Detection of Silver Nanoparticles inside Marine Diatom Thalassiosira pseudonana by Electron Microscopy and Focused Ion Beam

PASCUAL GARCIA Cesar; BURCHARDT Alina; NEGRÃO DE CARVALHO Raquel; GILLILAND Douglas; ROSSI Francois; LETTIERI Teresa; ANTONIO Diana C.

Detection of Silver Nanoparticles inside Marine Diatom Thalassiosira pseudonana by Electron Microscopy and Focused Ion Beam

2013

The use of colloidal silver in industry is making small organisms like diatoms face an increasing toxicity risk, but the mechanisms of interaction are still unknown and aspects like the precise contribution of the nanomaterials in comparison to the ion release are still unidentified due to the lack of adequate methods to visualize the NPs inside the cells. Here we present an electron microscopy study to investigate the uptake of silver nanoparticles (AgNPs) by the marine diatom Thalassiosira pseudonana, a primary producer aquatic species selected as representative model for the lower trophic organisms in the marine habitat. This important organism in the environment presents a particular morphology characterized by a silica exoskeleton that could represent a barrier for NP’s uptake. Here we study the morphology of the diatom and present a method able to detect in a convenient way the NPs interacting with the cell based on a fixation procedure that allows to explore the cell using transmission electron microscopy avoiding prior slicing of the cell. Employing a combination of electron and ion microscopy techniques to selectively cut the cell where the NPs were detected, we are able to demonstrate and visualize for the first time the presence of AgNPs inside diatoms.

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JRC.H.1 - Water Resources

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