Cell separation by non-inertial force fields in microfluidic systems

Abstract

Cell and microparticle separation in microfluidic systems has recently gained significant attention in sample preparations for biological and chemical studies. Microfluidic separation is typically achieved by applying differential forces on the target particles to guide them into different paths. This paper reviews basic concepts and novel designs of such microfluidic separators with emphasis on the use of non-inertial force fields, including dielectrophoretic force, optical gradient force, magnetic force, and acoustic primary radiation force. Comparisons of separation performances with discussions on physiological effects and instrumentation issues toward point-of-care devices are provided as references for choosing appropriate separation methods for various applications.

Three-dimensional matrixlike focusing of microparticles in flow through minichannel using acoustic standing waves: An experimental and modeling study

“…Equation (1) shows that the force experienced by a particle is a function of the cube of its radius (r 3 ) and of the material contrast factors 1 and 2 between the particle and the fluid. When the acoustic force is integrated in the propagation direction, the acoustic contrast factor can be defined as a linear combination of the material contrast factors 1 and 2 , and is commonly used to predict the particle behavior under ASWs.…”

“…Acoustic standing waves (ASWs) have been extensively studied as an efficient means of focusing particles or cells into pressure node or antinode positions for further processing such as separation [1], observation, agglutination [2][3][4] and concentration [5,6]. Most of these studies were carried out in rectangular channels and in a layered configuration, where a piezo actuator constitutes the bottom wall of the channel and an additional reflector is used to enhance the acoustic energy transmission.…”

Continuous-flow ferrohydrodynamic sorting of particles and cells in microfluidic devices

“…Compared to high-specificity and label-based cell sorting techniques such as 0fluorescence-activated cell sorter (FACS) (Bonner et al 1972) and magnetic-activated cell sorter (MACS) (Miltenyi et al 1990), microfluidic sortings are mostly label-free, relying on cells' intrinsic properties such as size, shape, density, deformability, electric and magnetic properties for manipulation specificity (Pamme 2007;Tsutsui and Ho 2009;Gossett et al 2010;Lenshof and Laurell 2010). When applicable, microfluidic sortings are favored over label-based ones, because they are inexpensive and require minimal user training for operation (Gossett et al 2010).…”

Acoustofluidics 23: acoustic manipulation combined with other force fields

“…At the beginning of each subsection the system properties that influence the complementary force are briefly discussed. For a recent overview of magnetic, dielectrophoretic and optical forces in microfluidic systems, and a comparison with acoustic forces, the reader is referred to Tsutsui and Ho 21 .…”