title: Transport Mechanisms of Solid Lipid Nanoparticles across Caco-2 Cell Monolayers and their Related Cytotoxicology.
abstract: Solid lipid nanoparticles (SLNs) have been extensively investigated and demonstrated to be a potential nanocarriers for improving oral bioavailability of many drugs. However, the molecular mechanisms related to this discovery are not yet understood. Here, the molecular transport mechanisms of the SLNs crossing simulative intestinal epithelial cell monolayers (Caco-2 cell monolayers) were studied. The cytotoxicology results of the SLNs in Caco-2 cells demonstrated that the nanoparticles had low cytotoxicity, had no effect on the integrity of the cell membrane, did not induce oxidative stress, and could significantly reduce cell membrane fluidity. The endocytosis of the SLNs was time-dependent, and their delivery was energy-dependent. For the first time, the transport of the SLNs was directly verified to be a vesicle-mediated process. The internalization of the SLNs was mediated by macropinocytosis pathway and clathrin- and caveolae (or lipid raft)-related routes. Transferrin-related endosomes, lysosomes, endoplasmic reticulum (ER), and Golgi apparatus were confirmed to be the main destinations of the SLNs in Caco-2 cells. As for the transport of the SLNs in Caco-2 cell monolayers, the results demonstrated that the SLNs transported to the basolateral side were intact, and the transport of the nanoparticles did not destroy the structure of tight junctions. The transcytosis of the SLNs across the Caco-2 cell monolayer was demonstrated to be mediated by the same routes as that in the endocytosis study. The ER, Golgi apparatus, and microtubules were confirmed to be important for the transport of the SLNs to both the basolateral and apical membrane sides. This study provides a more thoroughly understand of SLNs transportation crossing intestinal epithelial cell monolayers and could be beneficial for the fabrication of SLNs.
authors: Institute of Pharmaceutics, Zhejiang University , 866 Yuhangtang Road, Hangzhou 310058, China.
authors: Gui-Hong
authors: GH
authors: Chai
authors: Key Laboratory of Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, Zhejiang University , Hangzhou 310027, China.
authors: Yingke
authors: Y
authors: Xu
authors: Institute of Pharmaceutics, Zhejiang University , 866 Yuhangtang Road, Hangzhou 310058, China.
authors: Shao-Qing
authors: SQ
authors: Chen
authors: Institute of Pharmaceutics, Zhejiang University , 866 Yuhangtang Road, Hangzhou 310058, China.
authors: Bolin
authors: B
authors: Cheng
authors: Institute of Pharmaceutics, Zhejiang University , 866 Yuhangtang Road, Hangzhou 310058, China.
authors: Fu-Qiang
authors: FQ
authors: Hu
authors: Institute of Pharmaceutics, Zhejiang University , 866 Yuhangtang Road, Hangzhou 310058, China.
authors: Jian
authors: J
authors: You
authors: Institute of Pharmaceutics, Zhejiang University , 866 Yuhangtang Road, Hangzhou 310058, China.
authors: Yong-Zhong
authors: YZ
authors: Du
authors: Institute of Pharmaceutics, Zhejiang University , 866 Yuhangtang Road, Hangzhou 310058, China.
authors: Hong
authors: H
authors: Yuan
mesh_terms: D018938:Caco-2 Cells; D002462:Cell Membrane / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D004705:Endocytosis / Q000187:drug effects; D004721:Endoplasmic Reticulum / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism; D036681:Fluorescence Recovery After Photobleaching; D006046:Gold / Q000737:chemistry; D006056:Golgi Apparatus / Q000378:metabolism; D006801:Humans; D008055:Lipids / Q000737:chemistry*; D008247:Lysosomes / Q000378:metabolism; D053758:Nanoparticles / Q000737:chemistry* / Q000378:metabolism / Q000633:toxicity; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D008055:Lipids; D017382:Reactive Oxygen Species; D006046:Gold
keywords: Caco-2 cell monolayer; cytotoxicology; oral drug delivery; solid lipid nanoparticles; transport mechanisms; vesicle-mediated process