Influence of Hydrodynamics and Hematocrit on Ultrasound-Induced Blood Plasmapheresis

Abstract

Acoustophoretic blood plasma separation is based on cell enrichment processes driven by acoustic radiation forces. The combined influence of hematocrit and hydrodynamics has not yet been quantified in the literature for these processes acoustically induced on blood. In this paper, we present an experimental study of blood samples exposed to ultrasonic standing waves at different hematocrit percentages and hydrodynamic conditions, in order to enlighten their individual influence on the acoustic response of the samples. The experiments were performed in a glass capillary (700 µm-square cross section) actuated by a piezoelectric ceramic at a frequency of 1.153 MHz, hosting 2D orthogonal half-wavelength resonances transverse to the channel length, with a single-pressure-node along its central axis. Different hematocrit percentages Hct = 2.25%, 4.50%, 9.00%, and 22.50%, were tested at eight flow rate conditions of Q = 0:80 µL/min. Cells were collected along the central axis driven by the acoustic radiation force, releasing plasma progressively free of cells. The study shows an optimal performance in a flow rate interval between 20 and 80 µL/min for low hematocrit percentages Hct ≤ 9.0%, which required very short times close to 10 s to achieve cell-free plasma in percentages over 90%. This study opens new lines for low-cost personalized blood diagnosis.

Ultrasonic Particle Manipulation in Glass Capillaries: A Concise Review

“…They demonstrated 2D concentration of microparticles by actuation of two vertically placed PZTs, and reasonable focusing performances were reported with flow rates up to 100 µL/min. Similarly, Gonzalez et al [ 56 ] showed acoustic enrichment of blood cells from whole blood in a square glass capillary ( a = 0.7 mm) by a half-wavelength standing wave generated in the lateral direction of the channel. Recently, Koo et al [ 54 ] showed acoustic cell patterning in hydrogel in a square glass capillary ( a = 0.4 mm), shown in Figure 6 B.…”

Microfluidics geometries involved in effective blood plasma separation

“…Further, SE has an uncommon definition in several research articles based on 0 and Hct, etc. A widespread definition is found as [(( C s – C P )/ C s ) × 100] (Jaggi et al 2007 ; Lenshof et al 2009 ; Kersaudy-Kerhoas et al 2010b ; Tripathi et al 2015a , b ; Gonzalez et al 2018 , 2020 ; Li et al 2020 ). Here, C s represents the number of cells per μL of blood at the main channel inlet; C P represents the number of cells per μL of extracted plasma from the plasma outlet.…”

“…It shows SE greater than 80% at Q 0 = 80 μL/min. Most recently, the geometry has been chosen by Gonzalez et al ( 2020 ), and they introduced a new separation technique for plasma extraction, such as an ultrasonic standing wave. In general, the geometry includes one inlet and three outlets, Fig.…”

Engineered Membranes for Residual Cell Trapping on Microfluidic Blood Plasma Separation Systems: A Comparison between Porous and Nanofibrous Membranes

“…Microfluidic-based methods for blood plasma separation usually rely on active and passive techniques [5]. Active approaches involve the use of external forces (e.g., acoustic [6], electrical [7], or magnetic [8]). Passive techniques rely on internal hydrodynamics (e.g., cell focusing [9]), sedimentation [10], or microfiltration [11].…”