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Proceedings Paper

Probing intra-cellular drug release event using activatable (OFF/ON) CdS:Mn/ZnS quantum dots (Qdots): spectroscopic studies to investigate interaction of Qdots with quencher
Author(s): Jeremy Tharkur; Andrew Teblum; Srijita Basumallick; Rikhav Shah; Karishma Cantarero; Niharika Maity; Sara Rifai; Mona Doshi; Andre J. Gesquiere; Swadeshmukul Santra
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Paper Abstract

In recent years, activatable Quantum Dots (AQdots) are gaining popularity in a number of chemical and biological sensing applications. A basic design of AQdot probes involves a suitable quencher which is capable of altering optical properties of the Qdots. In our previous studies we have shown that CdS:Mn/ZnS fluorescence can be effectively quenched using small molecule quenchers (such as dopamine, chemotherapeutic drug) as well as iron oxide nanoparticle via electron/energy transfer process. We have also shown that the quenched Qdot fluorescence can be restored when the Qdots are separated from the quencher. Using Qdot based activatable probes, we detected intracellular drug release event. Qdot fluorescence was restored upon interaction with the intracellular glutathione (GSH). In this paper, we report a GSH induced quenching of water-soluble N-Acetyl Cysteine (NAC) surface-conjugated Cds:Mn/ZnS Qdots. Quenching of NAC-Qdots was due to aggregation of Qdots in solution. This aggregation induced fluorescence quenching phenomenon resembles with the self-quenching phenomenon of traditional organic fluorescence dyes at high concentrations. UV-VIS and fluorescence emission spectroscopy data support the interaction and binding of GSH with the NAC-Qdots. Increase in particle size due to GSH induced aggregation of NAC-Qdots was confirmed by the Dynamic Light Scattering (DLS) data.

Paper Details

Date Published: 21 February 2013
PDF: 11 pages
Proc. SPIE 8596, Reporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications V, 85960C (21 February 2013); doi: 10.1117/12.2008983
Show Author Affiliations
Jeremy Tharkur, Univ. of Central Florida (United States)
Andrew Teblum, Univ. of Central Florida (United States)
Srijita Basumallick, Univ. of Central Florida (United States)
Rikhav Shah, Univ. of Central Florida (United States)
Karishma Cantarero, Univ. of Central Florida (United States)
Niharika Maity, Univ. of Central Florida (United States)
Sara Rifai, Univ. of Central Florida (United States)
Mona Doshi, Univ. of Central Florida (United States)
Andre J. Gesquiere, The College of Optics and Photonics, Univ. of Central Florida (United States)
Swadeshmukul Santra, Univ. of Central Florida (United States)


Published in SPIE Proceedings Vol. 8596:
Reporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications V
Samuel Achilefu; Ramesh Raghavachari, Editor(s)

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