Silver nanoparticles (AgNPs) internalization and passage through the Lactuca sativa (Asteraceae) outer cell wall

Area of Science:

• Environmental Science
• Plant Biology
• Nanotechnology

Background:

• Silver nanoparticle (AgNP) toxicity is a growing concern in environmental and agricultural science.
• Understanding AgNP interaction with plant cells is crucial for assessing their ecological impact.
• Reactive oxygen species (ROS) play a key role in cellular responses to nanomaterials.

Purpose of the Study:

• To investigate the interaction mechanism between silver nanoparticles (AgNPs) and plant cell walls.
• To elucidate the role of ROS in AgNP-induced cellular changes.
• To propose a model for AgNP transport across the plant outer cell wall (OCW).

Main Methods:

• Transmission electron microscopy (TEM) was used to visualize AgNP interaction with Lactuca sativa roots.
• Analysis of cellular changes, including ROS production and cell wall conformation.
• Proposed a transport model based on observed interactions.

Main Results:

• AgNP interaction alters plant cell wall conformation, increasing intracellular ROS.
• Ionic silver (Ag+) released from AgNPs acts as an oxidant, breaking hydrogen bonds in cellulose.
• Modified cell wall structure facilitates AgNP passage towards the plasma membrane.

Conclusions:

• AgNP interaction with plant cell walls is a multi-step process involving ROS generation and structural modification.
• Ionic silver plays a critical role in the initial stages of AgNP-cell wall interaction.
• A transport model is proposed, detailing AgNP passage through the outer cell wall, potentially via caveolae-mediated endocytosis.