A Feasibility Study of Controlled Release Using Graphene Oxide

Graphene oxide (GO) is a newly discovered two-dimensional carbon material with a myriad of potential applications. One of the biomedical applications hitherto unexamined is drug delivery. This research project examines the feasibility of using GO-based architectures, such as free standing films and cargo-filled nano/micro sacks, to make a suitable candidate for controlled release technology. Cesium chloride (CsCl) is used as a model for the drug being encapsulated by both the film and sacks, and its release over time is measured indirectly through the change in electrical conductivity of the water-nanosacks mixture over time. The release of CsCl from the nanosacks was found to be virtually immediate; however, various techniques were also explored in an attempt to prolong the release. Among them are: using emulsion technique to enlarge the dimensions of the graphene oxide sacks to microscale; simultaneous encapsulating a polymer (Carboxymethyl cellulose, CMC) with CsCl; and finally, heat- and chemical-treatment of the sacks. The release of CsCl from free-standing films was also rapid; however, similarly to the nano/micro-sacks, chemically treating the salt-film with Triethylenetetramine prolonged the release from a matter of seconds to several days. The detailed results and mechanism of various controlled release techniques will be discussed.