Rheological and pH dependent properties of injectable and controlled release hydrogels based on mushroom hyperbranched polysaccharide and xanthan gum

Abstract Hydrogels with thixotropic and pH-sensitive properties exhibit injectablity and response to external stimulation. Thixotropic and pH-responsive hydrogels were fabricated from xanthan gum (XG) and a hyperbranched β-D-glucan (TM3a) crosslinked with sodium trimetaphosphate (STMP) for injectable and release-controlled application. Thixotropy and creep-recovery tests were carried out to determine injectable and viscoelastic properties of the XG-TM3a-STMP hydrogels. Introduction of TM3a and formation of chemically crosslinking structures resulted in higher yield stress (43.6–168.9 Pa) and elastic modulus (146.9–1245.7 Pa), lower retardation time (32.6–44.4 s), and higher recovery percentage (49.5–66.7%) for XG-TM3a-STMP compared to XG-STMP and XG-TM3a-water. FTIR spectra and SEM observation demonstrated that TM3a disassembled XG aggregates by partially breaking hydrogen bonds, resulting in a relatively thin wall of the grids for XG-TM3a-STMP. The XG-TM3a-STMP hydrogels exhibited pH dependant swelling property and controlled release behavior. The hybrid hydrogels have potential applications in 3D printing or injectable tissue engineering and drug release fields.