In cancer radiotherapy, gold nanoparticles (AuNPs) have emerged as promising radiosensitizers, which, when accumulated in the tumor, increase the effectiveness of external beam radiotherapy by local production of reactive oxygen species (ROS) and secondary electrons upon irradiation. At UNamur, 5 nm gold nanoparticles coated with an organic shell of polyallylamine are produced by plasma vapor deposition (AuNPs@PPAA). Optionally, the AuNPs@PPAA can be conjugated to anti-EGFR antibodies (Cetuximab) (AuNPs@PPAA-Ctxb) which actively target EGFR-overexpressing cancer cells in vitro and in vivo. However, In vivo biodistribution studies have demonstrated a significant accumulation in the liver and the spleen. Therefore, the cytotoxicity profile of the gold nanoparticles should be properly investigated in healthy cell types prior to use the AuNPs@PPAA-Ctxb in clinical applications.
Human kidney (HK-2) cells and telomerase-immortalized microvascular endothelial (TIME) cells were studied as examples of healthy cells. We performed MTS cytotoxicity assays after 3 hours and 24 hours of incubation and live cell imaging with apoptotic markers Annexin V and caspase 3/7 during 72 hours of incubation with AuNPs. Transmission electron microscopy (TEM) was performed to visualize nanoparticle uptake after 30 minutes, 3 hours and 24 hours in the presence of nanoparticles with concentrations ranging from 0.001 mg/ml to 0.05voevjoesvfhoqeurfhcqoefhcqoefhq<oudhf<qoud