INCREASED THROUGHPUT AND CAPACITY OF NM-PARTICLE AND EXTRACELLULAR VESICLE TRAPPING USING AN ULTRASOUND ACTIVATED PACKED BED

Research on EVs is gaining increased attention given their potential to discover new biomarkers.State-of-the-art EV isolation methods demand large sample volumes, significant manual labor, and long processing times, not amenable for diagnostics.An alternative for efficient isolation of EVs is acoustic particle trapping using levitated seed particles in a resonator [1], however, demanding critical requirements on electric feed-back loop control for levitation.Here we present a new method based on the fundamentals of acoustic trapping, capable of isolating extracellular vesicles (EVs) from blood plasma with high efficiency and throughput.The method is independent of device material and any system resonances in contrast to reported acoustic trapping techniques [1,2,3].Further, it is easily upscalable, providing a promising approach for automation and future industrial processing of EVs.We filled a glass capillary (4x0.4 mm) with 100 m diameter polystyrene (PS) particles and attached a piezoelectric element (Fig. 1 a).Ultrasonic waves generated by the piezo are scattered by the PS particles which leads to exosome trapping (Fig. 1 b).The experimental setup consisted of two syringe pumps connected to a valve, the traping device and a fluorescnce microscope for trapping efficiency analysis (Fig. 1 c).The trapping protocol was as follows: 1. Flush with buffer, 2. Sample injection, 3. Wash with buffer, 4. Release particles by turning off the acoustics.The trapping efficiency was determined by integrating the area of the fluorescent signal from the released particles (step 4) and divide it by the total fluorescence (step 2+3+4) (Fig. 2 a).