Cell encapsulation in a flow focusing microchannel: Effects of viscoelasticity

The effect of viscoelasticity of working fluids on cell encapsulation dynamics is investigated in an axisymmetric flow focusing configuration using a three-phase front-tracking method. A series of cells with predefined size and frequency are encapsulated by the disperse phase forming compound droplets suspended in an outer fluid. Viscoelasticity of the fluids is modeled using a model called FENE-CR. Following Nooranidoost et al [1,2], compound droplet formations are examined for viscoelastic parameters including Weissenberg number, polymeric viscosity ratio, and extensibility parameter. It is found that these parameters have a significant influence on droplet size, size distribution and frequency of droplet generation. Depending on the flow rate of the outer and inner fluids, viscoelasticity of the fluids may increase/decrease the droplet size and its distribution. It is also found that the viscoelasticity has a similar effect as decreasing flow rate ratio and acts to delay transition from squeezing to dripping regime. This study can be useful to improve single cell encapsulation.

¹M. Nooranidoost, D. Izbassarov and M. Muradoglu, Phys. Fluids 28, 123102 (2016).

²M. Nooranidoost, M. Haghshenas, M. Muradoglu and R. Kumar, Bull. Am. Phys. Soc. Volume 62, Number 14, (2017).