Biomolecular Photonics, Department of Physics, University of Bielefeld, Universitätsstrasse 25, 33615 Bielefeld, Germany.
NSF Center for Biophotonics, University of California, 2700 Stockton Boulevard, Suite 1400, Davis, Sacramento, California 95817, USA.
Nat Commun. 2016 Dec 13;7:13711. doi: 10.1038/ncomms13711.
Imaging non-adherent cells by super-resolution far-field fluorescence microscopy is currently not possible because of their rapid movement while in suspension. Holographic optical tweezers (HOTs) enable the ability to freely control the number and position of optical traps, thus facilitating the unrestricted manipulation of cells in a volume around the focal plane. Here we show that immobilizing non-adherent cells by optical tweezers is sufficient to achieve optical resolution well below the diffraction limit using localization microscopy. Individual cells can be oriented arbitrarily but preferably either horizontally or vertically relative to the microscope's image plane, enabling access to sample sections that are impossible to achieve with conventional sample preparation and immobilization. This opens up new opportunities to super-resolve the nanoscale organization of chromosomal DNA in individual bacterial cells.
目前，由于悬浮状态下非贴壁细胞的快速运动，使用超分辨率远场荧光显微镜对其进行成像仍无法实现。全光学捕获（HOTs）技术能够自由控制光阱的数量和位置，从而可以在焦平面周围的体积中不受限制地操作细胞。本文中我们证明，通过光镊将非贴壁细胞固定，使用定位显微镜即可实现低于衍射极限的光学分辨率。单个细胞可以任意方向定向，但优选地相对于显微镜的像平面水平或垂直，从而可以获取用传统的样品制备和固定方法无法实现的样品截面。这为在单个细菌细胞中对染色体 DNA 的纳米级结构进行超分辨成像提供了新的机会。
