(color online) Schematic illustration of a workflow of cell-based screening using DA sandwich chip. LMA slide is prepared by printing of substances of interest on a glass slide (step 1); DA slide is prepared by seeding cells using the effect of discontinuous dewetting (step 1). For parallel addition of library into individual droplets LMA slide is aligned and sandwiched with DA slide containing cells (step 2). After substances are transferred into droplets LMA slide is removed and DA slide is placed into cell culturing incubator (step 3). As a read-out cells can be either directly subjected to live imaging (step 4, upper panel) or after live staining by sandwiching DA slide containing cells with identical DA slide containing CalceinAM solution (Fig. 1(c), step 4, middle panel) or by immersing DA slide containing cells into CalceinAM solution (step 4, lower panel) (from Ref. [31], Fig. 1).