Dual-wave acoustofluidic centrifuge for ultrafast concentration of nanoparticles and extracellular vesicles

Extracellular vesicles (EVs) are secreted nanostructures that play various roles in critical cancer processes. They operate as an intercellular communication system, transferring complex sets of biomolecules from cell to cell. The concentration of EVs is difficult to decipher, and there is an unmet technological need for improved (faster, simpler, and gentler) approaches to isolate EVs from complex matrices.

Researchers at Cardiff University have developed a method for acoustofluidic concentration of extracellular vesicles (ACEV), based on a thin-film printed circuit board with interdigital electrodes mounted on a piezoelectric substrate. An angle of 120° is identified between the electrodes and the reference flat of the piezoelectric substrate for simultaneous generation of Rayleigh and shear horizontal waves. The dual waves create a complex acoustic field in a droplet, resulting in effective concentration of nanoparticles and EVs. The ACEV is able to concentrate 20 nm nanospheres within 105 s and four EV dilutions derived from the human prostate cancer (Du145) cell line in approximately 30 s. Cryo-electron microscopy confirmed the preservation of EV integrity. The ACEV device holds great potential to revolutionize investigations of EVs. Its faster, simpler, and gentler approach to EV isolation and concentration can save time and effort in phenotypic and functional studies of EVs.

Acoustofluidic centrifuge for ultra-fast concentration of extracellular vesicles (ACEV)

a) The ACEV device is made by mounting a thin-film printed circuit board (TPCB) with interdigital electrodes to a 128° Y-cut LiNbO3 substrate. EV suspension is added to a PDMS ring as the sample reservoir. The concentration is achieved by the micro-streaming induced by surface acoustic wave (SAW), produced by the TPCB-based transducer. An inset shows the EV sample inside the PDMS ring before and after SAW concentration. b) Process flow for using the ACEV device. 1. The PDMS ring is prepared for accommodating EV culture supernatant. 2. An EV suspension (50-µL) is loaded into the PDMS ring. 3. SAW is turned on to concentrate the EV supernatant. 4. Extensive microstreaming is noted in the EV sample, rising the sample higher. 5. The concentrated EVs form a pellet, which can be extracted using a pipette. 6. Harvested EVs are subjected to follow-up analysis, such as electron microscopy.

Dumčius P, Mikhaylov R, Zhang X, Bareford M, Stringer M, Errington R, Sun C, Gonzalez E, Krukovski T, Falcon-Perez JM, Liang D, Fu YQ, Clayton A, Yang X. (2023) Dual-Wave Acoustofluidic Centrifuge for Ultrafast Concentration of Nanoparticles and Extracellular Vesicles. Small 19(35):e2300390. [article]

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