Detection, identification and quantification of metallic nanoparticles in aquaculture using electron microscopy and Surface-enhanced Raman scattering

Resumo

Nanomaterials are becoming more and more prevalent as ingredients or components for several consumer products such as paints, personal care products, food and cosmetics. It has been demonstrated that these nanomaterials are released in water bodies such as coastal seawater. These could be accumulating not only in the sediments but also in the aquatic organisms. In line with this, aquaculture is a key component of both the Common Fisheries Policy and the Blue Growth agenda and currently makes up over 50 % of the fish and seafood destined for human consumption. Many of the most consumed aquaculture species in the Atlantic area are marine. Therefore, these species are in contact with all the components contained in seawater. As human exposure to such nanomaterials increases, there is a growing need for a method to identify and characterize nanoparticles present in complex matrices. The assessment of the presence of these new emerging contaminants (i.e. nanomaterials) in products destined to the human consumption as well as the development of portable sensors to detect them in seawater are necessary, since those will allow a quick implementation of measures for risk mitigation. Specifically, there is two main challenges, besides the difficulty in sample preparation and in the controlled conditions during analysis, that could hinder the implementation of the portable sensors: (1) their miniaturization and (2) the matrix interferences, which compromise the robustness, selectivity and sensitivity of the portable sensors. Therefore, there is a need to develop sample preparation methods to reduce the matrix interferences present on real samples, reduce the lack of specificity and noise, and increase the robustness of these sensors. Thus, the main objectives to develop during the PhD are: 1. The assessment of the potential bioaccumulation and biodistribution of metallic nanoparticles in aquaculture products using electron microscopy techniques (TEM, SEM, STEM-EDX). 2. The development of sample preparation methods for the detection and characterization of metallic nanoparticles in both, water and aquaculture products. 3. The design and fabrication of Surface-enhanced Raman scattering (SERS)-based portable sensors for monitoring and detection of metallic nanoparticles in aquaculture waters.