Ordered adsorption of coagulation factor XII on negatively charged polymer surfaces probed by sum frequency generation vibrational spectroscopy
Ordered adsorption of coagulation factor XII on negatively charged polymer surfaces probed by sum frequency generation vibrational spectroscopy
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DOI：
10.1007/s00216-006-0999-8
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发表时间：
2007-05-01
影响因子：
4.3
通讯作者：
Chen, Zhan
中科院分区：
文献类型：
--
作者：
Chen, Xiaoyun;Wang, Jie;Chen, Zhan
采用和频振动光谱技术，结合衰减全反射傅里叶变换红外光谱（ATR-FTIR）、石英晶体微天平（QCM）、zeta电位测量和显色分析等技术，研究了带负电荷的聚合物表面与凝血因子XII（FXII）之间的静电相互作用。合成了一系列不同磺化度的磺化聚苯乙烯（sPS）作为具有不同表面电荷密度的模型表面。从FXII吸附在PS和sPS表面不同的表面电荷密度收集SFG光谱显示显着差异的光谱特征，特别是在光谱强度。显色测定实验表明，高度带电的sPS表面诱导FXII自激活。ATR-FTIR和QCM结果表明，尽管表面电荷密度不同，但PS和sPS表面的吸附量相似。没有观察到显着的构象变化，从FXII吸附到研究的表面上。使用理论计算，由表面电场引起的三阶非线性光学效应的可能贡献进行了评估，并发现它是无法产生的SFG信号增强观察。因此，可以得出结论，吸附的FXII的取向和有序的主要原因是显着的SFG酰胺I信号增加的sPS表面。这些调查表明，带负电荷的表面促进或诱导FXII自激活的分子水平上施加特定的方向和订购的吸附的蛋白质分子。
Electrostatic interactions between negatively charged polymer surfaces and factor XII (FXII), a blood coagulation factor, were investigated by sum frequency generation (SFG) vibrational spectroscopy, supplemented by several analytical techniques including attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), quartz crystal microbalance (QCM), zeta-potential measurement, and chromogenic assay. A series of sulfonated polystyrenes (sPS) with different sulfonation levels were synthesized as model surfaces with different surface charge densities. SFG spectra collected from FXII adsorbed onto PS and sPS surfaces with different surface charge densities showed remarkable differences in spectral features and especially in spectral intensity. Chromogenic assay experiments showed that highly charged sPS surfaces induced FXII autoactivation. ATR-FTIR and QCM results indicated that adsorption amounts on the PS and sPS surfaces were similar even though the surface charge densities were different. No significant conformational change was observed from FXII adsorbed onto surfaces studied. Using theoretical calculations, the possible contribution from the third-order nonlinear optical effect induced by the surface electric field was evaluated, and it was found to be unable to yield the SFG signal enhancement observed. Therefore it was concluded that the adsorbed FXII orientation and ordering were the main reasons for the remarkable SFG amide I signal increase on sPS surfaces. These investigations indicate that negatively charged surfaces facilitate or induce FXII autoactivation on the molecular level by imposing specific orientation and ordering on the adsorbed protein molecules.