In vitro and in situ experiments to evaluate the biodistribution and cellular toxicity of ultrasmall iron oxide nanoparticles potentially used as oral iron supplements

Abstract

Well-absorbed iron-based nanoparticulated materials are a promise for the oral management of iron deficient anemia. In this work, a battery of in vitro and in situ experiments are combined for the evaluation of the uptake, distribution and toxicity of new synthesized ultrasmall (4 nm core) Fe₂O₃ nanoparticles coated with tartaric/adipic acid with potential to be used as oral Fe supplements. First, the in vitro simulated gastric acid solubility studies by TEM and HPLC-ICP-MS reveal a partial reduction of the core size of about 40% after 90 min at pH 3. Such scenario confirms the arrival of the nanoparticulate material in the small intestine. In the next step, the in vivo absorption through the small intestine by intestinal perfusion experiments is conducted using the sought nanoparticles in Wistar rats. The quantification of Fe in the NPs suspension before and after perfusion shows Fe absorption levels above 79%, never reported for other Fe treatments. Such high absorption levels do not seem to compromise cell viability, evaluated in enterocytes-like models (Caco-2 and HT-29) using cytotoxicity, ROS production, genotoxicity and lipid peroxidation tests. Moreover, regional differences in terms of Fe concentration are obtained among different parts of the small intestine as duodenum > jejunum > ileum. Complementary transmission electron microscopy (TEM) images show the presence of the intact particles around the intestinal microvilli without significant tissue damage. These studies show the high potential of these NP preparations for their use as oral management of anemia.

Keywords:

• Iron nanoparticles
• anemia
• ICP-MS
• in vitro
• in situ

Acknowledgements

Authors kindly acknowledge Dr. Marcos García-Ocaña from Biotechnology and Biomedical Analysis Unit at University of Oviedo for the cell culture and advice. Funding from FC-15-GRUPIN14-010 (Principado de Asturias), CTQ2016-80069-C2-1R and the Excellence Initiative of the German Research Foundation (DFG) are also acknowledged. DTF acknowledges the Ministerio de Ciencia y Educación for the grant FPU15/02415.

Disclosure statement

The authors report no conflict of interest.

Additional information

Funding

This work was supported by Deutsche Forschungsgemeinschaft (Excellence Innitiative); Fundación para el Fomento en Asturias de la investigación Científica Aplicada y la Tecnología [FC-15-GRUPIN14-010]; Miniterio de Ciencia y Educacion [FPU15/02415]; Secretaría de Estado de Investigación, Desarrollo e Innovación [CTQ2016-80069-C2-1R].