Sodium alginate conjugated graphene oxide as a new carrier for drug delivery system

The biomedical applications of graphene-based materials, including drug delivery, have grown rapidly in the past few years. The aim of this present study is to enhance the efficiency and specificity of anticancer drug delivery and realize intelligently controlled release and targeted delivery. Graphene oxide (GO) was first prepared from purified natural graphite according to a modified Hummers' method. Then GO was functionalized with adipic acid dihydrazide to introduce amine groups, and sodium alginate (SA) was covalently conjugated to GO by the formation of amide bonds. The resulting GO-SA conjugate was characterized and used as a carrier to encapsulate the anticancer drug doxorubicin hydrochloride (DOX·HCl) to study in vitro release behavior. The maximum loading capacity of DOX on GO-SA was 1.843mg/mg and the drug release rate under tumor cell microenvironment of pH 5.0 was significantly higher than that under physiological conditions of pH 6.5 and 7.4. Methylthiazol tetrazolium (MTT) assay was applied to evaluate the Hela cells and NIH-3T3 cells cytotoxicity of GO-SA. Results showed that GO-SA had no obvious toxicity and GO-SA/DOX exhibits notable cytotoxicity to Hela cells. Cell uptake studies indicated that GO-SA could specifically transport the DOX into Hela cells over-expressing CD₄₄ receptors and showed enhanced toxicity.