Fig. 1: Overview of the droplet robotic system based on the mechanism of electret-induced polarization on droplet (EPD).

A Working principle of the EPD-based droplet actuation. B Optical image of the EPD-based droplet robotic system and its core components. C Overlaid sequential images (derived from video frames), which visualize the moving path of the droplet actuated by the EPD-based droplet robotic system, including the shapes of letter H, K, and U, respectively. Scale bars: 10 mm. D Comparison between the proposed EPD-based droplet robotic system and the existing automated droplet actuation system from 6 perspectives (left). The evaluations are conducted based on the detailed information in Supplementary Table 1. EPD’s wide range of operable liquid types and the compatibility with bio-sample are particularly demonstrated and compared with air-based EWOD and oil-based EWOD based on Supplementary Figs. 2, 3, respectively (right). Source data are provided as a Source Data file.