Effect of the size and shape of a red blood cell on elastic light scattering properties at the single-cell level

Abstract

We demonstrate the use of a double-beam optical tweezers system to stabilize red blood cell (RBC) orientation in the optical tweezers during measurements of elastic light scattering from the trapped cells in an angle range of 5-30 degrees. Another laser (He-Ne) was used to illuminate the cell and elastic light scattering distribution from the single cell was measured with a goniometer and a photomultiplier tube. Moreover, CCD camera images of RBCs with and without laser illumination are presented as complementary information. Light scattering from a RBC was measured in different fixed orientations. Light scattering from cells was also measured when the length of the cell was changed in two different orientations. Light scattering measurements from spherical and crenate RBCs are described and the results are compared with other cell orientations. Analysis shows that the measured elastic light scattering distributions reveal changes in the RBC’s orientation and shape. The effect of stretching on the changes in scattering is larger in the case of face-on incidence of He-Ne laser light than in rim-on incidence. The scattering patterns from RBCs in different orientations as well as from a spherical RBC were compared with numerical results found in literature. Good correlation was found.

Theoretical models for near forward light scattering by aPlasmodium falciparuminfected red blood cell

“…Tycko et al [26] found good agreement in flow cytometric measurements of sphered RBCs with the Mie theory. More recently Kinnunen et al [35] have compared the scattering patterns from actual RBCs as well as from a spherical RBC with Mie results. Good correlation was found in comparisons of Mie theory and sphered RBCs.…”

“…In fact, it is known that even the entire membrane contributes negligibly to the scattering properties of a RBC [26,30]. (ii) It has been observed that RBC volume and refractive index are the main factors in determining changes in scattering cross-sections and not the shape [35,36]. Thus, for blood in physiological concentrations, the Mie theory offers a good description of the absorption coefficient, even without sphering, in the spectral range 600 to 1100 nm where absorption is low [36].…”

Elliptical optical tweezers for trapping a red blood cell aggregate

“…It is evident that the orientation of the aggregate affects the near-field intensity distribution. As seen, the scattering intensity is much stronger than from single cells [29], due to the aggregate's larger scattering cross-section. By measuring the suspension's total refractive index and relative refractive index (m=n p /n t , where n p is the refractive index of the particle and n t is the total refractive index of the medium), we can estimate the effect of an additive on light scattering from a single particle.…”

“…For RBCs, however, most of the published results have been obtained through an image analysis of intensity images [27], [28]. Our recent results show the potential of the goniometric method for single RBC level measurements [29]. In these experiments, RBCs were suspended in a filtered PBS suspension.…”

Development of a Real-Time,In-SituParticle Sizing Technique: Real-Time Light Transmission Spectroscopy (RTLTS)

“…Among them, we chose Mieplot 4.3 by Laven (2011), which supports the import of external refractive indices. Its reliability has been verified by many researchers (Riley et al 2004;Husted et al 2009;Shen and Wang 2010;Kinnunen et al 2011). The refractive index value of polystyrene was adopted from Palik (1991).…”