(236i) Inertial Microfluidic Enrichment of Complex Fluids

Microfluidic emulsification, the microchannel-assisted production of stable, monodisperse aqueous droplets in a continuous organic phase, has been exploited to produce solid particles from polymerizable precursor solutions.  This has opened new avenues to particle synthesis and dispersions have been produced over a broad range of sizes with variable morphology and composition.  These efforts, however, have stopped short at the creation of low-concentration (high water content), photo-initiated hydrogel particles.  Such hydrogels, including poly(ethylene glycol) (PEG) and PEG mixtures, represent an important class of materials in drug delivery, tissue engineering and regenerative medicine.  We have adapted cytocompatible batch emulsification and polymerization techniques to the production of highly-swollen PEG suspensions, albeit with broad size distributions.  To achieve monodisperse particle size distributions from these polymerized emulsions, we employ inertial microfluidic focusing to perform passive, size-selective particle sorting at very high throughputs.  Inertial focusing behavior is highly sensitive to relative particle and channel confinement, which allows for the design of devices targeting any given particle size distribution.  Complicating factors, however, include dependencies upon fluid flow rate, particle volume fraction and particle deformability.  We have empirically developed predictive scaling relationships for the processing of complex fluids via inertial focusing and will demonstrate the applicability of this approach for particle size-based enrichment of arbitrary suspensions as well as other separations including “on-chip centrifugation”.