Synthesis of three kinds of surface-modified gold nanoparticles and comparison of their stability

Abstract

Objective To synthesize three kinds of surface- modified gold nanoparticles and to compare their size distribution,zeta potential,surface morphology,and stability.Methods Poly(vinyl pyrrolidone)(PVP)stabilized gold nanoparticles(PVP-AuNPs),didodecyldimethylammonium bromide(DODAB,a cationic lipid)coated gold nanoparticles(DODAB-AuNPs),and cysteamine modified gold nanoparticles(CA-AuNPs)were successfully synthesized by chemical reduction method.The size distribution,zeta potential,and surface morphology of the three kinds of gold nanoparticles were characterized by dynamic light scattering(DLS)and transmission electron microscopy(TEM);and the stability of them was evaluated in various concentrations of sodium ions(0.01,0.1,0.5and 1mol/L NaCl;pH=7.2)and at different pH values(1.0-14.0)by UV-Vis absorption spectra.Results The mean diameters of PVP-AuNPs,DODAB-AuNPs,and CAAuNPs were(15.0±3.1)nm,(22.7±6.1)nm,and(18.0±4.6)nm,respectively;and their zeta potentials were(-19.7± 4.1),(62.8±4.3),and(33.3±7.7)mV,respectively.It was also found that PVP-AuNPs and DODAB-AuNPs were very stable in NaCl solution and different pH environments.However,CA-AuNPs solution was sensitive to concentration of sodium ions and pH value changes and it could maintain stable only when the concentration of NaCl was 0.01mol/L or the pH value was within 4.5-6.5;otherwise there would be aggregation.Conclusion The three kinds of gold nanoparticles have a nano spherical shape and good stability,with different surface potentials when modified with different ligands;these findings provide reference for design of drug delivery carriers.