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Effective cellular internalization of silica-coated CdSe quantum dots for high contrast cancer imaging and labelling applications.

Vibin M, Vinayakan R, John A, Fernandez FB, Abraham A - Cancer Nanotechnol (2014)

Bottom Line: The strong fluorescence from the cytoplasm confirmed that the QDs were efficiently internalized by the cells.The internalization maxima were observed at the fourth hour of incubation in both stem and cancer cells.Moreover, high contrast in vivo tumor imaging efficiency of silica-coated CdSe QDs was performed in ultrathin sections of tumor mice, and the results confirmed its effective role in cellular imaging and labelling in cancer and other diseases.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, University of Kerala, Kariavattom campus, 695581 Thiruvananthapuram, Kerala India.

ABSTRACT

The possibility of developing novel contrast imaging agents for cancer cellular labelling and fluorescence imaging applications were explored using silica-coated cadmium selenide (CdSe) quantum dots (QDs). The time dependent cellular internalization efficiency study was carried out using Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) and Confocal Laser Scanning Microscopy (cLSM) after exposing QDs to stem cells and cancer cells. The strong fluorescence from the cytoplasm confirmed that the QDs were efficiently internalized by the cells. The internalization maxima were observed at the fourth hour of incubation in both stem and cancer cells. Further, the in vitro fluorescence imaging as well as localization study of QDs were performed in various cells. Moreover, high contrast in vivo tumor imaging efficiency of silica-coated CdSe QDs was performed in ultrathin sections of tumor mice, and the results confirmed its effective role in cellular imaging and labelling in cancer and other diseases.

No MeSH data available.


Related in: MedlinePlus

Percentage of cellular internalixzation of silica-coated CdSe QDs in stem cell (RADMSC) using ICP-OES. The peak internalization was observed at 4 h after the QD exposure.
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Fig2: Percentage of cellular internalixzation of silica-coated CdSe QDs in stem cell (RADMSC) using ICP-OES. The peak internalization was observed at 4 h after the QD exposure.

Mentions: The cytocompatibility of cadmium chalcogenides based QDs are of primary attention when there biological applications are concerned. The toxicological effect is attributed to the leaching out of core materials, particularly cadmium ions into the cell media [38,39]. The non-toxicity of the QDs used in our studies is ensured by generating a CdSe/Silica core shell structure preventing any leakage of core materials. Also, the silica shell ensures aqueous solubility which is essential for biological studies and applications [28]. One of the emerging applications of QDs is cellular labelling and imaging. In the current experiment, we have used a couple of cell models-HeLa cells and RADMSCs, to monitor the in vitro cellular internalisation efficiency of silica-coated QDs as a function of time. The results obtained from the ICP-OES studies undoubtfully prove the high internalisation efficiency and cytocompatibility of silica-coated CdSe QDs. These observations confirm their potential applications in cellular imaging. This aspect was further confirmed by confocal laser scanning microscopy (cLSM) studies. For this, cells were incubated with QDs for 1, 2, 3, 4 and 5 h and then washed to remove any unbound QDs. Percentage of cellular internalization of silica-coated CdSe QDs were studied by using Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). ICP-OES was performed utilizing an Optima 5300 DV instrument (Perkin Elmer). ICP-OES was used to measure the cadmium content to indicate the concentration of QDs in cells collected at predetermined time intervals (0–5 h). The ICP-OES instrument was initialized, optimized and standardized using the manufacturer’s recommendations. Standardization was performed using multielement standards (Perkin Elmer Life and Analytical Sciences). The result obtained from the ICP-OES studies is shown in Figures 2 & 3, where the percentage of internalised QDs is plotted as a function of incubation time. Results showed that the maximum internalization observed at 4 h in both stem and cancer cells after the QD exposure. Overall internalization efficiency was found to be significant high in cancer cells when compared to stem cells (Figures 2 & 3).Figure 2


Effective cellular internalization of silica-coated CdSe quantum dots for high contrast cancer imaging and labelling applications.

Vibin M, Vinayakan R, John A, Fernandez FB, Abraham A - Cancer Nanotechnol (2014)

Percentage of cellular internalixzation of silica-coated CdSe QDs in stem cell (RADMSC) using ICP-OES. The peak internalization was observed at 4 h after the QD exposure.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4631722&req=5

Fig2: Percentage of cellular internalixzation of silica-coated CdSe QDs in stem cell (RADMSC) using ICP-OES. The peak internalization was observed at 4 h after the QD exposure.
Mentions: The cytocompatibility of cadmium chalcogenides based QDs are of primary attention when there biological applications are concerned. The toxicological effect is attributed to the leaching out of core materials, particularly cadmium ions into the cell media [38,39]. The non-toxicity of the QDs used in our studies is ensured by generating a CdSe/Silica core shell structure preventing any leakage of core materials. Also, the silica shell ensures aqueous solubility which is essential for biological studies and applications [28]. One of the emerging applications of QDs is cellular labelling and imaging. In the current experiment, we have used a couple of cell models-HeLa cells and RADMSCs, to monitor the in vitro cellular internalisation efficiency of silica-coated QDs as a function of time. The results obtained from the ICP-OES studies undoubtfully prove the high internalisation efficiency and cytocompatibility of silica-coated CdSe QDs. These observations confirm their potential applications in cellular imaging. This aspect was further confirmed by confocal laser scanning microscopy (cLSM) studies. For this, cells were incubated with QDs for 1, 2, 3, 4 and 5 h and then washed to remove any unbound QDs. Percentage of cellular internalization of silica-coated CdSe QDs were studied by using Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). ICP-OES was performed utilizing an Optima 5300 DV instrument (Perkin Elmer). ICP-OES was used to measure the cadmium content to indicate the concentration of QDs in cells collected at predetermined time intervals (0–5 h). The ICP-OES instrument was initialized, optimized and standardized using the manufacturer’s recommendations. Standardization was performed using multielement standards (Perkin Elmer Life and Analytical Sciences). The result obtained from the ICP-OES studies is shown in Figures 2 & 3, where the percentage of internalised QDs is plotted as a function of incubation time. Results showed that the maximum internalization observed at 4 h in both stem and cancer cells after the QD exposure. Overall internalization efficiency was found to be significant high in cancer cells when compared to stem cells (Figures 2 & 3).Figure 2

Bottom Line: The strong fluorescence from the cytoplasm confirmed that the QDs were efficiently internalized by the cells.The internalization maxima were observed at the fourth hour of incubation in both stem and cancer cells.Moreover, high contrast in vivo tumor imaging efficiency of silica-coated CdSe QDs was performed in ultrathin sections of tumor mice, and the results confirmed its effective role in cellular imaging and labelling in cancer and other diseases.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, University of Kerala, Kariavattom campus, 695581 Thiruvananthapuram, Kerala India.

ABSTRACT

The possibility of developing novel contrast imaging agents for cancer cellular labelling and fluorescence imaging applications were explored using silica-coated cadmium selenide (CdSe) quantum dots (QDs). The time dependent cellular internalization efficiency study was carried out using Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) and Confocal Laser Scanning Microscopy (cLSM) after exposing QDs to stem cells and cancer cells. The strong fluorescence from the cytoplasm confirmed that the QDs were efficiently internalized by the cells. The internalization maxima were observed at the fourth hour of incubation in both stem and cancer cells. Further, the in vitro fluorescence imaging as well as localization study of QDs were performed in various cells. Moreover, high contrast in vivo tumor imaging efficiency of silica-coated CdSe QDs was performed in ultrathin sections of tumor mice, and the results confirmed its effective role in cellular imaging and labelling in cancer and other diseases.

No MeSH data available.


Related in: MedlinePlus