A novel functional CT contrast agent for molecular imaging of cancer.

The purpose of this study was to investigate the feasibility of using a 2-deoxy-d-glucose (2-DG) labeled gold nanoparticle (AuNP-2-DG) as a functionally targeted computed tomography (CT) contrast agent to obtain high-resolution metabolic and anatomic information of tumor in a single CT scan. Gold nanoparticles (AuNPs) were fabricated and were conjugated with 1-DG or 2-DG. 1-DG provides an excellent comparison since it is known to interfere with the ability of the glucose transporter to recognize the sugar moiety. The human alveolar epithelial cancer cell line, A-549, was chosen for the in vitro cellular uptake assay. Three groups of cell samples were incubated with the 1-DG or 2-DG labeled AuNP and the unlabeled AuNP. Following the incubation, the cells were washed with sterile phosphate buffered saline to remove the excess AuNPs and spun using a centrifuge. The cell pellets were imaged using a microCT scanner immediately after the centrifugation. Internalization of AuNP-2-DG is verified using transmission electron microscopy imaging. Significant contrast enhancement in the cell samples incubated with the AuNP-2-DG with respect to the cell samples incubated with the unlabeled AuNP and the AuNP-1-DG was observed in multiple CT slices. Results from our in vitro experiments suggest that the AuNP-2-DG may be used as a functional CT contrast agent to provide high-resolution metabolic and anatomic information in a single CT scan. These results justify further in vitro and in vivo experiments to study the feasibility of using the AuNP-2-DG as a functional CT contrast agent in radiation therapy settings.