RESUMEN
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.