Mechanisms of nanomaterial delivery to plant chloroplasts have been explored to improve plant stress tolerance, promote photosynthesis, facilitate genetic engineering, and manufacture self-repairing biomaterials, fuels, and biopharmaceuticals. However, the molecular interactions of nanomaterials with chloroplast membranes are not well understood. In this study, we examine the interactions of an important set of chloroplast membrane lipids including sulfoquinovosyl diacylglycerols with carbon nanodots varying in functional group charge. To accomplish this objective, we constructed a novel model chloroplast membrane and interrogated the influence of carbon nanodot functional group charge, model chloroplast membrane composition, and ionic strength on the carbon nanodot-chloroplast membrane interactions using a quartz crystal microbalance with dissipation monitoring. We further examined the interaction of carbon nanodots with native chloroplasts isolated from Arabidopsis thaliana using confocal laser-scanning microscopy. Our results indicate that carbon nanodot-chloroplast membrane interactions are dictated primarily by electrostatics. Despite being the least abundant lipids in chloroplast membranes, we find that the relative abundance of sulfoquinovosyl diacylglycerol in model membranes is the component that governs both the affinity for and capacity of the membrane to interact with positively charged carbon nanodots. Rates of carbon nanodot attachment to model chloroplast membranes varied with ionic strength in a manner consistent with electrical double layer compression on carbon nanodots. Our findings elucidate chemical interactions between nanomaterials and plant biosurfaces at the molecular level and potentially contribute to establishing structure–property-interaction relationships of sustainable nanomaterials with plant organelle membranes.

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硫脂密度决定了碳纳米点与叶绿体膜相互作用的程度

已经探索了将纳米材料输送到植物叶绿体的机制，以提高植物的抗逆性、促进光合作用、促进基因工程以及制造自我修复的生物材料、燃料和生物制药。然而，纳米材料与叶绿体膜的分子相互作用尚不清楚。在这项研究中，我们研究了一组重要的叶绿体膜脂（包括磺基喹诺糖基二酰基甘油）与官能团电荷不同的碳纳米点的相互作用。为了实现这一目标，我们构建了一种新的模型叶绿体膜并询问碳纳米点官能团电荷的影响，模型叶绿体膜组成，使用具有耗散监测的石英晶体微量天平对碳纳米点-叶绿体膜相互作用的离子强度和离子强度。我们进一步研究了碳纳米点与分离自天然叶绿体的相互作用拟南芥使用共聚焦激光扫描显微镜。我们的结果表明，碳纳米点-叶绿体膜相互作用主要由静电决定。尽管是叶绿体膜中含量最少的脂质，但我们发现模型膜中磺基奎诺糖基二酰基甘油的相对丰度是控制膜与带正电荷的碳纳米点相互作用的亲和力和能力的成分。碳纳米点附着到模型叶绿体膜的速率随离子强度的变化而变化，其方式与碳纳米点上的双电层压缩一致。