The effect of PEGylation on the stimulation of IL-1β by gold (Au) nanoshell/silica core nanoparticles.

Au nanoshell/silica core (GNS) nanoparticles have been used for the photothermal ablation of tumors and imaging, and have recently reached clinical trials. In this study, we compared the ability of bare (GNS) and PEGylated Au nanoshell/silica core (PEG-GNS) nanoparticles in stimulating the production of IL-1β in both macrophage cell lines. GNS particles formed large aggregates while PEG-GNS particles did not in cell culture medium. Correspondingly, GNS particles induced the production of IL-1β while PEG-GNS did not in THP-1 macrophage cell line. Corroborating with in vitro results, GNS induced a significant level of neutrophil influx in peritoneal cavity, and PEG-GNS reduced the level four times. The density of PEG on particle surface has little effect on both the induction of IL-1β and neutrophil influx by PEG-GNS. The ability of induction and scavenging reactive oxygen species(ROS) by GNS and PEG-GNS particles were also assessed. We demonstrated that GNS was able to induce and scavenge ROS while PEG-GNS was not. The excess of ROS induced by GNS potentially caused the activation of inflammasomes, and thus the secretion of IL-1β. Our finding in the reduction Il-1β production by PEGylation of nanoparticles has implications in other particulates used for drug delivery, imaging and therapy.