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Quantum dots (QDots)

Dernière mise à jour : mercredi 9 janvier 2013, par Aline NONAT

Fluorescent nanocrystals made of semiconductor material (such as CdSe, CdTe,...), also called Quantum Dots (QDots), have been found to outperform traditional organic fluorescent dyes in many ways (size-tuneable optical properties, high quantum yields, high extinction coefficients,…). [1] They are strongly resistant to photobleaching and chemical degradation, which make them ideal agents for long-term or real-time imaging. [2]

No cytotoxic effects were found at concentrations up to 1mg/mL for the CdSe nanoparticles when coated with a ZnS shell. [3] The size of the QDots (from 10 to 50 nm) is compatible with the labelling of biomolecules and the exploration of molecular mechanism at the sub-cellular scale, [4] [5] and in mouse models. [6] Moreover, several studies are now available on the QDots-bioconjugates and we can conclude that in many cases their biological activity (receptor, affinity) is not drastically changed upon conjugation to QDots. [4]

NIR-emissive Qdots are particularly suitable for biomedical applications because of low absorption, light scattering and auto-fluorescence in this region which leads to high photon penetration in the tissues. Such QDots have already been tested in patients for detecting breast cancer and the results are encouraging. X. [7]

In the laboratory, we are synthesizing water-soluble quantum dots with size-tuneable optical properties and interesting quantum yields.

[1W. B. Cai, A. R. Hsu, Z. B. Li, Nanosclale Res. Lett. 2007, 2(6), 265-281

[2W. B. Cai, X. Y. Chen, Small 2007, 3(11), 1840-1854

[3W. J. Parak, T. Pellegrino, C. Plank, Nanotechnology 2005, 16, R9-R25

[4I. L. Medintz, H. T. Uyeda, E. R. Goldman, H. Mattoussi, Nature Materials, 2005, 4(6), 435-446

[5F. Wang, W. B. Tan, Y. Zhang, X. P. Fan, M. Q. Wang, Nanotechnology, 2006, 17(1), R1-R13

[6H. S. Choi, I. Ipe, P. Misra, J. H. Lee, B. G. Bawendi, J. V. Frangioni, Nano Lett., 2009, 9(66), 2354-2359

[7Intes, Acad. Radiol., 2005, 12, 934-947