Research Highlight

Delivering quantum dots

doi:10.1038/nindia.2011.4 Published online 19 January 2011

New research has shown that chitosan-modified with cholesterol can deliver quantum dots into cells. This could be a new way to ferry various nanoparticles and vitamin into cells.

Delivering nanoparticles into the cell is often necessary for cellular and subcellular targeting, labeling, and imaging. Cationic nanoparticles are easily taken up by cells as they have stronger electrostatic interaction with the anionic cell membrane. However, anionic nanoparticles generally have low cellular uptake.

Researchers have designed a delivery vehicle by modifying chitosan with the use of cholesterol. They tested this vehicle to deliver cadmium-selenide and zinc sulpide into cells.

The results indicated that nanoparticle uptake in the presence of chitosan was low. Cholesterol modification of chitosan significantly enhanced the cellular uptake of the anionic nanoparticle. Cholesterol interacts with the lipid cell membrane and thus enhances the cellular uptake of the anionic particle.

In addition, the chitosan reagent can be separated after the nanoparticle is delivered into the cell. This type of nanoparticle delivery is attractive for anionic nanoparticles with oligonucleotide, vitamin and antibody. The chitosan-based reagent has low cytotoxicity which gives an added advantage as a delivery reagent, the researchers conclude.


  1. Maity, R. A. et al. Chitosan-cholesterol-based cellular delivery of anionic nanoparticles. J. Phys. Chem. C. 115, 137-144 (2011) | Article |