A controllable, centrifugal-based hydrodynamic microfluidic chip for cell-pairing and studying long-term communications between single cells.

Abstract

Investigation of cell-cell interactions between individual cells in a well-defined microenvironment is critical for the under-standing of specific intercellular communications and interactions. However, most current studies are in multicellular sys-tems often overwhelmed by additional complicated interactions. Cell-pairing based on microfluidic chip provides a potential strategy to simplify the studies. Here we report a robust and straightforward method, relying on a combination of hydrody-namic single-cell capture and centrifugation-assisted relocation of individual cells, which can be applied, in general, to vari-ous cell types for cell-pairing and studying cell interactions at the single-cell level. This microfluidic chip is simple to operate, and well controllable, which requires only two operational steps-capturing individual cells with hydrodynamic traps and sub-sequently relocating the capture cells by centrifugation. With this microfluidic chip, we demonstrated homotypic cell-pairing, heterotypic cell-pairing and long-term cell co-culture, which exhibited better or comparable performances compared with previous cell-pairing methods. Its single-cell trapping and cell-pairing efficiencies are ~74% and ~20%, respectively. As proof of concept, we paired individual dHL-60 cells and HeLa cells (HeLa-IL8, HeLa-IL10, and wild type HeLa cells) in multiple cell chambers. The HeLa-IL8 and HeLa-IL10, both engineered with a light-induced gene expression system, can secret inter-leukin-8 and interleukin-10, respectively, under blue light illumination. We found that these three HeLa cell lines give very different influences on the migration of dHL-60 cells. This platform demonstrates its potential applications in studies of in-tercellular communication (paracrine) and it can be extended to trap three or more individual cells for more complex biolog-ical systems.