For the monodisperse WPI-stabilized emulsions, only minor accumulation of CAMPO-AFDye 647 took place (Figure ). This finding indicates that little protein oxidation occurred at the interface, which we attribute to a more homogeneous protein coverage of the droplet interfaces due to the mildness of the microfluidic emulsification. In the panel in Figure we can, however, still observe the droplet with enhanced BODIPY 581/591 C11 oxidation, accompanied with a spot of CAMPO-AFDye 647 accumulation at the interface. Hence also for the monodisperse droplets some inter-droplet heterogeneity exists for lipid and protein oxidation, which is also in line with that protein oxidation is initiated by lipid oxidation. However, given the use of the AAPH initiator, we cannot exclude that this agent directly attacks proteins at the interface. We also note that there is a possibility that the fluorescence signals from the homogeneous thin protein layer in monodisperse emulsions might be not able to provide sufficient signal for CLSM measurements.