Fig. 4: Droplet stirring, photothermal stirring, and versatile droplet manipulation integration based on JO-robot.

a Schematic of the JO-robot stirring water droplet under the rotating magnetic field. The rotating magnetic field is generated by rotating the cube permanent magnet (25 mm × 25 mm × 25 mm) by the stepping motor. b The simulation of droplet internal flow field. c Time lapsed fluorescence images and normalized two-dimensional fluorescence distribution maps during droplet stirring. Scale bar is 500 μm. d Schematic diagram of the photothermal stirring. e Time lapsed fluorescence images and normalized two-dimensional fluorescence distribution maps during photothermal stirring of glycerol droplet. Scale bar is 500 μm. f The temperature curve of glycerol droplet during photothermal stirring. The inset shows the position of the temperature sensor during temperature detection. g The versatile droplet manipulation integration of JO-robot. Two dyed aqueous glycerol solutions (50% v/v) are used as demonstration. Scale bar is 2 mm. h The versatile droplet manipulation integration of JO-robot for microchemical reactions including micro-sampling, sample transportation, sample addition, rapid reaction and instant detection. Scale bar is 4 mm. i Versatile manipulation of nL-scale droplets based on the mini JO-robot, including droplet dispensing, transport, merging and mixing. Scale bar is 500 μm. The error bars represent the standard deviation of five independent measurements. Source data are provided as a Source Data file.