Synthetic Antiferromagnetic Gold Nanoparticles as Bimodal Contrast Agents in MRI and CT-An Experimental In Vitro and In Vivo Study

The use of multimodal contrast agents can potentially overcome the intrinsic limitations of individual imaging methods. We have validated synthetic antiferromagnetic nanoparticles (SAF-NPs) as bimodal contrast agents for in vitro cell labeling and in vivo cell tracking using magnetic resonance imaging (MRI) and computed tomography (CT). SAF-NP-labeled cells showed high contrast in MRI phantom studies (r(2)* = 712 s(-1) mM(-1)), while pelleted cells showed clear contrast enhancement in CT. After intravenous SAF-NP injection, nanoparticles accumulated in the liver and spleen, as visualized in vivo by significant MRI contrast enhancement. Intravenous injection of SAF-NP-labeled cells resulted in cell accumulation in the lungs, which was clearly detectable by using CT but not by using MRI. SAF-NPs proved to be very efficient cell labeling agents for complementary MRI- and CT-based cell tracking. Bimodal monitoring of SAF-NP labeled cells is in particular of interest for applications where the applied imaging methods are not able to visualize the particles and/or cells in all organs.

Automated summary

The use of synthetic antiferromagnetic nanoparticles (SAF-NPs) as bimodal contrast agents for cell labeling and tracking showed high contrast in both MRI and CT imaging. These nanoparticles accumulated in the liver and spleen after injection, leading to significant MRI contrast enhancement. Furthermore, the cell accumulation in the lungs after injection of SAF-NP-labeled cells was detectable using CT but not MRI. SAF-NPs are efficient agents for complementary MRI- and CT-based cell tracking, particularly useful in applications where visualization of particles and cells in all organs is needed.