An Insight into the Toxic Mechanism of Action of Engineered Nanomaterials to Photosynthetic Aquatic Organisms

The commercial applications of engineered nanoparticles (ENPs) have widely expanded over the last years covering from biomedicine to industrial applications, with a subsequent possible increased release into the environment in the near future. Their small size and their particular physicochemical properties have raised serious concerns about their potential health and environmental risks.

Algae and cyanobacteria are ecologically relevant organisms which are at the base of aquatic food webs and have essential roles in nutrient cycling therefore being especially well suited to study possible ecological impacts of nanomaterials.

In our research group, integrated by biologists from Universidad Autónoma de Madrid and chemical engineers from Universidad de Alcalá de Henares, we have applied a multi-method approach to understand the toxic mechanism of action of nanomaterials to these organisms. Within this approach, physicochemical properties of nanomaterials on relevant biological media were studied and linked with the biological information from the organisms. The biological characterization of the organisms’ response to ENPs include high-throughput techniques such as flow citometry, which allows to link toxicity, metabolic impairment in ROS homeostasis and damage in cell envelopes with physiological end-points such as photosynthetic yield and structural cell alterations assessed by confocal and TEM microscopy.

This approach has been applied to the study of the toxicological mode of action of cerium oxide nanoparticles which are nanomaterials with widespread applications due to their redox properties, and PAMAM dendrimers, organic globular macromolecules which have important applications as drug carriers in the pharmacology industry.