Fluorescent labeling application of graphene oxide quantum dots in living human periodontal ligament stem cells / 医学研究生学报

ABSTRACT

ObjectiveNano-graphene oxide quantum dots (GOQDs) can be used to target fluorescent markers. The stem cell labeling is an important method in studying stem cell treatments. Our study aims to explore the possibility of using GOQDs as living cell fluorescent marker materials for human periodontal ligament stem cells (hPDLSCs), and to evaluate the biosecurity and effect as live cell fluorescence markers of GOQDs.Methods GOQDs were testified by TEM, DLS, UV-vis, and PL spectra. hPDLSCs were obtained by tissue cultivation and separated by single cell-derived colony selection. Then the source of the cells was carried out by immunocytochemical staining of anti-vimentin, anti-cytokeratin, and multipotent differentiation was used in the identification of stem cells. hPDLSCs were incubated with different concentrations of GOODs (0, 10, 25, and 50 μg/mL) for 24h and 72 h. Cytotoxicity and proliferation effects were determined using CCK-8, and cell cycles were detected using flow cytometry after the co-culture of GOQDs and hPDLSCs. The fluorescent labeling effect of GOQDs was tested using laser scanning confocal microscopy.ResultsThe characterization of GOQDs showed that the nanoparticles were evenly dispersed in water and showing blue light at 365 nm. TEM and DLS showed GOQDs had good dispersion, and the particle size was (6.36±1.41) nm. Immunocytochemical staining of anti-vimentin was positive while anti-cytokeratin was negative. The results of cytotoxicity showed there were no significant differences in cell activity after incubated with different concentrations of GOODs (0, 5, 10, 25, 50, 100, 200, and 400 μg/mL) (P>0.05), and there was no significant decrease in cell activity between 24h and 72h (P>0.05). There was no significant difference in the proportional distribution of G1, G2, and S phases between the two concentrations of GOQDs (0 μg/mL and 50 μg/mL) (P>0.05). Fluorescent images showed that GOQDs could enter the cell membrane and increase the fluorescence intensity at the concertation of 50 μg/mL.ConclusionGOQDs were confirmed to have good biocompatibility and could be used for live cell labeling of hPDLSCs.