Time-resolved polarized optical waveguide spectroscopy is a powerful technique for the kinetic study of the adsorption of metal nanoparticles and chromophore molecules. We monitored the selfassembling processes of gold nanoparticles and cytochrome c in situ and in real time using this technique. A localized surface plasmon resonance (LSPR) absorption peak for the adsorbed gold nanoparticles gradually red shifted with an increase in the number of adlayers. Moreover, the red shift of the LSPR peak detected with the transverse magnetic (TM) modes is faster than that with the transverse electric (TE) modes. We found that with the TM modes the adsorption of cytochrome c on the gold-nanoparticle adlayer results in a significant red shift of the LSPR peak and a large increase in the peak intensity. In contrast, no obvious changes in the LSPR peak were detected with the TE modes. An analysis of the experimental data verified that the adsorption kinetic behavior of the gold nanoparticles follows a diffusioncontrol model and cytochrome c adsorption kinetics follows a Langmuir isotherm model. The kinetic parameters for cytochrome c adsorption including the adsorption and desorption rate constants as well as the adsorption free energy were estimated by best fitting the experimental data to the Langmuir model.%时间分辨偏振光波导分光光谱技术是一种用于研究表面分子吸附动力学的强大工具.利用该技术实时、原位监测纳米金与细胞色素c的静电自组装过程,发现随着吸附层数的增加,纳米金粒子吸附层产生的局域等离子体共振(LSPR)吸收峰发生了红移,而且在横磁(TM)模式下的红移比横电(TE)模式下的红移更快;细胞色素c在纳米金表面的吸附导致LSPR吸收峰的峰位和强度在TM模式下显著红移和升高,相比之下,TE模式下的LSPR吸收峰无明显变化.对实验数据的分析验证了纳米金在细胞色素c单分子层表面的吸附动力学行为遵循扩散控制模型,细胞色素c在纳米金单粒子层表面的吸附动力学行为遵循Langmuir等温吸附模型,进一步估算了细胞色素c在纳米金表面的吸附速率常数、脱附速率常数和吸附自由能.
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