In the last decade, gold nanoparticles have emerged as promising agents for in vitro bio-sensing and in vivo cancer theranostics. However, different investigations have reported widely varying cytotoxicity and uptake efficiency of gold nanoparticles depending upon their size. Therefore, more extensive studies are needed to standardize these biological effects as a function of size on a particular cell line. In addition, to obtain robust confirmation on the correlation of a size to biological effect, thorough mechanistic study must also be performed. In this study, the size dependent biological activities of gold nanoparticles on osteosarcoma cells is investigated towards exploring their potential theranostic application in bone cancer, for which very scarce literature reports are available. Tris-assisted citrate based method was optimized to synthesize stable gold naoparticles of 40-60 nm sizes. Nanoparticles were characterized through UV-Vis spectroscopy, field emission scanning electron microscope (FESEM) and dynamic light scattering (DLS). Increasing concentrations of gold nanoparticles (AuNPs) of 46 nm size, enhanced the rate of reactive oxygen species (ROS)-induced apoptosis in MG63 cells by disrupting their mitochondrial membrane potential. Considerably higher cell death was observed for 46 and 60 nm AuNPs compared to 38 nm at all concentrations of 200, 400 and 800 ng/mL. Further, molecular signatures of cellular apoptosis under nanoparticle treatment were optically assessed through surface enhanced Raman scattering (SERS). A significant Raman enhancement in cancer cells under treatment of larger gold nanoparticles (46 and 60 nm) at fixed wavelength of 785 nm and laser power of 8.0 mW was evident. In corroboration with molecular biology techniques, SERS observation confirmed the size-dependent apoptotic phenomena in osteosarcoma cells under treatment of gold nanoparticles. Study demonstrates a facile, non-active targeting approach for detection of size-dependent AuNP-induced apoptosis in osteosarcoma cells through label-free SERS method.

中文翻译：

---

金纳米颗粒对骨肉瘤细胞的大小依赖性凋亡活性与SERS信号相关。

在过去的十年中，金纳米粒子已成为有前途的试剂，可用于体外生物传感和体内癌症治疗。然而，不同的研究已经报道了金纳米颗粒的大小取决于其细胞毒性和吸收效率的变化。因此，需要更广泛的研究来标准化这些生物学效应作为特定细胞系大小的函数。此外，要获得有关大小与生物学效应之间相关性的可靠确认，还必须进行彻底的机理研究。在这项研究中，研究了金纳米颗粒对骨肉瘤细胞的大小依赖性生物学活性，以探索其在骨癌中的潜在治疗学应用，有关文献报道非常稀少。优化了基于Tris辅助柠檬酸盐的方法，以合成40-60 nm尺寸的稳定金纳米颗粒。通过紫外可见光谱，场发射扫描电子显微镜（FESEM）和动态光散射（DLS）对纳米颗粒进行了表征。46 nm大小的金纳米颗粒（AuNPs）浓度的增加，通过破坏线粒体膜电位，提高了活性氧（ROS）诱导MG63细胞凋亡的速率。在200、400和800 ng / mL的所有浓度下，观察到46和60 nm AuNP的细胞死亡明显高于38 nm。此外，通过表面增强拉曼散射（SERS）光学评估了纳米颗粒处理下细胞凋亡的分子标记。在较大的金纳米粒子（46和60 nm）以785 nm的固定波长和8.0 mW的激光功率处理下，癌细胞中的拉曼增强显着。在分子生物学技术的佐证下，SERS观察证实了金纳米颗粒治疗后骨肉瘤细胞的大小依赖性凋亡现象。研究表明，通过无标记SERS方法检测骨肉瘤细胞中大小依赖性AuNP诱导的凋亡的简便，非活性靶向方法。