Cytochromec-Capped Fluorescent Gold Nanoclusters: Imaging of Live Cells and Delivery of Cytochromec

• Published in: Chemphyschem Vol. 17; no. 13; p. 2088
• Main Authors: Chattoraj, Shyamtanu, Amin, Md Asif, Bhattacharyya, Kankan
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 04.07.2016
• ISSN: 1439-4235; 1439-7641
• DOI: 10.1002/cphc.201501163

Cytochromec-capped fluorescent gold nanoclusters (Au-NCs) are used for imaging of live lung and breast cells. Delivery of cytochromec inside the cells is confirmed by covalently attaching a fluorophore (Alexa Fluor594) to cytochromec-capped Au-NCs and observing fluorescence from Alexa594 inside the cell. Mass spectrometry studies suggest that in bulk water, addition of glutathione (GSH) to cytochromec-capped Au-NCs results in the formation of glutathione-capped Au-NCs and free apo-cytochromec. Thus glutathione displaces cytochromec as a capping agent. Using confocal microscopy, the emission spectra and decay of Au-NCs are measured in live cells. From the position of the emission maximum it is shown that the Au-NCs exist as Au8 in bulk water and as Au13 inside the cells. Fluorescence resonance energy transfer from cytochromec-Au-NC (donor) to Mitotracker Orange (acceptor) indicates that the Au-NCs localise in the mitochondria of live cells.