近年来，纳米材料被广泛应用于生物医学的研究中，功能化纳米颗粒与靶标细胞之间的动态相互作用影响其靶向递送效率。目前，研究者们利用生物表征方法对纳米颗粒与细胞的相互作用进行了表征，例如纳米颗粒进入细胞的方式、细胞内分布和细胞内吞量等。然而，这些宏观的定性或者定量的表征无法呈现单个纳米颗粒与细胞的动态相互作用。定位单个纳米颗粒的单颗粒示踪技是研究复杂体系的时空异质性过程的有力工具，已经被广泛应用于纳米颗粒与细胞相互作用的研究中。此外，在纳米颗粒与细胞相互作用的体外研究中，二维平面细胞培养模型是主要的细胞培养模型，该模型培养的细胞在形貌、外环境和功能上与体内细胞存在显著差异。本文基于单颗粒示踪技术系统地研究了纳米颗粒与细胞之间的动态相互作用，发展了模拟体内细胞环境的三维（3D）细胞培养方法。主要研究工作如下：
1. 利用暗场成像研究方法分析了金纳米棒与二维（2D）平面培养细胞的动态相互作用。发现金纳米棒在与细胞发生相互作用时，经历了四个阶段：吸附、膜上扩散、跨膜和膜内运输，金纳米棒在不同阶段的运动行为不同。
2. 利用盖玻片和活体提取的Collagen I发展了3D细胞培养方法，其中Collagen I为三维细胞生长提供支撑结构。利用该方法培养的3D细胞伸展良好，可以进行纳米颗粒与细胞相互作用的单颗粒示踪成像实验。

In recent years, nanomaterials have been widely used in biomedical research, and the dynamic interaction between functionalized nanoparticles and target cells affects their on-target delivery efficiency. At present, researchers have used biological characterization methods to characterize the interactions between nanoparticles and cells, such as the way nanoparticles enter cells, their intracellular distribution, and the amount of endocytosis. However, these macroscopic qualitative or quantitative characterizations cannot represent the dynamic interactions of individual nanoparticles with cells. Single-particle tracer techniques for localizing individual nanoparticles are powerful tools to study the spatiotemporal heterogeneity of complex systems and have been widely used in the study of nanoparticle-cell interactions. In addition, the two-dimensional planar cell culture model is the main cell culture model in the in vitro study of nanoparticle-cell interactions, and the cells cultured in this model are significantly different from in vivo cells in morphology, external environment, and function. In this paper, we systematically study the dynamic interactions between nanoparticles and cells based on single-particle tracking technology, and develop a three-dimensional (3D) cell culture method that mimics the in vivo cellular environment. The main research work is as follows:
1. The dynamic interaction between gold nanorods and two-dimensional (2D) planar cultured cells was analyzed using dark-field imaging research methods. It was found that gold nanorods experienced four stages when interacting with cells: adsorption, diffusion on the membrane, transmembrane and intra-membrane transport, and the movement behavior of gold nanorods in different stages was different.
2. 3D cell culture methods have been developed using coverslips and in vivo extracted Collagen I, where Collagen I provides a support structure for three-dimensional cell growth. The 3D cells cultured by this method stretch well and can be used for single-particle tracking imaging experiments of nanoparticle-cell interactions.