Treating cancer with sonodynamic therapy: A review

Abstract

Sonodynamic therapy (SDT) has emerged as a promising option for the minimally invasive treatment of solid cancerous tumours. SDT requires the combination of three distinct components: a sensitising drug, ultrasound, and molecular oxygen. Individually, these components are non-toxic but when combined together generate cytotoxic reactive oxygen species (ROS). The major advantage of SDT over its close relative photodynamic therapy (PDT), is the increased penetration of ultrasound through mammalian tissue compared to light. As a result, SDT can be used to treat a wider array of deeper and less accessible tumours than PDT. In this article, we critically review the current literature on SDT and discuss strategies that have been developed in combination with SDT to enhance the therapeutic outcome.

Nanoparticle-assisted ultrasound: A special focus on sonodynamic therapy against cancer

“…Although SDT therapeutic efficacy has been extensively demonstrated, the exact working mechanism is still under debate and will be further discussed below. Sonosensitizer could be activated by light through the sonoluminescence process [9] or with pyrolytic reactions, or upon the increase of acoustic cavitation effects [87]. SDT derives from the photodynamic therapy (PDT), where the light (typically in the ultraviolet range) is used as an external stimulus to activate a photosensitizer.…”

Oxygen and indocyanine green loaded phase-transition nanoparticle-mediated photo-sonodynamic cytotoxic effects on rheumatoid arthritis fibroblast-like synoviocytes

“…Compared with the light used in PDT, ultrasound has better penetrability, which can easily act on the lesion at a deep site. 11,12 Besides, it is currently believed that the combination of PDT and sonodynamic therapy (SDT) may decrease the sensitizer dosage and ultrasound/ light energy, which can further reduce the side effects, while enhancing the curative effect dramatically. [13][14][15][16][17] Thus, PDT combined with SDT (PSDT) is considered for the lesion of deep site in the present study.…”

Ultrasound-Mediated Cancer Therapy as a Noninvasive and Repeatable Treatment Strategy

“…Stable cavitation could be identified with the periodic oscillations of gas bubbles that have already existed in the tissue and that could be observed as the waxing bubble during the negative pressure half cycle and the shrinking bubble during the positive pressure half cycle as response to an ultrasound wave field [9,13,17,18]. Although stable cavitation do not collapse violently at any point of the pressure cycles, inertial cavitation or transient cavitation collapses violently after rapid bubble growth during the negative pressure half cycle and the collapse of cavitation at high-pressure amplitudes leads to instantaneously discharge of highly condensed energy at collapse center that induces localized increase in temperature (104 -106 K) and pressure (81 MPa) in surrounding microenvironment [9,15,19]. The sonomechanical influences of cavitation collapse near solid boundaries (such as a tissue interface) can be observed as shock waves propagation and micro-jets travelling at high speed (~ 100 m/s) towards the rigid surface [15,20].…”

“…principally use these sonomechanical effects to disrupt the normal functions of the cellular membranes [21]. The sonochemical effects of the bubble collapse can be monitored as the generation of free radicals, singlet oxygen and reactive oxygen species, and / or the occurring of sonoluminescence that can activate the sonosensitizer molecules [19]. Although it is not a surprise to expect light emission due to the high temperature releasing by transiently cavitating bubbles collapse, the precise mechanism of light production is still unclear.…”

“…Although it is not a surprise to expect light emission due to the high temperature releasing by transiently cavitating bubbles collapse, the precise mechanism of light production is still unclear. Sonoluminescence may be occurred due to the blackbody radiation, bremsstrahlung radiation, recombination radiation, or combinations thereof [19,[22][23][24][25].…”