Effects of viscoelasticity of cytoplasm on the complex viscosity of red blood cell suspensions

Abstract

To consider the effects of the viscoelasticity of cytoplasm on the relaxation phenomenon of red blood cell suspensions, we calculate the complex intrinsic viscosity $[{\mathit{\eta }}^{\ast }]=\underset{\mathit{c}\to 0}{lim}\mathrm{(}{\mathit{\eta }}^{\ast }-\mathit{\eta }\mathrm{)}\mathrm{/}{\mathit{\eta }}^{\mathrm{c}}$ of the disperse system of spherical cells as a function of the frequency, where ${\mathit{\eta }}^{\ast }$ is the complex viscosity in suspensions, η the medium viscosity and c the volume concentration of the cells. The cell consists of a viscoelastic membrane and a viscoelastic cytoplasm. The viscoelasticity of the membrane is described by the Voigt model, while the viscoelasticity of the cytoplasmic region is described either by the Maxwell model or by the Voigt model. The interfacial tension is taken into account on both the interfaces of the membrane. The results of $[{\mathit{\eta }}^{\ast }]$ are compared with the ones in the case in which the cytoplasmic region is purely viscous liquid.