Fig. 1
![Fig. 1](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs12951-018-0360-3/MediaObjects/12951_2018_360_Fig1_HTML.gif)
Characterizations of PCM-E2/PFPs. a Optical microscopy image of PCM-E2/PFPs. b TEM image of PCM-E2/PFPs. c Macroscopic views of free PFP and PCM-E2/PFPs at the same PFP concentration in PBS. d, e Size distribution and Zeta potential of PCM-E2/PFPs. f Size distributions of E2/H2Os, PCM-E2/H2Os and PCM-E2/H2Os. g Size changes of PCM-E2/PFPs at 4 °C after long-term storage (n = 3)