Progress on acoustic radiation force-based subnano- and nanometer size particles manipulation. (A) Exosomes, a subpopulation of 30–200 nm macrovesicles, are separated from blood sample using double separation module with increased frequency SAW fields [28]. (B) The approach for generating lateral and vertical standing wave fields, lateral standing wave field is generated by opposite propagating traveling waves from double IDTs, and vertical standing wave field is generated by the leakage waves and reflected leakage waves from glass bottom of the channel [68]. (C) The high frequency IDT generates uneven acoustic field with the center area dominated by acoustic radiation force and edge areas dominated by acoustic streaming caused vortices, parameters including aperture length of IDT and channel structure can influence this uneven distribution (left), this phenomenon is caused by diffraction during acoustic wave propagation, which induces distribution deterioration with distance increasing [34]. (D) Utilization of unidirectional IDTs can generate stronger acoustic fields with less uneven distribution, indicating improvement on IDT design can avoid diffraction problems [76].