Design of a tunable nanocomposite double network hydrogel based on gellan gum for drug delivery applications

The design of an efficient drug delivery platform relies on the fabrication of a suitable polymeric network that can modulate the release of therapeutic molecules. In this study, we aimed to reach this goal by fabricating a novel nanocomposite double network (nDN) hydrogel, which contains the synthetic clay Laponite as the nanofiller necessary to influence the mechanical, physical and releasing properties of the designed carrier. Laponite concentration was varied from 0.5% up to 1.5% w/v to modulate the mechanical and swelling behavior of a hydrogel made of a methacrylate derivate of gellan gum (GG-MA), which served as the first brittle network of the nDN system. Additionally, polyethylene glycol dimethacrylate (PEG-DMA) was chosen as the second soft and elastic network. The inclusion of the clay at a concentration as low as 0.5% w/v positively influenced the single network (SN) hydrogel properties by increasing the stiffness and reducing the swelling ratio of the GG-MA hydrogels. The presence of Laponite (R) affected the amount of PEG-DMA diffused within the SN of GG-MA. The resulting stretchable and tough nDN system presented a higher swelling ratio in deionized water, and elasticity when compared to the DN hydrogels without any Laponite. Finally, the nDN system showed increased drug adsorption and displayed a better control in modulating the release kinetics of the model drug ofloxacin. Overall, these findings suggest the possible use of the designed nDN system as a novel drug delivery platform for the sustained release of therapeutic molecules.