金纳米粒子比色测定细胞色素c构象变化

金纳米粒子(AuNPs)的颜色会随着细胞色素c(Cytc)构象变化而发生较大的变化,作者在改变原测定流程的基础上利用这种有规律的变化研究和测定了H+和L-半胱氨酸(L-Cys)对Cytc的构象变化.实验中分别加入pH=1-13的Cytc,可以使AuNPs显示青、蓝、紫、红等明显不同的颜色,从而可以利用AuNPs比色快速测定不同pH值的Cytc构象变化.在pH=7时,当附加L-Cys浓度从低浓度变化到高浓度时,AuNPs颜色逐渐从紫色变化到蓝色、青色,从而实现利用AuNPs比色测定由L-Cys所引起Cytc构象变化.圆二色(CD)光谱证实了pH=1-13和不同浓度L-Cys下的Cytc构象变化.借助紫外-可见吸收光谱和扫描电子显微镜(SEM)进一步明确了加入Cytc后AuNPs的不同聚集状态与其颜色变化的关系.

Au Nanoparticles Based Colorimetric Detection of Conformational Changes in Cytochrome c

The colors of Au nanoparticles (Au NPs) change along with conformational changes in cytochrome c (Cyt c). We exploited this property for the colorimetric detection of Cyt c conformational changes induced by H⁺ and L-cysteine (L-Cys). We improved the conventional procedure for this detection. After the addition of Cyt c within different pH values, the Au NPs are either cyan, blue, purple or red. This indicates that the Au NPs can be applied to the rapid colorimetric detection of pH-induced conformational changes in Cyt c. At pH 7 the color of Au NPs changes from purple to blue and then cyan upon the addition of L-Cys, which suggests that the Au NPs can be used for the colorimetric detection of Cyt c conformational changes caused by interaction with L-Cys. The conformational changes of Cyt c were verified by circular dichroism (CD) spectroscopy. The relationship between the aggregation states and colors of the Au NPs after the addition of Cyt c was characterized by UV-Vis absorption spectroscopy and scanning electron microscopy (SEM).