Gold nanoprobes for multi-modality tumor imaging

Gold nanoparticles have been shown to possess x-ray attenuation higher than that of clinically used iodine based contrast agents. Additionally, gold nanoparticles have also been used in enhancing the Raman signal through a phenomenon called Surface Enhanced Raman Scattering (SERS). The development of Gold nanoparticle based probes (nanotags) for combined SERS and x-ray computed tomography (CT) are reported. These nanotags comprise quasi-spherical gold nanoparticles encoded using a Raman active molecule and encapsulated by a monolayer of polyethylene glycol with carboxylate functional groups for bioconjugation. The nanotags, made from ~65 nm gold nanoparticles, display large SERS cross-section and x-ray absorption which are used for dual modality imaging of tumor cells in of an orthotropic prostate cancer tumor animal model.