Synthesis And Application Of Stable Vesicles Derived From Multi-Arm Star Copolymers

In this article, the terminal hydroxyl groups of amphiphilic multiarm starcopolymers with a hydrophilic hyperbranched polyethylenimine (PEI) core andhydrophobic poly(-caprolactone)(PCL) arms were partially or completelytransformed into the radical-crosslinkable methacrylate (MA) groups(PEI-b-PCL-MA).The resulting PEI-b-PCL-MA polymers with100%MA substitutionself-assembled in water into simple vesicles, whereas those with partial MAsubstitution aggregated into complex vesicles. These structures could be proved bytransmission electron microscopy and dynamic light scattering only after crosslinkingthe intra-vesicular MA groups that generated the covalently stabilized vesicles (CSVs).A and it was found that the corona of the vesicles was not the simple double-layerstructure, but contained a certain amount of star polymeric units between thedouble-layers.The obtained CSVs could be used as host for the formation of gold nanoparticle(AuNP) cluster, and the AuNP clusters stabilized by the CSVs were stable under awider range of CSV/AuNP feed ratio than those stabilized by the uncrosslinkedprecursors. The diameter of AuNPs in the clusters was in the range of4–6nm, andthe distance of adjacent AuNPs could be modulated through altering the feed ratio ofCSV/AuNP. The color of the solutions of AuNPs with CSV could be tuned frombrown to red, purple, even blue. The composites of CSV and AuNPs could be furtherused as nanocarriers to accommodate hydrophobic guest of pyrene, and a higheramount of AuNPs in the nanocarriers led to a lower encapsulation capacity for pyreneguests.