A Magnetofluorescent Nanoparticle for Ex-Vivo Cell Labeling by Covalently Linking the Drugs Protamine and Feraheme

作者：Chen Suelin; Alcantara David; Josephson Lee^*

来源：Journal of Nanoscience and Nanotechnology, 2011, 11(4): 3058-3064.

DOI：10.1166/jnn.2011.4164

• Cell Tracking
• Nanoparticle
• MRI
• Protamine

We synthesized a nanoparticle (NP) for ex-vivo cell labeling and MRI tracking by covalently coupling the C-terminus of a rhodamine-labeled protamine (Pro Rho) to Feraheme (FH) in order to yield the nanoparticle denoted ProRho-FH. Since protamine can adsorb to certain charged surfaces, we confirmed a covalent interaction between Pro Rho and FH by heparin affinity chromatography. ProRho-FH lacks a net charge (zeta potential similar to 0) due to the combination of negative FH and positive Pro Rho charges. ProRho-FH was readily internalized by U87 cells and mouse mesenchymal stem cells as determined by FACS and MR relaxometry. Finally, some 4,000 stem cells were implanted in a mouse brain and imaged by MRI. Due to its lack of net surface charge, ProRho-FH relies on the internalizing properties of the surface guanidinium groups present in the arginine-rich protamine to induce NP uptake. ProRho-FH is a unique cell-labeling agent due to its synthesis using two approved drugs, magnetofluorescence, site-specific covalent attachment chemistry, and lack of surface charge.

• 出版日期2011-4