Toxicological effects of pure and amine-functionalized ZnO nanorods on Daphnia magna and Lactuca sativa

Abstract

Zinc oxide (ZnO) is one of the most widely used inorganic materials as nanostructures. Thus, human and environmental exposures to NMs are inevitable and concerns about possible risks induced by exposure to artificial nanomaterials (NMs) are growing. In this study, we synthesized and characterized ZnO nanorods (NRs) and amino-functionalized ZnO NRs with the molecule 3-aminopropyltrimethoxysilane – @APTMS (ZnO@APTMS NRs), and the toxicity of these ZnO NMs was evaluated by exposing organisms of two different trophic levels: the freshwater microcrustacean Daphnia magna and the seeds of Lactuca sativa. ZnO NMs were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), effective diameter, zeta potential (ZP), surface area, and Fourier-transform infrared (FTIR) spectroscopy. The acute toxicity test with the microcrustacean D. magna and the L. sativa seeds showed the high toxicity of both pure and functionalized NRs, showing high sensitivity to functionalized ZnO@APTMS NRs, including ROS generation in the microcrustacean. With TEM, the structural damage (for both tested organisms) and internalization (for D. magna) of ZnO NMs were confirmed.