Which method uses high frequency sound waves to shear cells during lysis?
Ultrasonication is a mechanical lysis method that employs high-frequency sound waves, typically above 20 kHz, to disrupt cells. Acoustic cavitation generates localized microbubbles in the suspension that implode violently, producing intense shear forces, shock waves, and transient high pressure that rupture rigid cell walls and lipid membranes. This efficiently releases intracellular nucleic acids into buffer. In contrast, freeze-thaw relies on intracellular ice crystal formation, bead milling uses physical collision with glass beads, and liquid homogenization uses pressure-driven shear through a narrow gap, none involving ultrasonic cavitation.
Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.