Experimental Validation of Heteroclinic Orbit Dynamics in Inertial Microfluidics

This thesis explores particle dynamics in rectangular inertial microfluidic channels with the goal of improving label-free isolation of circulating tumor cells (CTCs) for liquid biopsy applications. CTCs are extremely rare in blood, making their separation both technically challenging and clinically significant. Inertial microfluidics offers a promising alternative to traditional methods by exploiting size-dependent lateral migration without the need for molecular labels. A critical challenge addressed in this work stems from prior ob- servations that smaller white blood cells (WBCs) can unexpectedly migrate toward the channel centerline, reducing separation purity. To investigate this phenominon, a compu- tational model based on heteroclinic orbit theory was used to simulate particle trajectories. Complementary experiments were conducted using 15μm polystyrene beads across four dif- ferent flow configurations (ranging from 1:1:1 to 1:6:1 buffer-to-sample ratios). The results confirmed that particle migration is continuous and strongly size-dependent, and that in- creasing buffer flow enhanced particle confinement which improves orbital alignment and reduced velocity variability. Among the tested configurations, the 1:6:1 ratio configuration produced the most uniform migration and closely matched the computational predictions, validating the model under experimental conditions. Although biological samples were not included in the present study, the findings establish a foundation for future investi- gations involving CTCs and WBCs. These results suggest a plausible explanation for the unexpected migration observed, which serves as a central motivation for this work.

Author dc:creator

• Chiara Francesca Ghera (23292043)

• Inertial Microfluidics
• Liquid Biopsy

Statement dc:rights

• In Copyright
• Open Access after 2028-01-01

DOI dc:identifier

https://doi.org/10.25417/uic.31451731.v1

OAI identifier oai:identifier

oai:figshare.com:article/31451731