Colloidal gold nanoparticles as a blood-pool contrast agent for x-ray computed tomography in mice

Objectives: To present the pharmacokinetics and computed tomographic imaging efficacy of colloidal gold nanoparticles (AuNPs) as a blood-pool agent for x-ray computed tomography (CT). Methods and Materials: To prepare the colloidal AuNPs, gold nanocrystals were modified using sulfhydrated polyethylene glycol (PEG). Cytotoxicity and histopathologic tests were carried out for toxicity evaluation. Six adult Balb/c mice underwent microcomputed tomography scans after injection of colloidal AuNPs (2.5 mu mol Au/g body weight). Four mice with HT-1080 tumors were imaged for visualization of the tumor vasculature. Results: The PEG coated colloidal AuNPs appeared as spherical nanoparticles with 38-nm diameters. The AuNPs-PEG showed a biocompatibility without toxicity in the mice. We identified a stable imaging window for visualizing the vasculature system, immediately to 24 hours after injection. Microcomputed tomography imaging using AuNPs-PEG clearly visualized the tumor vascular structures. Conclusion: Colloidal AuNPs show potential as a blood-pool agent for x-ray CT imaging.