Electrical signal could be changed into physical vibration directed toward a target substance through sonication. Sonicators are important lab devices and applied in a variety of fields. Sonication is typically conducted to break apart compounds or cells for the purpose of further evaluation. The vibration exerts a strong impact on solutions, breaking apart the molecules and rupturing cells. A typical case is its usage in detecting DNA. The sonication could break apart the cells in which with DNA information in order to obtain the DNA proteins for examination.
The ultrasonic electric generator is the main component of a sonication device. It can generate a signal (around 20 KHz), which could drive a transducer to change the electric signal into physical vibration through piezoelectric crystals or crystals which could react directly to the electricity and create a mechanical vibration. And then this physical vibration arose in molecular level is well kept and magnified through the sonicator, ultimately delivered to the probe.
The mechanical vibration on the probe could be further transmitted to the sonicated solution. The probe is well designed and could move constantly with the vibration. Such the mechanical vibration is successfully transmitted to the solution being sonicated. The amplitude of the vibration can be adjusted according to the qualities of the sonicated solution. However, the probe still moves up and down rapidly.
The fast vibration of the probe lead to a phenomenon called cavitation. When a large number of tinny bubbles in micro-scale generates through vibrations, cavitation takes place, pockets of space are created between molecules, forming and collapsing constantly under the weight of the solution being sonicated. A great number of bubbles can form and collapse repeatedly, causing intensive waves of vibration, which can cycle into the surrounding solution and ultimately break the cells apart.
There are many probes in different size, suitable for different kind of sonification process. A small-sized probe can generate excellent cavitation process and exerts easy disruption on nearby cells. However its effective acting area is limited due to the small probe size. A large-sized probe can ensure a greater effective solution quantity, while its reaction intensity is relatively low.
Sonication is a strong process for cell-disrupter. It may sometimes be too strong for the treated cells and proteins. For a more delicate treatment, a substitute alternative is taking traditional procedure such as enzyme digestion (disruption through chemical reaction) or grinding with a special material (such as sand).