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Proceedings Paper

Red blood cell membrane viscoelasticity, agglutination, and zeta potential measurements with double optical tweezers
Author(s): Adriana Fontes; Heloise P. Fernandes; Maria L. Barjas-Castro; André A. de Thomaz; Liliana de Ysasa Pozzo; Luiz C. Barbosa; Carlos L. Cesar
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Paper Abstract

The red blood cell (RBC) viscoelastic membrane contains proteins and glycolproteins embedded in, or attached, to a fluid lipid bilayer and are negatively charged, which creates a repulsive electric (zeta) potential between the cells and prevents their aggregation in the blood stream. There are techniques, however, to decrease the zeta potential to allow cell agglutination which are the basis of most of the tests of antigen-antibody interactions in blood banks. This report shows the use of a double optical tweezers to measure RBC membrane viscosity, agglutination and zeta potential. In our technique one of the optical tweezers trap a silica bead that binds strongly to a RBC at the end of a RBCs rouleaux and, at the same time, acts as a pico-Newton force transducer, after calibration through its displacement from the equilibrium position. The other optical tweezers trap the RBC at the other end. To measure the membrane viscosity the optical force is measured as a function of the velocity between the RBCs. To measure the adhesion the tweezers are slowly displaced apart until the RBCs disagglutination happens. The RBC zeta potential is measured in two complimentary ways, by the force on the silica bead attached to a single RBC in response to an applied electric field, and the conventional way, by the measurement of terminal velocity of the RBC after released from the optical trap. These two measurements provide information about the RBC charges and, also, electrolytic solution properties. We believe this can improve the methods of diagnosis in blood banks.

Paper Details

Date Published: 21 February 2006
PDF: 10 pages
Proc. SPIE 6088, Imaging, Manipulation, and Analysis of Biomolecules, Cells, and Tissues IV, 608811 (21 February 2006); doi: 10.1117/12.646682
Show Author Affiliations
Adriana Fontes, Univ. Estadual de Campinas (Brazil)
Heloise P. Fernandes, Univ. Estadual de Campinas (Brazil)
Maria L. Barjas-Castro, Univ. Estadual de Campinas (Brazil)
André A. de Thomaz, Univ. Estadual de Campinas (Brazil)
Liliana de Ysasa Pozzo, Univ. Estadual de Campinas (Brazil)
Luiz C. Barbosa, Univ. Estadual de Campinas (Brazil)
Carlos L. Cesar, Univ. Estadual de Campinas (Brazil)


Published in SPIE Proceedings Vol. 6088:
Imaging, Manipulation, and Analysis of Biomolecules, Cells, and Tissues IV
Daniel L. Farkas; Dan V. Nicolau; Robert C. Leif, Editor(s)

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