Fu Kexin, Wang Xiaojie, Yuan Xinxin, Wang Dekun, Mi Xue, Tan Xiaoyue, Zhang Yuying
School of Medicine, Nankai University, Tianjin 300071, China.
ACS Omega. 2021 Jan 28;6(5):3791-3799. doi: 10.1021/acsomega.0c05458. eCollection 2021 Feb 9.
Nanoprobes have been increasingly applied in the biomedical field due to their superior optical, electronic, or magnetic properties. Among the many aspects involved in the interaction between nanoprobes and biospecimens, size plays an essential role. Although the influence of size on their internalization behavior and distribution in live cells has been extensively studied, how does the size affect penetration of nanoprobes into fixed cells remains unknown. We investigate here the influence of size on the penetration behavior of gold nanoprobes into fixed mammalian cells by dark-field microscopy and surface-enhanced Raman scattering (SERS) microspectroscopy. We show that 14, 20, and 29 nm nanoprobes can readily enter into methanol-fixed MCF-7 cells, while 42 and 55 nm nanoprobes cannot cross the cell membrane. For 4% paraformaldehyde-fixed cells, even 14 nm nanoprobes can hardly get into the cells, but after treatment with permeabilization reagents, 14 and 20 nm nanoprobes are permitted to enter the cells. These findings provide important implications in future design of nanoprobes for cellular immunostaining.
由于其优异的光学、电子或磁性特性，纳米探针在生物医学领域的应用越来越广泛。在纳米探针与生物样本相互作用所涉及的诸多方面中，尺寸起着至关重要的作用。尽管尺寸对其内化行为和在活细胞中的分布的影响已得到广泛研究，但尺寸如何影响纳米探针进入固定细胞的穿透能力仍不清楚。在此，我们通过暗场显微镜和表面增强拉曼散射（SERS）显微光谱研究了尺寸对金纳米探针进入固定哺乳动物细胞的穿透行为的影响。我们发现，14、20和29纳米的纳米探针能够轻易进入甲醇固定的MCF-7细胞，而42和55纳米的纳米探针则无法穿过细胞膜。对于4%多聚甲醛固定的细胞，即使是14纳米的纳米探针也很难进入细胞，但在用通透试剂处理后，14和20纳米的纳米探针能够进入细胞。这些发现为未来用于细胞免疫染色的纳米探针设计提供了重要启示。
