(1) Background. The main goal of this work was to develop a fluorescent dye-labelling
technique for our previously described nanosized platform, citrate-coated Prussian
blue (PB) nanoparticles (PBNPs). In addition, characteristics and stability of the
PB nanoparticles labelled with fluorescent dyes were determined. (2) Methods. We adsorbed
the fluorescent dyes Eosin Y and Rhodamine B and methylene blue (MB) to PB-nanoparticle
systems. The physicochemical properties of these fluorescent dye-labeled PBNPs (iron(II);iron(III);octadecacyanide)
were determined using atomic force microscopy, dynamic light scattering, zeta potential
measurements, scanning- and transmission electron microscopy, X-ray diffraction, and
Fourier-transformation infrared spectroscopy. A methylene-blue (MB) labelled, polyethylene-glycol
stabilized PBNP platform was selected for further assessment of in vivo distribution
and fluorescent imaging after intravenous administration in mice. (3) Results. The
MB-labelled particles emitted a strong fluorescent signal at 662 nm. We found that
the fluorescent light emission and steric stabilization made this PBNP-MB particle
platform applicable for in vivo optical imaging. (4) Conclusion. We successfully produced
a fluorescent and stable, Prussian blue-based nanosystem. The particles can be used
as a platform for imaging contrast enhancement. In vivo stability and biodistribution
studies revealed new aspects of the use of PBNPs.
