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Proceedings Paper

Bio-orthogonal coupling on PEG-modified quantum dots (Conference Presentation)
Author(s): Naiqian Zhan; Goutam Palui; Hedi Mattoussi

Paper Abstract

We have designed two sets of aldehyde- and azide-modified ligands; these ligands also present lipoic acid anchors and PEG hydrophilic moieties (LA-PEG-CHO and LA-PEG-azide). We combined this design with a photoligation strategy to prepare QDs with good control over the fraction of intact reactive groups per nanocrystal. We first applied the extremely efficient hydrazone coupling ligation to react the QD with hydrozinopyridine, which produces a well-defined absorption feature at 354 nm ascribed to the hydrazone chromophore. We exploited this signature to measure the number of aldehyde groups per QD when the fraction of LA-PEG-CHO per nanocrystal was varied, by comparing the optical signature at 354 with the molar extinction coefficient of the chromophore. This allowed us to extract an estimate for the number of LA-PEG ligand per QDs for a few distinct size nanocrystals. We further complemented these findings with the use of NMR spectroscopy to estimate of the ligand density using well defined signatures of the terminal protons of the ligands, and found a good agreement between the two techniques. We then showed that bio-orthogonal reactions based on CLICK and hydrazone coupling can be achieved using QDs presenting a mixture of azide and CHO functions. We anticipate that this strategy could be applied other nanoparticles such as those of Au and metals and semiconductor nanocrystals.

Paper Details

Date Published: 24 April 2017
PDF: 1 pages
Proc. SPIE 10078, Colloidal Nanoparticles for Biomedical Applications XII, 100780R (24 April 2017); doi: 10.1117/12.2253064
Show Author Affiliations
Naiqian Zhan, Florida State Univ. (United States)
Goutam Palui, Florida State Univ. (United States)
Hedi Mattoussi, Florida State Univ. (United States)

Published in SPIE Proceedings Vol. 10078:
Colloidal Nanoparticles for Biomedical Applications XII
Marek Osiński; Wolfgang J. Parak; Xing-Jie Liang, Editor(s)

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