Removal of nonspecific bindings in on-chip ELISAs with low power ultrasound

We present a novel method for removing nonspecifically bound proteins for on-chip ELISAs (Enzyme-Linked-Immuno-Sorbent-Assays) by integrated ultrasonic washing of the reaction chamber. Low power ultrasound is concentrated into the reaction chamber with an ultrasonic horn contained in the base of the measurement system. Application of ultrasonication during the last washing step of the ELISA protocol removes adsorbed proteins from the wall while not affecting specifically bound analytes. This method reduces the cost of the disposable assay-chips, while delivering comparable results with standard blocking methods.