Journal of Fluorescence

, Volume 21, Issue 4, pp 1635–1642 | Cite as

Liposome Encapsulation of Thiol-Capped CdTe Quantum Dots for Enhancing the Intracellular Delivery

  • Jun-Yong Wang
  • Jin-Feng Zhao
  • Pei-Nan Wang
  • Wu-Li Yang
  • Ji-Yao Chen
Original Paper


Although water soluble thiol-capped quantum dots (QDs) have been widely used as photoluminescence (PL) probes in various applications, the negative charges on thiol terminals limit the cell uptake hindering their applications in cell imaging. The commercial liposome complex (Sofast®) was used to encapsulate these QDs forming the liposome vesicles with the loading efficiency as high as about 95%. The cell uptakes of unencapsulated QDs and QD loaded liposome vesicles were comparatively studied by a laser scanning confocal microscope. We found that QD loaded liposome vesicles can effectively enhance the intracellular delivery of QDs in three cell lines (human osteosarcoma cell line (U2OS); human cervical carcinoma cell line (Hela); human embryonic kidney cell line (293 T)). The photobleaching of encapsulated QDs in cells was also reduced comparing with that of unencapsulated QDs, measured by the PL decay of cellular QDs with a continuous laser irradiation in the microscope. The flow cytometric measurements further showed that the enhancing ratios of encapsulated QDs on cell uptake are about 4–8 times in 293 T and Hela cells. These results suggest that the cationic liposome encapsulation is an effective modality to enhance the intracellular delivery of thiol-capped QDs.


Quantum dots Living cells Intracellular delivery Cell imaging Liposome encapsulation 



This work was supported by the Shanghai Municipal Science and Technology Commission (06ZR14005), the National Natural Science Foundation of China (10774027 and 11074053).


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Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  • Jun-Yong Wang
    • 1
    • 2
  • Jin-Feng Zhao
    • 1
  • Pei-Nan Wang
    • 3
  • Wu-Li Yang
    • 4
  • Ji-Yao Chen
    • 1
  1. 1.State Key Laboratory of Surface Physics and Department of PhysicsFudan UniversityShanghaiPeople’s Republic of China
  2. 2.State Key Laboratory of Genetic Engineering and Institute of GeneticsFudan UniversityShanghaiPeople’s Republic of China
  3. 3.Department of Optical Science and EngineeringFudan UniversityShanghaiPeople’s Republic of China
  4. 4.Department of Macromolecular ScienceFudan UniversityShanghaiPeople’s Republic of China

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