Dual purpose Prussian blue nanoparticles for cellular imaging and drug delivery: a new generation of T1-weighted MRI contrast and small molecule delivery agents

A simple and improved aqueous synthetic procedure using flash heating for preparing biocompatible Prussian blue nanoparticles (PBNPs) with the single-crystal-like feature was developed. This method entailed the use of citric acid as a chelator to complex ferric ions in the precursor and as an in situ capping agent to prevent the PB nanoparticles formed in solution from aggregation. The citrate-coated PBNPs, which can be surface functionalized with small molecules, were readily internalized by cells and exhibited no detectable cytotoxicity. Furthermore, such nanoparticles do not trigger the production of reactive oxygen species (ROS) in cells via the Fenton reaction. The potential of using such PBNPs as an effective T1-weighted cellular MRI contrast agent has also been demonstrated. These properties suggest that PBNPs are an attractive dual purpose nanoplatform for developing the next generation of nanoparticle-based T1-weighted MRI contrast agents as well as delivery vehicles for small molecules.