title: Hemoglobin consumption by P. falciparum in individual erythrocytes imaged via quantitative phase spectroscopy.
abstract: Plasmodium falciparum infection causes structural and biochemical changes in red blood cells (RBCs). To quantify these changes, we apply a novel optical technique, quantitative phase spectroscopy (QPS) to characterize individual red blood cells (RBCs) during the intraerythrocytic life cycle of P. falciparum. QPS captures hyperspectral holograms of individual RBCs to measure spectroscopic changes across the visible wavelength range (475-700 nm), providing complex information, i.e. amplitude and phase, about the light field which has interacted with the cell. The complex field provides complimentary information on hemoglobin content and cell mass, which are both found to dramatically change upon infection by P. falciparum. Hb content progressively decreases with parasite life cycle, with an average 72.2% reduction observed for RBCs infected by schizont-stage P. falciparum compared to uninfected cells. Infection also resulted in a 33.1% reduction in RBC's optical volume, a measure of the cells' non-aqueous components. Notably, optical volume is only partially correlated with hemoglobin content, suggesting that changes in other dry mass components such as parasite mass may also be assessed using this technique. The unique ability of QPS to discriminate individual healthy and infected cells using spectroscopic changes indicates that the approach can be used to detect disease.
authors.affiliation: Dept. of Biomedical Engineering, Duke University, Durham, NC 27708, US.
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Rinehart
authors.affiliation: Dept. of Biomedical Engineering, Duke University, Durham, NC 27708, US.
authors.forename: Han Sang
authors.initials: HS
authors.lastname: Park
authors.affiliation: Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, US.
authors.forename: Katelyn A
authors.initials: KA
authors.lastname: Walzer
authors.affiliation: Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, US.
authors.forename: Jen-Tsan Ashley
authors.initials: JT
authors.lastname: Chi
authors.affiliation: Dept. of Biomedical Engineering, Duke University, Durham, NC 27708, US.
authors.forename: Adam
authors.initials: A
authors.lastname: Wax
mesh_terms: D004912:Erythrocytes / Q000737:chemistry / Q000469:parasitology*; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D010963:Plasmodium falciparum / Q000737:chemistry*; D059010:Single-Cell Analysis / Q000379:methods; D013057:Spectrum Analysis
chemical_list: D006454:Hemoglobins