Comment on "Pinched Flow Fractionation: Continuous Size Separation of Particles Utilizing a Laminar Flow Profile in a Pinched Microchannel"

TL;DR

This paper critically examines the physics underlying the pinched flow fractionation technique, questioning how the width of segments influences particle separation performance in microfluidic devices.

Contribution

It provides a detailed analysis and critique of the physical principles claimed to govern the separation efficiency in PFF, clarifying misconceptions or assumptions.

Findings

The width of the pinched segment significantly affects separation performance.

The physics behind PFF's effectiveness is more complex than initially described.

Clarification of the factors influencing size-based particle separation in microchannels.

Abstract

[First paragraph] In a recent paper Yamada et al. propose the novel concept of "pinched flow fractionation" (PFF) for the continuous size separation and analysis of particles in microfabricated lab-on-a-chip devices. In their description of the basic principle they claim that especially the width of the pinched and broadened segments will affect theseparation performance. In the following we comment on the physics behind this statement.