Hepatospheres formed in quasi-spherical microwells to study the therapeutic efficacy of novel liver-targeted iron chelator-loaded nanoformulations

Hepatocyte-based in vitro culture models are widely used to study liver metabolism and drug uptake. However, conventional two-dimensional monolayer hepatocyte cultures do not closely recapitulate liver-specic functions and morphological properties.1 Hepatospheres have been recog- nized as a better in vitro liver model for drug screening and toxicity studies. Here, quasi-spherical microwells (spheriwells) were fabricated using an ice lithographic bench-top microfabrication strategy.2 The concave microwells prepared enabled the formation of dense and homogeneous hepatospheres that we have used as a model to study targeted nano-therapy. Signicant pathology accompanies body iron accumulation in iron loading disorders such as thalassemia, and therapy involves the chemical removal of iron using iron chelators. Current chelator treatments remain suboptimal. Clinically, desferrioxamine is the most effective iron binding compound with the most favorable safety prole, but an onerous parenteral administration regimen means that patient compliance is low. We have developed chelator-loaded polymeric nanoparticles (NPs) that specically target hepatocytes, cells particularly prone to iron loading, using galactose as a targeting ligand for the asialoglycoprotein receptor. Uptake of targeted NPs into three-dimensional hepatospheres was studied by confocal micros- copy. Higher accumulation of galactose-NPs was observed compared with non-targeted nanoparticles. This nanoparticle-based chelating system could potentially benet patients suffering from iron overloading disorders.