In vitro cytotoxicity of superparamagnetic iron oxide nanoparticles on neuronal and glial cells. Evaluation of nanoparticle interference with viability tests

Abstract

Superparamagnetic iron oxide nanoparticles (ION) have attracted great interest for use in several biomedical fields. In general, they are considered biocompatible, but little is known of their effects on the human nervous system. The main objective of this work was to evaluate the cytotoxicity of two ION (magnetite), coated with silica and oleic acid, previously determining the possible interference of the ION with the methodological procedures to assure the reliability of the results obtained. Human neuroblastoma SHSY5Y and glioblastoma A172 cells were exposed to different concentrations of ION (5-300 μg ml -1 ), prepared in complete and serum-free cell culture medium for three exposure times (3, 6 and 24 h). Cytotoxicity was evaluated by means of the MTT, neutral red uptake and alamar blue assays. Characterization of the main physical-chemical properties of the ION tested was also performed. Results demonstrated that both ION could significantly alter absorbance readings. To reduce these interferences, protocols were modified by introducing additional washing steps and cell-free systems. Significant decreases in cell viability were observed for both cell lines in specific conditions by all assays. In general, oleic acid-coated ION were less cytotoxic than silica-coated ION; besides, a serum-protective effect was observed for both ION studied and cell lines. These results contribute to increase the knowledge of the potential harmful effects of ION on the human nervous system. Understanding these effects is essential to establish satisfactory regulatory policies on the safe use of magnetite nanoparticles in biomedical applications.

Evaluation of cytotoxicity and genotoxicity induced by oleic acid‐coated iron oxide nanoparticles in human astrocytes

“…Physicochemical characterization of the O‐ION used in the present study was previously reported in Costa et al (). In brief, it showed that they are spherical particles with a magnetite core average diameter of 10.9 nm; the effectiveness of oleic acid coating was confirmed, because less than 7% of the nanoparticle surface presents iron.…”

“…Accordingly, the present study aimed to evaluate the possible cytotoxic and genotoxic effects of O‐ION on human glial cells (A172 astrocytes). In a previous study conducted by our research group (Costa et al ), effects induced by O‐ION on viability of A172 glial cells were evaluated. Results showed that O‐ION induced a significant decrease in astrocytes viability, besides a serum‐protective effect was observed.…”

“…O‐ION (magnetite core) were synthesized and prepared as stable water stock suspensions (19 mg/mL) following Maity and Agrawal (). Particle size, morphology, average hydrodynamic size, zeta potential, and surface chemistry were previously determined in water and A172 cell culture medium (with and without serum) (Costa et al ). A stock suspension of 1 mg/mL O‐ION in serum‐free or complete A172 culture medium (see composition below) was prepared and ultrasonicated in a water bath (Branson Sonifier) for 5 min.…”

“…For each experiment, unless indicated differently, cells cultured in serum‐free or complete medium were treated with four O‐ION concentrations (5, 25, 50, and 100 μg/mL) at 37°C for 3 or 24 hr. Concentrations and exposure times were selected on the basis of our previous results from cell viability assays (Costa et al ).…”

“…In a previous study conducted by our research group (Costa et al ), effects induced by O‐ION on viability of A172 glial cells were evaluated. Results showed that O‐ION induced a significant decrease in cell viability, besides a serum‐protective effect was observed.…”