Gadolinium chelate coated gold nanoparticles as contrast agents for both X-ray computed tomography and magnetic resonance imaging

Targeted gold nanoparticles enable molecular CT imaging of cancer

X-ray based computed tomography (CT) is among the most convenient imaging/diagnostic tools in hospitals today in terms of availability, efficiency, and cost. However, in contrast to magnetic resonance imaging (MRI) and various nuclear medicine imaging modalities, CT is not considered a molecular imaging modality since targeted and molecularly specific contrast agents have not yet been developed. Here we describe a targeted molecular imaging platform that enables, for the first time, cancer detection at the cellular and molecular level with standard clinical CT. The method is based on gold nanoprobes that selectively and sensitively target tumor selective antigens while inducing distinct contrast in CT imaging (increased X-ray attenuation). We present an in vitro proof of principle demonstration for head and neck cancer, showing that the attenuation coefficient for the molecularly targeted cells is over 5 times higher than for identical but untargeted cancer cells or for normal cells. We expect this novel imaging tool to lead to significant improvements in cancer therapy due to earlier detection, accurate staging, and microtumor identification.

Gold nanoparticles functionalised by Gd-complex of DTPA-bis(amide) conjugate of glutathione as an MRI contrast agent

The work is directed toward the synthesis of gold nanoparticles (Au NPs) coated with paramagnetic Gd-complex of DTPA-bis(amide) conjugate of glutathione (GdL) for use as a highly efficient MRI contrast agent. Well-dispersed spherical Au NPs coated with gadolinium complexes, abbreviated as Au@GdL, have been obtained; the mean size of Au@GdL is 5-7 nm, and the numbers of GdL are 1.36x10(4) per Au NP. Au@GdL exhibits high longitudinal (r1) and transverse (r2) relaxivities of 1.87x10(5) and 3.02x10(5) mM(-1) s(-1), respectively.