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BP: Fachverband Biologische Physik

BP 30: Posters: Physics of Cells

BP 30.29: Poster

Thursday, March 17, 2011, 17:15–20:00, P3

Quantification of adhesion of malaria infected erythrocytes on functionalized surfaces mimicking placental tissues. — •Harden Rieger^1,2, Hiroshi Yoshikawa¹, Michael Lanzer², and Motomu Tanaka¹ — ¹Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, D69120 Heidelberg, Germany — ²Department of Infectious Diseases, Parasitology, University of Heidelberg, Medical School, D69120 Heidelberg, Germany

Pregnancy-associated malaria is a serious health issues in tropical countries, as it causes an increase of newborn and maternal mortality. It has been demonstrated that the glycoaminoglycans, such as chondroitin sulfate A (CSA), play a major role in the adhesion of infected erythrocytes to placental tissue, but a quantitative study showing their relative contributions is still missing. The primary aim of this study is to design a quantitative model of placenta surface by functionalization of planar lipid bilayer membranes with CSA at defined surface densities. By controlling the self-assembling of anchor molecules, the average distance of CSA <d> can be regulated within nm accuracy. The specific adhesion of infected erythrocytes was firstly demonstrated on the membrane with <d> = 5.4 nm: In contrast, healthy erythrocytes show no detectable adhesion on the same surface. Furthermore, we found that the infected cells can detect a small change in <d>, undergoing a very sharp binding-unbinding transition. The strength of cell adhesion was quantitatively measured by two means: (a) analysis of cell shape near the surface and (b) a non-invasive assay that utilizes intensive shock wave generated by a ps laser pulse.