Fig. 4. Fabrication of single-cell-laden hydrogels.

a Schematic showing the process of crosslinking the alginate solution by Ca²⁺ diffusion. b Image of the formed monodisperse alginate microgels. Scale bar: 200 μm. c Design of the integrated channel to perform continuous droplet generation and sorting. d Image illustrating the sorting process: The droplets with single cells are driven to the positive channel, while the droplets without cells flow into the negative channel. Scale bar: 100 μm. e Comparison of the formed hydrogels without and with sorting after a Live/Dead assay. Scale bar: 100 μm. f A plot of the percentages of the droplets encapsulating zero, single and multiple cells without and with sorting