Synthesis, structural and in-vitro characterization of β-cyclodextrin grafted L-phenylalanine functionalized graphene oxide nanocomposite: A versatile nanocarrier for pH-sensitive doxorubicin delivery.

To enhance graphene stability, drug loading capacity and biocompatibility, β-cyclodextrin (β-CD) was grafted onto graphene oxide (GO) using L-plenylalanine (Phe) as a linker. The doxorubicin (DOX) loading efficiency and capacity of GO-Phe-CD were 78.7% and 85.2%, respectively. The cone shaped cavity of CD acts as a host for DOX loading through inclusion complex formation. The GO-Phe-CD nanocarrier showed higher release ratio of DOX in acidic milieu of cancer cells. In addition, general cytotoxicity of the nanocarriers was examined by MTT assay and trypan blue dye exclusion in MCF-7 cell lines. It was established that the MTT assay was not an appropriate technique for predicting the cytotoxicity of graphene based nanocarriers due to the spontaneous formation of MTT formazan by these materials; leading to a false high biocompatibility. According to the trypan blue experiment, the GO-Phe-CD had significant cytocompatibility, and the DOX-loaded GO-Phe-CD had outstanding killing capability to MCF-7 cells.