sonikation

Sonication is the application of sound energy, usually in the ultrasonic range, to a liquid or suspension to produce physical effects such as disruption of aggregates, emulsification, or cell lysis. In laboratories, common devices include bath and probe sonicators, operating at roughly 20 kHz to several hundred kilohertz with variable power.

The primary mechanism is acoustic cavitation: the formation, growth, and collapse of microbubbles create localized hotspots of high temperature and pressure, generating shock waves and shear forces that break apart particle clusters, disrupt cell walls, or homogenize mixtures. Effects depend on frequency, power, duration, temperature, and container geometry.

Typical applications include disrupting cells for protein or nucleic acid extraction, homogenizing tissue samples, dispersing nanoparticles and carbon nanotubes, emulsifying immiscible liquids, fragmenting DNA to desired lengths, and preparing samples for microscopy or sequencing. Sonication is also used to degas liquids and to aid chemical reactions under certain conditions.

Limitations and safety considerations include heat buildup that can denature biomolecules, risks of aerosol generation, potential contamination from the probe or bath, and uneven energy distribution within the sample. Exposure time and energy must be optimized to balance efficiency with sample integrity. Not all materials respond well to sonication, and alternative disruption methods may be preferred for sensitive applications.

The technique has been in use since the mid-20th century and has evolved with improvements in probe design, control systems, and diagnostics, enabling more consistent disruption and dispersion across research and industrial settings.