2.

Morphology and molecular distribution in multiphase coacervates. a) Confocal fluorescence microscopy images of multiphase coacervates prepared with DEAE-dextran/CM-dextran, pLys/pAsp, and pHis/ATP at pH 5.7. b) Comparisons of relative fluorescence intensity for each of the fluorescently labeled cations in the multiphase system (L to R): DEAE-dextran-FITC (green), pLys-Rhodamine (red), and pHis-Alexa Fluor 633 (introduced via a fluorescently tagged 20His-C peptide, blue). Fluorescence intensities are normalized to the maximum signal for each dye, such that the phase with the highest intensity is set to 100%. Intensities in the other phases are expressed as a percentage relative to this maximum. Error bars represent standard deviations of a minimum of 20 droplets. c) Raman spectrum of pHis and ATP Raman stretches of multiphase coacervate droplets at pH 6. d) MicroRaman maps plotted by characteristic peak: (left panel) ATP distribution represented by phosphate stretching, νs (P–O–P), at 719 cm^–1; , (middle panel) pHis distribution represented by imidazole ring C–C rocking or scissoring δ (R) at 989 cm^–1; , (right panel) overall organic content, represented by C–H stretching from 2800 to 3182 cm^–1. All maps have been normalized based on the area under their corresponding peaks. Scale bars are 10 μm unless otherwise noted.