Abstract
The nanocomposites of poly(diallyldimethylammonium chloride) (PDADMAC) and CdTe quantum dots (QDs) (i.e., QD-PDADMAC nanocomposites) have been prepared based on electrostatic interaction. Transmission electron microscopy, Fourier transform infrared spectroscopy, and Zeta potential analysis were used to characterize the prepared QD-PDADMAC nanocomposites. It was shown that the QD-PDADMAC nanocomposites have the specific curly-shaped band-like morphology with the width of 4–8 nm and unequal length, and there are rich positive charges on the surface of the nanocomposites. The prepared QD-PDADMAC nanocomposites also had good fluorescence stability. The usage based on their good stability has also been studied by cellular and in vivo imaging. In comparison with the QDs without PDADMAC protection, the obtained QD-PDADMAC nanocomposites have better fluorescence stability and staining effect in biology imaging. After incubation for 24 h at 37°C, A549 lung cancer cells were almost not stained by QDs, similarity to the culture medium control group, and could be clearly stained by QD-PDADMAC nanocomposites. For in vivo imaging of mice by intraperitoneal injection, the fluorescence of QDs could not be seen in abdominal cavity at 30 min, and the nanocomposites' one could still be clearly observed at a longer time (1 h). Moreover, the intestine in the large area of the abdominal cavity was effectively stained.
Acknowledgments
This research was supported by the grant from the National Natural Science Foundation of China (grant no. 81001686), the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions, and Jiangsu Province Projects of Innovative Research of University Graduate Students (grant no. CX2211-0113).
Notes
Xing-ru Dou and Dan-dan Zhang contributed equally to this paper.