Tang Xue-Rui, Lei Shou-Yang, Zhang Qiangqiang, Liu Yuan-Yuan, Wu Hao, Cao Aoneng, Wang Haifang
Institute of Nanochemistry and Nanobiology, Shanghai University, Shanghai 200444, China.
Institute of Nanochemistry and Nanobiology, Shanghai University, Shanghai 200444, China.
Colloids Surf B Biointerfaces. 2025 Jan;245:114272. doi: 10.1016/j.colsurfb.2024.114272. Epub 2024 Sep 26.
The mechanism of cellular uptake of nanoparticles (NPs) is critical for both bio-application and risk evaluation of NPs, but is still not fully understood due to many influencing factors, among which particle size is a major one. Recent studies show that there is an unusual interplay among differently-sized NPs when they simultaneously interact with cells, e.g., 100 nm silica NPs (SNP100) can promote the cellular uptake of 50 nm silica NPs (SNP50). However, the underlying mechanism is still unclear. Herein, we manage to capture individual endocytosis events in HeLa and A549 cells after co-exposure to SNP50 and SNP100 for 2 hours, using transmission electron microscopy (TEM). TEM images clearly show that there is a size threshold for SNPs to trigger clathrin-mediated endocytosis: One single SNP100 can efficiently trigger it, while it needs about 6 SNP50 to do so. Remarkably, TEM also captures how SNP100 triggers the endocytosis and carries nearby SNP50 into cells, and statistical data show that the average number of SNP50 carried by one SNP100 could be up to about 6. In addition, the mechanism was further verified by using mixed 60 nm SNPs (SNP60) and SNP100. This mechanism has an immediate implication for the design of drug-deliver nanocarriers, and as a proof-of-concept, more catalase functionalized SNP50 (CAT@SNP50) was delivered into HeLa cells by adding some SNP100, resulting in a more severe cell damage compared to CAT@SNP50 alone under same conditions. The findings have general impact on the nanotoxicity study of NP products that commonly have certain distributions in size, and provide new insights on designing efficient drug delivery systems by deliberately control the combinations of NPs of different sizes.
纳米颗粒（NPs）的细胞摄取机制对于NPs的生物应用和风险评估都至关重要，但由于许多影响因素，目前仍未完全了解，其中粒径是一个主要因素。最近的研究表明，不同尺寸的NPs在与细胞同时相互作用时存在异常的相互作用，例如，100nm的二氧化硅纳米颗粒（SNP100）可以促进50nm二氧化硅纳米颗粒（SNP50）的细胞摄取。然而，其潜在机制仍不清楚。在此，我们通过透射电子显微镜（TEM）设法捕捉HeLa和A549细胞在同时暴露于SNP50和SNP100 2小时后的单个内吞事件。TEM图像清楚地表明，SNP触发网格蛋白介导的内吞作用存在一个尺寸阈值：单个SNP100可以有效地触发它，而大约需要6个SNP50才能做到。值得注意的是，TEM还捕捉到SNP100如何触发内吞作用并将附近的SNP50带入细胞，统计数据表明，一个SNP100携带的SNP50的平均数量可达约6个。此外，通过使用混合的60nm SNP（SNP60）和SNP100进一步验证了该机制。该机制对药物递送纳米载体的设计具有直接意义，作为概念验证，通过添加一些SNP100，更多的过氧化氢酶功能化SNP50（CAT@SNP50）被递送到HeLa细胞中，与相同条件下单独的CAT@SNP50相比，导致更严重的细胞损伤。这些发现对通常具有一定尺寸分布的NP产品的纳米毒性研究具有普遍影响，并为通过故意控制不同尺寸NP的组合来设计高效药物递送系统提供了新的见解。
