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

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.

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

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.

Tras la huella de las células madre / On the track of stem cells

En los últimos años ha surgido un gran interés en conocer la biodistribución de las células madre en el organismo después que son infundidas o inyectadas directamente en una parte del cuerpo. Para esto se han usado diferentes procederes, entre ellos, el marcaje de las células con diferentes fluorocromos, tales como la proteína con fluorescencia verde y la proteína con fluorescencia roja; o bien se les hace una transfección con plasmidos que codifican proteínas fluorescentes o se emplean sondas moleculares fluorescentes para la identificación de cromosomas. Recientemente se han introducido técnicas imagenológicas de avanzada no invasivas, entre las que tenemos la resonancia magnético nuclear, así como procederes basados en el marcaje con radionúclidos para la obtención de imágenes detectadas por tomografía por emisión de positrones (PET, del inglés positron emission tomography), o por tomografía computarizada por emisión de fotón único (SPECT, del inglés single- photon emission computed tomography).

In past years there was an increasing interest by to know about the biodistribution of stem cells in organism after its perfusion or direct injection in a part of the body. Thus, we used different procedures including the cell labeling with distinct fluorochromes, such as the green fluorescence protein and the red fluorescence protein or a plasmid transfection codifying the fluorescent proteins of fluorescent molecular stents to identify the chromosomes. Recently non-invasive leading imaging techniques have been introduced including nuclear magnetic resonance. As well as procedures based on radionuclide labeling to obtain the positron emission tomography (PET) images or by photon-emission computed tomography (SPECT).

Application of quantum dots in clinical research / 中国介入影像与治疗学

Quantum dot is a new kind of nano-fluorescent material. It has unique optical properties and can be used for clinical research including cancer research, determination of metal content, microbe detection and developing of drug target. It will have the potential value in the study of disease mechanism, clinical diagnosis and treatment.