Ultrasound, Sonochemistry & Sonoluminescence The high frequency sounds made by dolphins can cause the same effects as medical ultrasound, such as microbubbleformation and cavitation. A bubble is a cavity and the collapse of a bubble can heat the steam inside it to some 6000 degrees Fahrenheit (near the surface temperature of the sun!). At such temperatures novel chemical reactions occur called sonochemistry.
The chemical effects of ultrasound, sonochemistry and sonoluminescence arise from acoustic cavitation: the formation, growth, and implosive collapse of bubbles in a liquid. Cavitational collapse produces intense local heating (~5000 K), high pressures (~1000 atm), and enormous heating and cooling rates (>10 9 K/sec). Acoustic cavitation provides a unique interaction of energy and matter, and ultrasonic irradiation of liquids causes high energy chemical reactions to occur, often accompanied by the emission of light… Thus, cavitation can create extraordinary physical and chemical conditions in otherwise cold liquids.30 Through these mechanisms, ultrasound causes improved healing of bone fractures and non-unions and improves healing soft tissue injuries etc. Ultrasound can affect cell membranes, and chemistry and even alter gene expression.
…exposure of cells to therapeutic ultrasound under nonthermal conditions modifies cellular functions…[can] modulate membrane properties, alter cellular proliferation, and produce increases in proteins associated with inflammation and injury repair. … these data suggest that nonthermal effects of therapeutic ultrasound can modify the inflammatory response. Exposure to … therapeutic doses of US …alter[ed] the expression of both the ALP and OP genes … in osteoblast-like cells. The two highest doses showed that ALP and OP expression were clearly up-regulated, particularly ALP, whereas at the lowest dose of 120 mW/cm2, the OP gene was down-regulated.
…recent reports demonstrat[e] that ultrasound affects enzyme activity and possibly gene regulation [We]…present a probable molecular mechanism of ultrasound's nonthermal therapeutic action. The frequency resonance hypothesis describes possible biological mechanisms that may alter protein function. [By] absorption of ultrasonic may…modify…[a protein’s] 3-dimensional structure …and alter [its] functional activity. Second, the resonance or shearing [caused by] the wave …may dissociate a multimolecular complex, thereby disrupting the complex's function. 31