Zinc ferrite spinel-graphene in magneto-photothermal therapy of cancer

A magneto-photothermal therapy for cancer (in vitro photothermal therapy of prostate cancer cells and in vivo photothermal therapy of human glioblastoma tumors in the presence of an external magnetic field) was developed using superparamagnetic zinc ferrite spinel (ZnFe2O4)-reduced graphene oxide (rGO) nanostructures (with various graphene contents). In vitro application of a low concentration (10 mu g mL(-1)) of the ZnFe2O4-rGO (20 wt%) nanostructures under a short time period (similar to 1 min) of near-infrared (NIR) irradiation (with a laser power of 7.5 W cm(-2)) resulted in an excellent destruction of the prostate cancer cells, in the presence of a magnetic field (similar to 1 Tesla) used for localizing the nanomaterials at the laser spot. However, in the absence of a magnetic field, ZnFe2O4-rGO and also rGO alone (10 mu g mL(-1)) resulted in only similar to 50% cell destruction at the most in the short photothermal therapy and also in a typical radiotherapy (similar to 2 min gamma irradiation with a dose of 2 Gy). The minimum concentrations required for the successful application of the nanostructures in the photothermal and radiotherapeutic methods were found to be similar to 100 and 1000 mu g mL(-1), while in the proposed magneto-photothermal therapy it was only similar to 10 mu g mL(-1). The in vivo feasibility of this method was also examined on mice bearing glioblastoma tumors. Furthermore, the localization of the magnetic nanomaterials injected into the tumors was studied in the presence and absence of an external magnetic field. These results will stimulate more applications of magnetic graphene-containing composites in highly efficient photothermal therapy.