Elucidation of bio-molecule recognition using semiconductor surface and its application to bioelectronics

在本研究中，我们旨在通过在半导体表面形成结构可控的有机薄膜，并利用红外光谱检测吸附在半导体表面上的生物分子和超分子的吸附状态，从而赋予半导体表面分子识别功能。我们需要用重水来代替普通水，因为DNA、蛋白质和细胞在与普通水的剪子模式相同的区域有红外吸收峰。当使用重水时，由于部分官能团发生氘取代反应，不能使用通用数据库。因此，我们将实验红外光谱结果与从头计算结果进行了比较。我们证明了(1)DNA杂交的高灵敏度检测和(2)固定在硅表面的DNA杂交的阐明。通过对比红外光谱变化和ab-initio计算发现，杂化反应对碱的C=O拉伸振动模式有强烈的影响。我们在溶液中建立了电泳，并证实电势有效地将DNA分子吸引到硅表面，以提高其灵敏度。绘制的DNA分子的红外光谱与漂浮的DNA分子的红外光谱不同。这种光谱变化归因于碱基的质子化。我们首次发现电极附近的电化学反应可以诱导这种众所周知的依赖于DNA溶液pH值的反应。我们展示了(5)使用多孔氧化铝和多孔硅等多孔薄膜进行DNA杂交的高灵敏度检测。此外，我们开始开发一种分析细胞功能的方法，我们使用红外光谱观察到“凋亡”，这是众所周知的设计死亡，我们可以追踪细胞中的化学变化，直到它导致细胞死亡。我们现在推广这项研究。

In this study, we aimed at giving a function of molecule recognition to a semiconductor surface by forming structurally controlled organic thin film on it and by detecting adsorption state of biomolecules and supramolecules which adsorb onto it using infrared spectroscopy.We need to use heavy water as substitute for ordinary water because DNA, protein, and cells have IR absorption peaks at the same region as the scissors mode of ordinary water. We cannot use general database because of deuterium substituion reaction at part of fuction groups when heavy water is used. Thus, we made new one by comparing results of experimental IR spectra and an ab-initio calculation. We demonstrated (1) highly sensitive detection of DNA hybridization and (2) elucidation of hybridization of DNA immobilized on silicon surface. We found that hybridization reaction strongly influences the C=O stretching vibration mode of bases by comparing IR spectral changes with the ab-initio calculation. We established electrophoresis in a solution and confirmed that electrical potential effectively draws DNA molecules up to silicon surface to enhance its sensitivity. An IR spectrum of drawn DNA molecules differed from one of floating DNA. This spectral change is attributed to protonization of bases. For the first time, we found that electrochemically reaction near the electrode can induce this phenomenon which is a well-known reaction depending on pH of a DNA solution. We demonstrated (5) highly sensitive detection of DNA hybridization using a porous thin film such as porous alumina and porous silicon. Furthermore, we started developing a method of analyzing functions of cells and we observed "apotosis" which is well-known as a designed death using IR spectroscopy and we could trace chemical changes in a cell until it resulted in the cell death. We now promote this study.