Abstract 1472: Comprehensive evaluation of PEGylated gold nanorods for two photon photoluminescence image guided radiation therapy enhancement

Abstract

Abstract Nanoparticle formulations of gold have shown a tremendous potential in various biomedical applications. The use of high atomic number (Z) materials presents an attractive approach in enhancing the therapeutic efficacy of the radiation therapy. The high Z number for gold (Z=79) makes them an ideal candidate for radiosensitization enhancement. The ability of the anisotropic gold nanorods to sustain the resonating surface plasmon with minimal damping results in highly efficient two-photon induced photoluminescence imaging. Here we present the synthesis and in vitro characterization of PEGylated gold nanorods as efficient radiosensitizing agents which can be imaged using inherent two-photon photoluminescence without a conjugated fluorophore. We have synthesized gold nanorods with an aspect ratio of 2.5 and functionalized the surface with different ratios of methoxy and amine PEG for modulating the charge and imparting the functional groups. The cellular uptake behavior in prostate cancer cell line PC3 was studied and the results indicated a robust uptake of the amine functionalized nanorods. The quantitative estimation of the nanorods uptake was performed with BCA assay as amount of nanorods present in per microgram of protein. Two photon photoluminescence imaging also confirmed a robust cellular uptake of the amine functionalized nanorods. The radiation damage enhancement of the gold nanorods was confirmed using PC3 cells. The cells treated with gold nanorods were irradiated with kilovoltage X-rays. A γH2AX assay was used for quantitation of the DNA damage with and without nanorods as controls. The results indicated an increased highly efficient DNA damage in cells treated with gold nanorods. The outcome of this research will enable further application of targeted nanorods in advanced animal models as efficient radiation dose enhancement agents wherein two-photon photoluminescence imaging will provide a real time assessment of the therapeutic response and disease progression. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1472. doi:1538-7445.AM2012-1472