US20140193837A1
University of Texas System
What is claimed is: 1 . A composition comprising a fluorescent noble metal nanoparticle, wherein the surface of the noble metal nanoparticle is coated with a first anti-fouling ligand and a second pH-dependent ligand, and wherein the noble metal nanoparticle is about 0.1 nm to 3 nm in diameter. 2 .