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.

A one-step synthesis of near infrared fluorescent platinum nanoclusters (PtNCs) in aqueous medium is described. The proposed optimized procedure for PtNC synthesis is rather simple, fast and it is based on the direct metal reduction with NaBH ₄ . Bidentated thiol ligands (lipoic acid) were selected as nanoclusters stabilizers in water media. The structural characterization revealed attractive features of the PtNCs, including small size, high water solubility, near-infrared luminescence centered at 680 nm, long-term stability and the highest quantum yield in water reported so far (47%) for PtNCs. Moreover, their stability in different pH media and an ionic strength of 0.2 M NaCl was studied and no significant changes in fluorescence emission were detected. In brief, they offer a new type of fluorescent noble metal nanoprobe with a great potential to be applied in several fields, including biolabeling and imaging experiments.