Sorting of extracellular vesicles has important applications in early stage diagnostics. Current exosome isolation techniques, however, suffer from being costly, having long processing times, and producing low purities. Recent work has shown that active sorting via acoustic and electric fields are useful techniques for microscale separation activities, where combining these has the potential to take advantage of multiple force mechanisms simultaneously. In this work, we demonstrate an approach using both electrical and acoustic forces to manipulate bioparticles and submicrometer particles for deterministic sorting, where we find that the concurrent application of dielectrophoretic (DEP) and acoustophoretic forces decreases the critical diameter at which particles can be separated. We subsequently utilize this approach to sort subpopulations of extracellular vesicles, specifically exosomes (<200 nm) and microvesicles (>300 nm). Using our combined acoustic/electric approach, we demonstrate exosome purification with more than 95% purity and 81% recovery, well above comparable approaches.
Keywords: acoustofluidics; dielectrophoresis; exosome purification; extracellular vesicles; submicrometer particle manipulation; surface acoustic waves.