"Effects of silver nanoparticles and thiram pesticide on giant unilamellar cell"

Autores: Cibely S. Martin, Marcelo J. S. Oliveira, Mateus D. Maximino, Carlos J.L. Constantino.

Instituições: UNESP.

Autor apresentador: Cibely S. Martin.

Resumo: The increasing world population has led to an increasing in the production and application of pesticides. However, their excessive concentration in industrial products, food, and the environment can be a risk to human health. Moreover, the nanotechnology application can contribute to human exposure to nanoparticles, which can occur through inhalation, dermal contact, or oral ingestion, which depend directly on the type of products we are exposed to. Thus, it is necessary to evaluate the effect of both pesticide and nanoparticle present in the same system. Here, we evaluated the individual and mixture effects of silver nanoparticles (AgNp) and thiram pesticide on mimetic systems of the lipid bilayer structure using DOPC (1,2-dioleoyl-sn-glycero-3-phosphocholine) forming giant unilamellar vesicles (GUVs). The studies were carried out by phase-contrast microscopy, obtaining the microscopy image for different exposition time (30 – 180 min). The microscopy analyses were carried out adding 50 µL of the GUVs suspensions into a chamber containing 200 µL of iso-osmolar glucose solution (0.2 mol/L) in the absence and presence of contaminants (AgNp, thiram, or their mixture). The interaction of DOPC bilayers with AgNp does not affect the morphology (shape) and phase contrast of the GUVs even after the whole exposition time, showing similar behavior for DOPC GUVs control. In the thiram exposition (10-5 mol/L) 39% of the GUVs showed a slightly wrinkled shape up to 180 min of exposition. However, the mixture of AgNp and thiram showed a strong effect in the phase contrast of DOPC GUVs after 150 min of exposition, and almost all the GUVs were affected up to 180 min. The results confirm the higher effect of the mixture in the phase-contrast of DOPC GUVs, which 53% from a total of 60 GUVs showing a loss in phase-contrast, being the GUVs with size higher than 30 µm more affected. This result indicates a disturbing synergetic effect of AgNp and thiram on the membrane mimetic system.

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