Biocompatibility and inflammatory response of silver tungstate, silver molybdate, and silver vanadate microcrystals

Silver tungstate (α-Ag 2 WO 4 ), silver molybdate (β-Ag 2 MoO 4 ), and silver vanadate (α-AgVO 3 ) microcrystals have shown interesting antimicrobial properties. However, their biocompatibility is not yet fully understood. Cytotoxicity and the inflammatory response of silver-containing microcrystals were analyzed in THP-1 and THP-1 differentiated as macrophage-like cells, with the alamarBlue™ assay, flow cytometry, confocal microscopy, and ELISA. The present investigation also evaluated redox signaling and the production of cytokines (TNFα, IL-1β, IL-6, and IL-8) and matrix metalloproteinases (MMP-8 and -9). The results showed that α-AgVO 3 (3.9 μg/mL) did not affect cell viability ( p > 0.05). α-Ag 2 WO 4 (7.81 μg/mL), β-Ag 2 MoO 4 (15.62 μg/mL), and α-AgVO 3 (15.62 μg/mL) slightly decreased cell viability ( p ≤ 0.003). All silver-containing microcrystals induced the production of O 2 − and this effect was mitigated by Reactive Oxygen Species (ROS) scavenger and N-acetylcysteine (NAC). TNFα, IL-6 and IL-1β were not detected in THP-1 cells, while their production was either lower ( p ≤ 0.0321) or similar to the control group ( p ≥ 0.1048) for macrophage-like cells. The production of IL-8 by both cellular phenotypes was similar to the control group ( p ≥ 0.3570). The release of MMP-8 was not detected in any condition in THP-1 cells. Although MMP-9 was released by THP-1 cells exposed to α-AgVO 3 (3.9 μg/mL), no significant difference was found with control ( p = 0.7). Regarding macrophage-like cells, the release of MMP-8 and -9 decreased in the presence of all microcrystals ( p ≤ 0.010). Overall, the present work shows a promising biocompatibility profile of, α-Ag 2 WO 4 , β-Ag 2 MoO 4 , and α-AgVO 3 microcrystals.