Water‐Soluble Fluorescent Silver Nanoclusters

Abstract

Ag nanoclusters consist of several to roughly a hundred atoms and possess sizes comparable to the Fermi wavelength of electrons; they exhibit molecule-like properties, including discrete electronic transitions and strong fluorescence. These nanoclusters are of significant interest because they provide the bridge between atomic and nanoparticle behavior in noble metals. Since the first observations of photoluminescence from Ag nanoclusters, substantial effort has been made to prepare Ag nanoclusters and explore their potential applications. The synthesis of well-defined Ag nanoclusters, however, is difficult due to aggregation of nanoclusters, especially in aqueous solutions. In this Research News article, we highlight some recent progress on solution-based synthesis of water-soluble Ag nanoclusters using radiolytic, chemical reduction and photochemical approaches to prepare fluorescent Ag nanoclusters.

DNA-stabilized, fluorescent, metal nanoclusters for biosensor development

“…This is a rapidly growing field and the number of publications is increasing exponentially. A number of review papers have already covered the physical chemistry [20][21][22][23], synthesis [24], DNA sensing [25][26][27], and other applications [28,29]. Herein, we review recent progress in using DNAtemplated metal NCs for biosensor development.…”

Recent developments on nanomaterials-based optical sensors for Hg2+ detection

“…Metal NPs (Au NPs) can serve as excellent fluorescence quenchers for FRET-based assays because of their high molar extinction coefficients and broad energy bandwidth [14]. Unlike large metal NPs, small metal NPs (< 2 nm) was known as metal NCs consisting of a few to several hundred metal atoms lacking an apparent SPR band, but fluorescing more strongly [15]. They are emerging as an alternative to QDs due to their nontoxicity and good biocompatibility.…”

“…Apart from the use as colorimetric and SERS sensors, Au NPs with strong molar absorptivities are super quenchers for fluorophores, which allows them to be employed in the fluorescence detection of Hg 2+ [14]. Metal NCs, QDs and CDs possess high fluorescence [15][16][17] and they can be used for the development of sensitive fluorescent sensors. Among them, QDs are the most commonly used fluorescent NPs [18].…”

Generation of fluorescent silver nanoclusters in reverse micelles using gamma irradiation: low vs. high dosages and spectral evolution with time

“…Metal nanoclusters (NCs) are at a length scale between atoms and nanoparticles and often have desirable properties typical of large organic molecules (bright fluorescence, for example) since their band structure is broken down into discrete energy levels (Xu and Suslick 2010;Diez and Ras 2011). NC synthesis can be challenging, however, because they tend to aggregate in solution to form larger particles.…”