| Fe3O4 nanoparticles exhibit excellent optical,electrical,thermal,and magnetic properties.They possess a significant gray-scale imaging contrast in the T2-weighted imaging of magnetic resonance imaging(MRI).Magnetic nanoparticles are promising in non-invasive tumor recognition,drug release,tissue repair,and stem cell therapy based on the higher spatial resolution of MRI.However,current biological studies mainly focused on in vitro investigation of cells.Therefore,it is necessary to develop versatile magnetic nanoparticles that can effectively realize MRI in vivo tracing.In the current study,citric acid(CA)modified magnetic iron oxide nanoparticles(CA@Fe3O4)were prepared via chemical co-precipitation method.The biological effects of nanoparticles in vitro and in vivo were studied.This paper mainly includes following three parts of work:1.Preparation of CA@Fe3O4 nanoparticles by chemical co-precipitation.The surface morphology,particle size,crystal structure,surface charge,and surface groups of the prepared CA@Fe3O4 nanoparticles were analyzed by TEM,XRD,DLS,and FTIR,respectively.2.Conjugation of prepared CA@Fe3O4 nanoparticles with cationic transfection agent poly-lysine(PLL)via electrostatic interaction to obtain PLL-CA@Fe3O4 nanoparticles.The PLL-CA@Fe3O4 nanoparticles were incubated with BMSCs in order to investigate,the effects of CA@Fe3O4 concentration on cell viability and MRI effectiveness.The relationship between the phagocytosis of PLL-CA@Fe3O4 and the incubation time was investigated by Prussian blue staining and single-cell iron content.Based on the abovementioned analysis,optimized concentration of PLL-CA@Fe3O4 nanoparticles was determized to label mesenchymal stem cells for following experiments.3.The low detection limit of labeled BMSCs was obtained by in vitro MRI.Subsequently,the distribution of labeled cells in vivo was monitored by MRI in real time,and the distribution patterns in MRI was verified by Prussian blue staining of tissue sections. |
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