Actas de congresos
Studying Red Blood Cell Agglutination By Measuring Membrane Viscosity With Optical Tweezers
Proceedings Of Spie - The International Society For Optical Engineering. , v. 6644, n. , p. - , 2007.
De Thomaz A.A.
The red blood cell (RBC) viscoelastic membrane contains proteins and glycoproteins embedded in a fluid lipid bilayer that are responsible for cell agglutination. Manipulating RBCs rouleaux with a double optical tweezers, we observed that the cells slide easily one over the others but are strongly connected by their edges. An explanation for this behavior could be the fact that when the cells slide one over the others, proteins are dragged through the membrane. It confers to the movement a viscous characteristic that is dependent of the velocity between the RBCs and justifies why is so easy to slide them apart. Therefore, in a first step of this work, by measuring the force as a function of the relative velocity between two cells, we confirmed this assumption and used this viscous characteristic of the RBC rouleaux to determine the apparent membrane viscosity of the cell. As this behavior is related to the proteins interactions, we can use the apparent membrane viscosity to obtain a better understanding about cell agglutination. Methods related to cell agglutination induced by antigen-antibody interactions are the basis of most of tests used in transfusion centers. Then, in a second step of this work, we measured the apparent membrane viscosity using antibodies. We observed that this methodology is sensitive to different kinds of bindings between RBCs. Better comprehension of the forces and bindings between RBCs could improve the sensibility and specificity of the hemagglutination reactions and also guides the development of new potentiator substances.6644Fontes, A., Fernandes, H.P., Barjas-Castro, M.L., Thomaz, A.A., Pozzo, L., Barbosa, L.C., Cesar, C.L., Red blood cell membrane viscoelasticity, agglutination and zeta potential measurements with double optical tweezers (2006) Proceedings of SPIE, 6088, pp. 296-305Eylar, E.H., Madoff, M.A., Brody, O.V., Oncley, J.L., The contribution of sialic acid to the surface charge of the erythrocyte (1962) J. Biol. Chem, 237, pp. 1992-2000Pollack, W., Reckel, R.P., A reappraisal of the forces involved in Hemagglutination (1977) Int Archs Allergy Appl. Immun, 54, pp. 29-42Fontes, A., Giorgio, S., de Castro Jr., A.B., Neto, V.M., Pozzo, L.Y., Marques, G.P., Barbosa, L.C., Cesar, C.L., Determination of femto Newton forces and fluid viscosity using optical tweezers: Application to Leishmania amazonensis (2005) Proceedings of SPIE, 5699, pp. 419-425Saffman, P.G., Delbruck, M., Brownian motion in biological membranes (1975) Proc. Nat. Acad. Sci. USA, 72, pp. 3111-3113Dimova, R., Danov, K., Pouligny, B., Ivanov, I.B., Drag of a solid particle trapped in a thin film or at an interface: Influence of surface viscosity and elasticity (2000) J. Colloid and Interface Science, 226, pp. 35-43