An enclosed live-imaging platform to reveal ultrasound-inflicted mechanolysis and wound healing response

Focused ultrasound (FUS) technology as a non-invasive therapy has been widely adopted in medical and life science research. Although various physical and biological effects of FUS have been well-documented, there is still a lack of understanding and direct evidence on the biological mechanism of therapeutic cell ablation caused by high-intensity ultrasound (HIFU) and the subsequent wound healing responses. Herein, this study designed and built an enclosed cell culture device that can synergistically combine non-invasive FUS stimulation and long-term live-cell imaging, serving as an in vitro platform to explore both short and long-term biological effects of ultrasound. Further, the process, mechanism and wound healing response of cell ablation induced by HIFU were studied, revealing a unique mechanism, termed ultrasound-inflicted mechanolysis, that is mediated by growing cavitation air bubbles under confined contact with cells. This discovery provides a previously unappreciated mechanism for understanding the biomechanical principles of ultrasound-based ablative therapy. We also found a post-ablation phantom layer (PAPL) remaining attached to neighboring live cell monolayer after HIFU stimulation. Such PAPL serves as a guiding cue for collective cell migration during post-ablation wound healing process, thereby providing a biomimetic model for studying wound healing after HIFU-inflicted damage. Together, the findings of this study might provide theoretical and technological basis for advancing our understanding of the biological effects of ultrasound-based ablative therapy and inspiring clinically relevant applications in the future. ### Competing Interest Statement The authors have declared no competing interest.