Biomimicking synthesis of photoluminescent molecular lantern catalyzed by in-situ formation of nanogold catalysts.

Bioluminescence has been widely recognized as a powerful imaging tool for biological investigations. Synthesis of molecular lanterns that mimic bioluminescence in nature is of great interest. Herein we report a synthesis of molecular lantern by utilizing the catalytic properties of ultrasmall (<2nm) gold nanoclusters (AuNC), which is inspired by the enzymatic light-up of luciferin in the biological system. Small molecules such as hydroquinone and Cys-Gly peptides are used to direct the synthesis of AuNC via a biotemplating approach, while the in-situ formation of AuNC simultaneously catalyze the formation of luciferin-like, brightly fluorescent dye (λ=520nm, QY=0.20). The as-formed dye species deposits on the surface of AuNC and prevents its agglomeration, thus forming a dye-decorated AuNC core-shell structure (AuNC@dye). The formation mechanism of the AuNC@dye composite material has been systematically studied using different characterization techniques including TEM, ultraviolet-visible spectroscopy, and photoluminescence measurements. The biocompatibility of as-formed AuNC@dye is verified by cellular uptake experiments, and it has been demonstrated as a good imaging probe by using Hela cells as a model.