Scanning acoustic microscopy imaging of cellular structural and mechanical alterations from external stimuli

Cells incur structural and functional damage from external stimuli. Under scanning acoustic microscopy (SAM), speed of sound (SOS), attenuation, and thickness values are plotted to visualize cellular stiffness, viscosity, and size. The obtained digital data are then compared using statistical analysis. In the present study, we aimed to investigate the alterations in the mechanical and structural characteristics of cancer cells in response to anticancer drugs, acidic fluids, and microwave burdens using SAM. We found that active untreated cells showed increased thickness and reduced SOS and attenuation, whereas dying treated cells displayed reduced thickness and increased SOS. Tannic and acetic acid treatments and microwave irradiation all increased SOS and attenuation and reduced thickness, which meant that these treatments made cells thinner, stiffer, and more viscous. Furthermore, the different anticancer drugs interacted with cancer cells to induce characteristic changes in SAM values. These structural and mechanical alterations induced in cells were difficult to observe under light microscopy. However, under SAM, cancer cell activity and function corresponded consistently with changes in SAM values. Cellular damage parameters were statistically compared between the different treatments, and time-dependent cellular changes were established. SAM observation can therefore reliably evaluate cancer cell damage and recovery after chemotherapy and physical therapy. These results may help evaluate the therapeutic efficacy of various treatments.