title: Preparation of multi-coloured different sized fluorescent gold clusters from blue to NIR, structural analysis of the blue emitting Au7 cluster, and cell-imaging by the NIR gold cluster.
abstract: Blue, green, orange-red, red and NIR emitting gold quantum clusters have been prepared in aqueous media by using a bioactive peptide glutathione (reduced) at physiological pH. Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) analyses show that the core structure sizes of the five different gold clusters are Au7 (blue), Au16 (green), Au19 (orange-red), Au21 (red) and Au22 (NIR). The photo-stability and pH-stability of these quantum clusters have been measured, and these are photo-stable against continuous UV irradiation for a few hours. They also exhibit moderate to good pH-stability within the pH range of 5-12.5. A computational study reveals the organisation of gold atoms in the thiolate-protected blue quantum cluster and its several structural parameters, including the mode of interaction of ligand molecules with Au atoms in the Au7 cluster. Interestingly, it has been found that NIR emitting gold quantum cluster can easily be internalized into the adenocarcinomic human alveolar basal epithelial cell line (A549 cell line). Moreover, a MTT assay indicates that our NIR emitting gold quantum cluster show very low cytotoxicy to A549 cancer cells.
authors.affiliation: Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India. bcab@iacs.res.in.
authors.forename: Subhasish
authors.initials: S
authors.lastname: Roy
authors.forename: Abhishek
authors.initials: A
authors.lastname: Baral
authors.forename: Rameswar
authors.initials: R
authors.lastname: Bhattacharjee
authors.forename: Batakrishna
authors.initials: B
authors.lastname: Jana
authors.forename: Ayan
authors.initials: A
authors.lastname: Datta
authors.forename: Surajit
authors.initials: S
authors.lastname: Ghosh
authors.forename: Arindam
authors.initials: A
authors.lastname: Banerjee
mesh_terms: D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D005978:Glutathione / Q000737:chemistry; D006046:Gold / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008856:Microscopy, Fluorescence; D011789:Quantum Theory; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013056:Spectrophotometry, Ultraviolet; D019265:Spectroscopy, Near-Infrared; D014466:Ultraviolet Rays
chemical_list: D006046:Gold; D005978:Glutathione