Measuring the mechanical properties of cells using acoustic microscopy

Time resolved acoustic microscopy was used to investigate the mechanical properties of MCF7 breast cancer cells at 375 MHz. The thickness, speed of sound, acoustic impedance, density, bulk modulus and attenuation were calculated using the amplitude and time of the ultrasound backscatter from the cellular membrane and substrate. The technique was first validated by measuring the mechanical properties of a material with well characterized properties, polyvinylidene fluoride (PVDF). The measured values agreed very well (within 4.5%) with those provided from the manufacturer. The same properties of MCF7 cells were then measured using the same technique. The speed of sound, acoustic impedance, density and bulk modulus were found to have values slightly higher than the medium they were testing in. In this paper, a technique to non-invasively measure the mechanical properties of cells using scanning acoustic microscopy is presented.