Quantification of Inter-Erythrocyte Forces with Ultra-High Frequency (410 MHz) Single Beam Acoustic Tweezer.

Abstract

Efforts on quantitative measurements of the interactive forces of red blood cells (RBC) have been pursued for many years in hopes of a better understanding of hemodynamics and blood rheology. In this paper, we report an approach based on an ultra-high frequency (410 MHz) single beam acoustic tweezer (SBAT) for quantitative measurements of inter-RBC forces at a single cell level. The trapping forces produced by this ultra-high frequency (UHF) SBAT can be quantitatively estimated with a micropipette. Since the focal beam diameter of the 410 MHz ultrasonic transducer used in this SBAT was only 6.5 micrometer (μm), which was smaller than that of a RBC (~7.5 μm), it was made possible to directly apply the beam to a single RBC and measure inter-RBC forces against the pre-calibrated acoustic trapping forces as another example of potential cellular applications of the SBAT. The magnitude of these forces was found to be 391.0 ± 86.4 pN. Finally, it is worth noting that unlike several other methods, this method does not require the measuring device to be in contact with the cells.