Spiral Microchannels

As fluid travels through the curved channel, inertial lift forces push particles toward preferred lateral positions, while curvature generates secondary Dean vortices that redistribute fluid across the channel. The resulting interaction determines where cells or particles migrate rather than allowing them to remain uniformly dispersed. This coordinated movement enables physical separation or enrichment without labeling the sample.

Particles of different sizes experience the balance between inertial lift and secondary Dean flow differently. That difference causes them to move toward distinct equilibrium positions within the channel. Because the separation depends on physical behavior rather than an added molecular label, the approach can distinguish sample components according to size or related physical properties before downstream characterization.

Channel curvature is central because it generates Dean vortices, which are secondary circulating flows superimposed on the main fluid movement. These vortices interact with inertial lift forces and alter the lateral migration of suspended cells and particles. Without considering this curvature-driven flow, the mechanism that produces distinct equilibrium positions and compact sample processing would be incomplete.

A sample is introduced into the microfluidic conduit and transported through its spiral path under flowing conditions. During passage, cells and other particles migrate according to their physical properties, allowing selected components to become separated, concentrated, or enriched. The processed material can then proceed to cell characterization, pathogen-related investigation, or another diagnostic analysis.

Their microscale conduits support compact processing with reduced sample volumes and fewer handling steps. The same flow-based separation can prepare material without relying on labeling, which simplifies handling before analysis. These features are especially relevant when researchers need faster preparation of blood-derived samples or immune-cell populations for subsequent characterization.

In immunology, the technique can help separate, concentrate, or enrich blood cells and immune-cell populations before characterization. In infection research, the processed sample may support pathogen-related studies by reducing unwanted components before analysis. The approach also fits diagnostic workflows because it combines compact, label-free sample preparation with the physical handling of heterogeneous biological material.