(168g) High-Density Single Cell Trap Array for High-Throughput Imaging of Cells

Quantitative systems biology and the pharmaceutical industry have created the need for high throughput single cell analysis. Flow cytometry is a common tool used to gather single cell data in bulk populations. However, to elucidate intracellular signaling or gene network regulation, one needs to track individual cells over time and be able to manipulate their environment. Imaging of thousands of individual cells also enables to uncover the high variability in cellular response and phenotype of genetically identical cells. Microfluidic tools have been developed to trap cells. However, in most designs available to date, there seems to be a compromise between loading efficiency and single cell trapping. We circumvent the need of the trade-off by using a new capture mechanism that enables very fast single cell trapping in a highly dense trap array. We present here a microfluidic tool for highly efficient and parallel trapping of more than 4000 single cells in less than 30 seconds, with a loading efficiency of ~ 95%. The one-layer PDMS device consists of eight chambers of highly packed single cell traps. Each chamber consists of a wide serpentine cell-delivery channel and an array of cross-flow channels that connect each section of the serpentine channel. Each cross-flow channel includes a cell pocket connected to a shallow channel. The geometry of the channels is optimized so that cells experience identical trapping condition throughout the entire array. Also, we integrated protruding walls and bypassing channels near each curves of the serpentine channel to focus cells towards the traps. This significantly increases trapping efficiency and minimizes cell loss. Cell capture occurs with minimal shear on the cells, as demonstrated with a 94% viability of Jurkat cells after 24 h of culture in the microfluidic device. Using this high-density single cell trap device, we were able to simultaneously image up to 500 cells at 10x, and 13 cells at 63x, for high resolution microscopy, e.g. for colocalization studies. The trap chamber array can be easily integrated with upstream microfluidic components for controlling the environment, therefore enabling real time kinetic studies, or steady state response to drug treatment.