A study of Gd loaded silica nanoparticles for both optical and magnetic resonance imaging of cells

• A new method was proposed to construct multifunctional silica nanoparticles for dual fluorescence and MRI imaging.
• Gd-silica nanohybrids via polyelectrolyte capping provides the enhancement of T1 relaxivity due to the increase in hydrophilicity.
• Polyelectrolyte encapping method was adopted to decorate Gd on the corona of Gd-silica nanohybrids.
• In vivo distribution of the Gd-silica nanohybrids was investigated by ICP-MS.

We have developed fluorescent nanoparticle-based T1 contrast enhancing magnetic resonance imaging (MRI) agents, for the purpose of dual imaging in vivo. Gd(III) chelated silica nanoparticles were successfully synthesized with dual-mode diagnostics feasibility in MRI and fluorescence imaging analysis. Gd-chelated silica nanoparticles were studied, which were formed via polyelectrolyte encapping methods. A 9.4T micro-image instrument was used to investigate the T1 contrast enhancement effects of the Gd-chelated silica nanoparticles. The resulting Gd chelated nanoparticles were used in cell tracking and bio-distribution experiments with dual mode imaging of A549 lung cancer cells and mouse models. These Gd-silica nanoparticles are promising dual mode materials, functioning as T1 MRI contrast agents and organ specific contrast agents.