<p>IR-enhanced photothermal therapeutic effect of graphene magnetite nanocomposite on human liver cancer HepG2 cell model</p>

Background: Graphene magnetite nanocomposites (G/Fe 3 O 4 ) exhibit light photothermal conversion upon enhancement by 808 nm IR laser excitation. We evaluated the cytotoxic and photothermal effects of G/Fe 3 O 4 on a HepG2 human liver cancer cell model. Methods: Graphene nanosheets (rGO), magnetite nanoparticles (Fe 3 O 4 ), and G/Fe 3 O 4 were prepared by chemical methods and characterized using transmission electron microscopy, Raman spectroscopy, zeta analysis, and vibrating sample magnemeter. Dark and light cytotoxicity were screened with colorimetric Sulforhodamine B cell viability assay after 24 and 48 hours. DNA fragmentation and some apoptotic genes on a transcriptional RNA level expression were performed. All prepared nanomaterials were evaluated for their photothermal effect at concentrations of 10 and 50 µg/mL. The power density incident on the cells by 300 mW 808 IR diode laser was 0.597 W/cm 2 . Results: Treatment of HepG2 with 400 µg/mL of rGO, Fe 3 O 4 , and G/Fe 3 O 4 showed alteration in cell morphology after 24 hours of cell treatment and revealed toxic effects on cellular DNA. Evaluation of the cytotoxic effects showed messenger RNA (mRNA) in β-actin and Bax apoptotic genes, but no expression of mRNA of caspase-3 after 24 hours of cell exposure, suggesting the involvement of an intrinsic apoptotic caspase-independent pathway. A photothermal effect was observed for G/Fe 3 O 4 after irradiation of the HepG2 cells. A marked decrease was found in cell viability when treated with 10 and 50 µg/mL G/Fe 3 O 4 from 40% to 5% after 48 hours of cell treatment. Conclusion: Results indicate that G/Fe 3 O 4 nanocomposite was effective at transformation of light into heat and is a promising candidate for cancer therapy.