Hydrophobicity-guided self-assembled particles of silver nanoclusters with aggregation-induced emission and their use in sensing and bioimaging

Abstract

Distinctive aggregation-induced emission (AIE) phenomenon of thiolate-protected silver nanoclusters (AgNCs) has been revealed; these AgNCs have shown great potential for exploitation and utilization, but their applications as a bright luminogen in the chemosensing and bioimaging areas are greatly limited by their ultralow brightness in an aqueous solution. Herein, we report facile fabrication of hydrophobicity-guided self-assembled particles of silver nanoclusters with aggregation-induced emission. A hydrophobic ligand, thiosalicylic acid, was adopted to prepare AgNCs via a one-step way, and thiosalicylic acid-capped AgNCs showed significant AIE behavior. This AIE property of AgNCs enables them to selectively respond to multiple external stimuli such as solvent polarity, pH and environmental temperature. The hydrophobic nature of thiosalicylic acid as capping ligands of AgNCs drives a self-assembly process of AgNCs in an aqueous solution that results in the formation of self-assembled particles of AgNCs with bright luminescence. Sensitive detection of mercuric ion based on the highly luminescent AgNC AIE particles was achieved in terms of a strong quenching effect of mercuric ion. Cellular viability and luminescence imaging performance of the AgNC AIE particles on living cells were also evaluated for the first time. This study demonstrates the fabrication of AIE particles of silver nanoclusters with bright luminescence guided by hydrophobic interaction and reveals excellent bioimaging performance of AIE particles in living cells.