Adjustment of surface condition for self-generation of droplet array using oil-water replacement

This paper demonstrates a method to self-generate a two-dimensional (2D) array of nanoliter-scale droplets. 2D droplet arrays are powerful tools for high throughput and low-cost processes in the field of biology or medicine. We recently developed a self-generation method of droplet array without precise liquid control such as precise pipetting or pumping. The next challenge of the self-generation is the further miniaturization of generated droplets. Here, we addressed it by applying a photoresist off-stoichiometry thiol-ene (OSTE), of which surface energy can be tuned by polymer chain grafting. We experimentally found the surface conditions to self-generate an array of nanoliter-scale droplets.