Clonogenic Survival Assay

All treatments were carried out in quadruplicate in Ф60-mm Petri dishes. Briefly, B16-F10 cells irradiated with carbon ions at doses of 0, 1.0, 2.0, 3.0, 4.0, and 6.0 Gy were trypsinized, harvested, counted using the Z1 Coulter particle counter, diluted, and then seeded into Φ60-mm Petri dishes with 5 mL complete media. After incubation for a week, cells were stained with crystal violet for 30 min and then carefully washed. Colonies with more than 50 cells were recorded as surviving cells and were counted manually under an inverted microscope. Cell survival data were fitted using the linear-quadratic (LQ) model, and the sensitizer enhancement ratio (SER) of mAuNPs was calculated at the 10% survival level.