Amphiphilic Diblocks Sorting into Multivesicular Bodies and Their Fluorophore Encapsulation Capabilities

Synthetic macromolecular diblocks sorting into mutivesicular
bodies (MVBs) and their fluorophore encapsulation pathways were reported.
Renewable resource based diblocks having hydrophobic units and flexible
hydrophilic polyethylene glycols (PEG) were custom designed for the
above purpose. Single crystal structure was resolved to prove the
existence of the strong intermolecular interactions and the formation
of unilamellar layer-like self-assemblies. These amphiphilic AB diblocks
underwent selective vesicular fission either by outward budding or
inward invagination to produce small unilamellar vesicles (SUVs) or
MVBs, respectively. Self-organization parameters such as relative
volume (νe) and reduced area difference (Δa0) were determined on the basis of theoretical
models, and very good correlation with the experimental results was
established for the synthetic-MVBs. Pyrene was encapsulated to study
the mechanistic aspects of the MVB formations. An unusual nonlinear
trend was observed in the pyrene dynamic excimer formation with respect
to the sorting of diblock membrane into MVBs. Strong intermolecular
interaction was found to be a critical deciding factor in synthetic
diblock membranes to facilitate MVBs. The approach demonstrated here
opens up new design strategies for biomimicking of MVBs in synthetic
macromolecules which are potential vectors for drug delivery.