The statistical results for the uptake of different AuNPs. (a) CL1-0 cells and (b) HeLa cells for AuNPs of 45 nm, 70 nm and 110 nm diameters. The statistics show that the total amounts of AuNPs interacted with cells has a maximum value for 45-nm-AuNPs. The percentage of AuNPs in cells also has a maximum value for 45-nm-AuNPs. The n indicates the number of cells investigated.