title: Cytochrome c-Capped Fluorescent Gold Nanoclusters: Imaging of Live Cells and Delivery of Cytochrome c.
abstract: Cytochrome c-capped fluorescent gold nanoclusters (Au-NCs) are used for imaging of live lung and breast cells. Delivery of cytochrome c inside the cells is confirmed by covalently attaching a fluorophore (Alexa Fluor 594) to cytochrome c-capped Au-NCs and observing fluorescence from Alexa 594 inside the cell. Mass spectrometry studies suggest that in bulk water, addition of glutathione (GSH) to cytochrome c-capped Au-NCs results in the formation of glutathione-capped Au-NCs and free apo-cytochrome c. Thus glutathione displaces cytochrome c 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 cytochrome c-Au-NC (donor) to Mitotracker Orange (acceptor) indicates that the Au-NCs localise in the mitochondria of live cells.
authors.affiliation: Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700 032, India), Fax: (91)-33-2473-2805.
authors.forename: Shyamtanu
authors.initials: S
authors.lastname: Chattoraj
authors.affiliation: Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700 032, India), Fax: (91)-33-2473-2805.
authors.forename: Md Asif
authors.initials: MA
authors.lastname: Amin
authors.affiliation: Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700 032, India), Fax: (91)-33-2473-2805. pckb@iacs.res.in.
authors.forename: Kankan
authors.initials: K
authors.lastname: Bhattacharyya
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002942:Circular Dichroism; D045304:Cytochromes c / Q000737:chemistry* / Q000378:metabolism; D003593:Cytoplasm / Q000737:chemistry / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D031541:Fluorescence Resonance Energy Transfer; D005456:Fluorescent Dyes / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D006046:Gold / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry*; D008928:Mitochondria / Q000737:chemistry / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D005456:Fluorescent Dyes; D006046:Gold; D045304:Cytochromes c
keywords: FRET; bio-imaging; cytochrome c; gold nanoclusters; live cells