Figure 1.

(A) Schematic of a microfluidic channel cross-section, illustrating the principle of inertial spiral microfluidics. The main flow (into the page) follows a curvilinear path leading to the development of secondary flows, known as Dean vortices (dashed lines). Dispersed particles experience a combination of lift forces (F_L) and Dean forces (F_D), which result in differential migration of the particles to unique equilibrium positions near the inner wall. (B) Illustration of the transition from switched focusing mode to traditional focusing mode with increasing flow rate for two particles, 15 μm (green) and 8 μm (red).