However, the particle needs to be positioned close to the thin wall to be influenced by the streaming vortex, which can be achieved by the acoustic radiation force. For particle attraction towards the thin wall, the Gor'kov potential minimum needs to be close to the embedded microbubble (see Equation ). As can be seen in Figure ), at the resonance frequency of 69.03 kHz a Gor'kov potential minimum is generated at half of the height of the thin wall; thus, particles are attracted to the displacement node of the thin PDMS wall. It is important to highlight, that the generated node is not based on a standing wave formation inside the channel and, thereby, does not rely on the geometrical dimensions of the PDMS as a whole. The experimentally determined relationship between the excitation voltage and the out-of-plane rotational speed of a specimen (rotation around x-axis). While the excitation frequency is kept constant at 69.2 kHz, an increase of the input power leads to stronger streaming velocities (Eq. 6) and subsequently to faster rotations of the specimen. The dashed line denotes a fitted quadratic curve with a coefficient of determination R 2 = 0.98.