Investigating Cell Viability under Shear Stress in Complex Microstreaming Flows Generated by Ultrasound-Driven Actuated Microbubbles

The analysis of rare or specialized cells is often a time-consuming process due to their low concentrations. In this study, we applied, for the first time, a method previously used on polymer particles to manipulate human cells. This technique enables the automatic direction and collection of target cells passing through a microchannel, significantly increasing their concentration for further analysis. The movement of the cells is controlled by an acoustically induced vortex flow generated by a microbubble. By modulating the activation of this microstreaming, the cells are shifted either to the upper or lower regions of the channel and directed into a side channel for collection downstream. The localized stress distribution, along with long-term testing that showed no cell damage, confirmed the biocompatibility of this method, making it a promising tool for lab-on-a-chip systems and biomedical diagnostics.