Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong China.
Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong China.
Nano Lett. 2022 Sep 28;22(18):7714-7723. doi: 10.1021/acs.nanolett.2c02232. Epub 2022 Aug 10.
Measuring the mechanical interplay between cells and their surrounding microenvironment is vital in cell biology and disease diagnosis. Most current methods can only capture the translational motion of fiduciary markers in the deformed matrix, but their rotational motions are normally ignored. Here, by utilizing single nitrogen-vacancy (NV) centers in nanodiamonds (NDs) as fluorescent markers, we propose a linear polarization modulation (LPM) method to monitor in-plane rotational and translational motions of the substrate caused by cell traction forces. Specifically, precise orientation measurement and localization with background suppression were achieved via optical polarization selective excitation of single NV centers with precisions of ∼0.5°/7.5 s and 2 nm/min, respectively. Additionally, we successfully applied this method to monitor the multidimensional movements of NDs attached to the vicinity of cell focal adhesions. The experimental results agreed well with our theoretical calculations, demonstrating the practicability of the NV-based LPM method in studying mechanobiology and cell-material interactions.
测量细胞与其周围微环境之间的力学相互作用在细胞生物学和疾病诊断中至关重要。目前大多数方法只能捕获变形基质中基准标记的平移运动，但通常忽略其旋转运动。在这里，我们利用纳米金刚石（NDs）中的单个氮空位（NV）中心作为荧光标记，提出了一种线性偏振调制（LPM）方法来监测细胞牵引力引起的基底的面内旋转和平移运动。具体来说，通过对单个 NV 中心进行光学偏振选择性激发，实现了精确的取向测量和背景抑制定位，精度分别约为 0.5°/7.5 s 和 2 nm/min。此外，我们成功地将该方法应用于监测附在细胞黏附点附近的 ND 的多维运动。实验结果与我们的理论计算吻合较好，证明了基于 NV 的 LPM 方法在研究机械生物学和细胞-材料相互作用中的实用性。
