Safety of acoustic separation in plastic devices for extracorporeal blood processing

BACKGROUND: Acoustic cell separation uses ultrasound waves to separate cells from plasma to perform plasmapheresis. Although the fundamental process has been studied for decades, no acoustic cell separation has been studied in a disposable plastic format suitable for clinical applications. STUDY DESIGN AND METHODS: We developed a disposable, rectangular, polystyrene microchannel acoustic cell-separation system and applied acoustic energy relevant for plasmapheresis. Fresh blood from healthy volunteers was exposed in vitro to acoustic energy in an open microfluidic circuit with and without ultrasound applied. Blood was tested for perturbations in red blood cells, platelets, and coagulation using clinical assays. RESULTS: Red blood cell and platelet size parameters as well as coagulation activation all were within 3% of baseline values. P-selectin expression on platelets increased by an average of 10.9% relative to baseline. Hemolysis increased with flow through the microfluidic channel, but percentage hemolysis remained below 0.3%. CONCLUSION: Blood parameters in a single-pass, microfluidic acoustic cell-separation apparatus remained within normal limits. In vivo animal studies that model continuous separation in a physiologic environment are warranted.