热变性对鱼胶原海绵材料性能的影响

Effect of thermal denaturation on the properties of collagen sponges from fish

以草鱼皮为原料提取天然胶原蛋白,经DSC、圆二色谱和SDS-PAGE分析证实为具有完整三螺旋分子结构的Ⅰ型胶原。在不同条件下对该胶原进行热处理后分别获得了低变性、高变性和完全变性的胶原样品,热变性焓测定结果表明热变性程度分别为16.9%,57.9%和100%。在此基础上,重点研究了热变性处理后胶原结构和胶原海绵材料性能的变化。结果表明,草鱼皮胶原变性的起始温度(To,33℃)是其分子结构和胶原海绵材料性能改变的阀值温度。高于该温度条件下的短暂受热历史即可导致胶原三螺旋结构的部分或完全解离。同时,胶原变性程度的增加,材料结构的有序性、材料力学性能和耐酶解能力也随之降低,但是促细胞增殖能力有所提升。可见,低于胶原热变性的起始温度是天然胶原提取和胶原材料应用的安全温度条件。

In this paper,native collagen(NC)was extracted from skin of grass carp,and it was proved typeⅠ collagen with intact triple helix structure via the DSC and circular dichroism and SDS-PAGE analysis.Low thermal denaturation(LD),high thermal denaturation(HD)and complete thermal denaturation(CD)collagen samples were obtained by heat treatment of NC under different conditions,and the degrees of thermal denaturation of them were 16.9%,57.9and 100%respectively,according to the changes of thermal denaturation enthalpy from DSC determination.On this basis,the research focused on the influences of heat treatment on the collagen structure and the corresponding properties of collagen sponges.The results show that the onset endothermic temperature(To)is the threshold temperature for the molecule structure and sponges properties stability.When subjected to temperatures above this threshold temperature even in a short time,the triple helix structure of collagen would completely or partially unfold.At the same time,the ordering of material structure,mechanical properties and enzymatic sensitivities of collagen sponges reduced,the cell proliferation ability enhanced along with the rise of degrees of thermal denaturation of collagen.The findings demonstrate Tois the crucial temperature and this temperature should not be exceeded during the production and utilization of native collagens.