Microfluidics Cell Loading-Dock System: Ordered Cellular Array for Dynamic Lymphocyte-Communication Study

It remains a great challenge to establish a high-throughput platform that can explore the interactions among multiple lymphocytes (>2 cells) and retrieve the interested cells for downstream analysis. This study demonstrates a microfluidics cell loading-dock system (Cell-Dock) to enclose multiple cells in 1D, 2D, and 3D chambers with high throughput and efficiency and single-cell accuracy. The loading efficiencies of 95%, 85%, and 74% for one-, three-, and five-cell systems are achieved, respectively. The Cell-Dock system provides precise and dynamic cell packing models to facilitate lymphocyte-interaction studies. The results demonstrate that individual natural killer (NK) cells may function independently rather than cooperate to lyse target cells in the defined microenvironment. Furthermore, the strong/weak NK cells are retrieved based on their on-chip cytotoxicity and mRNA sequencing is conducted to find the possible mechanisms for "serial killing," an important but unsolved issue. This study finds that the stronger NK cells overexpress multiple genes involved in cytotoxicity and adhesion molecules (including the well-known ICAM1 and seldom reported B4GALT1) might play important roles in the regulation of NK cytolysis.