The study reports first ever account of measurements of linear viscoelastic moduli under small amplitude oscillatory shear deformations, for commercially available juvenile and aged in vitro 3D reconstructed skin models. The results were compared with those of native male whole human and dermis-only foreskin samples, catering to a wide age group from 0.5 to 68 years, including samples from a 23-year-old male abdomen. In the strain sweep tests, the dermis of the juvenile/young age group assumed a higher intrinsic elastic modulus than the whole skin. A reverse qualitative trend was noted for the adult/aged age group. Confirmed by the histological examination of the stained cross-sections, this is attributed to the nascent epidermal differentiation and the high fiber density of dermal collagen. The oscillation frequency sweeps exposed a greater dependence of the elasticity on the frequency for the native male dermis foreskin samples as compared to the whole skins, irrespective of age. This is anticipated since the extremely structured epidermis confers higher resistance to the whole skins towards intracycle deformations compared to the dermis, thereby storing smaller elastic energy. The 3D skin models examined in this work exhibited a broader linear viscoelastic region, a larger viscoelasticity, and much higher dynamic moduli, compared to the native skin. The rheological trends are a significant addition to the literature and may be used as a reference for the design of next generation of scaffolds.

这项研究首次报道了商用和青少年体外在小振幅振荡剪切变形下线性粘弹性模量的测量结果3D重建的皮肤模型。将结果与本地男性全人类和仅真皮包皮样品进行了比较，这些样品适用于0.5至68岁的广泛年龄组，包括来自23岁男性腹部的样品。在应变扫描测试中，少年/年轻年龄组的真皮比整个皮肤具有更高的固有弹性模量。注意到成年人/年龄组的定性趋势是相反的。经染色横截面的组织学检查证实，这归因于新生表皮的分化和真皮胶原蛋白的高纤维密度。与整个皮肤相比，无论年龄多大，振荡频率扫描都显示出弹性对天然男性真皮包皮样品的频率依赖性更大。这是可以预料的，因为与真皮相比，极度结构化的表皮赋予整个皮肤更高的抵抗周期内变形的能力，从而存储了较小的弹性能。与天然皮肤相比，这项工作中检验的3D皮肤模型显示出更宽的线性粘弹性区域，更大的粘弹性和更高的动态模量。流变趋势是文献的重要补充，可以用作设计下一代支架的参考。