Multi-wavelength spectroscopy of oriented erythrocytes

Abstract

Accurate characterization of the optical properties of erythrocytes is essential for the applications in optical biomedicine, in particular, for diagnosis of blood related diseases. The observed optical properties strongly depend on the erythrocyte's size, hemoglobin composition and orientation relative to the incident light. We explored the effect of orientation on the absorption and scattering properties of erythrocytes suspended in saline using UV-visible spectroscopy and theoretical predictive modeling based on anomalous diffraction approximation. We demonstrate that the orientation of erythrocytes in dilute saline suspensions is not random and produces consistent spectral pattern. Numerical analysis showed that the multi-wavelength absorption and scattering properties of erythrocytes in dilute suspensions can be accurately described with two orientation populations. These orientation populations with respect to the incident light are face-on incidence and edge-on incidence. The variances of the orientation angles for each population are less than 15 degrees and the relative proportions of the two populations strongly depend on the number density of the erythrocytes in suspensions. Further, the identified orientation populations exhibit different sensitivities to the changes in the compositional and morphological properties of erythrocytes. The anomalous diffraction model based on these orientation populations predicts the absorption and scattering properties of erythrocytes with accuracy greater than 99%. Establishment of the optical properties of normal erythrocytes allows for detection of the disease induced changes in the erythrocyte spectral signatures.

Quantitative analysis of morphological alterations in Plasmodium falciparum infected red blood cells through theoretical interpretation of spectral measurements

“…2B), which were magnetically separated from non-infected RBCs to achieve parasitemia levels above 90%. Further, it must be noted that the spectral patterns of light attenuated in the forward direction by healthy RBCs as well as IRBCs are greatly influenced by the cell orientation (Serebrennikova et al, 2010b;Tarasov et al, 2007) as illustrated in Fig. 2C.…”

Characterization of Red Blood Cells with Multiwavelength Transmission Spectroscopy

“…The measured spectra of RBCs from healthy donors, anemic patients, and noninfected control RBCs were interpreted using the homogeneous case of modified Mie theory (MMT) model described in detail in [ 13 ]. The model utilized an ellipsoidal approximation to Mie theory to account for the effects of the RBC orientation and nonspherical shape.…”

“…Furthermore, since refractive index of any substance and therefore its absorption and scattering properties vary with wavelength, a single MWT measurement can provide a sufficient number of independent data points to extract information on multiple parameters (in cases of complex composition and/or complex structure) of measured objects. An interpretation model based on an ellipsoidal approximation to the modified Mie theory (MMT) has been found appropriate to extract the information from measured MWT spectra of RBCs [ 8 , 13 ].…”

Multi-wavelength laser from dye-doped cholesteric polymer films

“…Multi-wavelength lasers have attracted great attention [1][2][3] because of their wide range of applications, including telecommunications [4], high-precision broadband sensing and spectroscopy [5], metrology, molecular fingerprinting [6], optical clocks [7], and even attosecond physics. For example, a multi-wavelength laser is ideal for characterizing optical amplifiers where the gain profile must be saturated across its whole spectrum for reliable measurements, or polarization mode dispersion and polarization-dependent loss measurements that are usually carried out with tunable sources.…”