Ultrasonic cavitation is a very effective method for lysing cells. A sonicator for cell disruption is a probe which expands and contracts at high frequency. The expansion and contraction of the sonicator tip in the sample creates tiny vacuum cavities which implode with great local force; this cavitation creates shock waves in the sample. Typical frequency for ultrasonic cell disruptors is about 20 kHz and typical power output ranges from 50 to 700 watts. Sonication is one of the most effective tools for cell lysis for samples containing single cells or cell suspensions and microorganisms. Sonication is not as effective for tissue samples; these samples should be homogenized previous to using the sonicator. Sonication creates localized heating which can denature proteins and degrade the sample so many sonicators are designed with pulse options to mitigate the heat produced; typically samples are chilled before and during sonication. Most sonicators have options for using a probe/tip or a horn. When a horn is used the samples can be suspended in a bath and the sonic waves are transmitted through the liquid in the bath. This eliminates the need for the sonicator tip to come in contact with the sample; ideal for biohazardous samples or samples which must remain sterile.
For cell suspensions and microorganisms sonication is an extremely effective way to method of cell lysis. For other types of samples a combination of homogenization and sonication will be the most effective method.