Microfluidic Processes for Protein Separations

Abstract

Microfluidic continuous-flow separation techniques offer advantages to conventional batch-based methods. In this thesis, microfluidic continuous magnetophoretic protein separation and aqueous two-phase microdroplets for protein partitioning are explored. For microfluidic continuous magnetophoretic protein separation, superparamagnetic nanoparticles interact preferentially with hemoglobin in a mixture with bovine serum albumin, form protein-nanoparticle aggregates, and are recovered online by magnetophoresis. Detailed modeling reveals the importance of particle size distributions in estimating separation efficiency. Another approach for protein separation was explored using aqueous two-phase microdroplets. The generation of biphasic microfluidic droplets with tunable internal structures beyond the equilibrium drop-in-drop morphologies is demonstrated. Further, separation of a protein mixture, bovine serum albumin and cytochrome c, using these microdroplets is demonstrated. Finally, an exploration of aqueous-aqueous fluid interfaces for nanoparticle precipitation and macromolecule?assisted assembly is demonstrated. Hierarchically structured superparamagnetic iron oxide particles are fabricated and continuous generation of these structures using droplet microfluidics is also demonstrated.