Size Effect of Silver Nanoparticles Derived from Olive Mill Wastewater in THP-1 Cell Lines

Abstract

The constant demand of silver nanoparticles (AgNPs) for different applications requires a new selection of solvents and reagents for their synthesis, to make them less toxic to living organisms and the environment. Among the alternative technologies that can be used to exclude the use of toxic products, green chemistry is based on the employment of biomolecules derived from plants or microorganisms to achieve NPs. Therefore, with the aim of applying the principles of circular economy, the waste deriving from the production of olive oil represents a useful source of polyphenols to be used as reduction agents to obtain AgNPs. In our work, we employed the Olive Mill Wastewater (OMWW), the so-called vegetation water typical of the Mediterranean geographical area, to achieve two sizes of AgNPs, i.e., 50 nm and 30 nm. These NPs were tested on the human monocytic cell line (THP-1) using two concentrations (3 µM and 5 µM) to understand their ability to trigger or not the inflammatory response. This was undertaken following IL-6, IL-8, IL-5 and TNF-α secretion and the NF-kB translocation. We concluded that the AgNPs did not induce strong activation of these pathways, especially when the cells were treated with higher dimensional NPs. Consequently, the application of these NPs in vivo for therapeutic purpose could be significant.