Biosynthesis of iron nanoparticles by microorganisms: characterization and effects on human keratinocytes.

LOPEZ VENDITTI, ELIANA; BUSTOS, PAMELA SOLEDAD; CALIENNI, MARÍA NATALIA; MONTANARI, JORGE; PÁEZ, PAULINA LAURA; PARAJE, MARÍA GABRIELA; GUIÑAZÚ, NATALIA

Buenos Aires

Congreso; Reunión Conjunta SAIC-SAI-AAFE-NANOMED.AR 2021; 2021

Sociedad Argentina de Investigación Clínica

Green chemistry has been proven to be an efficient route for metal nanoparticle synthesis. Stable and well-functionalized nanoparticles have been produced from organisms like bacteria, among other microbes. Significant research on antimicrobial potential of metal NPs has been performed. Iron is abundant in nature, an essential metal for human beings, and a suitable candidate for green NP synthesis with possible microbicidal characteristics. The aim of this work was to biosynthetize FeNPs by microorganism and to study possible toxic effects in the human keratinocyte cell line -HaCaT.FeNPs were synthesized using Escherichia coli (ATCC 25922) and characterized by UV-Vis spectroscopy and by transmission electron microscopy. HaCaT cells were incubated for 4 and 24 h at different FeNPs dilutions (535; 214, 107, 53.5 and 26.75 ug/ml). Culture medium, the metal precursor salt solution FeSO4 (0.1 and 0.25 mM), and a bacterial growth control of biosynthesis (CCB, dilutions 1/2, 1/5, 1/10, 1/20, 1/40) were used as controls. Cell viability was evaluated by MTT and neutral red test (NRT); reactive oxygen species (ROS) were studied by DCF-DA and superoxide levels by NBT, superoxide dismutase (SOD) activity was determined by the riboflavin-NBT method; and glutathione (GSH) content by the Ellman method.The FeNPs obtained have a size of ≈ 20 nm and are spherical. The absorbance peak is at 272 nm corresponding to the plasmon resonance. Metabolic cell activity significantly decreased after 4 and 24 h incubation with FeNPs 535 ug/ml, and CCB 1/2, however no significant changes in NRT uptake were observed at 4 and 24 h. ROS levels were significantly increased after 4 h and 24 h incubation with all the concentrations of FeNPs assayed, CCB and FeSO4 0.25 mM. Superoxide anion significantly increased at 24 h incubation with FeNPs 535 ug/ml, and CCB 1/2. GSH content was not modified by any treatment at 24 h.Altogether these results suggest that the highest FeNPs concentration significantly modifies the cell viability, with increase in O2-, ROS, and SOD. In contrast other stimuli were able to modify human keratinocyte oxidant/antioxidant cell balance but not cell viability. Prolonged incubation studies are needed in order to determine if cell viability is altered at lower concentrations and to unravel the mechanisms underlying these alterations.