title: Mechanism of poly-l-lysine-modified iron oxide nanoparticles uptake into cells.
abstract: Poly-l-lysine-modified iron oxide nanoparticle (IONP-PLL), which is formed by modifying poly- l-lysine to the surface of iron oxide nanoparticles, can deliver exogenous genes to cells in vitro and in vivo. However, there is relatively little information available about how is IONP-PLL uptaken by cells. In this study, we are focusing on the transferrin receptor (TFR) mediated and TFR-independent cellular internalization of IONP-PLL. The cells were incubated with 1 µM of IONP-PLL with or without transferrin bound. Transferrin-TFR pathway blockers, such as NH4 Cl, CH3 NH2 , or trypsin, were added to the media and their effects were observed. Atomic absorption spectrophotometer was used to quantify the cellular concentration of iron. The cellular concentrations of iron were evaluated at 37°C or 4°C. (1) Transferrin-IONP-PLL uptake into cells was reliant on time and temperature. (2) The addition of blockers, either NH4 CL, CH3 NH2 , or trypsin, decreased the cellular transferrin-dependent IONP-PLL uptake, but not completely blocked the entry of IONP-PLL. (3) When the cells were culture at pH 6.5, under conditions which the binding of iron and transferrin were inhibited, IONP-PLL still had the capacity to enter into cells with time and temperature-dependent manner. These results suggest that the cellular internalization of IONP-PLL, much like iron ion, were mediated by TFR-dependent endocytosis and TFR-free uptake.
authors.affiliation: Cancer Research Institute, Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education, Key Laboratory of Carcinogenesis of Ministry of Health, Central South University, Changsha 410078, People's Republic of China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Li
authors.forename: Cijun
authors.initials: C
authors.lastname: Shuai
authors.forename: Xiayu
authors.initials: X
authors.lastname: Li
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Li
authors.forename: Juanjuan
authors.initials: J
authors.lastname: Xiang
authors.forename: Guiyuan
authors.initials: G
authors.lastname: Li
mesh_terms: D000643:Ammonium Chloride / Q000494:pharmacology; D004705:Endocytosis / Q000187:drug effects; D005290:Ferric Compounds / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008744:Methylamines / Q000494:pharmacology; D053758:Nanoparticles / Q000737:chemistry*; D011107:Polylysine / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D011990:Receptors, Transferrin / Q000378:metabolism; D013696:Temperature; D014357:Trypsin / Q000494:pharmacology
chemical_list: D005290:Ferric Compounds; D008744:Methylamines; D011990:Receptors, Transferrin; D000643:Ammonium Chloride; C000499:ferric oxide; D011107:Polylysine; C027451:methylamine; D014357:Trypsin
keywords: poly-l-lysine-modified iron oxide nanoparticles; transferrin receptor; uptake