pH响应的包覆超顺磁性纳米颗粒的γ-聚谷氨酸二级结构研究  

Study on the pH-Sensitive Secondary Structure of γ-PGA Embedded with Magnetite Nanoparticles

作　　者：张菊花[1,2] 邢建民[1] 江洋洋[1,2] 高红帅[1,2] 刘会洲[1] 

机构地区：[1]中国科学院过程工程研究所,中国科学院绿色过程与工程重点实验室,北京100190 [2]中国科学院研究生院,北京100049

出　　处：《光谱学与光谱分析》2009年第8期2148-2151,共4页Spectroscopy and Spectral Analysis

基　　金：国家"973"重点基础研究发展规划项目(2007CB714301);国家"863"高技术研究发展计划项目(2006AA02Z215);国家自然科学基金重大基金项目(20490200)资助

摘　　要：用傅里叶红外光谱法(FTIR)定量研究了pH对包覆超顺磁性纳米颗粒的γ-聚谷氨酸(γ-PGA)二级结构变化的影响。结合傅里叶去卷积技术和二阶导数法对原始谱带(酰胺Ⅰ带)进行高斯拟合,计算了二级结构的相对百分含量。红外结果显示:pH变化影响γ-PGA的二级结构。γ-聚谷氨酸磁性纳米微球中γ-PGA的β-折叠和β-转角的总含量很大,达65%以上,而α-螺旋和无规卷曲的含量则比较少。随着pH值的增大,β-折叠的含量逐渐减少相反β-转角的含量逐渐增大。γ-PGA二级结构变化与γ-聚谷氨酸磁性纳米微球在水溶液的稳定性有关。考察了γ-聚谷氨酸纳米微球的zeta电位随pH的变化。结果表明,pH为10.2时zeta电位出现极小值,其绝对值最大,颗粒稳定性最好。The conformational transition of poly γ-glutamic acid （γ-PGA） embedded with magnetite nanoparticles under various pH conditions was investigated by Fourier transform infrared spectroscopy （FTIR）. The secondary structure content was determined through the analysis of amide I bands of Fourier deconvolution spectra, secondary derivative spectra and the Gaussian curve fitting of the original infrared spectra. The results showed that the conformation of the γ-PGA was affected by solution pH. The total contents of β-sheet and β-tum were higher than 65 %, while a-helix and random coil were low. The content of flturn increased with increasing pH, while the β-sheet decreased. Additionally, the zeta potential results showed that the pH-sensitive secondary structure of γ-PGA had influence on the stability of suspension of magnetic γ-PGA nanospheres. The minimum value of zeta potential （--35.4 mV） was obtained at pH 10.2.

关 键 词：傅里叶红外光谱法 Γ-聚谷氨酸 磁性纳米微球 PH ZETA电位 

分 类 号：O657.3[理学—分析化学]