Abstract
Previous studies revealed that cancer cells were more susceptible to heat injury than normal cells. Graphene exhibit physical properties that make them ideal candidates for application as mediators of photothermal cancer ablation. This study prepared dispersible graphene solution and investigated the cytotoxicity of graphene on the viability of colon cancer cells (HCT-8). This work demonstrates that the use of graphene to generate heat in response to near-infrared radiation (NIR) results in thermal destruction of colon cancer cell in vitro. We used electrolytic exfoliation to produce graphene which was conjugated with poly (sodium 4-styrenesulfonate) [PSS] to reduce the van der waals force between layers. Because the polymer has biocompatibility and low toxicity; thus, PSS is suitable for the application in the field of biology. Compared with other processes, this method can lower the production costs and performed at room temperature. The biological experiments were divided into three parts, the first stage tested the cell viability and migration ability of HCT-8 cells after cultured with different concentration of graphene solution. The result showed that, high dose of graphene solution can inhibit obviously the migration ability of HCT-8 cells. We found that the cell migration rate was reduced with increasing in the dose of graphene by using wound healing assay and the quantitative statistics result were tested by Oris cell migration kit. Next, we used graphene as mediators of thermotherapy. After irradiating with NIR light, the cell viabilities were quantitative analyzed by using MTS cell viability assay. The study choose different graphene concentrations (10.0, 20.0, 40.0 ppm), thus the temperature of the solution can reach above 46℃after irradiating with NIR light (power: 2 W/cm2) in the short time. Moreover the quantitative results show that the cell viability were influenced by concentration of graphene solution, irradiated time, and the idle time after irradiating. The result showed that 20.0 ppm graphene solution has suitable concentration to kill the HCT-8 cells than that those of 10.0, 40.0 ppm graphene solution. The final stage used the confocal microscopy and fluorescence microscopy to trace the graphene in cells. The result showed almost graphene sheets were attached on the surface of cell, and only few graphene can get into the cells by endocytosis. The phenomenon can explain the better efficiency of thermotherapy, and imply that necrosis may result from the bursting of cell membrane or protein denaturation in the cell.