Figure 3.

Colloidal stability of citrate-capped (A) and pegylated Au NPs (PEG₁₀₈₀₀) (B) in solutions with high salt concentration (0.157 M NaCl). The evolution of the colloidal state was monitored over time by UV–visible spectroscopy. The pictures of the corresponding colloidal solutions are shown in the middle, corroborating the high stability of the PEG–Au NPs colloidal solution under high ionic strength conditions, compared to Au NPs–citrate that aggregate and precipitate. Reproduced from [39] with permission.