Novel synthesis of mussel inspired and Fe3+ induced pH-sensitive hydrogels: Adhesion, injectable, shapeable, temperature properties, release behavior and rheological characterization.

A novel EGCG-loaded DCKGM-CCKGM-Fe3+hydrogel was prepared by Dopamine-carboxymethyl konjac glucomannan (DCKGM) and an l-Cysteine-carboxymethyl konjac glucomannan (CCKGM) with Fe3+ as a cross-linking agent. Due to the dynamic property of Fe3+-phenolic hydroxyl coordination bond and intermolecular hydrogen bonding, the resultant hydrogel featured injectable, adhesive, temperature and pH-sensitive properties. The mechanisms were characterized using Rheological analysis, Fourier transform infrared spectroscopy, X-ray diffraction patterns, and scanning electron microscopy. Furthermore, the weak alkaline condition (pH 7.4) can trigger the release of EGCG, there was a cumulative release of 54.71 % of the loaded EGCG within 12 h in PBS at pH 1.2. When the pH of PBS was increased to 7.4, the cumulative release of EGCG increased to 68.54 %. Consequently, the EGCG-loaded DCKGM-CCKGM-Fe3+hydrogel (Fe3+Hydrogel) is a good candidate for the carrier for drug delivery. This paper provided a novel way for the preparation of hydrogel.