细菌视纸红质的光学性质在现代信息技术中的应用

细菌视紫红质(bR)是一种性能优良的生物光学材料。着重介绍其光学特性以及它在现代信息技术中的应用。     

细菌视紫红质在生物传感器中的应用进展

生物传感器是生物敏感材料、理化换能器与电信号放大装置等多学科交叉的综合集成技术装置.典型的生物传感器以特异性感知的生物活性材料作为敏感元件,结合基于微电子器件的物理化学换能器和调理电路,实现生物敏感信息的电信号转换及放大.换能器的灵敏度、抗干扰能力等因素直接影响生物传感器的性能.从嗜盐菌中提取的细菌视紫红质是一种具有良好光敏特性的生物材料,可直接将光信号转化成电信号,从而实现将敏感元件和换能器合二为一的功能,已广泛应用于多种生物传感器中.细菌视紫红质的感光灵敏度和稳定性适用于开发具有颜色灵敏度的光传感器,最早的应用方向是人工视网膜;其光敏感和换能一体化特性可实现使用单个传感元件进行光学运动检测的功能,应用可扩展到运动传感领域.除了在视觉传感领域的应用,细菌视紫红质在病原体检测、水体pH检测、细胞膜电位检测等领域均表现出良好的灵敏性、稳定性和特异性.其不仅在生物传感领域具有应用价值,而且为半导体传感方法的研究提供了新途径.本文在简述细菌视紫红质的质子泵和光电响应特性等基本功能的基础上,阐述了细菌视紫红质构建生物传感器的应用进展,分析了不同传感器的特点,以期为细菌视紫红质的机理及其应用研究提供参考.     

嗜盐菌的嗜盐机制与应用前景

嗜盐菌能够在高盐环境下生存,而一定浓度的盐又为菌体生长所必须。为了适应高浓度的盐环境,嗜盐菌进化出了一系列独特的特征与机制如嗜盐菌的细胞壁没有肽聚糖,细胞膜上有细菌视紫红质等。嗜盐菌是极具应用前景的微生物资源。例如视紫红质可以用来开发光学开关,某些嗜盐古菌还可以用来降解塑料等。     

细菌纤维素及其复合材料在环境领域应用的研究进展

细菌纤维素(Bacterial cellulose, BC)是一种由微生物发酵产生的细胞外多糖,作为一种新型的环境友好生物材料,细菌纤维素具有高纯度、高吸水性,优异的机械强度及生物相容性高等优点,在生物医学、化工及食品等诸多领域展现出广阔的应用前景。本文系统性地介绍了BC的结构和特性,对BC的制备工艺和影响因素进行了总结,并分析了化学改性、原位改性和纳米材料复合改性等改性方法对BC的结构与特性的影响,对BC在环境处理技术(吸附、过滤、光催化)中的应用进展进行了概述,最后对BC的研究进展及其发展方向进行了总结和展望。      

生物材料伴生感染——研究与对策

本文综述了生物材料伴生感染（ＢＡＩ）研究的进展，重点阐述了生物材料的表面特性、细菌特性及宿主因素对细菌粘附过程及细菌粘附数量的影响，描述了生物膜的产生及其特性，指出了ＢＡＩ的防治对策。     

细菌纤维素纳米复合物的研究进展

细菌纤维素是一种新型的生物材料,具有很多优良的性能,在伤口敷料、人造血管、人工皮肤及组织工程领域有着广阔的应用前景.近年来,国外研究者采用纳米复合技术对细菌纤维素进行了修饰,以赋予细菌纤维素新的性能.综合介绍了目前国外关于细菌纤维素纳米复合物的研究进展及其应用情况.     

生物材料伴生感染——研究与对策

本文综述了生物材料伴生感染（ＢＡＩ）研究的进展，重点阐述了生物的材料表面特性，细菌特性及宿主因素对细菌粘附过程及细菌粘附数量的影响，描述了生物膜的产生及其特性，指出了ＢＡＩ的防治对策。     

纳米TiO2光催化氧化灭菌的研究进展

概述了二氧化钛光催化氧化灭菌的最新研究进展,讨论了其灭菌机理,TiO2光催化产生的活性成分(·OH、·O2、HO2·、H2O2)攻击细菌的细胞壁、细胞膜及内部成分,使细菌功能单元失活而导致细菌死亡;综合分析了影响氧化灭菌的各种因素,并展望了今后的研究.     

纳米酶:一种抗微生物感染新方法（英文）

细菌和病毒一直对人类健康构成威胁。SARS-CoV-2已经在世界各地肆虐了近三年,给人类健康带来了巨大危险。面对细菌的抗药性和抗生素治疗效果不佳等种种挑战,人们迫切需要新的方法来对抗致病微生物。最近,具有内在酶活性的纳米酶作为一种有前途的新型“抗生素”,通过催化生成大量活性氧,在生理条件下表现出卓越的抗菌和抗病毒活性。此外,基于纳米酶的治疗中,纳米材料在独特的物理化学特性(如光热和光动力效应)的帮助下可以增强治疗效果。本文综述了纳米酶在抗菌、抗病毒-方向的研究进展,从机制角度系统总结分析了纳米酶消除细菌、病毒等微生物的原理,对未来的新型纳米抗菌抗病毒材料的研发方向及其所面临的挑战进行了展望,为开发下一代抗微生物感染纳米酶提供了思路。     

藻类水华的微生物防治研究进展

文章简述了藻类水华的危害及生物防治的必要性，概述了微生物防治藻类水华的方式，介绍了病毒、细菌、真菌以及原生动物等在藻类水华防治中的研究进展。     

Integration of optical protein with electronics for bio-nanosensors

A novel technique for the patterning of bacteriorhodopsin (bR) films is presented. The photolithography based bacteriorhodopsin patterning technique (PBBPT) utilizes conventional photolithographic techniques to pattern purple membrane (PM) films containing bR. Several key process variables are investigated and characterized. The photoelectric response of PM films patterned using the PBBPT are presented, and the process is shown not to have a negative impact on the response of PM films to light. The possibility of integrating patterned PM films with single electron transistors is explored.     

The intensity dependent refractive index change of bacteriorhodopsin measured by the Z-scan and phase-modulated beams techniques

A comparative analysis of intensity dependent refractive index change of a thin polymer bacteriorhodopsin (bR) film by the Z-scan and phase-modulated beams techniques is given. The analysis is conducted at two excitation wavelengths, λ=543 and 633 nm, corresponding to the opposite slopes of the bR ground-state absorption band resulting in opposite signs of the refractive index change. A three-level model of the bR photo-cycle is proposed to describe the experimental data.     

Detergent-free incorporation of a seven-transmembrane receptor protein into nanosized bilayer lipodisq particles for functional and biophysical studies

SMA-Lipodisq nanoparticles, with one bacteriorhodopsin (bR) per 12 nm particle on average (protein/lipid molar ratio, 1:172), were prepared without the use of detergents. Using pulsed and continuous wave nitroxide spin label electron paramagnetic resonance, the structural and dynamic integrity of bR was retained when compared with data for bR obtained in the native membrane and in detergents and then with crystal data. This indicates the potential of Lipodisq nanoparticles as a useful membrane mimetic.     

Photo-induced anisotropic photoelectric response in oriented bacteriorhodopsin films

The photo-induced anisotropic properties of the chromophore protein bacteriorhodopsin (bR) are of interest for possible applications in optical image processing and spatial filtering. Here we report experimental results on the photo-induced anisotropic photoelectric response of dried oriented bR films. A polarization dependent photovoltage is measured across an ITO/bR/ITO photodetector. The anisotropy is introduced by a 632.8 nm linearly polarized pump beam and is detected with a 594.1 nm polarized probe beam. The influence of the pump light intensity on the photovoltage anisotropy has also been investigated. A model, based on the polarization dependent photoselection of the bR molecules reasonably explains the behavior of the measured data. The observed effect can be used to construct a polarization sensitive bR-based bio-photoreceiver.     

Motion-sensitive position sensor using bacteriorhodopsin

A concept of motion-sensitive position sensing that uses a film of bacteriorhodopsin (bR) treated with a high-pH buffer is proposed. The polarity of photo-emf, which depends on the excited intermediates of the bR molecule, can be used to determine movement direction. The M intermediate state with a long lifetime can be used to record the initial position. The bR-based position sensor can sense two positions of a moving object at two different times.     

Layer-by-layer of liposomes and membrane protein as a recognition element of biosensor

Layer-by-layer (LBL) assembly composed of liposome and membrane protein, bacteriorhodopsin (bR) was fabricated on quartz crystal microbalance (QCM) as a sensor element for bio-recognition. The LBL assembly was prepared by stacking of liposome/bR solutions alternately with a flowing system. By atomic force microscopy (AFM) and the QCM monitoring the bR and the liposome were found to be stacked regularly until the 8th layer of the liposome. The fabricated LBL assembly on the QCM was engaged to detect nonylphenol in solution, which is one of the endocrine disrupting chemicals. It was confirmed that the existence of nonylphenol in solution can be detected by a mass decrease of the LBL assembly on the QCM, which is caused by the disruption of the liposome through nonylphenol, in the low concentration range of 0.1–10 ppm.     

Optical protein modulation via quantum dot coupling and use of a hybrid sensor protein

Harnessing the energy transfer interactions between the optical protein bacteriorhodopsin (bR) and CdSe/ZnS quantum dots (QDs) could provide a novel bio-nano electronics substrate with a variety of applications. In the present study, a polydimethyldiallyammonium chloride based I-SAM technique has been utilized to produce bilayers, trilayers and multilayers of alternating monolayers of bR, PDAC and QD's on a conductive ITO substrate. The construction of multilayer systems was directly monitored by measuring the unique A570 nm absorbance of bR, as well as QD fluorescence emission. Both of these parameters displayed a linear relationship to the number of monolayers present on the ITO substrate. The photovoltaic response of bilayers of bR/PDAC was observed over a range of 3 to 12 bilayers and the ability to efficiently create an electrically active multilayered substrate composed of bR and QDs has been demonstrated for the first time. Evaluation of QD fluorescence emission in the multilayer system strongly suggests that FRET coupling is occurring and, since the I-SAM technique provide a means to control the bR/QD separation distance on the nanometer scale, this technique may prove highly valuable for optimizing the distance dependent energy transfer effects for maximum sensitivity to target molecule binding by a biosensor. Finally, preliminary studies on the production of a sensor protein/bR hybrid gene construct are presented. It is proposed that the energy associated with target molecule binding to a hybrid sensor protein would provide a means to directly modulate the electrical output from a sensor protein/bR biosensor platform.     

Selective Electroless Deposition of Metal Clusters on Solid‐Supported Bacteriorhodopsin: Applications to Orientation Labeling and Electrical Contacts

Controlling the orientation of bacteriorhodopsin (bR) monolayers is an important step in studying and utilizing such membranes in a solid‐state configuration in, for example, photoelectric applications. Macroscopic monolayers of bR have been fabricated in a variety of ways, but characterization of the distribution of the two possible orientations in which the membrane fragments can adsorb has not yet been addressed experimentally. Here, an approach is presented that labels only one of the membrane surfaces by electroless growth of metal nanoparticles on top of the solid‐supported membranes. In this way, it is possible to observe which surface of the membranes is actually adsorbed to the substrate. How this technique serves to interface the membranes with a top metal contact for further electrical measurements is also demonstrated.     

Tailoring plasmonic and electrostatic field effects to maximize solar energy conversion by bacteriorhodopsin, the other natural photosynthetic system

We have explored the plasmonic field enhancement of current production from bacteriorhodopsin (bR) by maximizing the blue light effect, where the influx of blue photons absorbed by the long-lived M intermediate drastically shortens the time scale of the bR photocycle, leading to current enhancement. To this end, we used three approaches in our solution-based cell: (1) We improved the charge carrier separation in solution through the use of a proton-selective Nafion membrane. (2) We maximized the plasmonic surface field effects by selecting the capping polymer with minimum surface field screening and best nanoparticle stability. (3) We selected the plasmonic nanoparticle with the strongest plasmonic field whose surface plasmon resonance has the largest spectral overlap with the blue light absorbing M-intermediate. Theoretical models are used to explain experimental results, which show a 40 nm cuboidal nanoparticle capped with 55k PVP polymer to give the best photocurrent enhancement. Enhanced by this particle, bR in our Nafion membrane solution cell gave a photocurrent of 0.21 μA/cm(3), which is 5000 times larger than the published results for thin film bR electrochemical cells even with an applied bias. Additional possible enhancements are proposed.     

Optical wavelet-matched filtering with bacteriorhodopsin films

We present here the experimental and numerical results to demonstrate the superior performance of optical wavelet-matched filtering over conventional matched filtering. For this purpose, the biomolecule material bacteriorhodopsin (bR) as the recording media and the improved dual-axis joint transform correlator configuration as the preferred optical setup have been used. Compared with the dual-axis joint Fourier transform correlator, the dual-axis joint wavelet transform correlator provides better correlation performance.