Modeling and Imaging of GHz Ultrasonic Impedance of C. elegans

Exoskeletal and muscular degeneration in C. elegans, which can be correlated to the rigidity of the worm, is associated with aging, genetic mutations, and nutrient deficiency. There are many efforts that have investigated the worm’s rigidity but are destructive or unable to capture the worms’ full-body mechanical properties. In this work, we present the use of GHz-frequency ultrasonic imaging as a non-invasive technique to map the mechanical properties of a whole C. elegans. The ultrasonic impedance was measured using a system consisting of 128 x 128, 50μm wide AlN transducers at 3-4 fps. The experimentally obtained reflection coefficients were compared to numerically computed reflections obtained through a 1D simulation approach of acoustic wave propagation based on signal transformation using the ABCD-matrix method. The experimental imaging and modeling approach offers a promising tool to visualize and study biomechanics in small biological organisms using non-destructive, high-resolution measurements.