Gold nanoparticles were synthesized using a previously published procedure (Zhang et al., 2009). Hydrogen tetrachloroaurate(III) trihydrate aqueous solution (1mM, 50 mL) was heated with
stirring on a hotplate.
the solution was slowly titrated with 5mL of 38.8mM sodium citrate.
The dimension and spectroscopic properties of AuNPs were characterized by aTEM and UV–vis-NIR scanning spectrophotometer.