title: Investigation of folate-conjugated fluorescent silica nanoparticles for targeting delivery to folate receptor-positive tumors and their internalization mechanism.
abstract: Multifunctionalized nanoparticles (NPs) are emerging as ideal tools for gene/drug delivery, bioimaging, labeling, or intracellular tracking in biomedical applications, and have attracted considerable attention owing to their unique advantages. In this study, fluorescent silica NPs were synthesized by a modified Stöber method using conjugates of 3-mercaptopropyltrimethoxysilane (MPS) and maleimide-fluorescein isothiocyanate (maleimide-FITC). Mean diameters of the NPs were controlled between 212-2111 nm by regulating MPS concentration in the reaction mixture. Maleimide-FITC molecules were doped into NPs or conjugated to the surface of NPs through the chemical reaction of maleimide and thiol groups. The data showed that the former NPs are better than the latter by comparing their fluorescence intensity. Furthermore, folate molecules were linked to the FITC-doped silica NPs by using polyethylene glycol (PEG) (NH2-PEG-maleimide) as a spacer, thus forming folate receptor targeting fluorescent NPs, referred to as NPs(FITC)-PEG-Folate. The quantitative analysis of cellular internalization into different cancer cells showed that the delivery efficiency of KB cells (folate receptor-positive cells) is more than six-fold higher than that of A549 cells (folate receptor-negative cells). The delivery efficiency of KB cells decreased significantly after free folate addition to the cell culture medium because the folate receptors were occupied by the free folate. The NPs endocytosis mechanism was also investigated. It was shown that clathrin, an inhibitor of cell phagocytosis, markedly decreased the NPs uptake into KB cells, suggesting that it plays an important role in NPs cellular internalization. These results demonstrated that the novel particles of NPs(FITC)-PEG-Folate are promising for fluorescent imaging or targeting delivery to folate receptor-positive tumors.
authors: Department of Biophysics, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, Sichuan, People's Republic of China.
authors: Hong
authors: H
authors: Yang
authors: Changchun
authors: C
authors: Lou
authors: Mingming
authors: M
authors: Xu
authors: Chunhui
authors: C
authors: Wu
authors: Hirokazu
authors: H
authors: Miyoshi
authors: Yiyao
authors: Y
authors: Liu
mesh_terms: D002277:Carcinoma / Q000188:drug therapy; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004705:Endocytosis / Q000502:physiology; D016650:Fluorescein-5-isothiocyanate; D058973:Folate Receptors, GPI-Anchored / Q000378:metabolism*; D005492:Folic Acid / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000493:pharmacokinetics / Q000494:pharmacology; D006801:Humans; D007624:KB Cells; D046529:Microscopy, Electron, Transmission; D058726:Nanoconjugates / Q000737:chemistry / Q000627:therapeutic use / Q000648:ultrastructure; D017646:Organosilicon Compounds; D011092:Polyethylene Glycols / Q000737:chemistry / Q000494:pharmacology; D012821:Silanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry* / Q000493:pharmacokinetics
chemical_list: D058973:Folate Receptors, GPI-Anchored; D058726:Nanoconjugates; D017646:Organosilicon Compounds; D012821:Silanes; C552831:poly(ethylene glycol)-folate; D011092:Polyethylene Glycols; D012822:Silicon Dioxide; C102833:(3-mercaptopropyl)trimethoxysilane; D005492:Folic Acid; D016650:Fluorescein-5-isothiocyanate