Faculty of Engineering and the Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, 5290002, Israel.
Department of Physics and the Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, 5290002, Israel.
Sci Rep. 2019 Feb 7;9(1):1650. doi: 10.1038/s41598-018-38375-9.
Gold nanoparticles are widely exploited in phototherapy. Owing to their biocompatibility and their strong visible-light surface plasmonic resonance, these particles also serve as contrast agents for cell image enhancement and super-resolved imaging. Yet, their optical signal is still insufficiently strong for many important real-life applications. Also, the differentiation between adjacent nanoparticles is usually limited by the optical resolution and the orientations of non-spherical particles are unknown. These limitations hamper the progress in cell research by direct optical microscopy and narrow the range of phototherapy applications. Here we demonstrate exploiting the optical anisotropy of non-spherical nanoparticles to achieve super-resolution in live cell imaging and to resolve the intracellular nanoparticle orientations. In particular, by modulating the light polarization and taking advantage of the polarization-dependence of gold nanorod optical properties, we realize the 'lock-in amplification', widely-used in electronic engineering, to achieve image enhancement in live cells and in cells that undergo apoptotic changes.
金纳米颗粒在光疗中得到了广泛的应用。由于其生物相容性和强可见光表面等离子体共振，这些颗粒还可用作细胞图像增强和超分辨成像的对比剂。然而，对于许多重要的实际应用，其光学信号仍然不够强。此外，相邻纳米颗粒之间的区分通常受到光学分辨率的限制，并且非球形颗粒的取向是未知的。这些限制通过直接光学显微镜阻碍了细胞研究的进展，并缩小了光疗应用的范围。在这里，我们展示了利用非球形纳米颗粒的各向异性来实现活细胞成像中的超分辨率，并解析细胞内纳米颗粒的取向。具体来说，通过调制光的偏振，并利用金纳米棒光学性质的偏振依赖性，我们实现了在活细胞和经历凋亡变化的细胞中广泛应用于电子工程的“锁相放大”，以实现图像增强。
