Modification of aminosilanized superparamagnetic nanoparticles: feasibility of multimodal detection using 3T MRI, small animal PET, and fluorescence imaging.
OBJECTIVE
The aim of our study was to modify an aminosilane-coated superparamagnetic nanoparticle for cell labeling and subsequent multimodal imaging using magnetic resonance imaging (MRI), positron emission tomography (PET), and fluorescent imaging in vivo.


METHODS
We covalently bound the transfection agent HIV-1 tat, the fluorescent dye fluorescein isothiocyanate, and the positron-emitting radionuclide gallium-68 to the particle and injected them intravenously into Wistar rats, followed by animal PET and MRI at 3.0 T. As a proof of principle hepatogenic HuH7 cells were labeled with the particles and observed for cell toxicity as well as detectability by MRI and biodistribution in vivo.


RESULTS
PET imaging and MRI revealed increasing hepatic and splenic accumulation of the particles over 24 h. Adjacent in vitro studies in hepatogenic HuH7 cells showed a rapid intracellular accumulation of the particles with high labeling efficiency and without any signs of toxicity. In vivo dissemination of the labeled cells could be followed by dynamic biodistribution studies.


CONCLUSIONS
We conclude that our modified superparamagnetic nanoparticles are stable under in vitro and in vivo conditions and are therefore applicable for efficient cell labeling and subsequent multimodal molecular imaging. Moreover, their multiple free amino groups suggest the possibility for further modifications and might provide interesting opportunities for various research fields.
Stelter
Lars
L
Klinik für Strahlenheilkunde, CC6, Charité Campus Virchow-Klinikum, Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany. lars.stelter@charite.de
Pinkernelle
Jens G
JG
Michel
Roger
R
Schwartländer
Ruth
R
Raschzok
Nathanael
N
Morgul
Mehmet H
MH
Koch
Martin
M
Denecke
Timm
T
Ruf
Juri
J
Bäumler
Hans
H
Jordan
Andreas
A
Hamm
Bernd
B
Sauer
Igor M
IM
Teichgräber
Ulf
U
D000818:Animals; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival; D005240:Feasibility Studies; D005453:Fluorescence; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism; D008099:Liver / Q000166:cytology; D008279:Magnetic Resonance Imaging; D008280:Magnetics; D057054:Molecular Imaging / Q000379:methods*; D053758:Nanoparticles; D049268:Positron-Emission Tomography; D051381:Rats; D017208:Rats, Wistar; D012821:Silanes / Q000378:metabolism*; D013154:Spleen / Q000166:cytology; D013194:Staining and Labeling; D014018:Tissue Distribution
D012821:Silanes