Resonance Raman microspectroscopy of normal erythrocytes and Plasmodium berghei-infected erythrocytes

Abstract

Resonance Raman microspectroscopy has been applied to study normal and Plasmodium berghei-infected mouse erythrocytes. The spectra of these two types of samples can be distinguished by the CaNCa deformation mode band at 747 cm-1 for the normal erythrocytes and at 754 cm-1 for the infected erythrocytes. It is believed that this difference in the spectra is due to the presence of haemozoin in the parasite, as a result of the polymerization of haem. The spectra obtained for the normal erythrocytes are due to the porphyrin group in the haemoglobin, whereas the spectra for the infected erythrocytes are due to those in the haemozoin. The spectral difference between the normal and infected erythrocytes enables us to identify the infected cells in the trophozoite or schizont stage from the normal cells. When the normal erythrocytes are subjected to high laser power, photoreduction of the sample occurs, and the spectra of these erythrocytes correspond to the spectra of deoxy Hb.