Gold Nanoparticle Shape and Protein Corona Effects on Radiosensitization in Neuroblastoma Cells

Abstract Gold nanoparticle (GNP) radiosensitization is influenced by particle shape and the protein corona acquired in biological environments. We investigated how GNP shape and a preformed human plasma protein corona affect the radiation response of SH-SY5Y neuroblastoma cells exposed to 6 MV X-rays. PEGylated gold nanospheres (PEG-GNSp), nanorods (PEG-GNR), and nanostars (PEG-GNS) were characterized by transmission electron microscopy, UV−visible spectroscopy, dynamic light scattering, zeta-potential analysis, and proton nuclear magnetic resonance (1H NMR) spectroscopy, while hard-corona protein profiles were examined by LC−MS-based proteomics. Cellular association was evaluated by flow cytometry using rhodamine B-conjugated PEG (PEGRb)-labeled GNPs, with qualitative localization by confocal laser scanning microscopy; cell-associated gold was measured separately by graphite furnace atomic absorption spectrometry (GFAAS). Radiation response was assessed by metabolic activity, clonogenic survival, γH2AX, and post-irradiation reactive oxygen species measurements. PEGRb-associated fluorescence followed PEG-GNR > PEG-GNS > PEG-GNSp and decreased after corona formation for all three shapes, whereas GFAAS showed a different pattern of cell-associated gold. Hard-corona profiles showed shape-associated differences in protein representation, with greater coagulation/contact-system-associated proteins for PEG-GNR and relatively greater immunoglobulin-associated proteins for PEG-GNSp and PEG-GNS. PEG-GNS + PC showed the lowest D50 (0.81 Gy) and the largest numerical SER50 (1.49; 95% CI, 0.85−2.61), although the confidence interval included unity. PEG-GNS + PC also showed the highest mean γH2AX response at 6 Gy, whereas delayed DCF-detectable oxidative activity was greatest for PEG-GNR. These findings indicate that GNP shape and the acquired protein corona are associated with distinct radiation-response patterns not captured by any single measured cellular parameter. The results support considering nanoparticle shape and corona-associated interfacial properties together when developing GNP-based radiosensitizers.