Hybrid hyrogel based on poly (N-Isopropylacrylamide) copolymer and silanol groups for controlled delivery of drugs

Abstract

Hydrogels which adjust their properties in response to environmental factors such as temperature, pH and ionic strength are rapidly evolving, being known as smart materials. A functional monomer, 3-(trimethoxysilyl) propylmethacrylate (TSPM) with methoxysilyl group (-SiOCH3) was copolymerized with N-isopropylacrylamide (NIPAAm), acrylamide (AAm) and N,N’-methylene-bis-acrylamide (Bis), to yield a thermo-sensitive hydrogel [P(NIPAAm-co-AAm-co-TSPM)]. After treatment with NaOH (0.1 M), these hybrid hydrogels became anionically charged, due to ionisation of silanol and carboxylic groups from hydrolysed TSPM and AAm, respectively. Hydrogel morphology, before and after hydrolysis, as well as the physico-chemical properties, before and after Methylene Blue (MB) loading, were investigated by Scanning Electron Microscopy (SEM), Fourier-transform infrared (FTIR) and Ultraviolet-visible (UV) spectroscopy. The ionized hybrid hydrogels showed delayed release profiles compared to conventional hydrogels, which makes them suitable for controlled drug delivery.

Keywords

• hybrid hydrogels
• thermo-sensitive hydrogels
• drug delivery