A highly effective and facile way to prepare cellular labelling quantum dots with cetyltrimethylammonium bromide

Abstract

We report a facile and effective way to prepare cell labelling quantum dots (QDs) using cetyltrimethylammonium bromide (CTAB) and to enhance biocompatibility of the QD labels. There are several reports on the use of this ligand to encapsulate nanoparticles including QDs. However, due to its high cellular toxicity, CTAB has still not been employed to prepare QDs for cellular labelling. After removing the free ligand by dialysis, we could successfully use CdSe/CdS/ZnS (core/shell/shell) QDs for cellular labelling. In addition, we found that the simple introduction of a sonication step to cause the emulsion of the QDs in the aqueous surfactant solution could lead to a five-times higher encapsulation of the QDs as compared to other methods. Fluorescent microscopy images of HeLa cells revealed that the QDs were evenly dispersed inside them. Furthermore, fluorescent morphological images of the QD labelled cells were more distinct than bright field images.