Phagocytosis and Cytotoxicity Analysis of Thioflavin-T Doped Silica-Coated Superparamagnetic Iron Oxide Nanoparticles Bound to Amyloid Beta 1–42

Abstract

With superparamagnetic iron oxide nanoparticles (SPIONs) increasingly attracting interest in life sciences, especially in applications such as cancer or Alzheimer's disease, the need for in vitro and in vivo investigation of their behavior, when taken up by structures of the immune system, becomes imperative. In this letter, thioflavin-T tagged core-shell SPIONs bound to amyloid beta 1–42 (A β 1-42) were imbued into macrophages in order to fully understand the effect of phagocytosis on functionalized T-SPIONs and cellular structures. Results after 24 h of exposure in macrophage cultures at various concentrations of T-SPIONs (both free and bound) indicate that the material is successfully phagocytosed, with an uptake above 60%, and cannot be considered cytotoxic, as proven by both tetrazole MTT colorimetric assays and trypan blue measurements. Concurrently, it does not affect the prooxidant–antioxidant balance in the cell culture. Taking into consideration that Α β 1-42 dissolves during phagocytosis, whereas the magnetic and fluorescent character of the silica-coated nanoparticles is maintained after a second phagocytosis cycle, a reuse process of T-SPIONs seems feasible, presenting multiple advantages.