pH-responsive polymeric nanoassemblies encapsulated into alginate beads: morphological characterization and swelling studies

Abstract

The aim of this study is to design and develop novel hybrid pH-responsive hydrogels. For this purpose, new copolymers with different molecular weights and different content of the hydrophobic part are synthesized. The self-assembly behavior of PSMA-co-PDMAEMA copolymerswasstudiedin two different dispersion media (simulated gastric fluid-SGF, pH = 1.2 and simulated intestinal fluid-SIF, pH = 6.8) and in different concentrations. The physicochemical characteristics of the nano-assemblies were found to be dependent on the composition of the copolymer and the aqueous environment. Having a complete knowledge of the self-assembly behavior of the copolymers in aqueous media, the encapsulation of the PSMA-co-PDMAEMA 1/2 nano-assemblies into Alginate beads was achieved by following the protocol of the preparation of hydrogels. The Calcium:Alginate hydrogels were used as reference systems for comparison reasons. The size and the morphology of pure and mixed beads were found to be dependent on the composition of the block copolymer, as revealed from SEM images. The behavior of the mixed hydrogels was the same during the swelling studies, but the rate of the swelling and the amount of weight change were found to be additionally dependent on the composition of the polymeric guest. The hydration state of the polymeric chains plays a key role inthe swelling behavior of the mixed hydrogels. In conclusion, pH-responsive hybrid hydrogels were developed and their behavior and morphology are strongly dependent on the molecular characteristics of the polymeric guest. © 2018, Springer Science+Business Media B.V., part of Springer Nature