Experimental and theoretical study of light scattering by individual mature red blood cells by use of scanning flow cytometry and discrete dipole approximation

TL;DR

This study combines experimental scanning flow cytometry measurements with theoretical discrete dipole approximation simulations to analyze light scattering by individual mature red blood cells, validating a biconcave disk model and comparing different shape approximations.

Contribution

It introduces a combined experimental and theoretical approach to model light scattering by RBCs, validating the biconcave disk model and comparing shape approximations.

Findings

Good agreement between simulated and measured indicatrices validates the biconcave disk model.

The oblate spheroid model for rim-on incidence closely matches the biconcave disk results.

Orientation significantly affects light scattering patterns of RBCs.

Abstract

Elastic light scattering by mature red blood cells (RBCs) was theoretically and experimentally analyzed with the discrete dipole approximation (DDA) and the scanning flow cytometry (SFC), respectively. SFC permits measurement of angular dependence of light-scattering intensity (indicatrix) of single particles. A mature RBC is modeled as a biconcave disk in DDA simulations of light scattering. We have studied the effect of RBC orientation related to the direction of the incident light upon the indicatrix. Numerical calculations of indicatrices for several aspect ratios and volumes of RBC have been carried out. Comparison of the simulated indicatrices and indicatrices measured by SFC showed good agreement, validating the biconcave disk model for a mature RBC. We simulated the light-scattering output signals from the SFC with the DDA for RBCs modeled as a disk-sphere and as an oblate spheroid. The biconcave disk, the disk-sphere, and the oblate spheroid models have been compared for two orientations, i.e. face-on and rim-on incidence. Only the oblate spheroid model for rim-on incidence gives results similar to the rigorous biconcave disk model.