Fig. 4.
Payload reorganisation in self-reconfigurable host–guest protocells. a-f Confocal fluorescence microscopy images showing host–guest protocells consisting of GOx-containing FITC-labelled proteinosomes (green) entrapped within micelle coacervate droplets (unlabelled) prepared in the presence of red fluorescent RITC-HRP (a), RITC-ALP (b) or TAMRA-ssDNA (c), and after proteinosome-mediated disassembly of the host coacervate droplets (d–f, respectively). Initially, RITC-HRP and RITC-ALP are sequestered in the coacervate phase (a, b), whilst TAMRA-ssDNA is confined to the water-filled proteinosome interior and external solution (c). Enzyme-mediated disassembly gives rise to RITC-HRP transfer to the lumen of fatty acid vesicles housed within the proteinosome interior or present in the external solution (d), RITC-ALP transfer to vesicles formed outside the proteinosomes (e, blue arrow), but excluded from the proteinosome-internalised vesicles (e, orange arrow) and release of TAMRA-ssDNA to the external solution without transfer to the vesicles (f). Insets in d–f show 3D reconstructions of the proteinosomes. g Control experiments involving addition of RITC-HRP after completion of the micelle coacervate-to-vesicle transition showing no uptake of the solute by the preformed fatty acid vesicles. h Plot of normalised solute fluorescence intensity (IIN/IOUT) associated with vesicle-in-proteinosome hybrid protocells showing dependence of molecular weight and surface potential on payload uptake into the reconfigured nested protocells. Error bars represent the standard deviation of the ratio of fluorescence intensities. i Confocal fluorescence microscopy image of a single guest proteinosome prepared with a non-fluorescent membrane and containing FITC-GOx, and recorded after disassembly and transformation of the host–guest protocell. FITC-GOx molecules are excluded from the proteinosome-internalised Nile Red-stained fatty acid vesicles. Inset in i shows high-magnification image. j 3D reconstruction of a single guest proteinosome prepared with a non-fluorescent membrane and containing FITC-GOx, and recorded after disassembly and transformation of a host coacervate encapsulating RITC-HRP. RITC-HRP-containing vesicles (red) are housed within the FITC-GOx-containing (green) proteinosome. k Plots of time-dependent HRP-mediated conversion of Amplex Red into resorufin measured for vesicle/proteinosome guest–host protocells containing vesicle-entrapped HRP (blue), or control experiments in which HRP was added to the external phase of a vesicle suspension (black). Error bars represent the standard deviation of the substrate conversion (n = 3)