Lateral Deformation of Human Red Blood Cells by Optical Tweezers

Abstract

In this paper, we studied the lateral deformation of human red blood cells (RBCs) during lateral indentation by an optically trapped silica bead with a diameter of 4.5 µm (Bangs Laboratories, Inc. Fishers, IN, USA). The images were captured using a CCD camera and the Boltzmann statistics method was used for force calibration. Using the Hertz model, we calculated and compared the elastic stiffness resulting from the lateral force, showing that the differences are important and that the force should be considered. Besides the lateral component, this setup also allowed us to examine the lateral cell–bead interaction. The mean values of the cell shear stiffness measured during indentation were 3.37 ± 0.40 µN/m for biconcave RBCs, 3.48 ± 0.23 µN/m for spherical RBCs, and 3.80 ± 0.22 µN/m for crenelated RBCs, respectively. These results show that this approach can be used as a routine method for RBC study, because it enabled us to manipulate the cell without contact with the wall.

Analysis of Polarization Images in the Microphysical Blood Parameters Research for the Hematocrit Diagnostics

“…Whole blood consists of plasma (55% by volume) and formed elements (45% by volume), 99% of which are erythrocytes (hemoglobin-containing elements) and 1% are leukocytes and platelets [23,24]. Under normal physiological conditions (erythrocytes are not deformable), the optics of whole blood, as a highly concentrated turbid medium, is determined by the properties of erythrocytes and plasma.…”

In vitro investigation of the mechanics of fixed red blood cells based on optical trap micromanipulation and image analysis

“…These microspheres have a regular shape and can be easily calibrated for light-trapping mechanics using a thermal motion calibration method [ 26 ]. Yale et al obtained the shear modulus of cells by manipulating red blood cells adhered to a carrier stage, squeezing silica microspheres in a light trap [ 27 ]. In contrast, Liu et al utilized an acousto-optic deflection (AOD) system to actively manipulate the microspheres for stretching the erythrocytes, a more sensitive manipulation [ 28 ].…”