Plasma-Enabled Biocompatible Graphene Quantum Dot Hydrogels as Smart and pH Responsive Cancer Therapeutic Agents

Cancer is none arguably one of the world’s most dreadful diseases striking everyone without any exceptions. Current treatments rely on surgical intervention, radiation, and chemotherapeutic drugs which usually not only kill the cancers cells, but also affect healthy cells causing toxicity and severe side effects to the patients or even death. Therefore, it is urgent to develop a drug delivery system (DDS) capable of either passively or actively targeting cancer cells only to avoid all those possible occurring side effects during therapy. Resembling physicochemical and biological properties of extracellular matrix coupled with their biocompatibility and biodegradability, hydrogels with stable 3D hydrated network emerge as suitable candidate for many biomedical applications, including drug delivery, scaffold engineering, wound treatment, antibacterial, and antioxidant. Here we report rapid and environmental-friendly plasma engineering of microporous carbon-based NGQD hydrogels from a single chitosan biomass using non-thermal microplasmas at ambient conditions without toxic chemicals and high temperature treatment. The highly reactive species derived from the non- equilibrium plasma regime allows simultaneous conversion of NGQDs and initiation of covalent bond formations within the polymeric chitosan network in a short time. Moreover, synergistic effect manifested by the inclusion of NGQDs in the chitosan matrix framework coupled with energetic plasma treatment can accelerate the cross-linking of chitosan to form a robust 3D porous composite without any toxic chemicals and harsh conditions. Endowed by the presence of NGQDs, the fabricated composites have enhanced anticancer drug loading capacity and pH-controlled sustained drug release. Since the fabricated composites also exhibit stable solid- state PL properties, it is envisaged that our method can advance toward a novel combination of therapeutic and monitoring. Our work provides a rational design of carbon-based composite with defined structures and properties suitable not only for biomedical application, but also other emerging applications.