Acoustofluidic centrifuge for nanoparticle enrichment and separation

Abstract

Liquid droplets have been studied for decades and have recently experienced renewed attention as a simplified model for numerous fascinating physical phenomena occurring on size scales from the cell nucleus to stellar black holes. Here, we present an acoustofluidic centrifugation technique that leverages an entanglement of acoustic wave actuation and the spin of a fluidic droplet to enable nanoparticle enrichment and separation. By combining acoustic streaming and droplet spinning, rapid (<1 min) nanoparticle concentration and size-based separation are achieved with a resolution sufficient to identify and isolate exosome subpopulations. The underlying physical mechanisms have been characterized both numerically and experimentally, and the ability to process biological samples (including DNA segments and exosome subpopulations) has been successfully demonstrated. Together, this acoustofluidic centrifuge overcomes existing limitations in the manipulation of nanoscale (<100 nm) bioparticles and can be valuable for various applications in the fields of biology, chemistry, engineering, material science, and medicine.

Microfluidic technologies for nanoparticle formation

“…Microfluidic platforms combined with supersonic fields (acoustofluidics) have been extensively used for manipulation and separation of particles in a label-free manner. 100,101 Recent studies from our and other groups have shown that externally applied supersonic waves (either This journal is © The Royal Society of Chemistry 2022 by PZT embedded on the substrate or bulk acoustic resonator) can induce intensive acoustic pressures in the order of hundreds of KPa within the confined microchannel to reform NPs (Fig. 4a).…”

Advanced Nanotechnologies for Extracellular Vesicle‐Based Liquid Biopsy

“…[ 71 ] Huang's team developed an acoustofluidic centrifuge for nanoparticle enrichment and separation by entanglement of SAW actuation and the spin of a fluidic droplet (Figure 2g ). [ 72 ] Generally, SAW‐based acoustic nanofilters enable a simple contact­free method for EV isolation in a size‐tunable manner, but the farraginous cell debris and protein aggregates cannot be separated clearly.…”

“…g) Acoustofluidic centrifugation. Reproduced with permission [72]. Copyright 2021, American Association for the Advancement of Science.…”

Acoustofluidic Droplet Sorter Based on Single Phase Focused Transducers

“…Acoustofluidics, the fusion of acoustics and microfluidics, can effectively manipulate and sort picolitre droplets via noninvasive, mild, and highly biocompatible acoustic forces. [ 35–53 ] Therefore, acoustofluidic sorters often have advantages in biocompatibility. [ 54–56 ] However, current acoustofluidic droplet sorters have deficiencies in their energy conversion rate, which hinders their further development.…”