Luminescence mechanisms of ultrasmall gold nanoparticles

Huang, Yingyu; Fuksman, Lirit; Zheng, Jie

doi:10.1039/c8dt00420j

Cited by 72 publications

(53 citation statements)

References 50 publications

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“…This gentle reduction method leaves 40–50 % of gold atoms in the Au I state . Based on the S−Au I and Au I −Au I interactions, ligand‐to‐metal charge transfer (LMCT) and ligand‐to‐metal‐metal charge transfer (LMMCT) contribute to intrinsic luminescence of GS‐AuNPs with a large Stokes shift (>200 nm), microsecond lifetime, and quantum yield of 3.5 % in aqueous solution …”

Section: Synthesis Of Renal Clearable Luminescent Metal Nanoparticlesmentioning

confidence: 99%

Renal Clearable Luminescent Gold Nanoparticles: From the Bench to the Clinic

Zheng

2019

Angew Chem Int Ed

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124

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With more and more engineered nanoparticles being translated to the clinic, FDA has recently issued a draft guidance on nanomaterial-containing drug products with an emphasis on understanding their in vivo transport and nano-bio interactions in the physiological environment; so that nanoparticles can be designed in a way that they can target and treat diseases more efficiently than small molecules, have minimum accumulation in the normal tissues and organs and induce minimum toxicity and health hazards. In this review, we integrate this guidance with our ten-year studies on developing renal clearable luminescent gold nanoparticles. These gold nanoparticles highly resist serum protein adsorption, escape the liver uptake, target cancerous tissues through enhanced permeability and retention (EPR) effect, and report kidney dysfunction at early stages. In the meantime, "off-target" gold nanoparticles can be eliminated through the kidneys with minimum accumulation in the body. This revisit also allows us to identify future work towards the translation of renal clearable gold nanoparticles from bench to clinics.

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Section: Synthesis Of Renal Clearable Luminescent Metal Nanoparticlesmentioning

confidence: 99%

Renal Clearable Luminescent Gold Nanoparticles: From the Bench to the Clinic

Zheng

2019

Angew Chem Int Ed

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124

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“…In general, the PL‐QYs of as‐prepared GSH‐AuNCs dissolved in solution is very low due to efficient non‐radiative relaxation by surface‐ligand motions (0.5–1%) . Interestingly, the PL‐QY was significantly enhanced up to 25% obtained by the absolute PL‐QY measurement, as shown in Figure (a).…”

Section: Resultsmentioning

confidence: 95%

Eco‐Friendly, High‐Loading Luminescent Solar Concentrators with Concurrently Enhanced Optical Density and Quantum Yields While Without Sacrificing Edge‐Emission Efficiency

et al. 2019

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A luminescent solar concentrator (LSC) consists of loaded luminophores and a waveguide that can concentrate direct and diffuse sunlight, which is a crucial ingredient for developing solar glasses. In general, the loading concentration in LSCs is strongly restricted (typically <1 wt.%) to mitigate concentration-induced quenching (CIQ), reabsorption losses, and aggregation-induced scattering (AIS). However, this will induce transmission losses in particular for thin-film LSCs. To address all aforementioned issues, large-Stoke-shift LSCs with different loadings are simply prepared based on thiolated gold nanoclusters (GSH-AuNCs) dispersed in the polyvinylpyrrolidone (PVP) matrix. In contrast to conventional luminophores with a severe CIQ effect, photoluminescence quantum yields (PL-QYs) can be significantly enhanced up to %25% (from 0.5 to 1%) even under high loading of %26 wt.%. Such PL-QY enhancement is attributed to the synergistic effects of the suppression of non-radiative relaxation and enhancement of radiative decay processes due to surface ligand-matrix coordination. In addition, our high-loading LSCs also exhibit excellent optical quality and film uniformity without introducing noticeable AIS effects. Thanks to those unique properties, eco-friendly LSCs with high optical density can still hold a high edge-emission efficiency of %70% due to minimal reabsorption and scattering losses, yielding an external quantum efficiency of %15% at the wavelength of 400 nm.

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“…The photoluminescence (PL) emission of AuNPs was centered at 650-680 nm due to the recombination between the electron in e-LUMO and hole-HOMO of plasmonic effect of AuNPs which represented by Mie theory [17].The PL spectra of Au-glycogen in Cyanothece sp. was shifted to longer wavelength with compared the PL of prepared Au-glycogen due to the bigger size diameter of AuNPs [18].…”

Section: Resultsmentioning

confidence: 96%

Cyanobacteria as nanogold Factories: The chemical validation and perspective of the association between gold nanoparticles and cyanobacterial glycogen

Bakir

ElSemary

2020

Preprint

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Background : Glycogen is the cyanobacterial reserve carbohydrate which is currently the focus of many studies. However, quantification of intercellular glycogen needs thorough investigation. The hypothesis is that glycogen can bind to nanogold. This binding can be used as an important tool for the quantification of intracellular glycogen. Methods: Two strains of cyanobacteria were demonstrated to biosynthesise nanogold intracellularly and to bind to cellular glycogen. Then, spherical gold nanoparticles were chemically prepared and tested for binding to the glycogen molecule of cyanobacterial strains; Lyngbya majuscula and Cyanothece sp. via biochemical method. Experimental analyses were conducted to determine the morphological and optical properties of the Au–glycogen hydrocolloids, together with the analysis of the absorption spectra. The luminescence emission of AuNPs that resulted from recombination between electron in excited state HOMO and hole in ground state LUMO of gold nanoparticles according to Mie theory was recorded. The size diameter and shape of AuNPs were measured via scanning electron microscope and dynamic light scattering techniques. The stability of Au-glycogen was studied by the sequential addition of standard solutions of glycogen in the concentration range (10–100 µmol l− 1) into the prepared AuNPs colloidal solution by recording the SPR and luminescence intensity of AuNPs. Results: The color of the cyanobacterial strains turned into purple color that indicated the formation gold nanoparticles inside the cell (intracellularly). To confirm binding between nanogold and glycogen, the absorption spectrum of AuNPs-glycogen showed plasmon band that was centered at 520–540 nm, suggesting that gold nanoparticles were attached to the surface of the glycogen particles. The interaction of the gold nanoparticles with the biopolymer was further confirmed by photoluminescence spectroscopy analysis. The size diameter of the Au-glycogen in both Lyngbya majuscula and Cyanothece sp. were observed to be 41.7 ± 0.2 nm and 80 ± 30 nm, respectively. FTIR analysis showed that the glycogen absorption peak was observed at 1,000 to 1,200 cm− 1 and exhibited an increase corresponding to the increase in glycogen content in both cyanobacteria. In cyclic voltammetry scans, the Au3+/Au0 redox coupling was observed in case of Lyngbya majuscula indicating the formation of AuNPs-glycogen but in Cyanothece sp. the oxidation anodic peak of AuNPs disappeared which indicated that the AuNPs were highly stabilized in Lyngbya majuscula rather than in Cyanothece sp. This may be attributed to the presence of many thiazole peptides in Lyngbya majuscule. The luminescence of AuNPs showed more stability by the addition of gradual concentrations of glycogen and stronger emission of AuNPs as glycogen protected AuNPs agglomeration. The validation method applied to detect the concentration of glycogen was the use of the change in luminescence of AuNPs in correspondence to binding with glycogen. The detection limit (LOD) and quantitation limit (LOQ) were observed to be 0.89 and 2.95 µmol L-1 respectively. Correlation convention (R) was 0.995. The good chemical stability of this colloidal system and the glycogen biomolecules are studied via density functional theory (DFT). The HOMO level of glycogen unit was closed near to LUMO level of Au3+ that supported the bioconversion of Au3+ into AuNPs via glucose units of glycogen. The detection limit (LOD) and quantitation limit (LOQ) were observed to be 0.89 and 2.95 µmol L− 1 respectively, with R (correlation convention) equal to 0.995. Computational calculations such as density functional theory (DFT) was used to confirm the Au-glycogen complex in bio-system. The HOMO level of glycogen unit was closed near to LUMO level of Au3+ that supported the bioconversion of Au3+ into AuNPs via glucose units of glycogen. Conclusion: The associations formed between the gold nanoparticles and glycogen resulted in good chemical stability. The aggregation of the gold nanoparticles is related to the glycogen concentration and has a profound influence on the absorption properties of Au-glycogen systems. The interparticle distance between AuNPs and glycogen molecule induced the shift in the plasmon band.

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Luminescence mechanisms of ultrasmall gold nanoparticles

Cited by 72 publications

References 50 publications

Renal Clearable Luminescent Gold Nanoparticles: From the Bench to the Clinic

Renal Clearable Luminescent Gold Nanoparticles: From the Bench to the Clinic

Eco‐Friendly, High‐Loading Luminescent Solar Concentrators with Concurrently Enhanced Optical Density and Quantum Yields While Without Sacrificing Edge‐Emission Efficiency

Cyanobacteria as nanogold Factories: The chemical validation and perspective of the association between gold nanoparticles and cyanobacterial glycogen

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