A tightly bonded reduced graphene oxide coating on magnesium alloy with photothermal effect for tumor therapy

Photothermal therapy becomes a hotspot in the treatment of bone tumors. Magnesium and its alloys are regarded as potential bone implants for their favorable mechanical property and biodegradable in vivo. However, there is few research devoted to fabricating a photothermal coating on Mg alloy. In the present study, reduced graphene oxide coating with a strong photothermal effect was prepared on the surface of AZ31 via two steps. Firstly, graphene oxide coating was deposited on the surface via electrophoresis deposited (GO#), followed by a reduction process of the graphene oxide coating in ultrapure water (rGO#). GO# and rGO# coatings were characterized by SEM, Raman, XRD, FTIR, and XPS. The results revealed that, compared with GO# coating, the content of oxygen-containing (C–O/C–O-C, C=O, O–C=O) groups on rGO# coating was significantly decreased. rGO# coating was found tightly adhered to AZ31 substrate. According to the first-principles calculations, the well-bonded heterostructure between MgO and rGO is the main reason for the strong bonding force. Moreover, the prepared rGO# coating showed a superior photothermal effect, which brings a new strategy to the treatment of bone tumors with Mg-based implants.