2004.4
About Instruments Today No. 139
Single Molecule Measurement
Introduction of Single Molecule Measurement [ 下載 PDF ]
Ta-Chau Chang
Introduction and Application of Single Molecule Spectroscopy and Fluorescence Microscopy [ 下載 PDF ]
Ta-Chau Chang, Jui-Hung Hsu, Yih-Pey Yang, Cheng-Chung Chang
Conventional spectroscopic methods provide the average values of an ensemble of probe molecules. Single molecule (SM) spectroscopy enables to give the spectral properties of individual molecule and to completely eliminate the ensemble averaging. The SM measurement provides new insights into any system with spatial or temporal inhomogeneity. Here we begin with two examples, exciton dynamics and quadruplex structure of telomeric DNA, to emphasize the importance of SM methods. We will briefly describe the setup of single molecule spectroscopy and fluorescence microscopy, some preliminary results of time-resolved SM lifetime measurements and fluorescence images. Currently, we study the structural conversion of guanine-rich DNA by using SM-FRET method. In addition, we plan to apply SM imaging to trace the pathway of the drug delivery into cell and to monitor the function of drug upon interacting with the target.
Observing Behaviors of Individuals in an Ensemble－ The Technique and Application of Single Particle Tracking [ 下載 PDF ]
Chang-Ju Chiu, Tzyy-Schiuan Yang
The peculiar aspect of the single particle tracking technique is that it enables us to visualize the temporal movements of individual molecules in space and therefore to know the type of movement, the velocity, and motional areas. This technique has illustrated many interesting biological processes such as the transportations of molecular motors, the penetration processes of a virus through cell membrane, the diffusion of protein and lipid molecules on membrane and etc. In this report, we describe the details about this technique, including the experimental setup, the detection concerns, the choices of labeling fluorophores, and the comparison of different methods. We use the experimental results of single dye tracking of lipid motions on an artificial membrane for demonstration of this technique.
One- and Two- Photon Auto-Fluorescence Micro- Spectroscopy of A Single Cell: Protoplast of Arabidopsis Thaliana And PC12 Cells [ 下載 PDF ]
He-Je Kuo, Fu-Jen Kao
Fluorescence analysis is an important tool in life science research. The employment of laser in optical microscopy has greatly facilitated the advance in fluorescence excitation and analysis. In this article, we introduce the use of ultrafast laser in simultaneously forming optical trap and generating two-photon excitation. Specifically single cells prepared from the protoplast of Arabidopsis thaliana and PC12 cell culture are used to demonstrate the application of auto-fluorescence in monitoring the cellular status.
Application of Atomic Force Microscopy in Single Molecule Force Measurement [ 下載 PDF ]
Wei-Han Huang, Yao-Yin Chuang, Cheng-Wei Wu, Wei-Hau Chang
Scanning microscopy is one of the most important inventions in last century. Atomic force microscopy is one kind of scanning microscopy that is capable of detecting near-atomic features in liquid phase and at ambient temperature, hence, has become a very powerful tools for biologists and chemists. Recently, like optical tweezers, atomic force microscopy has been applied to perform force measurement at single molecule level. Single molecule measurement can reveal detailed information hidden in bulk measurement and is expected to bring revolutionary impact to researches on complicated biological systems. Here, we choose to introduce three areas in single molecule atomic force measurement. They are: a classical example of single protein folding and unfolding force study on titin, a new generation of atomic force microscope combined with a confocal microscope and a fluorescence aided force biosensor.
Atomic Force Microscopic and Theoretical Study of Protein Folding and Unfolding [ 下載 PDF ]
Y. L. Yeh, C. H. Chang, C. L. Chyan, S. H. Lin
In this paper, a theoretical model for the force-extension experiment applied to protein foldingunfolding is presented. This model explicitly takes into account the interplay between the mechanical energy and chemical energy. It can treat the effect of denaturing agents (like pH, GdnHCl, urea etc.) and temperature on the force-extension experiment of protein folding-unfolding. We further apply the model to analyze our own force-extension experiment on ubiquitin tetramers and further to the experimental data of other protein systems reported in literatures. We have found that the proteins adsorbed on gold surfaces are partially unfolded in comparison with the bulk state.
"New Generation Technology of Specimen Preparation for Transmission Electron Microscope: Application in Magnetic, Optoelectronic, and Semiconductor Devices" [ 下載 PDF ]
Rong-Tan Huang, Cheng-Cheng Chiang, Kai-Min Yin, Ji-Ju Kai, Fu-Rong Chen
As a result of the high resolution, transmission electron microscope plays a decisive role on fabrication controlling and failure analyses, etc. during the minimization of device. However, if there were no high quality TEM specimen, it would yield half the result with twice the effort. In this article, we introduce a new generation technology of specimen preparation for TEM, which is the Ttool tripod polisher wedge technique, and describe the tricks of TEM specimen preparation in detail. Afterwards, we also launch the difficulty and resolved methods of TEM specimen preparation for magnetic, optoelectronic and semiconductor devices from practical application. Accordingly, the expectant results could be obtained by using corresponding TEM analytic technique.
Recent Research and Development in Friction Stir Processing [ 下載 PDF ]
C. I. Chang, J. C. Huang
The friction stir technique is a newly developed processing mean, comprising the friction stir welding (FSW) technique aimed for the bonding of metallic materials and the friction stir processing (FSP) for materials refinement and materials modification with micro or nano ceramic particles. The current paper describes the basic operation mechanisms and parameters, facility and pin tool design, onion ring formation, microstructure, and the potential in grain size refinement and surface modification. The existing and future applications in aerospace, aircraft, transportation vehicle, and architecture are also introduced.
Atomic Force Microscopy and Its Application in Microbiology [ 下載 PDF ]
Ji-Liang Chen, Shiming Lin, Liang-Ping Lin
The atomic force microscopy (AFM), invented by Binning et al. in 1986, was a technique for surface analysis at nanometer scale. This technique not only provides, in real time, three-dimensional information of the bio-specimen surface under physiological conditions, but also can be used to probe the physical properties of the specimen, e.g., molecular interaction force, surface topograph, surface charge distribution, and various mechanical properties. The measurements performed by AFM provide the information on related structure and function of a variety of microbial surfaces.
A Novel Method for Real-Time Monitoring the Thickness of a Silicon Membrane During Wet Etching [ 下載 PDF ]
Chi-Yuan Lee, Tsung-Tsong Wu, Yung-Yu Chen, Wen-Jong Chen, Ying-Chou Cheng, Shih-Yung Pao, Pei-Zen Chang, Ping-Hei Chen
This paper proposes a novel method based on the surface acoustic wave (SAW) sensor for monitoring in situ the thickness of a silicon membrane during batch chemical etching. Like pressure sensors and accelerometers, some micro-electro-mechanical systems (MEMS) devices require the thickness of silicon membranes to be known precisely. Precisely controlling the thickness of a silicon membrane during batch chemical etching is important, because it strongly influences postprocessing and device performance. In summary, the proposed method for measuring the thickness of a silicon membrane in real time from tenths of µm to 80 µm, is highly accurate, is simple to implement and can be mass-produced. The principles of the method, detailed process flows, the setup for measuring thickness and simulation and experimental results are all discussed. The theoretical and measured values differ by an error of less than 3.00 µm, so the experimental and theoretical values correlate well with each other.
Optical Alignment Instruments — Optic Rotation and Linear Stages [ 下載 PDF ]
Chieh Ho
Optic rotation and linear stages are one of the most important instruments in optic alignment jobs. When joining two optic fibers, adjusting path of the laser light or positioning optical lens, optic rotation and linear stages play very good roles. The structure of the optic stages includes three linear stages and one tilt and one rotation stage. It is very important that when moving in one axis the gesture of the other four axes should not be changed, which means the disturbance would be reduced to a minimum value. To demonstrate the precision of the stages, the calibration method is also introduced in this paper. Hopefully readers will have some ideas in optic stages after reading it.
