scholarly journals Origin of the Bright Photoluminescence of Thiolate-protected Gold Nanoclusters: Confined Structural Water Molecules as Real Emitters

2021 ◽  
Author(s):  
Bo Peng ◽  
kun zhang
Keyword(s):  
Gold Nanoclusters ◽  
Electron Interaction ◽  
Water Molecules ◽  
Photoluminescence Intensity ◽  
Metal Nanoclusters ◽  
Structural Water ◽  
Ligand Interactions ◽  
Interfacial States ◽  
Bright Color ◽  
Interfacial Adsorption

The availability of a range of excited states has enriched zero-, one- and two- dimensional quantum nanomaterials with interesting luminescence properties, in particular for noble metal nanoclusters (NCs) as typical examples. But, the elucidation and origin of optoelectronic properties remains elusive. In this report, using widely used Au(I)-alkanethiolate complex (Au(I)-SRs, R = -(CH2)12H) with AIE characteristics as a model system, by judiciously manipulating the delicate surface ligand interactions at the nanoscale interface, together with a careful spectral investigations and an isotope diagnostic experiment of heavy water (D2O), we evidenced that the structural water molecules (SWs) confined in the nanoscale interface or space are real emitter centers for photoluminescence (PL) of metal NCs and the aggregate of Au(I)-SRs complexes, instead of well-organized metal core dominated by quantum confinement mechanics. Interestingly, the aggregation of Au(I)-SRs generated dual fluorescence-phosphorescence emission and the photoluminescence intensity was independent on the degree of aggregation but showed strong dependency on the content and state of structural water molecules (SWs) confined in the aggregates. SWs are different from traditional hydrogen bonded water molecules, wherein, due to interfacial adsorption or spatial confinement, the p orbitals of two O atoms in SWs can form a weak electron interaction through spatial overlapping, which concomitantly constructs a group of interfacial states with π bond characteristics, consequently providing some alternative channels (or pathways) to the radiation and/or non-radiation relaxation of electrons. Our results provide completely new insights to understand the fascinating properties (including photoluminescence, catalysis and chirality, etc.) of other low-dimension quantum dots and even for aggregation-induced emission luminophores (AIEgens). This also answers the century old debate on whether and how water molecules emit bright color.

scholarly journals Structural Water Molecules Confined in Soft and Hard Nanocavities as Bright Color Emitters

2021 ◽  
Author(s):  
Jiafeng Zhou ◽  
Taiqun Yang ◽  
Bo Peng ◽  
Bingqian Shan ◽  
Meng Ding ◽  
...  
Keyword(s):  
Water Molecules ◽  
Structural Water ◽  
Bright Color

A New Strategy to Construct Gold Nanoclusters-Based Optical Probe Using Luminescence Resonance Energy Transfer

2021 ◽  
Author(s):  
Shuyang Zhai ◽  
Wei Hu ◽  
Chen Fan ◽  
Wenqi Feng ◽  
Zhi-hong Liu
Keyword(s):  
Energy Transfer ◽  
Gold Nanoclusters ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Optical Probe ◽  
Luminescent Materials ◽  
Metal Nanoclusters ◽  
New Strategy ◽  
Photoluminescence Efficiency

Monolayer-protected metal nanoclusters (MPCs) are emerging as intriguing luminescent materials, but the construction of MPCs-based optical probe is still scarce because of both the limited photoluminescence efficiency of MPCs and...

scholarly journals Synthesis of Exosome-Based Fluorescent Gold Nanoclusters for Cellular Imaging Applications

2021 ◽  
Vol 22 (9) ◽  
pp. 4433
Author(s):  
Eun Sung Lee ◽  
Byung Seok Cha ◽  
Seokjoon Kim ◽  
Ki Soo Park
Keyword(s):  
Photoelectron Spectroscopy ◽  
Low Cost ◽  
Stokes Shift ◽  
Gold Nanoclusters ◽  
Human Colon ◽  
Cellular Imaging ◽  
Metal Nanoclusters ◽  
Human Colon Cancer ◽  
X Ray ◽  
High Concentrations

In recent years, fluorescent metal nanoclusters have been used to develop bioimaging and sensing technology. Notably, protein-templated fluorescent gold nanoclusters (AuNCs) are attracting interest due to their excellent fluorescence properties and biocompatibility. Herein, we used an exosome template to synthesize AuNCs in an eco-friendly manner that required neither harsh conditions nor toxic chemicals. Specifically, we used a neutral (pH 7) and alkaline (pH 11.5) pH to synthesize two different exosome-based AuNCs (exo-AuNCs) with independent blue and red emission. Using field-emission scanning electron microscopy, energy dispersive X-ray microanalysis, nanoparticle tracking analysis, and X-ray photoelectron spectroscopy, we demonstrated that AuNCs were successfully formed in the exosomes. Red-emitting exo-AuNCs were found to have a larger Stokes shift and a stronger fluorescence intensity than the blue-emitting exo-AuNCs. Both exo-AuNCs were compatible with MCF-7 (human breast cancer), HeLa (human cervical cancer), and HT29 (human colon cancer) cells, although blue-emitting exo-AuNCs were cytotoxic at high concentrations (≥5 mg/mL). Red-emitting exo-AuNCs successfully stained the nucleus and were compatible with membrane-staining dyes. This is the first study to use exosomes to synthesize fluorescent nanomaterials for cellular imaging applications. As exosomes are naturally produced via secretion from almost all types of cell, the proposed method could serve as a strategy for low-cost production of versatile nanomaterials.

scholarly journals Streptavidin-conjugated gold nanoclusters as ultrasensitive fluorescent sensors for early diagnosis of HIV infection

2018 ◽  
Vol 4 (11) ◽  
pp. eaar6280 ◽  
Author(s):  
Aditya Dileep Kurdekar ◽  
L. A. Avinash Chunduri ◽  
C. Sai Manohar ◽  
Mohan Kumar Haleyurgirisetty ◽  
Indira K. Hewlett ◽  
...  
Keyword(s):  
Hiv Infection ◽  
Limit Of Detection ◽  
Gold Nanoclusters ◽  
Enzyme Linked Immunosorbent Assay ◽  
Dependent Manner ◽  
Metal Nanoclusters ◽  
Detection Range ◽  
In Silico Studies ◽  
P24 Antigen ◽  
Hiv 1

We have engineered streptavidin-labeled fluorescent gold nanoclusters to develop a gold nanocluster immunoassay (GNCIA) for the early and sensitive detection of HIV infection. We performed computational simulations on the mechanism of interaction between the nanoclusters and the streptavidin protein via in silico studies and showed that gold nanoclusters enhance the binding to the protein, by enhancing interaction between the Au atoms and the specific active site residues, compared to other metal nanoclusters. We also evaluated the role of glutathione conjugation in binding to gold nanoclusters with streptavidin. As proof of concept, GNCIA achieved a sensitivity limit of detection of HIV-1 p24 antigen in clinical specimens of 5 pg/ml, with a detection range up to1000 pg/ml in a linear dose-dependent manner. GNCIA demonstrated a threefold higher sensitivity and specificity compared to enzyme-linked immunosorbent assay for the detection of HIV p24 antigen. The specificity of the immunoassay was 100% when tested with plasma samples negative for HIV-1 p24 antigen and positive for viruses such as hepatitis B virus, hepatitis C virus, and dengue. GNCIA could be developed into a universal labeling technology using the relevant capture and detector antibodies for the specific detection of antigens of various pathogens in the future.

Gold nanoclusters and fluorescence-based sensing

2017 ◽  
Author(s):  
◽  
Xi Chen
Keyword(s):  
Fluorescence Intensity ◽  
Cholesterol Oxidase ◽  
Gold Nanoclusters ◽  
Green Emission ◽  
Mapping Method ◽  
Metal Nanoclusters ◽  
Molecular Rotor ◽  
Great Resistance ◽  
University Of Missouri ◽  
Thermal Reversibility

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] The main topic of this dissertation focuses on development of analytical methods, mainly modification and application of metal nanoclusters in fluorescence-based sensing. Based on bovine serum albumin passivated gold nanoclusters (AuNCs@BSA) we firstly developed a fluorescent biosensor platform, combining cholesterol oxidase with assistance of surfactant, for selective detection of water insoluble analyte, cholesterol in aqueous condition. Moreover, we designed a series of modification strategy to enhence thermal reversibility of AuNCs@BSA, aiming at reducing hysteresis remained during thermal cycles. Taking advantage of optimized thermal reversibility in terms of fully recoverable fluorescence intensity, analytical performance of modified AuNCs@BSA was investigated and an aqueous-phase temperature sensor was achieved. In addition to AuNCs, we developed novel glutathione stabilized copper NCs with green-emission in assistance of ascorbic acid reduction, which showed great resistance to nitro compounds. Further, analytical application of as-prepared Cu NCs to ratiometric sensing on explosive molecules, cooperating with AuNCs@BSA, was investigated. In the last, a novel and facile temperature mapping method using ionic liquid and organic fluorescent molecular rotor were described. Making use of viscosity-sensitive fluorescent dye, temperature was converted to ratio value of fluorescence intensity and recorded, enabling visualized thermal map.

scholarly journals Gas Transfer of Metals during the Destruction of Efflorescent Sulfates from the Belovo Plant Sulfide Slag, Russia

Minerals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 344
Author(s):  
Svetlana Bortnikova ◽  
Natalya Abrosimova ◽  
Nataliya Yurkevich ◽  
Valentina Zvereva ◽  
Anna Devyatova ◽  
...  
Keyword(s):  
Major And Trace Elements ◽  
Water Molecules ◽  
Gas Transfer ◽  
Structural Water ◽  
Fermentation Products ◽  
X Ray ◽  
Gas Condensates ◽  
Gas Phase Transport ◽  
Phase Transport

This paper demonstrates the results of experiments for the determination of the composition of gases during the dehydration of sulfates (Na-jarosite, melanterite, and chalcanthite) collected at the surface of pyrometallurgical waste heaps. The volatilization of various elements, and vapor–gas phase transport from three sulfate groups were investigated by stepwise laboratory heating at 45, 55, and 65 °C. The sample of yellow efflorescence mainly consisted of Na-jarosite, the white efflorescence contained melanterite as the major mineral, and the blue efflorescence sample consisted of chalcanthite. These all contained a few impurities up to 5 %. The highest total dissolved solids (TDS) was found in the gas condensates from melanterite (59 mg/L), followed by chalcanthite (29 mg/L) and Na-jarosite (17 mg/L). It was determined that major and trace elements in the condensate can be trapped by water vapor and can migrate with the vapor phase during the desorption and dehydration of hydrous sulfates. X-ray diffractograms showed that Na-jarosite remained stable throughout the temperature range, whilst the separation of melanterite’s structural water occurred at 40 °C, and chalcanthite completely lost two water molecules at 50 °C. The gas condensates contained acetates and formates, which could be the fermentation products of bacterial communities. Some of the strains—Micrococcaceae sp., Bacillus sp., and Microbacteriaceae sp.—were cultivated.

Protein-based fluorescent metal nanoclusters for small molecular drug screening

2014 ◽  
Vol 50 (89) ◽  
pp. 13805-13808 ◽  
Author(s):  
Yong Yu ◽  
Siu Yee New ◽  
Jianping Xie ◽  
Xiaodi Su ◽  
Yen Nee Tan
Keyword(s):  
Drug Screening ◽  
Screening Method ◽  
Gold Nanoclusters ◽  
Metal Nanoclusters

This communication reports a facile, fast (<10 min), and hitherto unreported drug screening method by comparing the fluorescence intensities of the in situ formed gold nanoclusters templated by drug-loaded proteins.

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