The acoustic microscope is used to investigate the elastic properties of living biological cells. A quantitative model is developed relating acoustic microscope image contrast to cellular elastic properties. Cytoplasmic acoustic attenuation is measured by focusing the acoustic microscope on the surface of the underlying substrate. Cytoplasmic acoustic impedance is measured by focusing the acoustic microscope on the top surface of the cell. The model allows the acoustic microscope to give quantitative information about cellular elasticity on a subcellular scale.

Acoustics↗

PubMed1981

Acoustic microscopy of living cells.

This paper reports preliminary results of the observation by acoustic microscopy of living cells in vitro. The scanning acoustic microscope uses high-frequency sound waves to produce images with submicrometer resolution. The contrast observed in acoustic micrographs of living cells depends on the acoustic properties (i.e., density, stiffness, and attenuation) and on the topographic contour of the cell. Variation in distance separating the acoustic lens and the viewed cell also has a profound effect on the image. When the substratum is located at the focal plane, thick regions of the cell show a darkening that can be related to cellular acoustic attenuation (a function of cytoplasmic viscosity). When the top of the cell is placed near the focal plane, concentric bright and dark rings appear in the image. The location of the rings can be related to cell topography, and the ring contrast can be correlated to the stiffness and density of the cell. In addition, the character of the images of single cells varies dramatically when the substratum upon which they are grown is changed to a different material. By careful selection of the substratum, the information content of the acoustic images can be increased. Our analysis of acoustic images of actively motile cells indicates that leading lamella are less dense or stiff than the quiescent trailing processes of the cells.

Animals↗

PubMed1980

Acoustic microscopy of human metaphase chromosomes.

Acoustic micrographs of human metaphase chromosomes have been recorded with wavelengths as short as 470 nm using liquid argon near 85 K as the acoustic wave coupling medium. Chromosomes prepared by trypsin-Giemsa staining exhibit acoustic banding patterns similar to the G-bands seen in optical images. Unstained chromosomes exhibit acoustic markings that do not correspond to traditional banding patterns. The observed acoustic contrast may arise from spatial variations in chromosomal mechanical properties, or from thickness variations in the fixed chromosomes.

Azure Stains↗