title: Change in spectrum of Brownian fluctuations of optically trapped red blood cells due to malarial infection.
abstract: We study the properties of single red blood cells (RBCs) held in an optical-tweezers trap. We observe a change in the spectrum of Brownian fluctuations between RBCs from normal and malaria-infected samples. The change, caused by infection-induced structural changes in the cell, appears as a statistical increase in the mean (by 25%) and standard deviation (by 200%) of the corner frequency measured over approximately 100 cells. The increase is observed even though the ensemble of cells being measured consists mostly of cells that do not actually host the parasite, but are from an infected pool. This bystander effect appears to vindicate other observations that infected cells can affect the biomechanical properties of uninfected cells. The change is also observed to be independent of the stage of infection and its duration, highlighting its potential for disease detection.
authors.affiliation: Indian Institute of Science, Department of Physics, Bangalore 560012, India.
authors.forename: Vishal
authors.initials: V
authors.lastname: Saraogi
authors.forename: P
authors.initials: P
authors.lastname: Padmapriya
authors.forename: Apurba
authors.initials: A
authors.lastname: Paul
authors.forename: Utpal S
authors.initials: US
authors.lastname: Tatu
authors.forename: Vasant
authors.initials: V
authors.lastname: Natarajan
mesh_terms: D016009:Chi-Square Distribution; D004912:Erythrocytes / Q000737:chemistry / Q000469:parasitology* / Q000473:pathology*; D006801:Humans; D016778:Malaria, Falciparum / Q000097:blood*; D016011:Normal Distribution; D052898:Optical Tweezers; D013816:Thermodynamics