Polyacrylic acid-coated iron oxide nanoparticles could be a useful tool for tracking inflammatory monocytes.

AIM: To establish the effect of poly(acrylic acid)-coated iron oxide nanoparticles (PAC-IONs) and later exposure to a magnetic field on the differentiation of mononuclear phagocytes into macrophages. METHODS: By flow cytometry, cell death was evaluated with DIOC6 and PI, Poly (ADP-ribose) Polymerases (PARP) fragmentation, H2AX phosphorylation and TUNEL assay. Cytokines by Cytokine bead array and the intracellular amount of iron by atomic absorption spectrometry. RESULTS: PAC-IONs did not induce apoptosis, modify the cell membrane integrity or alter the mitochondrial membrane potential. They did not affect the cell morphology, the pattern of cytokine accumulation or the activating role of differentiation of mononuclear phagocytes into macrophages on the proliferation of autologous T cells. CONCLUSION: This evidence indicates that the PAC-IONs are safe and biocompatible. Moreover, the selectivity of the PAC-IONs for mononuclear phagocytes, as well as their increased uptake by non-classical monocytes, warrant future research with a view to their use as a contrast agent, a useful tool for in vivo tracking of tissue-infiltrating mononuclear phagocytes.

Poly(acrylic acid)-Coated Iron Oxide Nanoparticles interact with mononuclear phagocytes and decrease platelet aggregation.

Poly(acrylic acid)-Coated Iron Oxide Nanoparticles (PAC-IONs) did not compromise the viability of mononuclear cells and potentially interact with cells through scavenger receptors. This study evaluated: 1) The capacity of the PAC-IONs to induce platelet activation and aggregation, and 2) The effect of the PAC-IONs in two functions of Monocyte-Derived Macrophages (MDMs) when differentiated in their presence; that is, the removal of apoptotic cells (ACs) and the levels of cytokines induced by Lipopolysaccharide (LPS) and the ACs. The PAC-IONs did not affect the platelet activation but antagonized their aggregation. On the other hand, the differentiation of MDMS in the presence of PAC-IONs did not inhibit the ability of these cells to phagocytose latex beads but decreased the number of apoptotic bodies internalized by them. MDMs differentiated in the presence of PAC-IONs and stimulated with LPS or ACs exhibited an overall decrease of the cytokine levels. The altered synthesis of cytokines could be attributed to a high production of Reactive Oxygen Species (ROS) caused by the increase in the intracellular iron content. The effect of the PAC-IONs on the cell cycle of U937 and Jurkat cells was also studied; there was not either cell accumulation in any phase of the cell cycle or changes in the DNA content. It is clear that PAC-IONs affect neither the viability nor compromise some cellular functions. However, they could alter the functioning of the immune system; therefore, in the case of being used as a diagnostic tool, their permanence in the body should be considered.