Synergistic influence of tetraethyl orthosilicate crosslinker on mixed matrix hydrogels

Abstract

Hydrogel is a 3D framework of hydrophilic polymeric material that quickly absorbs and retains a huge amount of water (or other fluid) and offers versatile functionality. A series of unique carboxymethyl cellulose/Xanthan gum/polyvinyl alcohol (CXP) blended hydrogels, containing both the natural and synthetic polymers, were prepared by following the blending and casting approach. The polymers were incorporated through chemical crosslinking by tetraethyl orthosilicate (TEOS). The fabricated hydrogels showed all required features: non-toxicity, biocompatibility, and improved mechanical strength. The addition and variation in TEOS (crosslinker) significantly impacted the key characteristics of CXP hydrogel. The scanning electron microscopy (SEM) images showed the porous structure and indicated that the pore's size and intensity were reduced with the surge in TEOS content. Fourier transform infrared spectroscopy (FTIR) results confirmed the successful incorporation of various polymeric strands through crosslinking by TEOS. The thermogravimetric analysis (TGA) highlighted the greater stability of all the hydrogels over high temperatures. The crosslinked hydrogel displayed higher thermal resilience than the uncross-linked one. The differential thermal analysis (DTA) also confirmed that the addition of TEOS content drastically enhanced the thermal endurance of crosslinked hydrogels in comparison with the neat hydrogel. All the specimens exhibited good swelling ability in distilled water during the swelling studies. This study also reflected that the addition of crosslinker in a limited amount (50 µL) has significantly enhanced the swelling but further increase in concentration hindered the water uptake. The swelling response of blends towards pH revealed low swelling of films in acidic and basic pH, but maximal swelling in neutral media. This unique pH response of hydrogels at neutral pH along with the biocompatibility made them suitable for injectable managed drug carrier.