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The Interactions of CdTe Quantum Dots with Serum Albumin and Subsequent Cytotoxicity: The Influences of Homologous Ligands


With spreading applications of fluorescent quantum dots (QDs) in biomedical fields in recent years, there is increasing concern over their toxicity. Among various factors, surface ligands play critical roles. Previous studies usually employed QDs with different kinds of surface ligands, but general principles were difficult to be obtained since it was hard to compare these surface ligands of varied chemical structures without common features. Herein, the physicochemical properties of two CdTe QDs were kept very similar, but different in the surface ligands with mercaptoacetic acid (TGA) and 3-mercaptopropionic acid (MPA), respectively. These two homologous ligands only had difference in one methylene group (-CH2-). The interactions of the two CdTe QDs with bovine serum albumin (BSA), which was one of the main components of cell culture, were studied by fluorescence, UV-vis absorption, and circular dichroism spectroscopy. It was found that the fluorescence quenching of BSA by both CdTe QDs followed a static quenching mechanism, and there was no obvious difference in the Stern−Volmer quenching constants and binding constants. The thermodynamic parameters of both QDs were similar. BSA underwent conformational changes upon association with these QDs. By comparing the cytotoxicity of these two QDs, TGA-capped QDs was less cytotoxic than MPA-capped QDs. Besides, in the presence of serum proteins, the cytotoxicity of the QDs were relieved. QDs in the absence of serum proteins had a higher internalization efficiency, compared with those in the medium with serum. To the best of our knowledge, this is a rare study focusing on surface ligands with such small variations at the biomolecular and cellular level. These findings can provide new insights for the design and applications of QDs in complex biological media.

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Publication details

The article was received on 09 Nov 2017, accepted on 10 Jan 2018 and first published on 11 Jan 2018

Article type: Paper
DOI: 10.1039/C7TX00301C
Citation: Toxicol. Res., 2018, Accepted Manuscript
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    The Interactions of CdTe Quantum Dots with Serum Albumin and Subsequent Cytotoxicity: The Influences of Homologous Ligands

    R. Yan, B. Yu, M. Yin, Z. Zhou, X. Xiang, X. Han, Y. Liu and F. Jiang, Toxicol. Res., 2018, Accepted Manuscript , DOI: 10.1039/C7TX00301C

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