A hybrid acoustofluidic device with Parafilm® that operates as a traditional bulk acoustic wave or flexural plate wave device

In this article we describe new hybrid microfluidic acoustic devices (HMADs) composed of two types of materials: soft elastic lateral walls made of Parafilm® that include a channel, and rigid top and bottom walls consisting of a glass slide and a glass coverslip. Depending on the selected vibration frequency of two small piezoelectric transducers, these HMADs can operate as Bulk Acoustic Wave (BAW) or as Flexural Plate Wave (FPW) devices, which induce either levitating circular or linear particle aggregates at higher frequencies when operating as BAW-like devices, or at acoustic frequencies close to those of the transducer's thickness mode when operating as FPW-like devices. The use of a soft, elastic material permits a range of different geometrical channel configurations. These HMADs in the BAW-like mode induce the formation of very stable aggregates, and in the FPW-like mode allow manipulation and control of the position or angular motion of particles and cells with micrometric precision when a phase change is induced between the two transducers.