Supramolecular Self-Assembly of Atomically Precise Silver Nanoclusters with Chiral Peptide for Temperature Sensing and Detection of Arginine

Abstract

Metal nanoclusters (NCs) as a new type of fluorescent material have attracted great interest due to their good biocompatibilities and outstanding optical properties. However, most of the studies on metal NCs focus on the synthesis, atomic or molecular assembly, whereas metal NCs ability to self-assemble to higher-level hierarchical nanomaterials through supramolecular interactions has rarely been reported. Herein, we investigate atomic precise silver NCs (Ag9-NCs, [Ag9(mba)9], where H2mba = 2-mercaptobenzoic acid) and peptide DD-5 were used to induce self-assembly, which can trigger an aggregation-induced luminescence (AIE) effect of Ag9-NCs through non-covalent forces (H-bond, π–π stacking) and argentophilic interactions [Ag(I)–Ag(I)]. The large Stokes shift (~140 nm) and the microsecond fluorescence lifetime (6.1 μs) indicate that Ag9-NCs/DD-5 hydrogel is phosphor. At the same time, the chirality of the peptide was successfully transferred to the achiral Ag9-NCs because of the supramolecular self-assembly, and the Ag9-NCs/DD-5 hydrogel also has good circularly polarized luminescence (CPL) properties. In addition, Ag9-NCs/DD-5 luminescent hydrogel is selective and sensitive to the detection of small biological molecule arginine. This work shows that DD-5 successfully induces the self-assembly of Ag9-NCs to obtain high luminescent gel, which maybe become a candidate material in the fields of sensors and biological sciences.

Enhancing photoluminescence efficiency of atomically precise copper(i) nanoclusters through a solvent-induced structural transformation

“…Atomically precise coinage metal clusters, with a well-defined structure and discrete energy levels, [1][2][3] have drawn extensive attention in many research fields including photolumines-cent materials, [4][5][6][7] chirality, [8][9][10] catalysis, [11][12][13] sensing [14][15][16] and biomedicine. 17,18 In the past decade, many synthetic strategies were developed for constructing Au/Ag nanoclusters (Au/AgNCs) with excellent photoluminescence (PL) properties and several kinds of ligands have been employed as protecting groups such as thiols, phosphines and alkynes.…”

Morphological studies of self-assembled cyclotides extracted fromViola odorataas novel versatile platforms in biomedical applications

“…Also, it could be related to the preparation of a helical pitch angle with β-sheets arranged on helical paths along the tube surface. 38,39 Also, the cyclotides showed the diffraction peak that yield a d -spacing of 4.71 Å, corresponding to the inter-strand hydrogen-bonding repeat and affirmed the formation of a β-sheet structure; the β-sheet layer is ∼0.5 nm in height. 40,41 A similar intensity profile for nanotubes is observed with a meridional reflection at a d -spacing of 4.76 Å which also corresponds to the spacing of the β-strands in the nanotubes’ structure.…”

Luminescent Sensors Based on the Assembly of Coinage Metal Nanoclusters

“…At present, metal NCs as a fluorescent probe for temperature mainly stayed at ultra-low temperature for temperature detection, while the luminescent hydrogel prepared in this paper had good sensitivity to high temperature (20-100 • C) (Figure 10). Later, Xin et al induced Ag 9 (mba) 9 (H 2 mba = 2-mercaptobenzoic acid) self-assembly by peptide DD-5 for temperature sensing [20]. The non-luminescent Ag 9 NCs and DD-5 constructed the luminescent hydrogel through the non-covalent force and argentophilic interaction.…”

“…The targets are recognized via the interaction with recognition components, and the ensuing signals are transduced and/or amplified into the forms that can be read out. Focusing on the luminescent sensor on the basis of metal NCs, common sensing mechanisms include aggregation-induced emission/quenching [16][17][18], ligand-induced charge transfer [19,20], fluorescence resonance energy transfer [21] and internal filtration effect [22]. Most of these optical sensors are constructed with colloidal metal NCs.…”