Centre for Advanced Jet Engineering Technology (CaJET), Key Laboratory of High-efficiency and Clean Mechanical Manufacture (Ministry of Education), National Experimental Teaching Demonstration Center for Mechanical Engineering (Shandong University), School of Mechanical Engineering, Shandong University, Jinan 250061, China.
School of Mechanical Engineering, Yanshan University, Qinhuangdao 066004, China.
Soft Matter. 2024 Sep 18;20(36):7270-7283. doi: 10.1039/d4sm00740a.
Quantitative investigation of the adhesive behavior between cells and the extracellular matrix (ECM) through molecular bonds is essential for cell culture and bio-medical engineering . Cell adhesion is a complex multi-scale behavior that includes temporal and spatial scales. However, the influence of the cell and matrix creep effect and the complex spatial morphology characteristics of the matrix on the cell adhesion mechanism is unclear. In the present study, an idealized theoretical model has been considered, where the adhesion of cells and the matrix is simplified into a planar strain problem of homogeneous viscoelastic half-spaces. Furthermore, a new viscoelastic-stochastic model that considers the morphological characteristics of the matrix, the viscoelasticity of the cell and the viscoelasticity of the substrate was developed under the action of a constant external force. The model characterizes the matrix topographical features by fractal dimension (FD), interprets the effects of FD and medium viscoelasticity on the molecular bond force and the receptor-ligand bond re-association rate and reveals a new mechanism for the stable adhesion of molecular bond clusters by Monte Carlo simulation. Based on this model, it was identified that the temporal and spatial distribution of molecular bond force was affected by the matrix FD and the lifetime and stability of the molecular bond cluster could be significantly improved by tuning the FD. At the same time, the viscoelastic creep effect of the cell and matrix increased the re-association rate of open bonds and could expand the window of stable adhesion more flexibly.
通过分子键定量研究细胞与细胞外基质（ECM）之间的黏附行为对于细胞培养和生物医学工程至关重要。细胞黏附是一种复杂的多尺度行为，包括时间和空间尺度。然而，细胞和基质的蠕变效应以及基质的复杂空间形态特征对细胞黏附机制的影响尚不清楚。在本研究中，考虑了一个理想化的理论模型，其中细胞和基质的黏附简化为各向同性粘弹性半空间的平面应变问题。此外，在恒外力作用下，开发了一种新的粘弹性随机模型，该模型考虑了基质的形态特征、细胞的粘弹性和基底的粘弹性。该模型通过分形维数（FD）来描述基质的形貌特征，解释了 FD 和介质粘弹性对分子键力和受体-配体键再结合率的影响，并通过蒙特卡罗模拟揭示了分子键簇稳定黏附的新机制。基于该模型，发现分子键力的时空分布受基质 FD 的影响，通过调整 FD 可以显著提高分子键簇的寿命和稳定性。同时，细胞和基质的粘弹性蠕变效应增加了开键的再结合率，可以更灵活地扩展稳定黏附的窗口。
