Department of Mechanical Engineering, McGill University, Montreal, QC, Canada.
Ann Biomed Eng. 2012 Oct;40(10):2122-30. doi: 10.1007/s10439-012-0595-3. Epub 2012 May 30.
This paper reports the first quantitative comparison study of elastic and viscoelastic properties of oocytes from young and aged mice. A force measurement technique, including a poly(dimethylsiloxane) (PDMS) cell holding device and a sub-pixel computer vision tracking algorithm, is utilized for measuring forces applied to an oocyte and resultant cell deformations in real time during oocyte manipulation. To characterize elastic and viscoelastic properties of the oocytes, a stress-relaxation indentation test is performed. A two-step, large-deformation mechanical model is developed to extract the mechanical properties of the oocytes from the measured force-deformation data. The experimental results demonstrate that the aged oocytes are significantly softer (instantaneous modulus: 2.2 vs. 5.2 kPa in young oocytes) but more viscous (relaxation time: 4.1 vs. 2.3 s in young oocytes) than the young oocytes.
本文报道了首例对年轻和年老小鼠卵母细胞弹性和粘弹性特性的定量比较研究。采用力测量技术，包括聚二甲基硅氧烷（PDMS）细胞保持装置和亚像素计算机视觉跟踪算法，实时测量卵母细胞操作过程中施加在卵母细胞上的力和细胞产生的变形。为了描述卵母细胞的弹性和粘弹性特性，进行了应力松弛压痕试验。建立了两步大变形力学模型，从测量的力-变形数据中提取卵母细胞的力学特性。实验结果表明，年老的卵母细胞明显更软（瞬时模量：年轻卵母细胞为 2.2kPa，年老卵母细胞为 5.2kPa），但粘性更大（松弛时间：年轻卵母细胞为 2.3s，年老卵母细胞为 4.1s）。
