Laboratory for Bio- and Nano-Photonics, Department of Microsystems Engineering-IMTEK, University of Freiburg, 79110, Freiburg, Germany.
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Nat Commun. 2021 Nov 26;12(1):6922. doi: 10.1038/s41467-021-27262-z.
In modern 3D microscopy, holding and orienting arbitrary biological objects with optical forces instead of using coverslips and gel cylinders is still a vision. Although optical trapping forces are strong enough and related photodamage is acceptable, the precise (re-) orientation of large specimen with multiple optical traps is difficult, since they grab blindly at the object and often slip off. Here, we present an approach to localize and track regions with increased refractive index using several holographic optical traps with a single camera in an off-focus position. We estimate the 3D grabbing positions around several trapping foci in parallel through analysis of the beam deformations, which are continuously measured by defocused camera images of cellular structures inside cell clusters. Although non-blind optical trapping is still a vision, this is an important step towards fully computer-controlled orientation and feature-optimized laser scanning of sub-mm sized biological specimen for future 3D light microscopy.
在现代 3D 显微镜中，用光学力代替盖玻片和凝胶柱来固定和定向任意生物物体仍然是一个愿景。尽管光学捕获力足够强，并且相关的光损伤是可以接受的，但由于多个光学陷阱盲目抓取物体，并且经常滑脱，因此精确（重新）定向具有多个光学陷阱的大样本是困难的。在这里，我们提出了一种使用单个相机在离焦位置的多个全息光学陷阱来定位和跟踪具有增加折射率的区域的方法。我们通过分析光束变形来并行估计几个捕获焦点周围的 3D 抓取位置，这些变形通过离焦的细胞簇内细胞结构的相机图像连续测量。虽然非盲目的光学捕获仍然是一个愿景，但这是朝着完全计算机控制的方向迈出的重要一步，可优化亚毫米大小生物样本的特征，用于未来的 3D 光学显微镜。
