The Modulation Of Dendritic Cell Maturation By Gold Nanoparticles With Gradient Change In Surface Hydrophobicity

Nanotechnology has been widely used in energy, materials, environment, medicine and some other fields. It has made breakthrough in the past few decades, and may become one of the most important technic platforms in many industries in the future. With the increased production and commercialization of various kinds of nanoparticles, large amounts of nanoparticles will be released into the environment, increasing the chances of human exposure to nanoparticles. For example, nanoparticles could enter human body via skin contact, breathing or food intake; Nanoparticles applied in the medical fields, as drug carriers, biomarkers or imaging agents, can directly enter blood and organs. After entering human body, nanoparticles might affect physiological functions of various organs. As one of the essential organizing signaling networks involved in health and disease, the immune system are sensitive in the recognition of foreign agents. Therefore, the evaluation of the interaction between nanoparticles and the immune system is an important content for the nanoparticles’ biomedical application.Dendritic cells (DCs) are the primary antigen presenting cells, which play key roles in the initiation of immune responses and tolerance induction. To evaluate the immune-modulatory effect of nanoparticles (NPs) on DCs is a vital component of the immunological effect of nanoparticles. Nanoparticles possess large surface area and powerful surface activity, thereby their surface properties will affect their bioactivity directly. Recent reports showed that the surface modification modulated the immune activity of DCs, however, those researches were restricted to certain individual physicochemical properties. It is urgently needed to investigate the correlation between the surface properties and its immunological effects systematically.Due to their chemical inertness, and easy to synthesis, modify, detect and control particle size, gold nanoparticles (GNPs) gained their widespread applications in nanometer sensor, drug-loading, nano-vaccine and other medicine fields. They have been even served as model nanoparticles in studying the role of nanoparticles’ physicochemical properties in regulating their biological effects. In this study, we synthesized several kinds of GNPs with gradient change in surface hydrophobicity to explore how surface hydrophobicity of nanoparticles modulate the maturation of mouse bone marrow-derived dendritic cells (BMDCs) in the presence or absence of lipopolysaccharides (LPS). We detected the uptake of GNPs by BMDCs, the GNP-induced cytotoxicity, secretion of cytokines and the expression of cell surface markers. Results showed that surface hydrophobicity of GNPs modulated BMDCs maturation in different manners in the absence or presence of LPS. Under normal conditions, DCs maturation is correlated with the surface hydrophobicity of GNPs, the more hydrophobic, the more maturation of BMDCs except HY7; Hydrophobic nanoparticles induced pro-inflammatory response. By contrast, pretreatments with GNPs with a more hydrophobic surface significantly suppressed the maturation of BMDCs induced by LPS, and hydrophobic GNPs exhibited significant anti-inflammatory effects. Besides, altered maturation of BMDCs induced by GNPs exposure were in correlation with nanoparticles uptake. This study provides the theoretical basis for the understanding of the immunological effects between GNPs and DCs.