Mesenchymal stem cells (MSCs) are multipotent cells, using in regenerative medicine; However one of the challenges is to noninvasively monitor the delivery and biodistribution of administered cells during treatment without adverse effect on behavior of MSCs and targeted tissue. In this line, ZnO: MgO quantum dots were synthesized and cytotoxicity were evaluated on MSCs. ZnO: MgO nanocomposite were synthesized with Co-Precipitation method and then characterized by FT-IR, TEM and photoluminescence (PL) analyses. The cytotoxicity of nanocomposite was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl-tetrazolium bromide (MTT) assay. The FT-IR spectrum showed bands at 450 and 860 cm-1 which are related to the Zn-O and Mg-O groups, respectively. TEM images showed that the ZnO: MgO nanocomposite had a spherical shape with the mean dimeter of 6- 8 nm.PL analysis revealed a significant emission at 510 nm, favoring ZnO: MgO nanocomposite for stem cell labeling. based on the result of MTT assay, ZnO: MgO nanocomposite did not have any cytotoxic effect on the viability of the mesenchymal stem cells up to 0.8 mg/ mL Fluorescent properties and nontoxic effect of ZnO: MgO nanocomposite favor them for imaging and tracing of the MSCs as these cells are used in regenerative medicine.

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