title: On the birefringence of healthy and malaria-infected red blood cells.
abstract: The birefringence of a red blood cell (RBC) is quantitatively monitored as it becomes infected by a malarial parasite. Large changes occur in the cell's refractive index at different stages of malarial infection. The observed rotation of an optically trapped, malaria-infected RBC is not a simple function of shape distortion: the malarial parasite is found to itself exercise a profound influence on the rotational dynamics by inducing stage-specific birefringence. Our measurements shed new light on the competition between shape- and form-birefringence in RBCs. We demonstrate the possibility of using birefringence to establish very early stages of infected parasites and of assessing various factors that contribute to birefringence in normal and infected cells. Our results have implications for the development and use of noninvasive techniques of quantifying changes in cell properties induced by malaria disease pathology.
authors.affiliation: Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400 005, India.
authors.forename: Aditya K
authors.initials: AK
authors.lastname: Dharmadhikari
authors.forename: Himanish
authors.initials: H
authors.lastname: Basu
authors.forename: Jayashree A
authors.initials: JA
authors.lastname: Dharmadhikari
authors.forename: Shobhona
authors.initials: S
authors.lastname: Sharma
authors.forename: Deepak
authors.initials: D
authors.lastname: Mathur
mesh_terms: D000818:Animals; D001718:Birefringence; D004912:Erythrocytes / Q000737:chemistry* / Q000469:parasitology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D016778:Malaria, Falciparum / Q000469:parasitology; D051379:Mice; D061848:Optical Imaging / Q000379:methods*; D052898:Optical Tweezers; D010963:Plasmodium falciparum / Q000737:chemistry*