A novel digitonin/graphene oxide/iron oxide nanocomposite: synthesis, physiochemical characterization and antioxidant activity

In this work, iron oxide (Fe₃O₄) magnetic nanoparticles (MNPs) and graphene oxide (GO) nanosheets were prepared via the co-precipitation technique and the Modified Hummer method. Fe₃O₄ MNPs and GO nanosheets were combined to prepare Fe₃O₄/GO nanocomposite and subsequently conjugated with Digitonin (DIG) in order to obtain a dual-targeted delivery system based on DIG/Fe₃O₄/GO nanocomposite. SEM images reveal the presence of Fe₃O₄ MNPs at a scale of 100 nm, exhibiting dispersion between the GO nanosheets. Aggregation of the DIG/Fe₃O₄/GO nanocomposite was observed at various size scales. The XRD structural analysis confirms the crystal structure of the prepared samples. The Fe₃O₄ MNPs demonstrated the main XRD-diffracted peaks. Also, GO nanosheets exhibit crystalline characteristics on the (001) and (002) planes. The predominant peaks observed in the DIG/GO/Fe₃O₄ nanocomposite are attributed to the crystal phases of Fe₃O₄ MNPs. The FT-IR vibrational modes observed in the GO/DIG/Fe₃O₄ nanocomposite indicate the presence of crosslinking between GO nanosheet layers and the Fe₃O₄ MNPs. The antioxidant activity of the prepared samples was measured and the DIG/GO/Fe₃O₄ nanocomposite demonstrated a significantly high antioxidant activity in both 2-diphenyl-1-picrylhydrazyl (DPPH^·) and 2,2-azino-bis-3-ethylbenzthiazoline-6-sulfonic acid (ABTS^·+) tests.