Dextran/Bioactive Glass Nanocomposite Hydrogels: Effect of Dextran Molecular Weight and Content on Swelling Behavior and Structural Characteristics

Design and fabrication of hydrogel scaffolds with the required characteristics are the major issues of their development in tissue engineering. A wide variety of physicochemical, mechanical, and morphological properties of hydrogel scaffolds has provided new opportunities to overcome various challenges in tissue engineering.

A series of nanocomposite hydrogels comprised of dextran (Dex) and sol-gel derived bioactive glass (BG) nanoparticles were prepared as scaffolds for bone tissue engineering. The swelling behaviour and mechanical strength of the obtained hydrogel scaffolds by different contents and chain molecular weights of dextran were evaluated.

Fourier transforms infrared spectroscopy study provides information on intermolecular interaction between the dextran chain and the bioactive glass nanoparticles through influence on hydrogen bond strength. The influence of the given parameters on the morphology of scaffolds was probed using field emission scanning electron microscopy (FE-SEM). The results of FE-SEM showed that Dex/BG scaffolds consisted of a porous 3D microstructure with a pore size range of 102-156 μm. The effects of hydrogen bonding and chain entanglements showed significant differences in pore morphologies of the prepared hydrogels. According to the obtained apparent density and equilibrium swelling, the increase in the dextran content showed that the change in the gel porosity results in reduced free water of the network. Meanwhile, the amount of equilibrium swelling dropped while the compressive modulus increased due to the effective interaction between the dextran chains and bioactive glass nanoparticles. Furthermore, the results obtained by thermogravimetric analysis indicated an increase in thermal stability of dextran nanocomposites hydrogel, which could be due to the effective interaction between dextran chains and bioactive glass nanoparticles.