Systems and methods for cleansing blood are disclosed herein. The methods include acoustically separating target particles from elements of whole blood. The whole blood and capture particles are flowed through a microfluidic separation channel formed in a thermoplastic. At least one bulk acoustic transducer is attached to the microfluidic separation channel. A standing acoustic wave, imparted on the channel and its contents by the bulk acoustic transducer, drives the formed elements of the blood and target particles to specific aggregation axes.