Graphene derivatives (GDs), such as graphene oxide (GO), have emerged as a diversified materials for biological applications. The huge specific surface area, aromatic structure, and excellent mechanical stability of GDs can be used to endow polymeric drug delivery systems (DDS) with new properties and improved performances. Major problem associated with DDS composed of thermosensitive poly(N-isopropylacrylamide) (PNIPAAm) spheres is a burst release of carried drug molecules and poor mechanical stability. Here we report the rational design and synthesis of PNIPAAM-co-PS hollow microspheres coated with GO.
In our DDS, the diffusion-driven drug release is controlled by ultrathin layer of GO nanosheets, which effectively suppresses the initial burst release and enables sustained drug release in in vitro testing. Moreover, the hybrid microspheres showed improved drug encapsulation by 46.4% which is attributed to the diffusion barrier properties and π-conjugated structure of GO. The studied hybrid system shows an advantage over reported drug-loaded PNIPAAM spheres where temperature-influenced drug release cannot be controlled or requires sophisticated drug loading approach.