Efficacy of Indocyanine Green-Mediated Sonodynamic Therapy on Rheumatoid Arthritis Fibroblast-like Synoviocytes

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

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

Nanomaterials for Ultrasound Imaging- Guided Sonodynamic Therapy

Ultrasound examination is becoming the most popular medical imaging modality because of its low cost and high safety profile. Ultrasound contrast agents enhance the scattering of sound waves, which can improve the clarity and resolution of images. Nanoparticle Ultrasound contrast agents have the characteristics of a large specific surface area and a modifiable surface, which can increase drug loading capacity, prolong circulation time, and enable drug enrichment in specific organs or tissues. This leads to improved therapeutic effects and reducing toxic and side effects. Compared with traditional ultrasound contrast agents, Nano-ultrasound contrast agents overcome the limitation of imaging solely within blood vessels and facilitate imaging within tumor tissues, thereby extending the duration of enhanced imaging. Sonodynamic therapy is an emerging treatment method that has been developed rapidly in recent years, which has the advantages of noninvasive, high spatial and temporal resolution, and low toxicity and side effects. Sonodynamic therapy utilizes a sonosensitizer that, when excited by ultrasound at the tumor site, produces toxic reactive oxygen species, inducing apoptosis or necrosis in tumor cells. Ultrasound-guided sonodynamic therapy allows for real-time observation of lesions, is convenient and flexible, and is free of radiation exposure. With the use of nanomaterials as carriers, ultrasound-guided sonodynamic therapy has made significant strides. This study categorizes and summarizes the current research on acoustic sensitizer carrier materials, including carbon-based, silicon-based, peptide-based, iron-based, metal-organic frameworks, polymers, and liposomes. It concludes by highlighting the current challenges in the integration of ultrasound imaging with sonodynamic therapy and suggests future directions for clinical application development.

Ultrasound-responsive matters for biomedical applications

Ultrasound (US) is a biofavorable mechanical wave that has shown practical significance in biomedical fields. Due to the cavitation effect, sonoluminescence, sonoporation, pyrolysis, and other biophysical and chemical effects, a wide range of matters have been elucidated to be responsive to the stimulus of US. This review addresses and discusses current developments in US-responsive matters, including US-breakable intermolecular conjugations, US-catalytic sonosensitizers, fluorocarbon compounds, microbubbles, and US-propelled micro- and nanorobots. Meanwhile, the interactions between US and advanced matters create various biochemical products and enhanced mechanical effects, leading to the exploration of potential biomedical applications, from US-facilitated biosensing and diagnostic imaging to US-induced therapeutic applications and clinical translations. Finally, the current challenges are summarized and future perspectives on US-responsive matters in biomedical applications and clinical translations are proposed.

Emerging Sonodynamic Therapy-Based Nanomedicines for Cancer Immunotherapy

Cancer immunotherapy effect can be greatly enhanced by other methods to induce immunogenic cell death (ICD), which has profoundly affected immunotherapy as a highly efficient paradigm. However, these treatments have significant limitations, either by causing damage of the immune system or limited to superficial tumors. Sonodynamic therapy (SDT) can induce ICD to promote immunotherapy without affecting the immune system because of its excellent spatiotemporal selectivity and low side effects. Nevertheless, SDT is still limited by low reactive oxygen species yield and the complex tumor microenvironment. Recently, some emerging SDT-based nanomedicines have made numerous attractive and encouraging achievements in the field of cancer immunotherapy due to high immunotherapeutic efficiency. However, this cross-cutting field of research is still far from being widely explored due to huge professional barriers. Herein, the characteristics of the tumor immune microenvironment and the mechanisms of ICD are firstly systematically summarized. Subsequently, the therapeutic mechanism of SDT is fully summarized, and the advantages and limitations of SDT are discussed. The representative advances of SDT-based nanomedicines for cancer immunotherapy are further highlighted. Finally, the application prospects and challenges of SDT-based immunotherapy in future clinical translation are discussed.

The promising interplay between sonodynamic therapy and nanomedicine

Sonodynamic therapy (SDT) is a non-invasive approach for cancer treatment in which chemical compounds, named sonosensitizers, are activated by non-thermal ultrasound (US), able to deeply penetrate into the tissues. Despite increasing interest, the underlying mechanisms by which US triggers the sonosensitizer therapeutic activity are not yet clearly elucidate, slowing down SDT clinical application. In this review we will discuss the main mechanisms involved in SDT with particular attention to the sonosensitizers involved for each described mechanism, in order to highlight how much important are the physicochemical properties of the sonosensitizers and their cellular localization to predict their bioeffects. Moreover, we will also focus our attention on the pivotal role of nanomedicine providing the sonodynamic anticancer approach with the ability to shape US-responsive agents to enhance specific sonodynamic effects as the sonoluminescence-mediated anticancer effects. Indeed, SDT is one of the biomedical fields that has significantly improved in recent years due to the increased knowledge of nanosized materials. The shift of the nanosystem from a delivery system for a therapeutic agent to a therapeutic agent in itself represents a real breakthrough in the development of SDT. In doing so, we have also highlighted potential areas in this field, where substantial improvements may provide a valid SDT implementation as a cancer therapy.

Recent developments of sonodynamic therapy in antibacterial application

The rapid emergence of pathogenic bacteria poses a serious threat to global health. Notably, traditional antibiotic therapies suffer from the risk of strengthening bacterial drug resistance. Sonodynamic therapy (SDT) combining sonosensitizers and low-intensity ultrasound (US) has broadened the way towards treating drug-resistant bacteria. The allure of this therapy emerges from the capacity to focus the US energy on bacterial infection sites buried deep in tissues, locally activating the sonosensitizers to produce cytotoxic reactive oxygen species (ROS) with the ability to induce bacterial death. The past decade has witnessed the rapid development of antibacterial SDT owing to their excellent penetration, favorable biocompatibility and specific targeting ability. This review summarizes available sonosensitizers for antibacterial SDT, and digs into innovative biotechnologies to improve SDT efficiency, such as enhancing the targeting ability of sonosensitizers, image-guided assisted SDT, improvement of hypoxia and combination of SDT with other therapies. Finally, we conclude with the present challenges and provide insights into the future research of antibacterial SDT.

Facile preparation of indocyanine green and tiny gold nanoclusters co-loaded nanocapsules for targeted synergistic sono-/photo-therapy

Photothermal therapy (PTT) and sono-photodynamic therapy (SPDT) are fast growing local treatment modalities with minimal invasiveness and high safety. Gold nanoparticles and indocyanine green (ICG) have been used as sensitizers for PTT and SPDT. However, long resident time of gold nanoparticles in tissues and fast elimination of ICG hampered their further clinical applications. Herein, we developed nanocapsules formed by hyaluronic acid and chitosan loading with ICG and tiny gold nanoclusters (TAuNCs) to overcome the shortcomings of gold nanoparticles and ICG for combined PTT and SPDT. The nanocapsules exhibited good biological stability, favorable photothermal effects, and ultrasound/near-infrared light (NIR)-responsive release behaviors. The hyaluronic acid could mediate the specific delivery of cargos to CD44 protein over-expressing cancer cells. The in vitro and in vivo results showed that TAuNCs and ICG could act synergistically to obtain satisfactory anticancer effects under NIR laser and/or ultrasound exposure induced by thermal ablation and reactive oxygen species (ROS) generation. Biodistribution and excretion studies showed that the nanocapsules had longer ICG retention time in tumor and most of the TAuNCs could be effectively excreted from the body within one month. This study thus provides a facile strategy for the development of a safe and high-performance nanoplatform for synergistic PTT/SPDT.

Organic Sonosensitizers for Sonodynamic Therapy: From Small Molecules and Nanoparticles toward Clinical Development

Sonodynamic therapy (SDT) is a novel noninvasive therapeutic modality that combines low-intensity ultrasound and sonosensitizers. Versus photo-mediated therapy, SDT has the advantages of deeper tissue penetration, high accuracy, and less side effects. Sonosensitizers are critical for therapeutic efficacy during SDT and organic sonosensitizers are important because of their clear structure, easy monitoring, evaluation of drug metabolism, and clinical transformation. Notably, nanotechnology can be used in the field of sonosensitizers and SDT to overcome the inherent obstacles and achieve sustainable innovation. This review introduces organic small molecule sonosensitizers, nano organic sonosensitizers, and their clinical translation by providing ideas and references for the design of sonosensitizers and SDT so as to promote its transformation to clinical applications in the future.

Mutual-reinforcing sonodynamic therapy against Rheumatoid Arthritis based on sparfloxacin sonosensitizer doped concave-cubic rhodium nanozyme

Rheumatoid arthritis (RA) is an autoimmune disease associated with synovitis and cartilage destruction. Ultrasound (US)-driven sonodynamic therapy (SDT) possess a good application prospect in RA therapy because of its non-invasiveness and strong tissue penetration capabilities, which can kill activated synovial inflammatory cells. Nevertheless, the tiny accumulation of sonosensitizers in the joints and the hypoxic synovial microenvironment severely limit the therapeutic effect of SDT. Hence, we developed a sonosensitizer spafloxacin (SPX) doped and human serum albumin (HSA) loaded concave-cubic rhodium (Rh) nanozyme (Rh/SPX-HSA) to realize mutual-reinforcing SDT during ultrasonic activation. On the one hand, SPX would cause mitochondrial dysfunction by inducing excessive reactive oxygen species (ROS) production, thus suppressing fibroblast-like synoviocyte (FLS) under US conditions. On the other hand, concave-cubic rhodium was utilized as a nanozyme with endogenous peroxidase (POD) and catalase (CAT)-like enzyme activities, which not only relieved the hypoxia of the joint to resist angiogenesis, but also enormously ascended the SDT efficacy by rising ¹O₂ levels. Interestingly, the activity of nanozymes was also improved by the ultrasonic cavitation effect, thereby realizing mutual-reinforcing SDT. Overall, our strategy provided Rh-based to achieve effective SDT under hypoxic microenvironment, which offered a promising prospect for highly efficient treatment of RA.

Safe and Targeted Sonodynamic Cancer Therapy Using Biocompatible Exosome-Based Nanosonosensitizers

Sonodynamic therapy (SDT), wherein sonosensitizers irradiated with ultrasound (US) produce cytotoxic reactive oxygen species (ROS), has garnered great attention as a promising alternative to photodynamic therapy owing to the significantly increased depth of tissue penetration. The development of nanocarriers that can selectively deposit sonosensitizers into tumor tissues without systemic toxicity is crucial to facilitate the translation of SDT to clinical use. In this study, exosomes, a class of naturally occurring nanoparticles, were utilized as nanocarriers for safe and cancer-targeted delivery of a sonosensitizer, indocyanine green (ICG). The exosomes were surface-engineered with an active cancer-targeting ligand, folic acid (FA), to increase the cancer specificity of the ICG-loaded exosomes (ExoICG). The FA-conjugated, ICG-loaded exosomes (FA-ExoICG) greatly improved aqueous stability and cellular uptake of ICG, resulting in significantly increased ROS generation in breast cancer cells. As a result, the FA-ExoICG demonstrated greater sonotoxicity against cancer cells than ExoICG and free ICG. The in vivo study revealed that compared to ExoICG, more FA-ExoICG accumulated in tumors, and their pharmacokinetic properties were superior. Notably, tumor growth in mice was significantly suppressed, without systemic toxicity, by a single intravenous injection of the FA-ExoICG and subsequent US irradiation. Therefore, this study demonstrated that active cancer-targeted FA-ExoICG could serve as effective nanosonosensitizers for safe and targeted cancer treatment.

Development of a Composite of Polypyrrole-Coated Carbon Nanotubes as a Sonosensitizer for Treatment of Melanoma Cancer Under Multi-Step Ultrasound Irradiation

Sonodynamic therapy (SDT) has established a novel route for treating solid cancers. Low-intensity ultrasound irradiation accompanied by a sonosensitizer has revealed remarkable advantages for cancer therapy such as targeted uptake, access to deeper tumors, insignificant side effects and invasiveness, compared with other therapeutic methods. In this study, we scrutinized synthesis and characterization of a polypyrrole-coated multi-walled carbon nanotubes composite (PPy@MWCNTs). PPy@MWCNTs can absorb ultrasound irradiation by both of its components, and it was introduced as a new sonosensitizer. The composite was characterized by field emission scanning electron microscopy (FESEM), and its ability to temperature elevation was explored. FESEM images revealed that PPy@MWCNTs comprised nanotubes of 36.3 ± 5.1 nm in diameter with up to several micrometer in length. Ultrasound irradiation at 1 MHz and 1.0 W cm^-2 for 60 s in four steps led to an efficient SDT in vitro (16.3 ± 2.8°C temperature increment for 250 μg mL^-1 of PPy@MWCNTs), in C540 (B16/F10) cell line and a melanoma tumor model in male balb/c mice. In vitro examinations revealed that PPy@MWCNTs represented a concentration-dependent cytotoxicity on multi-step ultrasound irradiation (a cell viability of 8.9% for 250 μg mL^-1 of PPy@MWCNTs). Histologic analyses and tumor volume decrement after 10 d revealed detrimental SDT effects of PPy@MWCNTs on tumors (75% necrosis and 50% decrement in tumor volume). Thermal effects and reactive oxygen species generation were the reasons of the working function of PPy@MWCNTs in SDT.

Energy Conversion-Based Nanotherapy for Rheumatoid Arthritis Treatment

Rheumatoid arthritis (RA) is characterized by synovial hyperplasia and cartilage/bone destruction, which results in a high disability rate on human health and a huge burden on social economy. At present, traditional therapies based on drug therapy still cannot cure RA, in accompany with the potential serious side effects. Based on the development of nanobiotechnology and nanomedicine, energy conversion-based nanotherapy has demonstrated distinctive potential and performance in RA treatment. This strategy employs specific nanoparticles with intrinsic physiochemical properties to target lesions with the following activation by diverse external stimuli, such as light, ultrasound, microwave, and radiation. These nanoagents subsequently produce therapeutic effects or release therapeutic factors to promote necrotic apoptosis of RA inflammatory cells, reduce the concentration of related inflammatory factors, relieve the symptoms of RA, which are expected to ultimately improve the life quality of RA patients. This review highlights and discusses the versatile biomedical applications of energy conversion-based nanotherapy in efficient RA treatment, in together with the deep clarification of the facing challenges and further prospects on the final clinical translations of these energy conversion-based nanotherapies against RA.

Efficient Delivery of Triptolide Plus a miR-30-5p Inhibitor Through the Use of Near Infrared Laser Responsive or CADY Modified MSNs for Efficacy in Rheumatoid Arthritis Therapeutics

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease for which treatment focuses on suppressing an overactive immune system and maintaining the physiological balance of synovial fibroblasts (SFs). We found that miR-30-5p was highly expressed in rheumatoid arthritis synovial fibroblasts (RASFs). Subsequently, we predicted that phosphatidylinositol 3-kinase regulatory subunit 2 (PIK3R2) might be a putative target of miR-30-5p. Recent studies have reported that PIK3R2 can maintain the physiological homeostasis of RASFs. Therefore, miR-30-5p inhibitor has the potential to be used in the treatment of RA, but low levels of miR-30-5p inhibitor internalization affect its application. Triptolide (TP) is an effective drug in the treatment of RA but induces severe toxicity and has a narrow therapeutic window. In this study, the cell internalization performance of miR-30-5p inhibitor was improved by loading it into cell membrane penetrating peptide (CADY)-modified mesoporous silica nanoparticles (MSNs), and the toxicity of TP was decreased by loading it into a controlled drug release system based on MSNs. The nanodrug carrier was constructed by filling a phase-change material (PCM) of 1-tetradecanol and drugs into MSNs that could be triggered by an NIR laser with thermo-chemo combination RA therapy. Our results show that the miR-30-5p inhibitor-loaded MSNs@CADY significantly inhibited RASF proliferation and increased apoptosis. In addition, MSNs@PCM@TP under 808 nm laser irradiation were effective in downregulating immune system activation in an RA rat model. Finally, the results of a pharmacodynamics study showed that the combination of MSNs@CADY@miR-30-5p inhibitor and MSNs@PCM@TP under 808 nm laser significantly increased the effectiveness of RA treatment. These findings provide a novel understanding of RA pathogenesis and a theoretical basis for RA treatment.

Enhanced anti-tumor efficacy of hyaluronic acid modified nanocomposites combined with sonochemotherapy against subcutaneous and metastatic breast tumors

Sonochemotherapy is a promising strategy for inhibiting tumor growth. However, achieving highly targeted and effective sonochemotherapy is still an enormous challenge. In this study, a novel chemotherapeutic-carrying nanocomposite (HPCID) was developed, which can effectively target metastatic cancer cells and provide an enhanced therapeutic effect. In detail, HPCID was composed of hyaluronic acid (HA), carboxyl-terminated PAMAM dendrimer, fluorochrome indocyanine green (ICG), and doxorubicin hydrochloride (Dox). The efficacy of this drug delivery system (DDS) in sonochemotherapy was assessed on the CD44-overexpressing metastatic breast cancer cell line 4T1 both in vitro and in vivo. The HA modification significantly improved the cellular internalization of HPCID, and the degradation of the HA shell by hyaluronidase that is abundant in the 4T1 cells resulted in enzyme-responsive drug release. Under ultrasound (US) stimulation, HPCID produced a high amount of reactive oxidant species (ROS), which induced significant cell apoptosis when combined with chemotherapy. In addition, the administration of HPCID in 4T1 xenograft-bearing mice combined with ultrasonic exposure significantly inhibited tumor growth and pulmonary metastasis, with no systemic toxicity. Taken together, the proposed HPCID-mediated sonodynamic therapy (SDT) is a novel strategy against breast cancer progression and metastasis.

A single-step multi-level supramolecular system for cancer sonotheranostics

A multi-level supramolecular system produced by single-step Fe³⁺-mediated ionic crosslinking self-assembly can overcome the critical issues of current sonodynamic therapy (SDT) and address the need to monitor therapeutic effects in vivo with a non-invasive approach. This rational design of organic sonosensitizer-based formulation shows great potential for clinical SDT against deep-seated cancer.