Effect of hydrophilic segment length on size and stability of core crosslinked micelles

Abstract

Polymeric micelles are being extensively studied in recent years for their potential use as drug carriers. They consist of hydrophilic and hydrophobic segments and due to the solubility difference between these segments, polymeric micelles are self-assembled into core-shell nanostructures formed in aqueous solution. The hydrophobic reservoir of micelles are capable of hosting low water soluble drug molecules, thus so-prepared micellar constructs have been widely utilized in preparation of sustained/controlled drug releasing platforms. In order to improve the stability of micelles and to achieve a more gradual release profile crosslinking strategies can be employed. In this thesis, several amphiphilic linear polymer-dendron conjugates have been synthesized via Huisgen type ‘click’ reaction using biodegradable, hydrophobic polyester dendron and biocompatible, hydrophilic p(PEGMA)-based copolymers. These conjugates differ from each other in terms of length of hydrophilic segment while the hydrophobic dendron part is constant. Since, the periphery of the dendron contains alkene units, core of the micelles were crosslinked using thiol-ene ‘click’ chemisty to increase the stability of the micelles. The micelle formation of conjugates were investigated in aqueous media, studying size and stability. The results demonstrated that as increasing the polymer length of the conjugates, critical micelle concentrations and size distributions did not change which means that stability of the micelles remained same.