120th General Meeting of the KCS

Type Poster Presentation
Area Life Chemistry
Room No. Exhibition Hall 2+3
Time 10월 19일 (목요일) 11:00~12:30
Code BIO.P-268
Subject Effects of Charge and Ligand Structure of Gold Nanoparticles on Mammalian Cells
Authors Jongyeon Go, Euiyeon Lee, Youngeun Kwon*
Department of Biomedical Engineering(BK21 plus), Dongguk University, Korea
Abstract Gold nanoparticles (AuNP) has been widely used and gained abundant interest due to its optical, ease of quantification in a biological system, and size/ shape dependent photothermal properties. In addition, due to the biocompatibility and flexibility of surface functionalization, AuNP has been actively studied for nanotechnology with the development of nanomaterials in a wide range of medical fields. However, the effects of physical properties of AuNP on biological effects have not yet been clarified, and it is also true that some studies have disagreed. Therefore, for safe usage of AuNPs in biomedical application, it is important to study systematically how physicochemical properties of gold nanoparticles change their biological interactions. Among many variables, we here focused on the effect of surface chemistry, charge and structure of ligands. For a systematic approach, we prepared mono-dispersed AuNPs of series of charges ranging from -42.8±11.8 mV to +41.8±3.8 mV with various functional groups based on a sequential ligand exchange method. Then various biological assays were performed to measure the effects of each AuNPs on cell viability as well as on various cellular functions of mammalian cell lines. Uptake efficiency of AuNPs by mammalian cells and the subsequent changes of cell morphologies and cytoskeletal structures were also monitored. This study showed that the anionic and neutral AuNPs did not show cytotoxicity, whereas the cationic AuNPs were classified as toxic and non-toxic according to their ligands. While all the cationic AuNPs tested were more effectively internalized by mammalian cells compared with anionic or neutral AuNPs, only the cytotoxic MUAM-AuNP showed inhibitory effects on the DNA replication and on the formation of actin filament. As MUAM carries both cationic head groups and hydrophobic moieties, we suspected that this structural characteristics of MUAM could be the origin of cytotoxicity. In order to further verify this idea, we prepared modified CP1-AuNP (RRRGYKC11C-AuNP), by introducing hydrophobic moiety and the cytotoxic effect of modified CP1-AuNP was studied. Introduction of a hydrophobic moiety on the AuNPs surface resulted in increased cytotoxicity. The results showed that not the charge of the AuNPs but the structure of the ligand was an important factor determining the biological effects of AuNPs. This work also proposed that properly designed cationic AuNPs could make a good candidate for low toxicity gene-delivery materials.
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