Dissolution of citrate-stabilized, polyethylene glycol-coated carboxyl and amine-functionalized gold nanoparticles in simulated biological fluids and environmental media

摘要

Dissolution is an important property utilized to elucidate both short- and long-term effects of nanoparticles for their potential to cause harm to humans and the environment. Nanoparticles may therefore be classified based on their (bio)durability between those that are amenable and those that are resistant to dissolution, biodegradation and/or disintegration. The dissolution kinetics of uncoated citrate-stabilized, polyethylene glycol-coated (PEGylated) gold nanoparticles functionalized with carboxyl and amine functional groups in simulated biological and environmental fluids at physiological and room temperature, respectively, were studied using the static dialysis protocol to predict their (bio)durability. Citrate-stabilized gold nanoparticles showed high degrees of resistance to dissolution in the simulated media unlike those which were coated with polyethylene glycol and functionalized with carboxyl and amine functional groups. Generally, the extent of AuNP dissolution in acidic media (phagolysosomal fluid and gastric fluid) was greater than that in neutral or alkaline media such as Gamble's fluid, blood plasma and intestinal fluids, freshwater and seawater. However, in all these experimental conditions, the particles did not completely dissolve. In the case of amine-functionalized AuNPs, the nanoparticles released a maximum of only 15 of their original concentration whereas carboxyl-functionalized and citrate-stabilized gold nanoparticles released 9 and 8.5 of gold ions, respectively. The rate and degree of dissolution depended on the surface functionalization, pH, ionic strength of the simulated fluid and particle aggregation. Therefore, the results indicate that gold nanoparticles with low dissolution rates are expected to be (bio)durable in biological and environmental surroundings; thus, they might impose long-term effects on humans and the environment. In contrast, those with high dissolution rate are not (bio)durable and hence may cause short-term effects.