Bottom-up Synthesis of Water-Soluble Gold Nanoparticles Stabilized by N-Heterocyclic Carbenes: From Structural Characterization to Applications |
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| Authors: | Dr Sophie R Thomas Wenjie Yang Dr David J Morgan Dr Thomas E Davies Dr Jiao Jiao Li Prof Roland A Fischer Prof Jun Huang Prof Nikolaos Dimitratos Prof Angela Casini |
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| Institution: | 1. Chair of Medicinal and Bioinorganic Chemistry, Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, 85747 Garching, Germany;2. School of Chemical and Biomolecular Engineering, University of Sydney, NSW, 2006 Australia;3. School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT U.K.;4. Kolling Institute, Faculty of Medicine and Health, University of Sydney, St Leonards, NSW, 2065 Australia;5. Chair of Inorganic and Metal–Organic Chemistry, Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, 85747 Garching, Germany;6. Department of Industrial Chemistry “Toso Montanari” Universita' degli Studi di Bologna, Viale Risorgimento, 40136 Bologna, Italy |
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| Abstract: | N-heterocyclic carbenes (NHCs) have become attractive ligands for functionalizing gold nanoparticle surfaces with applications ranging from catalysis to biomedicine. Despite their great potential, NHC stabilized gold colloids (NHC@AuNPs) are still scarcely explored and further efforts should be conducted to improve their design and functionalization. Here, the ‘bottom-up’ synthesis of two water-soluble gold nanoparticles ( AuNP-1 and AuNP-2 ) stabilized by hydrophilic mono- and bidentate NHC ligands is reported together with their characterization by various spectroscopic and analytical methods. The NPs showed key differences likely to be due to the selected NHC ligand systems. Transmission electron microscopy (TEM) images showed small quasi-spherical and faceted NHC@AuNPs of similar particle size (ca. 2.3–2.6 nm) and narrow particle size distribution, but the colloids featured different ratios of Au(I)/Au(0) by X-ray photoelectron spectroscopy (XPS). Furthermore, the NHC@AuNPs were supported on titania and fully characterized. The new NPs were studied for their catalytic activity towards the reduction of nitrophenol substrates, the reduction of resazurin and for their photothermal efficiency. Initial results on their application in photothermal therapy (PTT) were obtained in human cancer cells in vitro. The aforementioned reactions represent important model reactions towards wastewater remediation, bioorthogonal transformations and cancer treatment. |
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| Keywords: | Au nanoparticles catalysis N-heterocyclic carbenes photothermal therapy spectroscopy |
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