Inorganic Sonosensitizers for Sonodynamic Therapy in Cancer Treatment

Abstract

The rapid development of nanomedicine and nanobiotechnology has allowed the emergence of various therapeutic modalities with excellent therapeutic efficiency and biosafety, among which, the sonodynamic therapy (SDT), a combination of low‐intensity ultrasound and sonosensitizers, is emerging as a promising noninvasive treatment modality for cancer treatment due to its deeper penetration, good patient compliance, and minimal damage to normal tissue. The sonosensitizers are indispensable components in the SDT process because their structure and physicochemical properties are decisive for therapeutic efficacy. Compared to the conventional and mostly studied organic sonosensitizers, inorganic sonosensitizers (noble metal‐based, transition metal‐based, carbon‐based, and silicon‐based sonosensitizers) display excellent stability, controllable morphology, and multifunctionality, which greatly expand their application in SDT. In this review, the possible mechanisms of SDT including the cavitation effect and reactive oxygen species generation are briefly discussed. Then, the recent advances in inorganic sonosensitizers are systematically summarized and their formulations and antitumor effects, particularly highlighting the strategies for optimizing the therapeutic efficiency, are outlined. The challenges and future perspectives for developing state‐of‐the‐art sonosensitizers are also discussed. It is expected that this review will shed some light on future screening of decent inorganic sonosensitizers for SDT.

Comparative Study of Sonodynamic and Photoactivated Cancer Therapies with Re(I)-Tricarbonyl Complexes Comprising Phenanthroline Ligands

“…Reactive oxygen species (ROS) production during cellular metabolism plays an important role in maintaining cellular redox harmony. ,, But any artificial increment in the intracellular ROS levels results in the damage of many cellular components, such as lipids, proteins, DNA, etc., that highly compromises regular cellular activity and leads to cell death. , ROS generation have been a pivotal mechanism in PDT as well as in SDT, which holds promising potential for anticancer effects. − , The generation of ROS like 1 O 2 and OH • plays a vital role in cancer therapy due to their oxidative stress-mediated destruction of cancer cells. , The singlet oxygen production by photo/sono-sensitizers on light/ultrasound irradiation has been reported to induce cancer cell killing. , 1 O 2 generation by photosensitizers has been an important cofactor and well-explored cell death mechanism for anticancer activity. Similarly, sonosensitizers have also been explored to produce 1 O 2 upon ultrasound exposure.…”

“…8 To overcome the limitation associated with the light's tissue penetration, the concept of SDT with ultrasound as a drug activator was introduced recently. 8, 59,60 To use Re(I)tricarbonyl complexes for deep-seated tumor therapy, ultra-sound can be useful. 59,60 Ultrasound has excellent tissuepenetrating ability and thus can activate the drug even at the deep-seated tumor site.…”

“…8, 59,60 To use Re(I)tricarbonyl complexes for deep-seated tumor therapy, ultra-sound can be useful. 59,60 Ultrasound has excellent tissuepenetrating ability and thus can activate the drug even at the deep-seated tumor site. 59,60 Recently, we have shown that ultrasound can also release CO from the Re(I)-tricarbonyl complex.…”

“…59,60 Recently, we have shown that ultrasound can also release CO from the Re(I)-tricarbonyl complex. 59,60 To realize the efficacy of Re1−Re3 in SDT, their anticancer activities were studied under ultrasound irradiation (1.5 W cm −2 ). Moreover, we were interested in comparing the effects of light and ultrasound as drug activators.…”

Improvement of the effectiveness of sonodynamic therapy: by optimizing components and combination with other treatments

“…86 Unfortunately, it is obvious that inorganic sonosensitizers need to focus more attention on potential biosafety. [87][88][89][90] The combination of sonosensitizers and nanoplatforms can move beyond some of the inherent drawbacks of sonosensitizers and achieve higher tumor inhibition rates and improved ROS conversion rates.…”