Abstract

Since nanomaterials (NMs) are particulate contaminants, their first contact with organisms is a physical encounter ruled by physic-chemical processes that can determinate the potential NMs accumulation, toxicity, and trophic transfer. Freshwater ecosystems often become a final depository for NMs, so they can get in contact with the biota, especially primary organisms as algae. There are almost none comparative studies of this interaction using various NMs in the same conditions. This work identifies, analyzes, and compares the algae–NMs interaction by flow cytometry after a short-term contact test in which three freshwater algae (Raphidocelis subcapitata, Desmodesmus subspicatus, and Chlorella vulgaris) interact individually with a set of twelve metallic oxide NMs. Dose–response profiles and differences in the algae–NMs interaction were found according to each algae species (C. vulgaris had the most affinity, starting the interaction from 0.5 mg/L and D. subspicatus had the less affinity starting at 5 mg/L). Flow cytometry results were confirmed by optical microscopy. Some NMs characteristics were identified as key-factors that govern the algae–NMs interaction: NMs composition (no interaction for SiO₂ NMs), surface electric charge (higher interaction for the positively charged NMs and lower interaction for the negatively charged ones) and crystalline form (for TiO₂ NMs). The presented method can be useful for a rapid determination of the interaction between free cells organisms as microalgae and (nano)particulate substances.

摘要

由于纳米材料（NMs）是颗粒污染物，因此它们与生物的首次接触是由物理化学过程决定的物理接触，该过程可以确定潜在的NMs积累，毒性和营养传递。淡水生态系统通常成为NM的最终存放地，因此它们可以与生物群（尤其是藻类等主要生物）接触。几乎没有在相同条件下使用各种NM进行这种相互作用的比较研究。这项工作是在短期接触试验后，通过流式细胞术鉴定，分析和比较藻类与NMs的相互作用，其中三种淡水藻类（Raphidocelis subcapitata，Desmodesmus subspicatus和Chlorella vulgaris）与一组十二种金属氧化物NM相互作用。根据每种藻类，发现了剂量-反应曲线和藻类-NMs相互作用的差异（寻常小球藻的亲和力最大，从0.5 mg / L开始相互作用，而D. subspicatus的亲和力最低，从5 mg / L开始）。流式细胞术结果通过光学显微镜确认。某些NMs特性被确定为控制藻类与NMs相互作用的关键因素：NMs组成（SiO ₂ NMs无相互作用），表面电荷（带正电的NMs相互作用较高，带负电的NMs相互作用较低）和晶体形式（用于TiO ₂NMs）。所提出的方法可用于快速确定作为微藻的游离细胞生物与（纳米）微粒物质之间的相互作用。