On ‐Chip Generation of Vortical Flows for Microfluidic Centrifugation

An overview is presented of the current state ‐of‐the‐art in microfluidic vortex technology for driving on ‐chip rotational flows for a range of microcentrifugation processes such as micromixing, sample preconcentration, particle separation, component fractionation, and cell agglomeration, among others. AbstractMicrocentrifugation constitutes an important part of the microfluidic toolkit in a similar way that centrifugation is crucial to many macroscopic procedures, given that micromixing, sample preconcentration, particle separation, component fractionation, and cell agglomeration are essential operations in small scale processes. Yet, the dominance of capillary and viscous effects, which typically tend to retard flow, over inertial and gravitational forces, which are often useful for actuating flows and hence centrifugation, at microscopic scales makes it difficult to generate rotational flows at these dimensions, let alone with sufficient vorticity to support efficient mixing, separation, concentration, or aggregation. Herein, the various technologies —both passive and active—that have been developed to date for vortex generation in microfluidic devices are reviewed. Various advantages or limitations associated with each are outlined, in addition to highlighting the challenges that need to be overcome for their incorporation into integrated m icrofluidic devices.

Source: Small - September 18, 2019 Category: Nanotechnology Authors: Heba Ahmed, Shwathy Ramesan, Lillian Lee, Amgad R. Rezk, Leslie Y. Yeo Tags: Review Source Type: research