Control of the in vivo biodistribution of hybrid nanoparticles with different poly(ethylene glycol) coatings.

Fluorescent nanoparticles containing a gadolinium oxide core are very attractive because they are able to combine both imaging (fluorescence imaging, magnetic resonance imaging) and therapy (X-ray therapy and neutron-capture therapy) techniques. The exploitation of these multifunctional particles for in vivo applications requires accurate control of their biodistribution. The postfunctionalization of these particles by four different poly(ethylene glycol) derivatives, which differ by chain length and end group, exerts a great influence on the zeta potential of the nanoparticles and on their biodistribution after intravenous injection to HEK-beta3-tumor-bearing mice. This study reveals that the behavior of PEGylated nanoparticles, which was monitored by in vivo fluorescence imaging, depends on both the chain length and the end group of the PEG chain.