Figure 1

Schematic diagram and size distributions of the microdroplets: (A) The structure of the microdroplets consists of three layers: alginate hydrogel (aqueous phase)—HFE 7500 (oil phase)—CP NPs in PBS solution (aqueous phase) from outside to inside. (B) (a,b) are the images of microdroplets manufactured with and without surfactants, respectively. The scale bar is 25 μm. (C) Size distribution of the microdroplets with surfactants. The mean value of the normal distribution fit is 24.9 μm. (D) Size distribution of the microdroplets without surfactants. It has a mean value of 25.6 μm although is not normally distributed.