To quantify unencapsulated Mb after washing of the 1st fraction, the absorbance values after bicinchoninic acid assay (Merck Millipore, protocol according to manufacturer's manual) were compared in GUVs, GUVs after centrifugation (500 x g, 3 min, in an Eppendorf microcentrifuge, 2x) and washing with PBS, and the resulting washing supernatant. Volumes of both GUVs and supernatant were kept constant. conditions were imaged (either green or red fluorescent). Bacteria incubated at 95 °C for 10 minutes were the negative control.