Beyond traditional hydrogels: The emergence of graphene oxide-based hydrogels in drug delivery

Hydrogel applications in various medical fields especially in drug delivery have been widely investigated in the last few years. Introduction of biopolymers in the production of hydrogels leads to develop biodegradable, biocompatible, and non-immunogenic drug carriers. However, possessing such remarkable properties the role of hydrogels is still limited in drug delivery because of the factors such as insufficient loading capacity particularly for hydrophobic drugs, poor mechanical strength, low homogeneity, and inadequate response to stimuli. Hence to address such shortcomings the two-dimensional (2-D) carbon-based nanomaterial, graphene holding various significant properties has been introduced to this three-dimensional (3-D) structure for their more prominent performance in drug delivery. This 2-D and 3-D combination made researchers to develop required features to the already existed traditional polymer hydrogels. Graphene and its derivatives exploited the practical applications of conventional hydrogels by acting as gelator to self-assembled graphene-based hydrogels (GBH) as well as a filler to blend with small and macromolecules to produce multifunctional GBH. Herein the progress with GBH in various field focusing their role in drug delivery as a nanocarrier has been empathetically revealed. Amid the limitations and factors affecting the performance of graphene and hydrogels along with their properties and methods of preparations have also summarized. Further, the development and challenges of GBH have correspondingly prospected.