A total of 3% (w/v) dextran and 7% (w/v) PEG were dissolved into a 0.05-0.15% (w/v, counted by fibrils) fibril or fibril cluster suspensions, which was diluted by ultrapure water or high glucose Dulbecco's Modified Eagle Medium (H-DMEM, Gibco) supplemented with 10% fetal bovine serum (FBS, Gibco) and 1% penicillin/streptomycin (Gibco). A vortex was employed to prepare the emulsions and ThT (2 mM) was used to label the fibrils or clusters. For dextran/PEG emulsions in water, the pH of the system was adjusted to neutral pH using HCl. The emulsion stability was monitored after vortexing for 2 min under a fluorescence microscope (LWD300-38HMC, CEWEI). The fibril or fibril cluster partitioning in the emulsions were imaged. A blue laser with a maximum excitation wavelength of 445 nm was used to excite and detect the ThT-labelled fibrils or clusters. Besides, the fibril or cluster partitioning in emulsions were also characterized by a confocal laser scanning microscope (CLSM, Leica TCS SP8 STED 3X). Moreover, another method was used to characterize the partitioning of fibrils or clusters in two phases. Initially, the fibrils and clusters in the suspensions were labelled with ThT and incubated at 60 C for 15 min. Then the samples were washed using PBS through centrifugation (15000 rpm, 8 min) for 3 times to remove the free ThT. Subsequently, a 15% (w/v) dextran solution and an 8% (w/v) PEG solution in PBS were mixed at a 1:1 volume ratio, and the fibrils or clusters labelled with ThT were added to the mixture. After homogeneous mixing, the mixtures were centrifugated (800 rpm, 10 min) and gingerly transferred to the transparent sample cells. The partitioning of yellow fibrils or clusters can be observed by naked eyes.