Tailoring the protein conformation to synthesize different-sized gold nanoclusters

Yu, Yong; Luo, Zhentao; Teo, Chia Sin; Tan, Yen Nee; Xie, Jianping

doi:10.1039/c3cc46005c

Cited by 62 publications

(50 citation statements)

References 38 publications

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“…Recently, Xie et al. reported a CO‐mediated method to synthesize AuNCs with different sizes (i.e., Au 4 , Au 8 , Au 10 , Au 13 , and Au 25 ) in BSA 18. They showed that the size of AuNCs was mainly dependent on the conformation of BSA.…”

Section: Protein‐directed Approachesmentioning

confidence: 99%

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π‐Expanded α,β‐Unsaturated Ketones: Synthesis, Optical Properties, and Two‐Photon‐Induced Polymerization

et al. 2014

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A library of π-expanded α,β-unsaturated ketones was designed and synthesized. They were prepared by a combination of Wittig reaction, Sonogashira reaction, and aldol condensation. It was further demonstrated that the double aldol condensation can be performed effectively for highly polarized styrene- and diphenylacetylene-derived aldehydes. The strategic placement of two dialkylamino groups at the periphery of D-π-A-π-D molecules resulted in dyes with excellent solubility. These ketones absorb light in the region 400-550 nm. Many of them display strong solvatochromism so that the emission ranges from 530-580 nm in toluene to the near-IR region in benzonitrile. Ketones based on cyclobutanone as central moieties display very high fluorescence quantum yields in nonpolar solvents, which decrease drastically in polar media. Photophysical studies of these new functional dyes revealed that they possess an enhanced two-photon absorption cross section when compared with simpler ketone derivatives. Due to strong polarization of the resulting dyes, values of two-photon absorption cross sections on the level of 200-300 GM at 800 nm were achieved, and thanks to that as well as the presence of the keto group, these new two-photon initiators display excellent performance so that the operating region is 5-75 mW in some cases.

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Section: Protein‐directed Approachesmentioning

confidence: 99%

“…At pH 11, Au 25 was obtained due to the partially denatured conformation of BSA. However, no fluorescent properties of the synthesized AuNCs were reported 18…”

Section: Protein‐directed Approachesmentioning

confidence: 99%

π‐Expanded α,β‐Unsaturated Ketones: Synthesis, Optical Properties, and Two‐Photon‐Induced Polymerization

et al. 2014

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“…They show unique moleculelike properties, such as quantized charging and luminescence. Several synthetic routes have been applied for the synthesis of fluorescent gold quantum clusters including a) templateassisted synthesis inside the matrix of folded protein, 30 dendrimer 31 and cyclodextrin 32 b) core-etching of metallic nanoparticles or some other large core size noble metal quantum clusters to few atoms nanoclusters, 33 c) chemical reduction of Au III ions using different reducing agents in presence of definite stabilizing/capping agents [34][35][36] and conversion of an as-synthesized quantum cluster into a larger size quantum cluster by ligand exchange with thiol-terminated ligands. [10][11][12][13][14][15][16][17][18][19][20][21][22] Small size of these noble metal quantum clusters with very low toxicity and lack of blinking property than semiconducting nanocrystals make them attractive candidates for biological imaging, [23][24][25][26] chemical sensing [27][28] and other purposes.…”

Section: Introductionmentioning

confidence: 99%

Preparation of multi-coloured different sized fluorescent gold clusters from blue to NIR, structural analysis of the blue emitting Au₇cluster, and cell-imaging by the NIR gold cluster

et al. 2015

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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.

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“…18 The far-UV CD spectra of apo-a-LA in the absence of Hg 2+ shows two negative bands centered at 222 and 208 nm, which are characteristic of an a-helix. While the addition of [Hg 2+ ] up to 10 equivalents brings only marginal changes, the addition of up to 100 equivalents brings a signicant loss in the negative ellipticity of the band at 222 nm ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Mercuration of apo-α-lactalbumin: binding of Hg²⁺followed by protein-mediated nanoparticle formation

et al. 2014

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Nanoparticles and nanocrystals of mercury are formed when Hg 2+ salt reacts with apo-a-lactalbumin (apoa-LA). Reduction followed by nanoparticle formation is further augmented by the protein, as it also acts as a coating agent. The initial interaction of Hg 2+ with apo-a-LA was demonstrated by changes observed in absorption, emission, and CD spectroscopy, where the latter technique also detected structural changes in the protein. Such structural changes are expected when Hg 2+ binds to the protein, and therefore, the binding was determined by isothermal titration calorimetry (ITC). The binding was further proven by MALDI, which showed mercurated species of protein with a Gaussian distribution exhibiting a weighted average of 6 and 9 Hg 2+ ions bound to protein when apo-a-LA was treated with 10 and 100 equivalents, respectively. The molecular dynamics studies revealed the binding of Hg 2+ ions followed by the structural changes that occurred in the protein. The reaction between Hg 2+ and apo-a-LA yields noncrystalline nanoparticles at lower molar ratios of Hg 2+ and crystalline ones at higher molar ratios. The existence of both of these nanoparticles was proven by extensive TEM studies, and the mercury nanocrystals were further studied using fluorescence microscopy. X-ray photoelectron spectroscopy demonstrated that the protein has the ability to convert Hg 2+ to Hg 0 , and the resultant Hg 0 cluster is known to be less harmful than Hg 2+ to the organism. All of these studies support the use of apo-a-LA in the form of nanoparticles and nanocrystals to detoxify Hg 2+ .

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Tailoring the protein conformation to synthesize different-sized gold nanoclusters

Abstract: Gold nanoclusters with five discrete sizes (Au4, Au8, Au10, Au13, and Au25) are synthesized in a protein template with predefined conformation via a CO-mediated synthesis.

Cited by 62 publications

References 38 publications

π‐Expanded α,β‐Unsaturated Ketones: Synthesis, Optical Properties, and Two‐Photon‐Induced Polymerization

π‐Expanded α,β‐Unsaturated Ketones: Synthesis, Optical Properties, and Two‐Photon‐Induced Polymerization

Preparation of multi-coloured different sized fluorescent gold clusters from blue to NIR, structural analysis of the blue emitting Au₇cluster, and cell-imaging by the NIR gold cluster

Mercuration of apo-α-lactalbumin: binding of Hg²⁺followed by protein-mediated nanoparticle formation

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Tailoring the protein conformation to synthesize different-sized gold nanoclusters

Abstract: Gold nanoclusters with five discrete sizes (Au4, Au8, Au10, Au13, and Au25) are synthesized in a protein template with predefined conformation via a CO-mediated synthesis.

Cited by 62 publications

References 38 publications

π‐Expanded α,β‐Unsaturated Ketones: Synthesis, Optical Properties, and Two‐Photon‐Induced Polymerization

π‐Expanded α,β‐Unsaturated Ketones: Synthesis, Optical Properties, and Two‐Photon‐Induced Polymerization

Preparation of multi-coloured different sized fluorescent gold clusters from blue to NIR, structural analysis of the blue emitting Au7cluster, and cell-imaging by the NIR gold cluster

Mercuration of apo-α-lactalbumin: binding of Hg2+followed by protein-mediated nanoparticle formation

Contact Info

Product

Resources

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Preparation of multi-coloured different sized fluorescent gold clusters from blue to NIR, structural analysis of the blue emitting Au₇cluster, and cell-imaging by the NIR gold cluster

Mercuration of apo-α-lactalbumin: binding of Hg²⁺followed by protein-mediated nanoparticle formation