(142ae) Fractionation Dynamics of Soft and Stiff Particles in Micro-Flow

Recent studies have demonstrated the fractionation of different cell types (healthy and diseased) by cell mechanical properties in microfluidic channels [1,2,3]. We investigate the fractionation mechanism of soft and stiff particles in microfluidic flow with the lattice Boltzmann-Brownian dynamics (LB-BD) method.  For soft particles in microflow, it is found that lower particle volume fraction and higher shear rate enhances particle migration towards the microchannel center, due to particle deformation induced near-wall hydrodynamic field. For stiff particles, particle migration is found at non-dilute particle volume fractions, where flow inertia around the particle induces migration to an off-center position in the channel.  In a mixture of soft and stiff particles, contributions from shear-induced particle deformation, flow inertia and particle volume fraction are systematically investigated.  It is found that fractionation may be achieved with higher efficiency at higher soft particle volume fractions.

[1] H.W. Hou et al., Lab Chip 10, 2605 (2010).

[2] S.C. Hur et al., Appl. Phys. Lett. 99, 044101 (2011).

[3] E. J. Lim et al., Lab Chip, DOI: 10.1039/c2lc21100a (2012).