Applications of Magnetic Liposomes in Cancer Therapies.

MNPs find numerous important biomedical applications owing to their high biocompatibility and unique magnetic properties at the bottom level. Among several other biomedical applications, MNPs are gaining importance in treating various kinds of cancer either as a hyperthermia agent alone or as a drug/gene carrier for single or combined therapies. At the same time, another type of nano-carrier with lipid bilayer, i.e. liposomes, has also emerged as a platform for administration of pharmaceutical drugs, which sees increasing importance as a drug/gene carrier in cancer therapy due to its excellent biocompatibility, tunable particle size and the possibility for surface modification to overcome biological barriers and to reach targeted sites. MLs that combine MNPs with liposomes are endowed with advantages of both MNPs and liposomes and are gaining importance for cancer therapy in various modes. Hence, we will start by reviewing the synthesis methods of MNPs and MLs, followed by a comprehensive assessment of current strategies to apply MLs for different types of cancer treatments. These will include thermo-chemotherapy using MLs as a triggered releasing agent to deliver drugs/genes, photothermal/ photodynamic therapy and combined imaging and cancer therapy.

Magnetic Graphene Oxide for Dual Targeted Delivery of Doxorubicin and Photothermal Therapy.

To develop a pH-sensitive dual targeting magnetic nanocarrier for chemo-phototherapy in cancer treatment, we prepared magnetic graphene oxide (MGO) by depositing Fe3O4 magnetic nanoparticles on graphene oxide (GO) through chemical co-precipitation. MGO was modified with polyethylene glycol (PEG) and cetuximab (CET, an epidermal growth factor receptor (EGFR) monoclonal antibody) to obtain MGO-PEG-CET. Since EGFR was highly expressed on the tumor cell surface, MGO-PEG-CET was used for dual targeted delivery an anticancer drug doxorubicin (DOX). The physico-chemical properties of MGO-PEG-CET were fully characterized by dynamic light scattering, transmission electron microscopy, X-ray diffraction, Fourier transform Infrared spectroscopy, thermogravimetric analysis, and superconducting quantum interference device. Drug loading experiments revealed that DOX adsorption followed the Langmuir isotherm with a maximal drug loading capacity of 6.35 mg/mg, while DOX release was pH-dependent with more DOX released at pH 5.5 than pH 7.4. Using quantum-dots labeled nanocarriers and confocal microscopy, intracellular uptakes of MGO-PEG-CET by high EGFR-expressing CT-26 murine colorectal cells was confirmed to be more efficient than MGO. This cellular uptake could be inhibited by pre-incubation with CET, which confirmed the receptor-mediated endocytosis of MGO-PEG-CET. Magnetic targeted killing of CT-26 was demonstrated in vitro through magnetic guidance of MGO-PEG-CET/DOX, while the photothermal effect could be confirmed in vivo and in vitro after exposure of MGO-PEG-CET to near-infrared (NIR) laser light. In addition, the biocompatibility tests indicated MGO-PEG-CET showed no cytotoxicity toward fibroblasts and elicited minimum hemolysis. In vitro cytotoxicity tests showed the half maximal inhibitory concentration (IC50) value of MGO-PEG-CET/DOX toward CT-26 cells was 1.48 µg/mL, which was lower than that of MGO-PEG/DOX (2.64 µg/mL). The IC50 value could be further reduced to 1.17 µg/mL after combining with photothermal therapy by NIR laser light exposure. Using subcutaneously implanted CT-26 cells in BALB/c mice, in vivo anti-tumor studies indicated the relative tumor volumes at day 14 were 12.1 for control (normal saline), 10.1 for DOX, 9.5 for MGO-PEG-CET/DOX, 5.8 for MGO-PEG-CET/DOX + magnet, and 0.42 for MGO-PEG-CET/DOX + magnet + laser. Therefore, the dual targeting MGO-PEG-CET/DOX could be suggested as an effective drug delivery system for anticancer therapy, which showed a 29-fold increase in therapeutic efficacy compared with control by combining chemotherapy with photothermal therapy.