基于二维红外技术研究氧化羧甲基纤维素钠/胶原的相互作用及热稳定性  

Interaction and Thermal Stability of Oxidized Carboxymethyl Cellulose/Collagen Based on Two-Dimensional Infrared Spectroscopy

作　　者：田振华 何静瑄 王颖 段炼 李从虎 TIAN Zhen-hua;HE Jing-xuan;WANG Ying;DUAN Lian;LI Cong-hu(College of Bioresources Chemical and Materials Engineering,Shaanxi University of Science&Technology,Xi’an 710021,China;National Demonstration Center for Experimental Light Chemistry Engineering Education,(Shaanxi University of Science&Technology),Xi’an 710021,China;College of Sericulture,Textile and Biomass Sciences,Southwest University,Chongqing 400715,China;College of Life Science,Anqing Normal University,Anqing 246133,China)

机构地区：[1]陕西科技大学轻工科学与工程学院,陕西西安710021 [2]轻化工程国家级实验教学示范中心(陕西科技大学),陕西西安710021 [3]西南大学桑蚕纺织与生物质科学学院,重庆400715 [4]安庆师范大学生命科学学院,安徽安庆246133

出　　处：《光谱学与光谱分析》2021年第9期2782-2788,共7页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(21706151,22008201);陕西省自然科学基础研究计划项目(2019JQ-027)资助。

摘　　要：采用氧化羧甲基纤维素钠(OCMC)作为交联剂,对胶原溶液进行改性并采用二维红外技术分析OCMC与胶原之间的相互作用及其对胶原热稳定性的影响。一维红外图谱显示OCMC交联改性对胶原的主要特征吸收峰即酰胺Ⅰ,Ⅱ和Ⅲ带的峰位与强度无明显影响;改性前后胶原的酰胺Ⅲ带与1455 cm^(-1)处吸光度的比值A_(Ⅲ)/A_(1455)均接近于1.000,以上结果显示交联键的引入不会破坏胶原的三股螺旋结构,但无法获知胶原与OCMC之间的相互作用及胶原结构的变化。以OCMC用量为外扰条件建立二维红外相关图谱,进一步分析两者间相互作用。结合胶原结构与OCMC中基团的响应强度及顺序可知:OCMC首先通过羧基与胶原中精氨酸的胍基或赖氨酸的氨基发生静电作用,随后醛基与胶原氨基之间发生希夫碱反应;两者之间相互作用以希夫碱反应为主。由于静电作用与交联键的引入,改性后胶原的热稳定性得到提升。随着温度的升高,纯胶原与改性胶原的特征吸收峰均发生红移且A_(Ⅲ)/A_(1455)值不断降低,说明两者在升温过程中其氢键不断减弱,导致三股螺旋发生解旋,但与纯胶原相比,改性胶原特征吸收峰的红移程度与A_(Ⅲ)/A_(1455)值降低幅度较小,证实了改性后胶原的热稳定性有所提高。胶原与改性胶原在升温过程中结构变化的分析结果表明:改性前后胶原二级结构的崩塌均表现为三股螺旋结构被破坏转变成无规卷曲结构;然而在测试温度范围内,三股螺旋结构对温度的敏感度及响应顺序发生明显变化:(1)对于纯胶原,对温度最为敏感的结构是胶原的螺旋结构,而改性胶原的无规卷曲结构是最为敏感的、最不敏感的结构是胶原螺旋结构,反映出改性后胶原的螺旋结构得到稳定;(2)改性后胶原螺旋结构对温度的响应发生滞后,进一步证实胶原的稳定作用主要归功于三股螺旋结构的加固。Collagen was modified by oxidized carboxymethyl cellulose(OCMC)and then their interaction and thermal stability were investigated by two-dimensional infrared spectroscopy(2D-IR).One-dimensional infrared spectra showed that the positions and intensities of the main characteristic absorption peaks(amideⅠ,Ⅱand Ⅲ bands)for collagen had no significant change upon cross-linking;additionally,all the absorption ratios of amide Ⅲ bands to 1455 cm^(-1)(A_(Ⅲ)/A_(1455))of native and cross-linking collagen were close to 1.000.These results indicated that the triple helix of collagen was not demolished by the introduction of cross-linking.The 2D-IR spectra were constructed from OCMC amount-dependent infrared spectra,and then the interaction between OCMC and collagen was further analyzed.The response sensitivity and order of collagen structure and the groups of OCMC showed that electrostatic interaction formed firstly between carboxyl groups of OCMC and guanidine or amino groups of collagen.Then Schiff’s base reaction occurred between aldehyde groups of OCMC and amino groups of collagen,which was the dominated interaction.As a result,the thermal stability of cross-linked collagen increased.With the increase of temperature,the red-shift of absorption bands and the decreased A_(Ⅲ)/A_(1455) value reflected that hydrogen bonds were weakened,and the unwinding of triple helix occurred for both native and cross-linked collagens;whereas the fewer changes in red-shift and A_(Ⅲ)/A_(1455) value for cross-linked collagen also confirmed the increase in thermal stability.Furthermore,the 2D-IR spectra were constructed from the temperature-dependent infrared spectra and provided information about the thermally induced structural changes.It could be conjectured that the triple helix was transformed into random coils for the native and cross-linked collagen,resulting in the loss of secondary structure with increasing the temperature.Nevertheless,the response sensitivity and order of the triple helix to temperature changed signifi

关 键 词：胶原 结构 热稳定性 氧化羧甲基纤维素钠 二维红外光谱 

分 类 号：O657.3[理学—分析化学]