Microvortex-Induced Liquid Replacement Reveals Cellular Dynamic Behavior

We present a microvortex-induced liquid replacement method for investigating cellular dynamic behavior. Conventional microscale flow control techniques are limited to replacement frequencies below 10 Hz, making it difficult to study rapid cellular responses occurring within tens of milliseconds. To address this challenge, we developed a system based on high-speed on-chip flow control for the generation of microvortices. Remarkably, our system achieves millisecond-scale liquid replacement, providing both step- and pulse-like stimulation capabilities that previously uncovered inaccessible aspects of cellular dynamics. As results, we achieved high-speed replacements of 1.8 and 0.87 ms in step- and pulse-like replacements, respectively. Notably, pulse-like replacements provide a high frequency of 500 Hz and demonstrate hypertonic repetitive stimulation of a single cell, revealing the time scale of cellular osmoadaptation. This method offers a powerful platform for probing dynamic models of cellular behavior.