The labeling of cationic iron oxide nanoparticle-resistant hepatocellular carcinoma cells using targeted magnetoliposomes

The in vitro labeling of cultured cells with nanomaterials is a frequent practice but the efficiency, specificity and cytotoxicity of labeling specific cell types using targeted nanoparticles has only rarely been investigated. In the present work, functionalized anionic lipid-coated iron oxide cores (magnetoliposomes (MLs)) bearing galactose moieties were used for the specific labeling of asialoglycoprotein receptor 1 (ASGPR-1)-expressing HepG2 cells. The optimal number of galactose moieties per particle (±26) was determined and uptake efficiency was compared with galactose-lacking anionic and cationic MLs. Using a blocking assay with free galactose, electron microscopy and co-cultures of HepG2 and non-ASGPR-1 expressing C17.2 cells, the specificity of the particles for the ASGPR-1 receptor was demonstrated. The intracellular localization of the galactose-bearing MLs was further verified by confocal microscopy. The non-toxic ML concentration was determined to be 400 μg Fe/ml. Finally, the use of these MLs for visualization of labelled cells by magnetic resonance imaging (MRI) was demonstrated. The data show a high uptake and specificity of the galactose-bearing MLs, whereas the cationic MLs remain primarily surface-associated. Thus, targeted MLs offer a successful alternative for cell labeling when cationic particles fail to be efficiently internalized.