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.


a PL spectra of PAA-capped CdSe (dash) (4 time of original intensity) and CdSe/CdS (solid) nanocrystals. b Normalized fluorescence emission spectrum of CdSe/CdS QDs with various size.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: a PL spectra of PAA-capped CdSe (dash) (4 time of original intensity) and CdSe/CdS (solid) nanocrystals. b Normalized fluorescence emission spectrum of CdSe/CdS QDs with various size.

Mentions: Figure 3a shows a comparison of the PL spectra of the as-prepared CdSe and CdSe/CdS core–shell QDs. As observed, the PL emission at 650 nm originating from trap sites was completely inhibited by coating a thin CdS layer on the surface of CdSe QDs due to the surface passivation [19]. Meanwhile, the brighter luminescence was achieved. Moreover, the PL emission originating from the band to band of the CdSe/CdS core–shell QDs can be tuned from 531 to 590 nm by the size of CdSe (Figure 3b) with FWHM of 40–60 nm and a quantum yield of about 30% compared with Rhodamine B [20], which has been significantly improved comparing with the CdSe cores. The PAA-capped QDs are stable for several months without precipitation in aqueous dispersion. Therefore, the PAA-capped CdSe/CdS core–shell QDs with small size, well water solubility, good monodispersity, and bright PL emission show the promising applications as fluorescent biological labels.


One-Pot Synthesis of Biocompatible CdSe/CdS Quantum Dots and Their Applications as Fluorescent Biological Labels
a PL spectra of PAA-capped CdSe (dash) (4 time of original intensity) and CdSe/CdS (solid) nanocrystals. b Normalized fluorescence emission spectrum of CdSe/CdS QDs with various size.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: a PL spectra of PAA-capped CdSe (dash) (4 time of original intensity) and CdSe/CdS (solid) nanocrystals. b Normalized fluorescence emission spectrum of CdSe/CdS QDs with various size.
Mentions: Figure 3a shows a comparison of the PL spectra of the as-prepared CdSe and CdSe/CdS core–shell QDs. As observed, the PL emission at 650 nm originating from trap sites was completely inhibited by coating a thin CdS layer on the surface of CdSe QDs due to the surface passivation [19]. Meanwhile, the brighter luminescence was achieved. Moreover, the PL emission originating from the band to band of the CdSe/CdS core–shell QDs can be tuned from 531 to 590 nm by the size of CdSe (Figure 3b) with FWHM of 40–60 nm and a quantum yield of about 30% compared with Rhodamine B [20], which has been significantly improved comparing with the CdSe cores. The PAA-capped QDs are stable for several months without precipitation in aqueous dispersion. Therefore, the PAA-capped CdSe/CdS core–shell QDs with small size, well water solubility, good monodispersity, and bright PL emission show the promising 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.