Green synthesized colloidal silver is devoid of toxic effects on primary human nasal epithelial cells in vitro

• Published in: Food and chemical toxicology Vol. 157; p. 112606
• Main Authors: Feizi, Sholeh, Javadiyan, Shari, Cooksley, Clare M., Shaghayegh, Gohar, Psaltis, Alkis James, Wormald, Peter-John, Vreugde, Sarah
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.11.2021
• Subjects: Cell Membrane Permeability; Cells, Cultured; Cilia - drug effects; Dextrans - pharmacokinetics; Electric Impedance; Enzyme-Linked Immunosorbent Assay - methods; Epithelial integrity; Fluorescein-5-isothiocyanate - analogs & derivatives; Fluorescein-5-isothiocyanate - pharmacokinetics; Green Chemistry Technology - methods; Green synthesis; Humans; Interleukin 6; Lactate dehydrogenase; Metal Nanoparticles - toxicity; Nasal Mucosa - cytology; Nasal Mucosa - drug effects; Silver - chemistry; Silver - toxicity; Silver nanoparticle; Topical delivery; Interleukin 6; Lactate dehydrogenase; Green synthesis; Epithelial integrity; Topical delivery; Silver nanoparticle
• ISSN: 0278-6915; 1873-6351
• DOI: 10.1016/j.fct.2021.112606

Evaluating the safety of previously fabricated and effective green synthetized colloidal silver (GSCS) on the mucosal barrier structure and function is essential prior to conduct human trials. The GSCS was applied to primary human nasal epithelial cells (HNECs) grown in an air-liquid interface (ALI) culture. Epithelial barrier integrity was evaluated by measuring the transepithelial electrical resistance (TEER) and fluorescein isothiocyanate (FITC)-dextran paracellular permeability. Ciliary beat frequency (CBF) was quantified. Effects of the GSCS on cell viability and inflammation were examined through lactate dehydrogenase, the 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide viability assay and interleukin 6 (IL-6) enzyme linked immunosorbent assay. The localization and transportation of GSCS within HNECs and their HNEC-ALI cultures was assessed by transmission electron microscopy and inductively coupled plasma-mass-spectrometry, respectively. Application of GSCS to HNECs-ALI cultures for up to 2 h caused a significant reduction in the TEER values, however, it did not drop within the first 10 and 20 min for CRS and non-CRS control HNECs. The paracellular permeability, cell viability, IL-6 secretion and CBF remained unchanged. No GSCS was observed within or transported across HNECs. In conclusion, application of GSCS to HNECs is devoid of toxic effects.