Raman Imaging

Raman Line Imaging

As an example of the Raman line imaging technique applied to viable cells, we have performed measurements on red blood cells (RBCs). RBCs are biconcave diskocytes with a diameter of ~ 8 µm. The oxygen storage and transport protein, hemoglobin, occupies much of the volume of RBCs. We expect significant resonance enhancement of hemoglobin Raman bands because the 514.5 nm excitation wavelength is coincident with the b absorption band of the heme. Thus, it is likely that the Raman spectrum of an RBC will contain strong contributions from hemoglobin. We have obtained Raman images of human RBCs fixed on fused silica microscope slides coated with poly-l-lysine. An individual cell is illuminated with the scanned laser line, and individual line images are obtained by integrating for 20 s.