纳米生物材料细菌视紫红质的光吸收与光调制特性及其应用研究
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摘要
细菌视紫红质(bacteriorhodopsin，简称BR)是嗜盐菌细胞膜上的一种光敏蛋白质，具有光驱动质子泵功能。BR分子具有许多优良的特性，例如热和化学稳定性好、空间分辨率高(～5000lines/mm)、使用光谱范围宽(400～700nm)、感光灵敏度高(30～80mJ/cm~2)、响应速度快(～50μs)、量子效率高(～65％)和对比度高等等，这些特性使得它在信息领域成为研究的热点。而采用生物化学和生物物理技术，可以将BR分子某些特性进行改造，使BR材料在光信息处理领域有更广阔的应用。结合发展着的纳米技术和生物工程技术，科学家们认为BR作为一种纳米光生物分子材料，能够被用来研制纳米蛋白质分子器件并在未来的信息领域中发挥重要作用。
本论文概述了细菌视紫红质分子结构、功能特性及研究发展的历史与现状，介绍了目前已有的和潜在的一些重要应用，通过对吸收光谱响应特性的测试研究了三类BR分子薄膜(野生型，化学修饰型，基因修饰型)的光吸收特性，通过图像的记录/读取实验及图像的对比度分析探讨了基因改性型BR分子薄膜的光调制特性，着重研究作为一个光调制器件对调制波长和调制时间的响应特性。实验中发现，经过一段弛豫时间后，在出现吸收增强现象的550nm～620nm调制光波长范围内，有图像反转的现象。在532nm的调Q脉冲激发光和不同波长的连续探测光作用下，分析和研究了野生型的细菌视紫红质(WT3)膜的光循环过程中的快速响应特性及各中间态的快速光吸收特性，得到了微秒级的快速光开关结果。基于BR膜良好的非线性光学特性，开展了BR膜作为一种光寻址的空间光调制器(BR-OA-SLM)的研究，进行了相干光图像信息与非相干光图像信息的相互转换实验，实现了空间两束光的相互调制。
Bacteriorhodopsin (BR) is the sole protein present in the purple membrane of Halobacterium halobium. The biological function of the BR is acted as a light-driven proton pump. The BR molecule has many good properties such as excellent thermal, chemical and photochemical stability, very high spatial resolution (-5000 lines/mm), broad-spectrum scope (400-700nm), high photosensitivity (-10mJ/cm2), good quantum efficiency (-65%), fast response (-50μs) and high contrast etc. These attractive properties made it a generally interested light-sensitive media for optical information processing. Now the biochemical and biophysical knowledge on the BR makes it possible to modify some optical properties of the BR in order to make it more useful for many optical processing applications. All these make the BR adapt to use more widely in the field of optical information processing. With the nanometer technology and biotechnology developing, the scientists think the BR can be taken for a kind of nanometer scale optical biology material. In the future, the BR material will be used to develop nano-protein component and make an impact on the information field. In this article, the composition, structure, fundamental property and history and current status of the research of the BR is summarized. Its function properties are described also and its important optical features are analyzed too. The photoabsorption properties of three kinds of BR molecule films (the wild-type BR, the chemical enhanced BR, the gene-variant BR) are investigated by measuring their absorption spectrum. Using the gene-variant BR film as a light-modulator, by the experiment of write-readout image and the analysis of image contrast, the light-modulated property of the modulator is studied. The relationship between wavelength of the modulated light and response time of the modulator is discussed emphatically. It has been found in the experiment that a reverse of image appeared in the wavelength range between 550nm to 620nm at which the enhancement of absorption of the probe beam appeared after a while of the probe time or readout time delaying. With the joint action of the Q-switched pulse laser of 532nm and continuous probe light of different wavelengths, fast photoresponse characteristic of photocycle of a wild-type BR film (WT3) and photoabsorption characteristic of different intermediary in the photocycle are analyzed
and discussed. The optical switch action in the microsecond scale is observed in the experiment. An optically addressed spatial light modulator (OA-SLM) made of BRD96N and based on its good nonlinear optical characteristics is presented. An experiment study on the mutual conversion of coherent-to-incoherent image is carried out, and the mutual modulation of two spatial light beams can be realized base on the gene-variant BR films.
本论文概述了细菌视紫红质分子结构、功能特性及研究发展的历史与现状，介绍了目前已有的和潜在的一些重要应用，通过对吸收光谱响应特性的测试研究了三类BR分子薄膜(野生型，化学修饰型，基因修饰型)的光吸收特性，通过图像的记录/读取实验及图像的对比度分析探讨了基因改性型BR分子薄膜的光调制特性，着重研究作为一个光调制器件对调制波长和调制时间的响应特性。实验中发现，经过一段弛豫时间后，在出现吸收增强现象的550nm～620nm调制光波长范围内，有图像反转的现象。在532nm的调Q脉冲激发光和不同波长的连续探测光作用下，分析和研究了野生型的细菌视紫红质(WT3)膜的光循环过程中的快速响应特性及各中间态的快速光吸收特性，得到了微秒级的快速光开关结果。基于BR膜良好的非线性光学特性，开展了BR膜作为一种光寻址的空间光调制器(BR-OA-SLM)的研究，进行了相干光图像信息与非相干光图像信息的相互转换实验，实现了空间两束光的相互调制。
Bacteriorhodopsin (BR) is the sole protein present in the purple membrane of Halobacterium halobium. The biological function of the BR is acted as a light-driven proton pump. The BR molecule has many good properties such as excellent thermal, chemical and photochemical stability, very high spatial resolution (-5000 lines/mm), broad-spectrum scope (400-700nm), high photosensitivity (-10mJ/cm2), good quantum efficiency (-65%), fast response (-50μs) and high contrast etc. These attractive properties made it a generally interested light-sensitive media for optical information processing. Now the biochemical and biophysical knowledge on the BR makes it possible to modify some optical properties of the BR in order to make it more useful for many optical processing applications. All these make the BR adapt to use more widely in the field of optical information processing. With the nanometer technology and biotechnology developing, the scientists think the BR can be taken for a kind of nanometer scale optical biology material. In the future, the BR material will be used to develop nano-protein component and make an impact on the information field. In this article, the composition, structure, fundamental property and history and current status of the research of the BR is summarized. Its function properties are described also and its important optical features are analyzed too. The photoabsorption properties of three kinds of BR molecule films (the wild-type BR, the chemical enhanced BR, the gene-variant BR) are investigated by measuring their absorption spectrum. Using the gene-variant BR film as a light-modulator, by the experiment of write-readout image and the analysis of image contrast, the light-modulated property of the modulator is studied. The relationship between wavelength of the modulated light and response time of the modulator is discussed emphatically. It has been found in the experiment that a reverse of image appeared in the wavelength range between 550nm to 620nm at which the enhancement of absorption of the probe beam appeared after a while of the probe time or readout time delaying. With the joint action of the Q-switched pulse laser of 532nm and continuous probe light of different wavelengths, fast photoresponse characteristic of photocycle of a wild-type BR film (WT3) and photoabsorption characteristic of different intermediary in the photocycle are analyzed
and discussed. The optical switch action in the microsecond scale is observed in the experiment. An optically addressed spatial light modulator (OA-SLM) made of BRD96N and based on its good nonlinear optical characteristics is presented. An experiment study on the mutual conversion of coherent-to-incoherent image is carried out, and the mutual modulation of two spatial light beams can be realized base on the gene-variant BR films.
引文
1．来鲁华等编著，《蛋白质的结构预测与分子设计》，北京大学出版社，1993．12月P3
2．张立德 牟季美 著《纳米材料和纳米结构》 科学出版社 2002．5 P4
3．王静端 光敏蛋白质分子器件 半导体光电 1998，19(5)332～334
2．张立德 牟季美 著《纳米材料和纳米结构》 科学出版社 2002．5 P4
3．王静端 光敏蛋白质分子器件 半导体光电 1998，19(5)332～334