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Carbon Dots as Analytical Tools for Sensing of Thioredoxin Reductase and Screening of Cancer Cells

Abstract

Thioredoxin Reductase (TrxR) is a redox regulating enzyme that predestined for the maintenance of redox homeostasis of mammalian cells. However, the elevated level of TrxR is associated with progress of various type of tumors and therefore, this is a significant target for the detection of cancer cells. Herein, an easily engineered, ‘turn ON’ fluorescent sensor probe has been synthesized for the detection of TrxR and cell imaging using carbon dots. The emission intensity of fCDs on complexation with Cu2+ ion was drastically quenched. Subsequently, the addition of TrxR to the solution of fCDs-Cu2+ complex leads to the cleavage of disulfide bond of the fCDs, which acclaim the release of 3-mercaptopropionic acid. The 3-mercaptopropionic acid, being a strong bi-dentate chelate for Cu2+ ion, extracted the Cu2+ from the coordination sphere of fCDs and restored the original fluorescence intensity of fCDs. Thus, the probe is operating with a simple process of “ON-OFF” emission switching due to Cu2+ and “OFF-ON” switching with TrxR. The probe has been successfully used for real-time application to monitor TrxR activities in the complex biological system. The fluorescent images of MCF-7 and HeLa cells after incubation with fCDs-Cu2+ complex were recorded under confocal laser scanning microscope (CLSM) as a function of time. Enhancement in emission intensity of cancer cells after 2 h of treatment demonstrate the potential application of the sensor probe for the bioimaging of endogenous TrxR in living cells and screening of cancer cells. Such fluorescent probe will open the doors for the development of promising clinical devices for the diagnosis of cancer cells.

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Supplementary files

Publication details

The article was received on 18 Dec 2017, accepted on 10 Feb 2018 and first published on 12 Feb 2018


Article type: Paper
DOI: 10.1039/C7AN02040F
Citation: Analyst, 2018, Accepted Manuscript
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    Carbon Dots as Analytical Tools for Sensing of Thioredoxin Reductase and Screening of Cancer Cells

    J. S. Sidhu, A. Singh, N. Garg, N. Kaur and N. Singh, Analyst, 2018, Accepted Manuscript , DOI: 10.1039/C7AN02040F

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