ナノ粒子の表面化学構造変換による細胞内動態の制御

抄録

Nanoparticles and their applications in the biomedical research fields have attracted increasing interest over the past decade. Previous in vitro studies have demonstrated that synthetic nanoparticles could be incorporated into living cells mainly via endocytotic pathways depending on their size, shape, surface charge, and surface chemistry. It is thus important to investigate the effects of surface properties of nanoparticles on the possible interactions between nanoparticles and biomolecules for understanding the mechanisms of cellular uptake and the subsequent clearance from the cells. In the current research, we have examined chemical conversion of the surface structures of nanoparticles in living cells with the aim to directly observe intracellular uptake and localization of the nanoparticles before and after the conversion. We have developed （1） gold nanorods （GNRs） coated with coumarin-protected alkylamino-linkers and （2） silicananoparticles（SNPs） covered with dibenzylcyclooctyne（DBCO） structures. By using the former nanoparticles, we have accomplished esterase-catalyzed conversion of their surface chemical structures in living cells. On the other hand, DBCO structures on SNPs can be modified with various azido compounds via the bioorthogonal Huisgen [3+2] cycloaddition. We prepared phospholipids bearing an azido group and investigated intracellular localization of SNPs after the addition of the azido lipids. As expected, accumulation of nanoparticles on the plasma membrane was observed right after the addition of azido lipids, demonstrating that chemical conversion of their surface could alter the interactions between nanoparticles and cell membrane.