Aggregation Effect of Micro-Objects Induced by Sonotrodes with Different Shapes

Manipulation of micro/nano swimmers holds significant promise for environmental monitoring, clinical medicine, and intracellular communication. In these applications, the motion of most microparticles is driven by light, electric, acoustic, magnetic, or chemical energy, among which the acoustic energy shows absolute superiority in biocompatibility. However, accurate enrichment of micro-robot population is still difficult to achieve, which hinders the practical application of micro-robot population. Based on the acoustic wave excited by piezoelectric transducers, we propose an attractive strategy that combines the sonotrode into the microchannel. When the V-shaped sonotrode is immersed into the sample contained in the microchannel to a certain depth, the activation of the piezoelectric transducer will produce acoustic oscillation of the substrate and localized acoustic streaming around the tip of the sonotrode. In summary, the introduction of V-shaped sonotrodes into microchannels provides a method to promote rapid and active enrichment of micro/nano swimmers, offering a broad prospect for the next generation of sensitive portable detection microsystems.