Separation arises from the interaction between two hydrodynamic effects. Inertial lift forces act on particles moving through the channel, while curvature generates Dean vortices, which are secondary circulating flows. Their combined action drives particles toward different equilibrium positions, allowing a spiral microdevice to distinguish and focus populations without labels.
Particle size and other particle properties influence how strongly inertial lift and Dean-vortex transport act on each particle. Because those effects do not position every particle identically, populations can focus at distinct locations within the curved channel. This size- or property-dependent positioning provides the physical basis for separating mixed biological samples.
Its passive, continuous-flow operation can provide a compact and low-cost alternative to centrifugation and other complex separation systems. It also supports label-free processing, so cells do not need an added labeling step for the separation mechanism described. These features are relevant when workflows prioritize rapid handling, reduced system complexity, and sample enrichment.
A sample is introduced into the curved microchannel and carried through it under flow. As the sample travels along the spiral, curvature produces Dean vortices while inertial lift acts on suspended particles or cells. The resulting positional differences focus distinct populations at separate locations, enabling continuous-flow separation or enrichment for downstream analysis.
In bioengineering, the platform can support blood analysis, circulating tumor cell isolation, and sample preparation. Its label-free enrichment capability is relevant when cell-containing samples must be processed without relying on labels as the separating principle. These uses connect microfluidic hydrodynamics with diagnostic workflows and research studies that require rapid handling of biological material.
The main outcome is the focusing, separation, or enrichment of cells and other particles according to their hydrodynamic behavior in the spiral channel. Because the process is continuous and label-free, it can prepare samples for later analysis while avoiding the need for a more complex separation setup. The compact format also suits rapid diagnostics and research workflows.