Computed tomography imaging of cancer cells using acetylated dendrimer-entrapped gold nanoparticles.

We report a new use of acetylated dendrimer-entrapped gold nanoparticles (Au DENPs) for in vitro and in vivo computed tomography (CT) imaging of cancer cells. In this study, Au DENPs prepared using amine-terminated generation 5 poly(amidoamine) dendrimers were subjected to an acetylation reaction to neutralize the positive surface potential. The acetylated Au DENPs were used for both in vitro and in vivo CT imaging of a human lung adencarcinoma cell line (SPC-A1 cells). Micro-CT images show that SPC-A1 cells can be detected under X-ray after incubation with the acetylated Au DENPs in vitro and the xenograft tumor model can be imaged after both intratumoral and intraperitoneal administration of the particles. Transmission electron microscopy data further confirm that the acetylated Au DENPs are able to be uptaken dominantly in the lysosomes of the cells. Combined morphological observation of cells after hematoxylin and eosin staining, MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay of cell viability, and flow cytometric analysis of cell cycle show that the acetylated Au DENPs do not appreciably affect the cell morphology, viability, and cell cycle, indicating their good biocompatibility at the given concentration range. Findings from this study suggest that the developed acetylated Au DENPs have a great potential to be used for CT imaging of cancer cells.