Matlab program from Changes in the mechanical properties of human mesenchymal stem cells during differentiation

A thorough understanding of the changes in mechanical property behind intracellular biophysical and biochemical processes during differentiation of human mesenchymal stem cells (hMSCs) is helpful to direct and enhance the commitment of cells to a particular lineage. In this study, displacement creep of the mesenchymal cell lineages (osteogenic, chondrogenic and adipogenic hMSCs) were determined by using atomic force microscopy, which were then used to determine their mechanical properties. We found that at any stages of differentiation, the mesenchymal cell lineages are linear viscoelastic materials and well matched with a simple power-law creep compliance. In addition, the viscoelasticity of mesenchymal cell lineages showed different trends during differentiation. The adipogenic hMSCs showed continuous softening at all stages. The osteogenic and chondrogenic hMSCs only continuously soften and become more fluid-like in the early stage of differentiation, and get stiffened and less fluid-like in the later stage. These findings will help more accurately imitate cellular biomechanics in the microenvironment, and provided an important reference in the biophysics biomimetic design of stem cell differentiation.深入解析人源间充质干细胞（human mesenchymal stem cells, hMSCs）分化过程中细胞内生物物理与生化过程背后的力学特性变化，有助于引导并强化细胞向特定细胞谱系的定向分化。本研究通过原子力显微镜检测了三类间充质细胞谱系——成骨、成软骨与成脂分化的hMSCs——的位移蠕变特性，进而计算其力学性能。研究发现，在分化的任一阶段，间充质细胞谱系均属于线性粘弹性材料，且可通过简单的幂律蠕变柔量模型进行良好拟合。此外，不同细胞谱系的粘弹性在分化过程中呈现出各异的变化趋势：成脂分化的hMSCs在整个分化阶段均表现为持续软化；而成骨与成软骨分化的hMSCs仅在分化早期呈现持续软化且流动性增强的特征，在分化后期则逐渐变硬且流动性降低。本研究结果有助于更精准地模拟微环境中的细胞生物力学特性，可为干细胞分化过程的生物物理仿生设计提供重要参考依据。