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

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 (Ag-9-NCs, [Ag-9(mba)(9)], where H(2)mba = 2-mercaptobenzoic acid) and peptide DD-5 were used to induce self-assembly, which can trigger an aggregation-induced luminescence (AIE) effect of Ag-9-NCs through non-covalent forces (H-bond, pi-pi stacking) and argentophilic interactions [Ag(I)-Ag(I)]. The large Stokes shift (~140 nm) and the microsecond fluorescence lifetime (6.1 mu s) indicate that Ag-9-NCs/DD-5 hydrogel is phosphor. At the same time, the chirality of the peptide was successfully transferred to the achiral Ag-9-NCs because of the supramolecular self-assembly, and the Ag-9-NCs/DD-5 hydrogel also has good circularly polarized luminescence (CPL) properties. In addition, Ag-9-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 Ag-9-NCs to obtain high luminescent gel, which maybe become a candidate material in the fields of sensors and biological sciences.

Automated summary

Metal nanoclusters have attracted attention as a new type of fluorescent material due to their good biocompatibilities and outstanding optical properties. This study investigates the self-assembly of atomic precise silver nanoclusters through supramolecular interactions, and demonstrates their ability to form highly luminescent hydrogels with chiral properties. The resulting nanocluster-based hydrogel shows selectivity and sensitivity in detecting small biological molecules, making it a promising candidate material in the fields of sensors and biological sciences.