Xu Da-Di, Liu Liu, Zheng Yawen, Li Yu-Yao, Xu Peng-Fei, Liu Yang, Tang Hong-Wu
College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, People's Republic of China.
ACS Nano. 2025 Jun 3;19(21):20144-20152. doi: 10.1021/acsnano.5c04890. Epub 2025 May 16.
Optical tweezers are considered a tool for trapping and measuring forces on single molecules and small particles. Current research mainly focuses on measuring force spectral information on particles suspended in solution. However, the viscoelastic environment within the cell presents additional challenges for the in situ calibration of force spectroscopy data. To address this issue, we used an active-passive calibration method to calibrate the optical trap stiffness in live cells through sinusoidal oscillation and spontaneous fluctuation responses. This technique was applied to in situ measurements of the optical trap stiffness and viscoelastic modulus of viruses inside the host cell. The results indicate that this method can measure the optical trap stiffness and related parameters of intracellular viruses at different frequencies. Moreover, we proceeded to confirm that using quantum dots labeled viruses inside cells increased the stiffness of the viral optical trap similar to that in fluid. This provides more robust support for future force measurements and analysis of the transport mechanisms of viruses trapped within live cells using optical tweezers.
光镊被认为是一种用于捕获和测量单个分子及小颗粒上的力的工具。当前的研究主要集中于测量悬浮在溶液中的颗粒的力谱信息。然而，细胞内的粘弹性环境给力谱数据的原位校准带来了额外的挑战。为了解决这个问题，我们使用了一种主动-被动校准方法，通过正弦振荡和自发波动响应来校准活细胞中的光镊刚度。该技术被应用于宿主细胞内病毒的光镊刚度和粘弹性模量的原位测量。结果表明，该方法可以在不同频率下测量细胞内病毒的光镊刚度及相关参数。此外，我们进一步证实，在细胞内使用量子点标记病毒会增加病毒光镊的刚度，类似于在流体中的情况。这为未来使用光镊对活细胞内捕获的病毒的运输机制进行力测量和分析提供了更有力的支持。
