皮肤组织的热力学行为表征:Ⅱ.黏弹性行为

目的检验关于胶原蛋白是皮肤黏弹性主要决定因素的假设,重点考察皮肤组织在动态载荷下的热力学性能。方法采用不同的热加载实现皮肤组织中胶原质不同程度的热变性;使用差示扫描量热仪检测胶原质的热变性及其热稳定性,并通过热损伤积分方程分析了胶原质的热稳定性;采用动态热力学分析仪表征了温度和皮肤胶原质损伤对皮肤黏弹性特性的影响。结果由于水份的流失,储存模量随温度的升高而显著增大;与此相反,功耗因子却呈现出明显的温度不敏感性。结论热损伤和热变性程度对皮肤黏弹性性能的影响与温度的影响相类似,表明在恒定的频率下胶原蛋白分子的热变性对皮肤的黏弹性行为影响很大。

Characterization of thermomechanical behavior of skin tissue: Ⅱ.Viscoelastic behavior

Objective To test the hypothesis that collagen is a significant determinant of skin viscoelasticity,with particular attention paid to the thermomechanical properties of skin under dynamic loading.Methods Differential scanning calorimetry (DSC) was used to detect the denaturation of dermal collagen and assess its thermal stability.The DSC results obtained with various heating rates were used to derive the Arrhenius parameters in burn damage integration,which were subsequently used to calculate the degree of denatured collagen in the skin.The dynamic mechanical analyzer (DMA) was employed to evaluate the changes in skin viscoelastic properties as a function of temperature and collagen damage.Results The results showed remarkable changes in storage modulus,possibly due to the release of water,whilst there was no significant change in loss factor.Conclusion These results suggest that at a fixed frequency the denaturation of collagen molecules has a large effect on the viscoelastic behavior of skin tissue.