Physical principles of magnetic extraction from microfluidic droplets

Suny At Stony Brook, Stony Brook NY

Investigators

Abstract

New treatments for disease are enabled by technological advances that create, isolate, characterize, and test novel therapeutic agents and cellular reagents. To accelerate testing of millions of candidate therapeutics, researchers have miniaturized typical laboratory techniques onto small chips called microfluidic devices. Microfluidics control and handle extremely small volumes of fluids in networks of micron-size conduits. A sample of interest is immersed in a tiny droplet of highly stable carrier oil to be precisely controlled through the conduits at high speed. This approach has enabled millions of parallel tests to study treatments for cancer, autoimmune disorders, and many other diseases. However, recovery of the sample of interest from the oil is difficult, and is often essential for additional analysis or processing. To enable this technology, this project will use tiny magnets to extract the samples of interest from the oil carrier droplets, and elucidate the fundamental physics that govern the behavior of droplets in a magnetic field. This project will extract and capture molecules from droplets using functionalized magnetic beads. The beads will be concentrated into a corner of the droplet with an external magnetic field. Then, the droplet will be split to concentrate the beads into a smaller, daughter droplet. This project will provide a fundamental understanding of the complex hydrodynamic, magnetic, and capillary forces in this extraction process. The coupling between hydrodynamic and magnetic forces in flowing droplets will be correlated to bead dispersion. The capillary number will be related to non-parallel droplet splitting. The developed theory will be validated by magnetic extraction of messenger ribonucleic acid (RNA) from cell lysates, followed by quantification. This project will use microfluidics as a teaching tool to demonstrate physics fundamentals and engineering design, with outreach to underrepresented minority students and educators who drive statewide curriculum.