Study of the red blood cell aggregation by coherent anti-Stokes Raman spectroscopy

In this work, we studied the nature of the molecular bonds involved in the red blood cell aggregation process by the coherent anti-Stokes Raman spectroscopy technique. Images were acquired with a commercial Leica TCS SP8 CARS confocal microscope (Leica Microsystems GmbH, Wetzlar, Germany) temporally and spatially overlapping the pulses of two sources in the focal plane of the microscope. A pump wavelength of 810 nm to 817 nm was used for the CARS mode simultaneously with the Stokes beam at 1064 nm to excite the vibratory resonance of the symmetric hydrocarbon bonds in the lipids and that of the bonds in amino acids of the proteins. The Raman shift was also observed at the 1200 cm−1 range to study possible variations in the sialic acid on the cell membrane produced by concentrations of dextran 500 in the suspension medium. Curves of lifetime emission distribution were obtained for untreated erythrocytes and treated erythrocytes with dextran 500, particularly at a pump wavelength of 904 nm.