs), and their release from GRMs. Different nanosystems and their mediatory roles for efficient shuttling, targeting and release of these therapeutic gases are also reviewed extensively. This review thoroughly looks at the diverse ways in which these GRM prodrugs in delivery nanosystems are designed to respond to intrinsic and extrinsic stimuli for sustained release. In this review, we seek to provide a succinct summary for the development of therapeutic gases into potent prodrugs that can be adapted in nanomedicine for potential clinical use.