A Comprehensive Review of Inorganic Sonosensitizers for Sonodynamic Therapy

Abstract

Sonodynamic therapy (SDT) is an emerging non-invasive cancer treatment method in the field of nanomedicine, which has the advantages of deep penetration, good therapeutic efficacy, and minimal damage to normal tissues. Sonosensitizers play a crucial role in the process of SDT, as their structure and properties directly determine the treatment outcome. Inorganic sonosensitizers, with their high stability and longer circulation time in the human body, have great potential in SDT. In this review, the possible mechanisms of SDT including the ultrasonic cavitation, reactive oxygen species generation, and activation of immunity are briefly discussed. Then, the latest research progress on inorganic sonosensitizers is systematically summarized. Subsequently, strategies for optimizing treatment efficacy are introduced, including combination therapy and image-guided therapy. The challenges and future prospects of sonodynamic therapy are discussed. It is hoped that this review will provide some guidance for the screening of inorganic sonosensitizers.

An Ultrasound-Activated Nanozyme Sonosensitizer for Photoacoustic Imaging-Guided Breast Cancer Sonodynamic and Starvation Combination Therapy

“…16,17 Compared with organic sonosensitizers, inorganic sonosensitizers excel in enhancing the therapeutic effect of SDT due to their unique physical properties, such as stability and operability. 18,19 Moreover, some inorganic sonosensitizers not only convert O 2 to 1 O 2 but also break down water to produce hydroxyl radicals (• OH). 20−22 For example, gold-based nanoparticles have been reported to exhibit sonodynamic effects by the cavitation effect.…”

“…Sonodynamic therapy (SDT) is an interesting strategy for tumor treatment, which possesses a series of advantages, such as being safe, noninvasive, and highly penetrating. − The main therapeutic mechanism of SDT is that sonosensitizers absorb ultrasound (US) energy to produce reactive oxygen species (ROS), causing oxidative stress to cells. − Therefore, the performance of the sonosensitizer greatly influences the therapeutic effect of SDT. − Conventional organic sonosensitizers, such as hematoporphyrin, convert oxygen (O 2 ) into singlet oxygen ( 1 O 2 ). − However, this type of sonosensitizers inevitably suffers from disadvantages, such as poor water solubility and poor stability. , Compared with organic sonosensitizers, inorganic sonosensitizers excel in enhancing the therapeutic effect of SDT due to their unique physical properties, such as stability and operability. , Moreover, some inorganic sonosensitizers not only convert O 2 to 1 O 2 but also break down water to produce hydroxyl radicals (·OH). − For example, gold-based nanoparticles have been reported to exhibit sonodynamic effects by the cavitation effect . Alginate-coated Au nanorods could produce 1 O 2 and ·OH for SDT, and the production and collapse of gas bubbles further enhance the cavitation effect .…”

The Immunomodulatory Effects of Fluorescein-Mediated Sonodynamic Treatment Lead to Systemic and Intratumoral Depletion of Myeloid-Derived Suppressor Cells in a Preclinical Malignant Glioma Model

“…The sonosensitizers employed are nontoxic chemical compounds whose therapeutic activity is triggered by ultrasound. Ideal sonosensitizers should have high selectivity for the target lesion, a high clearance rate from healthy tissue, and no substantial in vivo toxicity [14]. To date, 5-aminolevulinic acid (5-ALA) and fluorescein are the two main investigated compounds for the application of SDT in neuro-oncology.…”