An Engineering Approach Investigating the Uptake and Phytotoxicity of One Type of Engineered Nanoparticle (CdSe/ZnS Quantum Dots) by Solanum lycopersicum

The novel and extraordinary physiochemical properties of engineered nanoparticles (ENPs) arecertain; however, their unique characteristics raise growing concerns regarding potentially adverseeffects on biological and ecological systems. It is becoming increasingly evident that, before the fullpotential of nanotechnology can be realized, standardized characterization of ENP behavior, fate,and effects on the ecosystem are essential to ensure the safe manufacturing and use of ENPproducts. Otherwise, the promise of such extraordinary advancements may find itself limited toapplications such as electronics and sporting equipment, industries in which ENPs currently reside.The current toxicity profile of engineered nanomaterials is not only preliminary, but highly variableamongst researchers. Consequently, there is great need for the development of a highly organized,efficient, and precise approach to assess the hazardous potential ENPs may pose, while addressingthe safety concerns surrounding and limiting nanotechnology. In response to such concerns, thepresent study took an engineering approach, in an otherwise traditionally viewed discipline, to assessthe potential impact of one type of engineered nanoparticle, water-soluble (MUA) CdSe/ZnSquantum dots (QDs), on tomato (Solanum lycopersicum) seedlings, by implementing a full factorialdesign of experiment (FDOE), in an effort to identify which factors, and their interactions, have asignificant (p ≤ 0.05) effect on root and shoot elongation, and if any observed effects are a result ofparticle uptake, evaluated via fluorescence microscopy imaging. By implementing factorialexperimental design methodologies, not only are we efficiently identifying the factors that affectphytotoxicity, we are providing, for the first time to our knowledge, the first scientific data to reportthe significant interaction effects between the factors responsible for ENP toxicity. (MUA)CdSe/ZnS quantum dots had a negative influence on root and shoot lengths of tomato seedlingsexposed for 3 days, as well as those exposed for 6 days. The observed influence depended on QDconcentration and exposure time, as statistical analyses found QD concentration, exposure time, andthe concentration-exposure time interaction significantly (p ≤ 0.05) affected root and shoot lengthsof tomato seedlings. Additionally, to minimize the observed phytotoxicity effects (i.e., to maximizetomato root lengths), our results suggest that exposure of tomato seeds to low QD concentrationlevels (125 mg/L) for short periods of time (maximum of 3 days) to yield maximum root lengths ofapproximately 2.21 cm, that is – minimal phytotoxicity effects.