Nanoscale Amphiphilic Star-like Macromolecules with Carboxy-,Methoxy- and Amine-terminated Chain Ends

摘要

Amphiphilic star-like macromolecules (ASMs) with chain ends terminating as methoxy-,carboxy- and amine groups were synthesized for use as drug solubilization and delivery systems.Hydrophobic mucic acid derivatives were conjugated to the pentaerythritol tetraacrylate as the core molecule,then poly(ethylene glycol) chains with specific functionalized chain ends were attached.With respect to size in solution,the ASMs with longer alkyl chains (C12) in the core were slightly larger than polymers with shorter alkyl chains (C6),and the carboxy-terminated ASMs displayed slightly larger sizes than the methoxy- and amine-terminated polymers.In aqueous solution,the ASMs maintained their nanosize,ranging from 20 to 40 nm in diameter in solutions with pH values of 2,7.4 and 9.The shorter C6 chain polymers displayed sizes that were independent of pH,whereas the longer chain polymers displayed a more pronounced response to pH changes.With respect to thermal properties,ASMs with larger hydrophobic cores had slightly lowered melting and crystallization temperatures.The methoxy-terminated ASMs have higher melting and crystallization temperatures (by ~8 deg C) than the ASMs terminated with carboxy and amine functionalities.