Research Article

Targeting somatostatin receptors using in situ-bioconjugated fluorescent nanoparticles

Varun KA Sreenivasan

Macquarie University, NSW 2109, Australia

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Eun J Kim

Department of Science Education – Chemical Education Major, Daegu University, Gyeonbuk, Republic of Korea

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Ann K Goodchild

Macquarie University, NSW 2109, Australia

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Mark Connor

Macquarie University, NSW 2109, Australia

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Andrei V Zvyagin

* Author for correspondence

Macquarie University, NSW 2109, Australia.

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Email the corresponding author at andrei.zvyagin@mq.edu.au

Published Online:13 Nov 2012https://doi.org/10.2217/nnm.12.42

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Abstract

Aim: The author’s group report, for the first time, on the development of a quantum dot (QD)-based fluorescent somatostatin (somatotropin release-inhibiting factor [SRIF]) probe that enables specific targeting of somatostatin receptors. Receptor-mediated endocytosis of SRIF was imaged using this probe. Materials & methods: Biotinylated SRIF-analog (SRIF-B) and streptavidin (Sav)-coated QDs were used for the probe synthesis. A dye-labeled streptavidin complex was used to evaluate the effect of Sav binding on the activity of SRIF-B. Results: A preconjugated probe of the form SRIF-B:Sav-QD, was inactive and unable to undergo receptor-mediated endocytosis. An alternative in situ bioconjugation strategy, where SRIF-B and Sav-QD were added in two consecutive steps, enabled visualization of the receptor-mediated endocytosis. The process of Sav binding appeared to be responsible for the inactivity in the first case. Conclusion: The in situ two-step bioconjugation strategy allowed QDs to be targeted to somatostatin receptors. This strategy should enable flexible fluorescent tagging of SRIF for the investigation of molecular trafficking in cells and targeted delivery in live animals.

Original submitted 14 November 2011; Revised submitted 27 February 2012; Published online 20 July 2012

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Papers of special note have been highlighted as: ▪ of interest ▪▪ of considerable interest

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Vol. 7, No. 10

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Published online 13 November 2012

Published in print October 2012

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Acknowledgements

Authors express their gratitude to N Packer and P Jenson for MALDI analysis.

Financial & competing interests disclosure

This research was primarily supported by a grant from the Macquarie University Research Innovation Fund and National Health and Medical Research Council Project Grants 1011979 and 1028183. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Ethical conduct of research

The authors state that they have obtained appropriate institutional review board approval or have followed the principles outlined in the Declaration of Helsinki for all human or animal experimental investigations. In addition, for investigations involving human subjects, informed consent has been obtained from the participants involved.

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