Abstract

Separation and sorting of particles (cells, beads, and droplets) is critical in a variety of biomedical applications including early disease diagnostics, therapeutics, cell tracking, and clinical research. Currently, standard microfluidic methods use 2D-chips fabricated using PDMS based soft lithography or embossing/etching materials such as Topas or glass. Often hydrodynamic flow focussing is used to spatially confine the sample flow to particular areas on the chip and so facilitate target species detection; however, 2D systems have limitations when it is necessary to make fine, micrometre scale, adjustments to flow profiles and/or the spatial position of the focused sample stream so as to match up with elements of external bulky equipment such as the laser or light paths of a spectrometer or internal fields used in electrical or acoustic actuation. These limitations can be overcome by using a 3D flow focussing method which can dynamically adjust the flow patterns within the sample chip (Figure 1a, left).

© 2019 IEEE