Effect of Surface Charge on Biobehavior of PEGylated Gold Nanoparticles

Three kinds of PEGylated gold nanoparticles (PEG-Au NPs) with different surface charges are prepared by assembly of thiolated polyethylene glycol (HS-PEG) with different terminal groups including methoxy, amino or carboxyl on gold nanoparticle surface through sulfur. gold covalent bond, respectively. The experimental results of cell co. culturing and tail intravenous injection in mouse indicate that the biological behaviors of PEG-Au NPs are affected significantly by their surface charges. The cellular internalization amounts of PEG-Au NPs are following the order, positive charge >neutral charge >negative charge. The PEG-Au NPs are gradually transferred to liver and spleen from main organs through the circulation of blood after tail intravenous injection in mouse. The negatively charged PEG-Au NPs have the slowest hepatic clearance rate while the positively charged PEG-Au NPs can cause the strongest response of immune system in mice.