Perpustakaan Digital ITB

Ultrasonication has emerged as a promising non-thermal method for bacterial inactivation, with acoustic cavitation identified as the primary mechanism responsible for structural disruption. This study presents a finite element analysis to investigate the mechanical response of E. coli under two distinct cavitation-induced loading scenarios: Asymmetric Pressure Load and Inclined Directional Force Load. These scenarios were designed to emulate the mechanical stress fields resulting from the collapse of cavitation bubbles near bacterial cells. A damage metric Damaged Cell Envelope Percentage (DCEP) is introduced to quantitatively assess the extent of structural compromise. The threshold for meaningful bacterial damage differs between the two scenarios. In the Inclined Directional Force Load, noticeable damage is already observed at a relatively low configuration of 1 MPa peak magnitude with a distribution of 500 nm. In contrast, the Asymmetric Pressure Load requires a higher threshold, with meaningful damage beginning only from 2 MPa peak magnitude and a distribution of 1000 nm. This comparison highlights the greater efficiency of shear-dominant directional forces in initiating cell envelope rupture compared to normal pressure loading. Contour plots of DCEP across different loading parameters provide insights into optimal conditions for bacterial damage.