Optical and spectroscopic properties of human whole blood and plasma with and without Y₂O₃ and Nd³⁺:Y₂O₃ nanoparticles.

The optical properties of human whole blood and blood plasma with and without Y₂O₃ and Nd³⁺:Y₂O₃ nanoparticles are characterized in the near infrared region at 808 nm using a double integrating sphere technique. Using experimentally measured quantities of diffuse reflectance and diffuse transmittance, a computational analysis was conducted utilizing the Kubelka-Munk, the Inverse Adding Doubling, and Magic Light Kubelka-Munk and Monte Carlo Methods to determine optical properties of the absorption and scattering coefficients. Room temperature absorption and emission spectra were also acquired of Nd³⁺:Y₂O₃ nanoparticles elucidating their utility as biological markers. The emission spectra of Nd³⁺:Y₂O₃ were taken by exciting the nanoparticles before and after entering the whole blood sample. The emission from the ⁴F(3/2) → ⁴I(11/2) manifold transition of Nd³⁺:Y₂O₃ nanoparticles readily propagates through the blood sample at excitation of 808 nm and exhibits a shift in relative intensities of the peaks due to differences in scattering. At 808 nm, in both whole blood and plasma samples, a direct relationship was found with absorption coefficient and Y₂O₃ nanoparticle concentration. Results for the whole blood indicate a small inverse relationship with Y₂O₃ nanoparticle concentration and scattering coefficient and in contrast a direct relation for the plasma.