光响应性树枝状偶氮苯单分子层

Photo-responsive Azobenzene-dendron Monolayers

偶氮苯树枝状分子通过中心羧基与金或者石英基体表面的氨基进行酰胺化反应得到树枝状分子单分子层修饰的表面,利用红外反射-吸收光谱(IRRAS)、UV-Vis和Raman光谱法研究了单分子层的结构和性能,利用椭偏谱法来测量四代树枝状(G-4)单分子层在不同异构化形态的分子层厚度,其中反式构象的单分子层厚度为(2.38±0.09)nm,顺式构象厚度为(1.88±0.08)nm。利用表面等离子体共振(SPR)研究不同形态下G-4单层与不同等电点的蛋白质之间的相互作用关系,结果表明,G-4单层为负电位表面,能够吸附正电位的蛋白质,而且当树枝状单分子层形态从反式变为顺式时,表面电位变为更负,能吸附更多正电位的蛋白质。

We prepared azobenzene dendron monolayers on the Au or quartz substrates by DCC （N,N-dicyclo- hexylcarbodiimide）-catalyzed surface amidation reactions between the carboxyl acid groups at the focal point of the dendrons and the amine groups on the surface of Au or quartz, infrared reflection-absorption spectroscopy （IRRAS）, UV-Vis absorption and Raman spectroscopies were performed to characterize these azobenzene dendron monolayers. The thickness of the G-4 monolayers with different isomeric forms was measured using ellipsometry spectra, and a value of （2. 38 ±0.09） nm was obtained for the trans-form, and （1.88 ±0. 08） nm for the c/s-form. The interaction between the G-4 monolayers in different isomeric forms and proteins with different isoelectric points （pI） was studied by surface plasma resonance （SPR）, which demonstrated that the G-4 monolayers had a negatively charged surface that preferentially adsorbed positive proteins. The surface potential of the dendron monolayers became more negative when the monolayers was changed from the trans-form to c/s-form, resulting in adsorbing more positively charged proteins.