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

Abstract

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. Impact StatementThis study presents an innovative use of ultrasound-driven microbubble streaming for the precise manipulation and sorting of human cells in microfluidic environments, all while maintaining cell viability. The research shows that the localized shear stress near the microbubble is significantly below the damage threshold for cells, confirming the biocompatibility of this method. The potential impact of this work is considerable for lab-on-a-chip systems and biomedical diagnostics. It offers a reliable, non-invasive solution for the manipulation, sorting, and removal of compromised cells, thus streamlining research and diagnostic procedures. By ensuring the safe and efficient handling of rare or specialized cells, this technique can accelerate various biomedical applications. Additionally, the studys evidence of sustained cell viability under microstreaming conditions suggests broader applicability in biomedical devices, particularly in automated dead cell removal and selective cell positioning.