Limits...
One-Pot Synthesis of Biocompatible CdSe/CdS Quantum Dots and Their Applications as Fluorescent Biological Labels

View Article: PubMed Central - HTML - PubMed

ABSTRACT

We developed a novel one-pot polyol approach for the synthesis of biocompatible CdSe quantum dots (QDs) using poly(acrylic acid) (PAA) as a capping ligand at 240°C. The morphological and structural characterization confirmed the formation of biocompatible and monodisperse CdSe QDs with several nanometers in size. The encapsulation of CdS thin layers on the surface of CdSe QDs (CdSe/CdS core–shell QDs) was used for passivating the defect emission (650 nm) and enhancing the fluorescent quantum yields up to 30% of band-to-band emission (530–600 nm). Moreover, the PL emission peak of CdSe/CdS core–shell QDs could be tuned from 530 to 600 nm by the size of CdSe core. The as-prepared CdSe/CdS core–shell QDs with small size, well water solubility, good monodispersity, and bright PL emission showed high performance as fluorescent cell labels in vitro. The viability of QDs-labeled 293T cells was evaluated using a 3-(4,5-dimethylthiazol)-2-diphenyltertrazolium bromide (MTT) assay. The results showed the satisfactory (>80%) biocompatibility of as-synthesized PAA-capped QDs at the Cd concentration of 15 μg/ml.

No MeSH data available.


Cell viability of Human embryonal kidney cell line 293T cells labeled with different concentration of QDs (mg Cd per mL) for 24 h at 37°C as measured by an MTT assay. The error bars show the standard deviations.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3211396&req=5

Figure 4: Cell viability of Human embryonal kidney cell line 293T cells labeled with different concentration of QDs (mg Cd per mL) for 24 h at 37°C as measured by an MTT assay. The error bars show the standard deviations.

Mentions: Human embryonal kidney cell line is chosen as typical kind of human cells to demonstrate the promising applications as fluorescent biological labels. MTT assays were performed to evaluate the cytotoxicity corresponding to the biocompatibility of PAA-capped QDs on 293T cells. Four groups of MTT tests were done for each quantum dots concentration. In Figure 4, the cell viability shows the average cell viability of four tests, while the error bars show the standard deviations. Satisfactory (>80%) biocompatibility of as-synthesized PAA-capped QDs is achieved at a particle concentration below 15 μg Cd/mL in 293T cell lines. No statistical difference in viability is evident with PAA-QDs-labeled cells and untreated cells for 24 h at the concentration of 7 μg Cd/mL. It is well known that without proper surface modification the Cd-related quantum dots will cause severe cell damage after 24 h. MTT analysis showed that the cell viability of MCF-7 cells was below 50% after 24-h exposure to QDs (10 mg mL-1) capped by mercaptopropionic acid [21]. Uncapped QDs were even more toxic [22]. As a result, further surface modification processes such as PEGylation are often taken place to enhance the biocompatibility [23]. In our case, PAA absorbed on the surface improves the hydrophilicity and biocompatibility of the nanoparticles. The cytotoxicity tests indicate that, without further surface modification, the as-synthesized PAA-capped QDs show good biocompatibility as biological labels, which is comparable with PEGylated nanoparticles [23]. It turns out that the PAA modification during the "one-pot" synthesis is both simple and effective.


One-Pot Synthesis of Biocompatible CdSe/CdS Quantum Dots and Their Applications as Fluorescent Biological Labels
Cell viability of Human embryonal kidney cell line 293T cells labeled with different concentration of QDs (mg Cd per mL) for 24 h at 37°C as measured by an MTT assay. The error bars show the standard deviations.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211396&req=5

Figure 4: Cell viability of Human embryonal kidney cell line 293T cells labeled with different concentration of QDs (mg Cd per mL) for 24 h at 37°C as measured by an MTT assay. The error bars show the standard deviations.
Mentions: Human embryonal kidney cell line is chosen as typical kind of human cells to demonstrate the promising applications as fluorescent biological labels. MTT assays were performed to evaluate the cytotoxicity corresponding to the biocompatibility of PAA-capped QDs on 293T cells. Four groups of MTT tests were done for each quantum dots concentration. In Figure 4, the cell viability shows the average cell viability of four tests, while the error bars show the standard deviations. Satisfactory (>80%) biocompatibility of as-synthesized PAA-capped QDs is achieved at a particle concentration below 15 μg Cd/mL in 293T cell lines. No statistical difference in viability is evident with PAA-QDs-labeled cells and untreated cells for 24 h at the concentration of 7 μg Cd/mL. It is well known that without proper surface modification the Cd-related quantum dots will cause severe cell damage after 24 h. MTT analysis showed that the cell viability of MCF-7 cells was below 50% after 24-h exposure to QDs (10 mg mL-1) capped by mercaptopropionic acid [21]. Uncapped QDs were even more toxic [22]. As a result, further surface modification processes such as PEGylation are often taken place to enhance the biocompatibility [23]. In our case, PAA absorbed on the surface improves the hydrophilicity and biocompatibility of the nanoparticles. The cytotoxicity tests indicate that, without further surface modification, the as-synthesized PAA-capped QDs show good biocompatibility as biological labels, which is comparable with PEGylated nanoparticles [23]. It turns out that the PAA modification during the "one-pot" synthesis is both simple and effective.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

We developed a novel one-pot polyol approach for the synthesis of biocompatible CdSe quantum dots (QDs) using poly(acrylic acid) (PAA) as a capping ligand at 240°C. The morphological and structural characterization confirmed the formation of biocompatible and monodisperse CdSe QDs with several nanometers in size. The encapsulation of CdS thin layers on the surface of CdSe QDs (CdSe/CdS core–shell QDs) was used for passivating the defect emission (650 nm) and enhancing the fluorescent quantum yields up to 30% of band-to-band emission (530–600 nm). Moreover, the PL emission peak of CdSe/CdS core–shell QDs could be tuned from 530 to 600 nm by the size of CdSe core. The as-prepared CdSe/CdS core–shell QDs with small size, well water solubility, good monodispersity, and bright PL emission showed high performance as fluorescent cell labels in vitro. The viability of QDs-labeled 293T cells was evaluated using a 3-(4,5-dimethylthiazol)-2-diphenyltertrazolium bromide (MTT) assay. The results showed the satisfactory (>80%) biocompatibility of as-synthesized PAA-capped QDs at the Cd concentration of 15 μg/ml.

No MeSH data available.