[Magnetic/luminescent quantum dots bifunctional nanoparticles labeling of rat bone mesenchymal stem cells].
OBJECTIVE
To evaluate the dual-labeling efficiency of magnetic and luminescent quantum dots bifunctional nanoparticles to rat bone mesenchymal stem cells (BMSC).


METHODS
Rat BMSC were isolated, purified, and expanded. Magnetic/luminescent bifunctional nanoparticles (Fe(3)O(4)@CdTe@SiO(2)), were prepared by using silicon dioxide (SiO(2)) to encapsulate simultaneously Fe(3)O(4) and CdTe quantum dots. BMSC were incubated with the Fe(3)O(4)@CdTe@SiO(2) nanoparticles which iron concentration was 25 microg/ml. Fluorescence microscope was used to detect the fluorescence of the intracellular nanoparticles. The dual-labeled BMSC with various concentration underwent ex vivo MR imaging with T(1)WI, T(2)WI and T(2)(*)WI sequences. To show the intracellular iron of labeled cells, prussian blue stain was performed. Spectrophotometer was used to detect the iron concentration in the cells.


RESULTS
Intracellular red fluorescence of Fe(3)O(4)@CdTe@SiO(2) can be observed via fluorescent microscopy. Rat BMSC could be effectively dual-labeled with approximately 90% efficiency. The MR images with T(2)WI and T(2)(*)WI sequences, especially with T(2)(*)WI sequence, showed that the signals of the dual-labeled BMSC were lower than those of the unlabeled cells. Cellular total iron is 14.05 + or - 4.15 pg per cell. Iron containing intracytoplasmic vesicles could be observed with Prussian blue staining.


CONCLUSIONS
Rat BMSC can be dual-labeled successfully with Fe(3)O(4)@CdTe@SiO(2) magnetic/luminescent bifunctional nanoparticles successfully, and might serve as a tool for magnetic resonance imaging and in vivo optical imaging.
Yan
Rong-hua
RH
Laboratory of Molecular Imaging, Department of Radiology, the Third Affiliated Hospital, Sun Yet-Sen University, Guangzhou 510630, China.
Shan
Hong
H
Nie
Li-bo
LB
Li
Dan
D
Wang
Jin
J
Zhu
Kang-shun
KS
Wang
Hong-fei
HF
Ma
Dong
D
Zhang
Li-ming
LM
D000818:Animals; D002478:Cells, Cultured; D003287:Contrast Media; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D059630:Mesenchymal Stem Cells; D045663:Quantum Dots; D016719:Radioimmunodetection; D051381:Rats; D017207:Rats, Sprague-Dawley
D003287:Contrast Media