This paper presents the results of a combined experimental and analytical/computational study of viscoelastic cell deformation and detachment from poly-di-methyl-siloxane (PDMS) surfaces. Fluid mechanics and fracture mechanics concepts are used to model the detachment of biological cells observed under shear assay conditions. The analytical and computational models are used to compute crack driving forces, which are then related to crack extension during the detachment of normal breast cells and breast cancer cells from PDMS surfaces that are relevant to biomedical implants. The interactions between cells and the extracellular matrix, or the extracellular matrix and the PDMS substrate, are then characterized using force microscopy measurements of the pull-off forces that are used to determine the adhesion energies. Finally, fluorescence microscopy staining of the cytosketelal structures (actin, micro-tubulin and cyto-keratin), transmembrane proteins (vimentin) and the ECM structures (Arginin Glycine Aspartate – RGD) is used to show that the detachment of cells during the shear assay experiments occurs via interfacial cracking between (between the ECM and the cell membranes) with a high incidence of crack bridging by transmembrane vinculin structures that undergo pull-out until they detach from the actin cytoskeletal structure. The implications of the results are discussed for the design of interfaces that are relevant to implantable biomedical devices and normal/cancer tissue.

本文介绍了粘弹性细胞变形和从聚二甲基硅氧烷（PDMS）表面脱离的组合实验和分析/计算研究的结果。流体力学和断裂力学概念被用来模拟在剪切试验条件下观察到的生物细胞的分离。分析和计算模型用于计算裂纹驱动力，然后与正常的乳腺细胞和乳腺癌细胞从与生物医学植入物相关的PDMS表面分离时的裂纹扩展有关。然后使用用于确定粘附能的拉脱力的力显微镜测量来表征细胞与细胞外基质或细胞外基质与PDMS底物之间的相互作用。最后，细胞骨架结构（肌动蛋白，微管蛋白和细胞角蛋白），跨膜蛋白（波形蛋白）和ECM结构（精氨酸谷氨酸天冬氨酸– RGD）的荧光显微镜染色用于显示在剪切测定实验过程中发生了细胞分离通过（ECM和细胞膜之间）的界面开裂，通过跨膜纽蛋白结构的裂纹桥接的发生率很高，这些结构会被拉出直到从肌动蛋白细胞骨架结构脱离。对于与可植入生物医学设备和正常/癌症组织相关的界面的设计，讨论了结果的含义。跨膜蛋白（波形蛋白）和ECM结构（精氨酸甘氨酸天冬氨酸-RGD）用于显示剪切试验过程中细胞的分离是通过（ECM和细胞膜之间的）界面裂纹而发生的，且裂纹的发生率很高通过跨膜纽蛋白结构桥接，该结构经历拉出直至从肌动蛋白细胞骨架结构脱离。对于与可植入生物医学设备和正常/癌症组织相关的界面的设计，讨论了结果的含义。跨膜蛋白（波形蛋白）和ECM结构（精氨酸甘氨酸天冬氨酸-RGD）用于显示剪切试验过程中细胞的分离是通过（ECM和细胞膜之间的）界面裂纹而发生的，且裂纹的发生率很高通过跨膜纽蛋白结构桥接，该结构经历拉出直至从肌动蛋白细胞骨架结构脱离。对于与可植入生物医学设备和正常/癌症组织相关的界面的设计，讨论了结果的含义。