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Ultrasonic waves are a form of sound energy with excellent directionality. They have a variety of characteristics. They are widely used in various fields. By utilizing the mechanical oscillation and cavitation of ultrasonics, it is possible to achieve the dispersion of solutions, emulsions, suspensions, and other liquids. Goals include ultrasonic dispersion, homogenization, stirring, and crushing.
Figure 1.Working principle of Siansonic's non-invasive ultrasonic sonication transducer
The cavitation effect of ultrasonics refers to the phenomenon where ultrasonic waves in a liquid cause microbubble within to oscillate. Under certain conditions, these microbubbles rapidly grow and then collapse. This generates and releases a tremendous amount of energy. As ultrasonic waves pass through a liquid, the sound pressure changes periodically throughout. Consequently, the cavitation nuclei (microbubbles) in the liquid also oscillate periodically with the ultrasonic frequency. At low sound intensities, the radial oscillations of bubbles are controlled by the sound pressure. Microbubbles perform periodic oscillations around their equilibrium radius (steady-state cavitation). Each oscillating microbubble generates radiation pressure and microjets. Microjets can produce very high shear stresses near the surface of the bubbles. This causes the bubbles to deform or even burst. It can affect nearby cells or biomolecules, thereby producing certain biological effects. As the sound intensity increases, when the amplitude of the bubble's oscillation becomes comparable to its equilibrium size, the vibration of the bubble is then controlled by the inertia of the surrounding medium. The cavitation nuclei rapidly expand during the negative pressure half-cycle of the ultrasonic field and sharply contract to implode during the positive pressure half-cycle. This type of cavitation is called transient cavitation or inertial cavitation. During transient cavitation, the bubble oscillation is very violent, with the bubble first explosively expanding, then rapidly collapsing. In the final stage of collapse, local high temperatures and pressures occur, accompanied by strong shock waves, high-speed microjets, and the generation of free radicals. These extreme physical conditions and the formation of chemical groups greatly damage the normal cellular structure and the biological activity of enzymes, effectively destroying tumor cells and the like.
Figure 2. Siansonic's non-invasive ultrasonic sonication transducer
Utilizing this characteristic of ultrasonics, their application spans multiple fields, giving rise to a variety of instruments and devices. For instance, Ultrasonic dispersion sampling devices used in the field of extracorporeal diagnostics have replaced traditional mechanical methods for mixing and crushing blood samples. This is a more efficient processing method. Additionally, focused ultrasound can be used for tumor treatment (HIFU surgery), thrombolysis, and liposculpture, among other applications.
Siansonic boasts nearly 40 years of experience in the research and manufacturing of ultrasonic transducers. Our ultrasonic dispersion transducers have been long-term purchases by several foreign molecular diagnostics companies, such as Cepheid in the United States and Biocartis in Belgium.
