All Hydroxyl-Thiol-Protected Gold Nanoclusters with Near-Neutral Surface Charge

Hydrophilic gold nanoclusters (Au NCs) whose physical and chemical properties are not susceptible to large changes in pH are greatly desired for diverse applications. Here, we design Au NCs protected by a hydroxyl-thiol ligand (e.g., 1-thioglycerol (TG)) with a molecular formula of Au-34(TG)(22) as a proof-of-concept for a Au NC model with near-neutral surface charge. Unlike hydrophilic thiols with charged functional groups (e.g., carboxylate-thiol) that are usually used for hydrophilic Au NCs, this type of Au NCs is protected by hydroxyl-thiols, which are less susceptible to the prevailing pH conditions as the hydroxyl group is less acidic than water. More interestingly, the resulting Au NCs also possess pH-independent fluorescence intensity, making them suitable for applications under strong acidic conditions, which are currently not available in the reported hydrophilic Au NCs.

Automated summary

In this study, a novel hydrophilic gold nanocluster model with near-neutral surface charge and pH-independent fluorescence intensity was designed, making it suitable for applications under strong acidic conditions. This type of gold nanocluster, protected by hydroxyl-thiols, is less susceptible to changes in pH compared to traditional hydrophilic thiol ligands, offering potential for diverse applications.