Ultra-thin patchy polymer-coated graphene oxide as a novel anticancer drug carrier

An ultra-thin, graphene oxide (GO) based, anticancer drug carrier was developed using Reversible Addition Fragmentation chain Transfer (RAFT) mediated emulsion polymerisation. Short chain macro-RAFT copolymer, BuPATTC-(BA4-stat-AA9-stat-StS5), was used to disperse the GO in water. Subsequent free radical emulsion polymerisation produced an aqueous suspension of partially polymer-coated GO (PPC-GO). The polymer coating was unevenly distributed, forming a patchy and extremely rough surface on the GO substrate. The use of macro-RAFT copolymers greatly improved the overall colloidal stability of the GO. Furthermore, particle morphologies were found to be controllable by adjusting the amount of monomer starve fed into the polymerisation. PPC-GO was demonstrated to be an effective carrier for the anti-cancer drug doxorubicin (Dox), storing equivalent to its own original weight in Dox. A releasing mechanism using L-ascorbic acid (L-AA) as an agent was reported. Dox release can be triggered by chemical reduction using L-AA, which weakens the hydrogen bonds between Dox and GO. After release of the Dox, the remaining PPC- reduced GO (PPC-rGO) was found to be stable in aqueous suspension.