Quenched Assembly of NIR-Active Gold Nanoclusters Capped with Strongly Bound Ligands by Tuning Particle Charge via pH and Salinity.

ABSTRACT: Gold nanospheres coated with a binary monolayer of bound citrate and cysteine ligands were assembled into nanoclusters, in which the size and near-infrared (NIR) extinction were tuned by varying the pH and concentration of added NaCl. During full evaporation of an aqueous dispersion of 4.5 ± 1.8 nm Au primary particles, the nanoclusters were formed and quenched by the triblock copolymer polylactic acid (PLA)(1K)-b-poly(ethylene glycol) (PEG)(10K)-b-PLA(1K), which also provided steric stabilization. The short-ranged depletion and van der Waals attractive forces were balanced against longer ranged electrostatic repulsion to tune the nanocluster diameter and NIR extinction. Upon lowering the pH from 7 to 5 at a given salinity, the magnitude of the charge on the primary particles

SUBMITTER: Stover RJ 

PROVIDER: S-EPMC4096191 | biostudies-literature | 2014 Jul

REPOSITORIES: biostudies-literature