WILKE NATALIA
Congresos y reuniones científicas
Título:
Mechanical properties of monolayers composed of dmpc:dspc mixtures
Autor/es:
F. VEGA MERCADO, B. MAGGIO, N. WILKE
Reunión:
Congreso; VII Iberoamerican Congreso of Biophysics; 2009
Resumen:
Many biologically relevant monolayers show coexistence of discrete domains of a long-range ordered condensed
phase dispersed in a continuous, disordered, liquid-expanded phase. In this work, we determined the viscous and elastic
components of the compressibility modulus and the shear viscosity of monolayers exhibiting phase coexistence with the
aim at elucidating the contribution of each phase to the observed monolayer mechanical properties. To this purpose,
mixed monolayers with different proportions of distearoylphosphatidylcholine (DSPC) and dimyristoylphosphatidylcholine
(DMPC) were prepared and their rheological properties were analyzed. The relationship between the phase
diagram of the mixture at 10 mN m-1 and the rheological properties was studied. We found that the monolayer shear
viscosity is highly dependent on the presence of domains and on the domain density. In turn, the monolayer
compressibility is only influenced by the presence of domains for high domain densities. For monolayers that look
homogeneous on the micrometer scale (DSPC amount lower that 23 mol %), all the analyzed rheological properties
remain similar to those observed for pure DMPC monolayers, indicating that in this proportion range the DSPC
molecules contribute as DMPC to the surface rheology in spite of having hydrocarbon chains four carbons longer
phase dispersed in a continuous, disordered, liquid-expanded phase. In this work, we determined the viscous and elastic
components of the compressibility modulus and the shear viscosity of monolayers exhibiting phase coexistence with the
aim at elucidating the contribution of each phase to the observed monolayer mechanical properties. To this purpose,
mixed monolayers with different proportions of distearoylphosphatidylcholine (DSPC) and dimyristoylphosphatidylcholine
(DMPC) were prepared and their rheological properties were analyzed. The relationship between the phase
diagram of the mixture at 10 mN m-1 and the rheological properties was studied. We found that the monolayer shear
viscosity is highly dependent on the presence of domains and on the domain density. In turn, the monolayer
compressibility is only influenced by the presence of domains for high domain densities. For monolayers that look
homogeneous on the micrometer scale (DSPC amount lower that 23 mol %), all the analyzed rheological properties
remain similar to those observed for pure DMPC monolayers, indicating that in this proportion range the DSPC
molecules contribute as DMPC to the surface rheology in spite of having hydrocarbon chains four carbons longer
