Abstract:Fluorescent copper nanoclusters (CuNCs) have been widely used in chemical sensors, biological imaging, and lightemitting devices. However, individual fluorescent CuNCs have limitations in their capabilities arising from poor photostability and weak emission intensities. As one kind of aggregationinduced emission luminogen (AIEgen), the formation of aggregates with high compactness and good order can efficiently improve the emission intensity, stability, and tunability of CuNCs. Here, DNA nanoribbons, containin… Show more
“…Ouyang et al succeeded in synthesizing fluorescent Cu NCs using DNA as template. The QY is as high as 12%, however the fluorescence intensity begin to decrease just after 165 min [28]. Therefore, there is a dire need to develop a synthetic protocol for preparing fluorescent Cu NCs with high QY and better stability that can easily be upscaled.…”
Copper nanoclusters (Cu NCs) are generally formed by several to dozens of atoms. Because of wide range of raw materials and cheap prices, Cu NCs have attracted scientists’ special attention. However, Cu NCs tend to undergo oxidation easily. Thus, there is a dire need to develop a synthetic protocol for preparing fluorescent Cu NCs with high QY and better stability. Herein, we report a one-step method for preparing stable blue-green fluorescent copper nanoclusters using glutathione (GSH) as both a reducing agent and a stabilizing agent. High-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and electrospray ionization mass spectrometer (ESI-MS) were used to characterize the resulting Cu NCs. The as-prepared Cu NCs@GSH possess an ultrasmall size (2.3 ± 0.4 nm), blue-green fluorescence with decent quantum yield (6.2%) and good stability. MTT results clearly suggest that the Cu NCs@GSH are biocompatible. After incubated with EB-labeled HEK293T cells, the Cu NCs mainly accumulated in nuclei of the cells, suggesting that the as-prepared Cu NCs could potentially be used as the fluorescent probe for applications in cellular imaging.
“…Ouyang et al succeeded in synthesizing fluorescent Cu NCs using DNA as template. The QY is as high as 12%, however the fluorescence intensity begin to decrease just after 165 min [28]. Therefore, there is a dire need to develop a synthetic protocol for preparing fluorescent Cu NCs with high QY and better stability that can easily be upscaled.…”
Copper nanoclusters (Cu NCs) are generally formed by several to dozens of atoms. Because of wide range of raw materials and cheap prices, Cu NCs have attracted scientists’ special attention. However, Cu NCs tend to undergo oxidation easily. Thus, there is a dire need to develop a synthetic protocol for preparing fluorescent Cu NCs with high QY and better stability. Herein, we report a one-step method for preparing stable blue-green fluorescent copper nanoclusters using glutathione (GSH) as both a reducing agent and a stabilizing agent. High-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and electrospray ionization mass spectrometer (ESI-MS) were used to characterize the resulting Cu NCs. The as-prepared Cu NCs@GSH possess an ultrasmall size (2.3 ± 0.4 nm), blue-green fluorescence with decent quantum yield (6.2%) and good stability. MTT results clearly suggest that the Cu NCs@GSH are biocompatible. After incubated with EB-labeled HEK293T cells, the Cu NCs mainly accumulated in nuclei of the cells, suggesting that the as-prepared Cu NCs could potentially be used as the fluorescent probe for applications in cellular imaging.
“…In comparison to the PMMA/Eu( D -facam) 3 film, the DNA-CTMA/Eu( D -facam) 3 films showed a stronger emission. Their emission intensity was enhanced with increasing ratios of DNA-CTMA, suggesting that a non-radiative deactivation caused by a molecular vibration was suppressed due to the immobilization onto the DNA backbone 49 , 50 . Figure 3 Emission spectra of DNA-CTMA/Eu( D -facam) 3 films at various Eu( D -facam) 3 :DNA-CTMA molar ratios and PMMA/Eu( D -facam) 3 film upon excitation at 330 nm, as shown by the original emission intensities ( a ) and normalized intensities ( b ).…”
Section: Resultsmentioning
confidence: 99%
“…The k nr value of PMMA was approximately 8400 s −1 ; it decreased to 1300 s −1 upon mixing with DNA. It is known that the molecular vibration can be suppressed when the molecules are immobilized on a DNA structure 49 , 50 . Therefore, the decrease in k nr clearly indicated a suppressed vibrational deactivation of the excited states of the Eu(III) ion due to the immobilization on a DNA molecule.…”
DNA-based materials have attracted much attention due to their unique photo-functional properties and potential applications in various fields such as luminescent and biological systems, nanodevices, etc. In this study, the photophysical properties of a chiral Eu(III) complex, namely (Eu(D-facam)3), within DNA films were extensively investigated. The enhancement of photoluminescence (more than 25-folds increase of luminescence quantum yield) and degree of circularly polarization in luminescence (glum = − 0.6) was observed upon interaction with DNA. Various photophysical analyses suggested that the emission enhancement was mainly due to an increase of the sensitization efficiency (high ηsens) from the ligands to Eu(III) and suppression of the vibrational deactivation upon immobilization onto the DNA molecule. From CD and VCD measurements, it was suggested that the coordination structure of Eu(D-facam)3 was affected by the interaction with DNA, suggesting that the structural change of Eu(D-facam)3 contributed to the improvement of its luminescent properties.
“…demonstrated DNA‐nanoribbon‐templated self‐assembly of Cu NCs. [ 285 ] The DNA‐nanoribbon templates (C‐DNR) composed of multiple units of single‐strand DNA were prepared by a simple and effective thermal annealing method. [ 286 ] Based on the position of DNA sequences, six types of C‐DNR assemblies were prepared.…”
Section: Molecular Interactions In Nc Self‐assemblymentioning
Ligand protected noble metal nanoparticles are excellent building blocks for colloidal self‐assembly. Metal nanoparticle self‐assembly offers routes for a wide range of multifunctional nanomaterials with enhanced optoelectronic properties. The emergence of atomically precise monolayer thiol‐protected noble metal nanoclusters has overcome numerous challenges such as uncontrolled aggregation, polydispersity, and directionalities faced in plasmonic nanoparticle self‐assemblies. Because of their well‐defined molecular compositions, enhanced stability, and diverse surface functionalities, nanoclusters offer an excellent platform for developing colloidal superstructures via the self‐assembly driven by surface ligands and metal cores. More importantly, recent reports have also revealed the hierarchical structural complexity of several nanoclusters. In this review, the formulation and periodic self‐assembly of different noble metal nanoclusters are focused upon. Further, self‐assembly induced amplification of physicochemical properties, and their potential applications in molecular recognition, sensing, gas storage, device fabrication, bioimaging, therapeutics, and catalysis are discussed. The topics covered in this review are extensively associated with state‐of‐the‐art achievements in the field of precision noble metal nanoclusters.
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