PH sensitive polymer nanoassemblies based on cyclodextrin polymer

Abstract

In this work, amphiphilic pH sensitive dextrans have been designed to elaborate complex systems with β-cyclodextrin polymers. The synthesized di-substituted dextrans bear purely hydrophobic groups (either dodecyl, C12, or adamantyl, Ada) and cyclohexancarboxylic acid groups (CHX). The assemblies formed by simply mixing the di-substituted dextrans and pβCD solutions show interesting pH dependence. At pH 7 (CHX groups fully charged), the polymers mixture leads to monophasic solutions; at pH 2 (CHX groups fully protonated), the polymers mixture leads to associative phase separations with precipitation. Between these two limiting cases (at pH around 4), associative phase separation still occurs but leads to the formation of metastable nanoassemblies.