Abstract
Coacervates, which are formed by liquid–liquid phase separation, have been extensively explored as models for synthetic cells and membraneless organelles, so their in-depth structural analysis is crucial. However, both the inner structure dynamics and formation mechanism of coacervates remain elusive. Herein, we demonstrate real-time confocal observation of a three-dimensional sponge-like network in a dipeptide-based coacervate. In situ generation of the dipeptide allowed us to capture the emergence of the sponge-like network via unprecedented membrane folding of vesicle-shaped intermediates. We also visualized dynamic fluctuation of the network, including reversible engagement/disengagement of crosslinks and a stochastic network kissing event. Photo-induced transient formation of a multiphase coacervate was achieved with a thermally responsive phase transition. Our findings expand the fundamental understanding of synthetic and biological coacervates, and provide opportunities to manipulate their physicochemical properties by engineering the inner network for potential applications in life-like material fabrication and biomedical research.
Content

Supplementary material

Supplementary information
A pdf file of supplementary information

Supplementary movie 1
A mp4 file of supplementary movie 1

Supplementary movie 2
A mp4 file of supplementary movie 2

Supplementary movie 3
A mp4 file of supplementary movie 3

Supplementary movie 4
A mp4 file of supplementary movie 4

Supplementary movie 5
A mp4 file of supplementary movie 5

Supplementary movie 6
A mp4 file of supplementary movie 6

Supplementary movie 7
A mp4 file of supplementary movie 7

Supplementary movie 8
A mp4 file of supplementary movie 8

Supplementary movie 9
A mp4 file of supplementary movie 9

Supplementary movie 10
A mp4 file of supplementary movie 10

Supplementary movie 11
A mp4 file of supplementary movie 11