Synthesis of Au(I) complex-based aqueous colloids for sensing of biothiols

Abstract

© 2018 The present work represents new facile route for synthesis of luminescent hydrophilic core-shell colloids, where the luminescence results from Au(I) complex (AuCl)2L with cyclic PNNP ligand (L). The synthesis is based on solvent mediated aggregation of (AuCl)2L in aqueous organic solutions. Instability of (AuCl)2L in aqueous organic solutions was minimized by specific hydrophilic shell deposition arisen from electrostatically driven adsorption of polyethylenimine onto (AuCl)2L-based cores. Luminescence of the colloids is stable for week at least due to restricted degradation of the luminescent complex at the interface and high positive exterior charge of the colloids. The sensing properties of the colloids towards thiols results from their complex formation with Au+ ions. The thiol-induced stripping of Au+ ions from the colloids quenches the luminescence. The optimal conditions for fluorescent recognition of cysteine, homocysteine and glutathione with lower detection limits about 1 μM are highlighted in the work.