Cell wall: An important medium regulating the aggregation of quantum dots in maize (Zea mays L.) seedlings.
Cell wall: An important medium regulating the aggregation of quantum dots in maize (Zea mays L.) seedlings.
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DOI：
10.1016/j.jhazmat.2020.123960
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发表时间：
2021-02
影响因子：
13.6
通讯作者：
Haifeng Sun;Meng Wang;Chunli Lei;Ruilong Li
中科院分区：
文献类型：
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作者：
Haifeng Sun;Meng Wang;Chunli Lei;Ruilong Li
量子点在许多领域有着广泛的应用，导致人们越来越关注它们的摄取以及随后与植物体内的相互作用。细胞壁(CW)作为与外源物质相互作用进入植物体内的第一个靶点，其在调控量子点细胞摄取中的作用有待进一步研究。在本研究中，玉米(Zea maysL.)用水培方法将幼苗分别置于带负电荷涂层和中性涂层功能化的聚乙二醇单甲氧基硫化镉锌量子点(QDS-PEGCOOH)和甲基硫化镉/锌硫化量子点(QDS-Mpa)中。由于静电对带负电荷的根Cw的排斥，Qds-PEG-COOH的摄取速率约为Qds-MPA的3.5倍。两种类型的量子点在主根、侧根和须根的表面都有明显的聚集，且量子点-MPA聚集体的大小约为Qds-PEG-COOH聚集体的1.8倍。CW纤维中的羟基与QDS-PEGCOOH膜表面的羧基形成的强氢键是QDS-PEGCOOH聚集的主要机理，而木质素与QDS-Mpa之间的共轭C-˭C链则是QDS-Mpa聚集的主要原因。这项工作的结果突出了植物CW在调节量子点的吸收速率和聚集方面的重要性，潜在地限制了它们在植物体内的内化和进入食物网。
Quantum dots (QDs) find various applications in many fields, leading to increasing concerns regarding their uptake and subsequent interaction with plant body. Cell wall (CW), serving as a first target place that interacts with xenobiotic substances into plant body, its role in regulating the QDs cellular uptake needs to be explored. In the present study, maize (Zea maysL.) seedlings were hydroponically exposed to PEG-COOH-CdS/ZnS QDs (QDs-PEG-COOH) and MPA-CdS/ZnS QDs (QDs-MPA) functionalized with negatively charged and neutral coatings, respectively. Uptake rate of QDs-PEG-COOH was approximately 3.5 times lower than that of QDs-MPA due to electrostatic repulsion to the negatively charged root CW. Both types of QDs had obvious aggregation on surfaces of taproot, lateral root and fibrous root, and QDs-MPA aggregates were approximately 1.8 times larger than QDs-PEG-COOH aggregates. The strong hydrogen bond formed by hydroxyl group in cellulose of CW and carboxyl group on surface coatings of QDs-PEG-COOH constituted the key mechanism for QDs-PEG-COOH aggregation, while conjugated C˭C chains between lignin and QDs-MPA dominated the occurrences of QDs-MPA aggregation. Results of this work highlight the importance of plant CW in regulating uptake rate and aggregation of QDs, potentially limiting their internalization into plant body and introduction into food webs.