School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong, China; Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China.
School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong, China; Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China.
Chemosphere. 2021 Oct;281:130762. doi: 10.1016/j.chemosphere.2021.130762. Epub 2021 May 12.
The uptake, intracellular dissolution, and cytotoxicity of silver nanowires (AgNWs) in two cell models (human keratinocytes - HaCaT cells and murine macrophages) were systemically investigated for the first time. Cellular uptake of AgNWs occurred mainly via pathways of clathrin-dependent endocytosis, caveolae-dependent endocytosis, and phagocytosis. AgNWs could be internalized by two types of cells with numerous lysosomal vesicles detected in close vicinity to AgNWs. Meanwhile, AgNWs exposure caused lysosomal permeabilization and release of cathepsisn B into cytoplasm. Furthermore, for the first time, this study found that AgNWs exposure inhibited the transmembrane ATP binding cassette (ABC) efflux transporter activity, which could make AgNWs as chemosensitizers to increase the toxicity of other xenobiotic pollutants. Toxicity assays evaluating reactive oxygen species production and mitochondrial activity indicated that cytotoxicity differed for different cell types and particles. The intracellular presence of AgNWs with different diameters induced similar toxic events but to different extents. AgNWs were absorbed by macrophages more efficiently than HaCaT cells, while AgNWs exhibited only marginal cytotoxicity towards macrophages compared to HaCaT cells. Using an Ag fluorescence probe, it was found that a fraction of AgNWs was dissolved inside the lysosomes. A higher amount of released Ag was detected in HaCaT cells than in macrophages, which might partially contribute to their higher cytotoxicity in HaCaT cells. The toxicity of AgNWs in HaCaT cells and macrophages is due to the high-aspect nature of the nanowires rather than the extracellular release of Ag. This study may be useful for risk assessments of AgNWs in their practical applications in the biomedical field.
首次系统研究了银纳米线（AgNWs）在两种细胞模型（人角质形成细胞 - HaCaT 细胞和鼠巨噬细胞）中的摄取、细胞内溶解和细胞毒性。AgNWs 的细胞摄取主要通过网格蛋白依赖内吞作用、小窝依赖内吞作用和吞噬作用途径发生。AgNWs 可以被两种类型的细胞内化，在 AgNWs 附近检测到大量溶酶体囊泡。同时，AgNWs 暴露导致溶酶体通透性增加，组织蛋白酶 B 释放到细胞质中。此外，本研究首次发现 AgNWs 暴露抑制了跨膜 ABC 外排转运体的活性，这使得 AgNWs 成为化学增敏剂，增加了其他异源污染物的毒性。评估活性氧产生和线粒体活性的毒性试验表明，不同细胞类型和颗粒的细胞毒性不同。不同直径的 AgNWs 的细胞内存在诱导相似的毒性事件，但程度不同。巨噬细胞比 HaCaT 细胞更有效地吸收 AgNWs，而与 HaCaT 细胞相比，AgNWs 对巨噬细胞仅表现出轻微的细胞毒性。使用 Ag 荧光探针发现，AgNWs 的一部分在溶酶体内部溶解。在 HaCaT 细胞中检测到的释放 Ag 量高于巨噬细胞，这可能部分导致它们在 HaCaT 细胞中更高的细胞毒性。AgNWs 在 HaCaT 细胞和巨噬细胞中的毒性是由于纳米线的高纵横比特性，而不是 Ag 的细胞外释放。本研究对于在生物医学领域实际应用中评估 AgNWs 的风险可能是有用的。
