Cholera toxin B conjugated quantum dots for live cell labeling
Subhasish K Chakraborty1, James A J Fitzpatrick, Julie A Phillippi
1Molecular Biosensor and Imaging Center, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, USA.
Nano Letters
|August 1, 2007
Summary
Cholera toxin subunit B (CTB) quantum dot conjugates offer a practical alternative for labeling mammalian cells. Unlike polyarginine conjugates, CTB conjugates distribute widely in the cytoplasm, avoiding rapid perinuclear accumulation.
Area of Science:
- Bioconjugation Chemistry
- Cellular Imaging
- Nanotechnology
Background:
- Quantum dots (QDs) are widely used for cell labeling.
- Polyarginine conjugates are common for QD cell labeling.
- Polyarginine conjugates can rapidly accumulate in perinuclear endosomes, limiting their utility.
Purpose of the Study:
- To develop and evaluate cholera toxin subunit B (CTB)--quantum dot conjugates as an alternative cell labeling agent.
- To compare the cellular uptake and intracellular localization of CTB-QDs with polyarginine-QDs.
Main Methods:
- Synthesis of CTB-QD conjugates.
- Incubation of various mammalian cell lines with CTB-QDs and polyarginine-QDs.
- Microscopic analysis of intracellular conjugate distribution.
Main Results:
- CTB-QD conjugates were internalized into small cytoplasmic vesicles across all tested cell lines.
- Polyarginine conjugates rapidly accumulated in large perinuclear endosomes.
- While some CTB-QDs eventually localized to perinuclear endosomes, many remained dispersed in cytoplasmic vesicles for extended periods.
Conclusions:
- CTB-QD conjugates provide a practical and effective alternative to polyarginine conjugates for general mammalian cell labeling.
- The distinct intracellular trafficking of CTB-QDs offers advantages over polyarginine conjugates by avoiding rapid perinuclear sequestration.
