Which Parameters Affect Biofilm Removal with Acoustic Cavitation? A Review

This review paper examines the parameters that affect biofilm removal using acoustic cavitation. Biofilms are coagulated masses of bacterial microorganisms that adhere to surfaces and cause contamination in various medical and biological settings.

The research investigate how ultrasound, as a mechanical energy, can effectively remove these biofilms through cavitation and acoustic streaming, which generate shear forces to disrupt biofilm from surfaces.

The paper identifies several key factors that significantly impact cavitation generation and biofilm removal effectiveness. These include properties of the liquid (gas content, temperature, surface tension) and properties of the ultrasound (frequency and acoustic pressure). The authors note that biofilms are often highly resistant to traditional antimicrobials like antibiotics, making physical disruption methods particularly valuable.

The review highlights the application of ultrasonic cavitation in various industries, from removing marine biofouling to eliminating food contamination. In healthcare settings, it can be used to remove oral biofilms on teeth and dental implants, biofilms on wounds, and contamination on medical instruments.

We conclude that while cavitation is somewhat unpredictable, it has strong disruptive action on biofilms when it occurs. They call for further research to optimize cavitation parameters for more effective biofilm removal, particularly using liquids with lower surface tension, different gas contents, low temperatures, or low acoustic frequencies. They also emphasize the need for more realistic physical and numerical models to simulate the interactions between cavitation bubbles, liquid flows, and biofilm removal.