Biocompatibility Of The PEI Coated Magnetic Fe₃O₄Nanoparticles In SHI-1Cells And Application Of Magetic Resonance Imaging

1. Biocompatibility of the PEI coated magnetic Fe₃O₄nanoparticles in SHI-1cellsObjective To explore the feasibility of the use of polyethylene imine （PEI） coatedmagnetic nanoparticles of Fe₃O₄（PEI-Fe₃O₄-MNPs） for magnetic resonance cell imagingtechnology to track cell biology behavior. Method （1） Taking SHI-1cells as the studysubject, endocytic PEI-Fe₃O₄-MNPs were observed by transmission electron microscopy（TEM）.（2） Iron contents of nano-labeled cells were analyzed by inductively coupledplasma-atomic emission spectroscopy （ICP-AES） and Prussian blue staining.（3） Wedetected the ability of proliferation of labeled cells by cell counting kit-8（CCK-8） assay,determine the ability of differentiation and apoptosis by flow cytometry, andcolony-forming ability according methyl cellulose semi-solid medium.（4） The invasivecapacity of labeled cells were investigated by transwell methods, and the mRNA ofMMP-2, MMP-9, CD44, CXCR4, TIMP-1, TIMP-2in SHI-1, HL-60, U937, NB4, K562were detected by quantitative RT-PCR. SHI-1cells without endocytosingPEI-Fe₃O₄-MNPs were used as control. Result （1） All the data showed thatPEI-Fe₃O₄-MNPs could label SHI-1cells.（2） The labeling efficiency was depended on thenanoparticles’concentration and the time of treating cells.（3） After SHI-1were treated by5¹00μg Fe/ml PEI-Fe₃O₄-MNPs for48h, compared with groups at5⁵0μg Fe/ml,inhibition rates of cells labeled by60¹00μg Fe/ml PEI-Fe₃O₄-MNPs were much higher（P<0.05）. Differentiation and colony-forming of labeled cells were similar with control inthe range of certain PEI-Fe₃O₄-MNPs concentration （P>0.05）.（4） The invasive capacity ofSHI-1cells reduced signifcantly after co-culture with PEI-Fe₃O₄-MNPs, while the rato ofapoptosis was increased （P<0.05）. And the expression of MMP-9in labeled SHI-1cellswere higher compared with controls, while the expression of TIMP-2were lower （P<0.05）. Conclusion （1） SHI-1cells were high efficiently labeled by PEI-Fe₃O₄-MNPs.（2）Although PEI-Fe₃O₄-MNPs could influence the invasive capacity of SHI-1cells and causecell apototic, but most of biocompatibilities were very well in proper concentration range,which may supply foundation for cell tracking in vivo by use of magnetic resonanceimaging （MRI）.2. In vivo magnetic resonance preliminary imaging tracking of PEI coated magnetic Fe₃O₄nanoparticles labeled SHI-1cells in ratsObjective Extramedullary infiltration of leukemia cells often become the source ofrelapse for leukemia after chemotherapy or transplantation. It is of great significance tofind leukemia extramedullary infiltration lesions timely for diagnosis and treatment ofleukemia. This study investigated the magnetic resonance preliminary imaging tracking ofPEI coated magnetic Fe₃O₄nanoparticles labeled SHI-1cells in rats, which may supplyfoundation in vivo for revealing the pathology bases of extramedullary infiltration forleukemia by the magnetic resonance （MR） imaging of the single cell labeled with MNPs,especially for the central nervous system leukemia （CNSL）, which is one of the mostfrequent extramedullary locations of acute leukemia. Method All20BALB/c nu/nu micepre-treated by cytoxan intraperitoneal injection. ALL the SHI-1cells labeled byPEI-Fe₃O₄-MNPs of different concentration groups or not were planted under the skin ofmice, respectively. The development of the subcutaneous tumor was observed, and then theMRI results were also obtained. And the expression of human mlL/AF6fusion gene intumors were detected by RT-PCR. Result The subcutaneous tumor formation rates ofSHI-1cells labeled by PEI-Fe₃O₄-MNPs or not were100.0%. There was no significantdifference among growth rates of subcutaneous tumors in different groups. The signalintensity of tumor decreaseed with the increase of the PEI-Fe₃O₄concentration, andincreased with the growth of the tumor （P<0.05）. The transcription of mlL/AF6fusiongene could be detected in tumors of all the mice. Conclusion SHI-1cells labeled by PEI-Fe₃O₄could grow in vivo and be detected by MR imaging.