Synthesis Of Fluorescent Silver Nanoclusters Research Articles

Synthesis of Fluorescent Silver Nanoclusters: Introducing Bottom-Up and Top-Down Approaches to Nanochemistry in a Single Laboratory Class

A laboratory class was developed and evaluated to illustrate the synthesis of metal nanoclusters (NCs) and to explain their photoluminescence properties for the case of silver. The described experi...

A signal-on fluorescence based biosensing platform for highly sensitive detection of DNA methyltransferase enzyme activity and inhibition.

DNA methylation mediated by DNA methyltransferase (MTase) enzyme is internal cell mechanism which regulate the expression or suppression of crucial genes involve in cancer early diagnosis. Herein, highly sensitive fluorescence biosensing platform was developed for monitoring of DNA Dam MTase enzyme activity and inhibition based on fluorescence signal on mechanism. The specific Au NP functionalized oligonucleotide probe with overhang end as a template for the synthesis of fluorescent silver nanoclusters (Ag NCs) was designed to provide the FRET occurrence. Following, methylation and cleavage processes by Dam MTAse and DpnI enzymes respectively at specific probe recognition site could resulted to release of AgNCs synthesizer DNA fragment and returned the platform to fluorescence signal-on state through interrupting in FRET. Subsequently, amplified fluorescence emission signals of Ag NCs showed increasing linear relationship with amount of Dam MTase enzyme at the range of 0.1-20 U/mL and the detection limit was estimated at 0.05 U/mL. Superior selectivity of experiment was illustrated among other tested MTase and restriction enzymes due to the specific recognition of MTase toward its substrate. Furthermore, the inhibition effect of applied Dam MTase drug inhibitors screened and evaluated with satisfactory results which would be helpful for discovery of antimicrobial drugs. The real sample assay also showed the applicability of proposed method in human serum condition. This novel strategy presented an efficient and cost effective platform for sensitive monitoring of DNA MTase activity and inhibition which illustrated its great potential for further application in medical diagnosis and drug discovery.

Synthesis and applications of luminescent nucleic acid based silver nanoclusters

The aim of this paper is to outline and discuss novel and promising findings focusing on (i) the synthesis of fluorescent silver nanoclusters (NCs) using DNA as the stabilizing scaffolds, (ii) the origins of fluorescence and (iii) recent applications in biosensing and imaging. By reviewing the recent synthesis methods and applications of DNA-based silver NCs, we hope to demonstrate that these novel nanolights have the potential to be successful in biomedicine beyond their typically envisioned purposes.

Synthesis and Applications of Luminescent Nucleic Acid-Based Silver Nanoclusters

The aim of this paper is to outline and discuss novel and promising findings focusing on (i) the synthesis of fluorescent silver nanoclusters (NCs) using DNA as the stabilizing scaffolds, (ii) the origins of fluorescence and (iii) recent applications in biosensing and imaging. By reviewing the recent synthesis methods and applications of DNA-based silver NCs, we hope to demonstrate that these novel nanolights have the potential to be successful in biomedicine beyond their typically envisioned purposes.

Facile Synthesis of Fluorescent Silver Nanoclusters as Simultaneous Detection and Remediation for Hg2+

Facile Synthesis of Fluorescent Silver Nanoclusters as Simultaneous Detection and Remediation for Hg²⁺

A facile synthesis of fluorescent silver nanoclusters with human ferritin as a synthetic and interfacing ligand.

Water-soluble fluorescent silver nanoclusters (NCs) formed on biomolecule ligands have been extensively studied due to their great potential as new biocompatible fluorescent materials for biosensors. As synthetic ligands, proteins in particular can provide unique structures and functions to the assembled fluorescent silver clusters. A key challenge, however, is to develop appropriate protein ligands and synthetic approaches for cluster formation, especially using native aqueous solutions, to fully preserve the valuable properties of the protein templates. Here we report a human ferritin-templated synthesis of fluorescent silver NCs under neutral aqueous buffer conditions. The unique metal binding property of ferritin and an optimized silver ion reduction allowed us to produce highly stable fluorescent silver NCs that are steadily assembled in the cage-like ferritin proteins. The fluorescent clusters were also successfully assembled on genetically engineered ferritin with antibody-binding protein G. The resulting protein G-ferritin-silver NC complex fully retained the ferritin structure as well as the antibody binding ability. The present silver nanoclusters on ferritin (Ft-Ag NCs) also showed highly specific Cu(2+)-induced fluorescence quenching. By exploiting the large but stable nature of ferritin, we fabricated a highly robust and porous hydrogel sensor system for rapid Cu(2+) detection, where the Ft-Ag NCs were stably encapsulated in surface-bound hydrogels with large pore sizes. Our Ft-Ag NCs that are formed under native aqueous conditions will have great potential as a new fluorescent material with the high structural and functional diversities of ferritin.

Heterogeneity of Threadlike Shape of DNA-Stabilized Silver Fluorescent Clusters

DNA is widely used as a stabilizing matrix in the synthesis of fluorescent silver nanoclusters (AgNCs) possessing good biocompatibility and high brightness. We studied a group of threadlike shaped clusters up to 8 atoms having an elongated shape, so that each atom is connected with only one or two neighbors. Such the choice have been proved by recent calculations of electronic excitation spectra of threadlike shaped silver clusters showing intense the lowest transition, energy of which depends strongly on the chain bend [1]. These properties are in a good agreement with a special feature of the experimental luminescence excitation spectra of Ag clusters stabilized by polymer matrix. The formation of elongated forms of clusters necessarily involves several binding sites regularly arranged on DNA. Following this approach we calculate geometry and electronic excitation spectra of threadlike silver clusters bound to the minor groove of polyC oligomer containing an ordered arrangement of the carbonyl oxygens as binding sites using density functional theory method. We also performed MD calculations for polyC oligomer in water-ionic solution. Conformational dynamics of DNA backbone causes the different equilibrium states of the clusters chain bend, which provides a large variety of emitting species.1. Ruslan R. Ramazanov, Alexei I. Kononov. Excitation Spectra Argue for Threadlike Shape of DNA-Stabilized Silver Fluorescent Clusters. J. Phys. Chem. C, 2013, 117 (36), pp 18681-18687.

A "light-up" and "spectrum-shift" response of aptamer-functionalized silver nanoclusters for intracellular mRNA imaging.

We have designed a novel multifunctional DNA scaffold for the synthesis of fluorescent silver nanoclusters (Ag NCs) using a one-pot approach. The obtained DNA/Ag NCs presented a "light-up" and "spectrum-shift" response to target DNA in vitro and could further image the tumor-related mRNA in living cells.

Short‐Peptide‐Based Hydrogel: A Template for the In Situ Synthesis of Fluorescent Silver Nanoclusters by Using Sunlight

N-terminally Fmoc-protected dipeptide, Fmoc-Val-Asp-OH, forms a transparent, stable hydrogel with a minimum gelation concentration of 0.2% w/v. The gelation property of the hydrogel was investigated by using methods such as transmission electron microscopy, field-emission scanning electron microscopy, atomic force microscopy and Fourier transform infrared spectroscopy. The silver-ion-encapsulating hydrogel can efficiently and spontaneously produce fluorescent silver nanoclusters under sunlight at physiological pH (7.46) by using a green chemistry approach. Interestingly, in the absence of any conventional reducing agent but in the presence of sunlight, silver ions were reduced by the carboxylate group of a gelator peptide that contains an aspartic acid residue. These clusters were investigated by using UV/Vis spectroscopy, photoluminescence spectroscopy, high-resolution transmission electron microscopy (HR-TEM), atomic force microscopy (AFM) and X-ray diffraction (XRD) studies. Mass spectrometric analysis shows the presence of a few atoms in nanoclusters containing only Ag(2). The reported fluorescent Ag nanoclusters show excellent optical properties, including a very narrow emission profile and large Stokes shift (>100 nm). The reported fluorescent Ag nanoclusters within hydrogel are very stable even after 6 months storage in the dark at 4 °C. The as-prepared hydrogel-nanocluster conjugate could have applications in antibacterial preparations, bioimaging and other purposes.