Schematic illustrations of the detailed architecture of a digital microfluidic droplet generation (DMDG) chip, working principle and chip-based screening. (A) A setup of DMDG chip in which food dyes were used to aid visualization of different components; (B) Schematic of a DMDG chip. The DMDG chip is composed of three functional parts: (1) droplet generation core, where droplets with specific compositions can be generated digitally; (2) on-chip peristaltic pump, which precisely produces serial compressed nitrogen pulses that can reliably deliver intact droplets to the desired location and (3) mixing channel. Inlets 1–8 are for cleaning, vacuum, cleaning/buffer 1, [18F]SFB, A2 Db, buffer 2, pH control buffer, and waste respectively. Section I is specifically used for [18F]SFB, section II for A2 Db and buffer 2, section III for pH control buffer, respectively. The fluidic channel width is ca 200 µm and height is ca 40 µm. (C) The reaction scheme of 18F-labeling diabody using [18F]SFB. (D) Schematic of adjusting pH in each droplet. (E) Schematic of adjusting the concentration of A2 Db in each droplet.