基因芯片中的微电子刻蚀技术

基因芯片是运用微电子加工技术以及基因分子的自组装技术在微小芯片上组装成千上万个不同的DNA微阵列,实现以基因为主的生命信息的大规模检测。本文利用氧化、光刻、蒸发、溅射等一系列集成电路刻蚀技术,研究了适于电化学检测的基因芯片微阵列的制备,并提出了这种芯片中微流路的制备工艺方案。     

神奇的基因芯片

基因芯片运用微电子加工技术以及基因分子的自组装技术在微小芯片上组装成千上万个不同的DNA微阵列 ,实现以基因为主的生命信息的大规模检测。其显著优点在于 :高速、高效、耗费低、便于系统集成和大规模信息的适时处理。基因芯片技术的出现将会给生命科学、医学、化学、新药开发、生物武器战争、司法鉴定、食品和环境卫生监测等领域带来一场革命。本文简要介绍了基因芯片及其应用和近期研究的进展。     

生物芯片的研究,发展和应用

生物芯片是运用大规模集成电路光刻充及生物分子的自组装技术，在一微小芯片上组装成千上肆个不同的ＤＮＡ或蛋白质的生物分子微阵列，实现以基因为主的分子信息大规模检测。这项技术有可能成为２１世纪重要的高新技术产业。     

二极管激光器和LEDs使"片上实验室"接近现实

光学生物芯片或微阵列通常被定义为可同时执行和测定数百个乃至数千个生物化学反应，利用玻璃、塑料或者硅材料制作的小型实验样品基片，在这些基片上。当把光学生物芯片与荧光剂(显示染料)和激光扫描仪(激光波长一般为532nm或者633nm)组合使用时，就构成各种商业用实验平台，例如：Affymetrix(Santa Clara，CA)公司生产的基因芯片(Gene Chip)——一种含液体流通微通道的芯片，其微通道是采用半导体工业中使用的加工方法刻蚀的。Agilent公司生产的互补脱氧核糖核酸，互补核糖核酸cDNA／cRNA微阵列是一种具有分子探针的微阵列，其探针是采用最初Hewlett Packard研发的喷墨技术制作的。这些实验平台能够解码单个基因，识别各种疾病特异蛋白，并能促进蛋白基生物药品的研发。     

重金属检测微纳传感器芯片批量制备与测试

设计并制备了一种基于玻璃-硅微纳米结构的重金属检测微纳传感器芯片用于检测铅.传感器芯片集成了Ag/AgCl参比电极、三维金微阵列工作电极、金对电极以及微检测腔.该传感器采用微电子机械系统(MEMS)批量制备工艺,一批次同时制备多片4英寸(1英寸=2.54 cm)晶圆,而每片晶圆上有20个芯片.在优化的实验条件下,即最优...     

硅微喷阵列芯片的设计、制作与应用研究

介绍了一种用于制作生物微阵列的新型微喷阵列芯片。基于半导体光刻技术和干法刻蚀技术,成功制作了喷孔外侧含有间隙环的硅微喷阵列芯片,解决了溶液进样难、微阵列样品点缺失、样品点漂移以及液体回流等问题。在5 kPa气压驱动下,该芯片中的样品能在3.4 mm×3.4 mm的玻璃片上制成5×5样品微阵列,25个点的直径平均值为356μm,直径的变异系数(25个点直径的标准偏差与算术平均值的比值)为2.8%。计算流体力学模拟结果和实验结果均表明,该微喷阵列芯片能快速、稳定地制作出样品点大小均一的微阵列,进一步推动了微阵列芯片的应用和发展。     

表面组装技术的发展趋势

分析了表面组装工艺和表面组装设备的发展趋势,指出了表面组装工艺的芯片级组装技术、多芯片模块技术和三维立体组装技术等三大发展趋势.同时给出了贴装机、印刷机、回流焊机、波峰焊机、清洗设备和检测设备的发展趋势.     

表面等离子共振成像非标记微阵列芯片检测

采用表面化学修饰的镀金玻片作为芯片基质,结合微阵列点样分配技术,设计制作了1种非标记寡核苷酸检测芯片和1种非标记蛋白检测芯片,使用自行构建的表面等离子共振成像(SPRI)检测仪器,成功实现了对寡核苷酸靶标和抗体靶标的非标记、高通量检测分析,研究了核酸和蛋白分子的特异性相互作用,并使用微珠有效增强了芯片的检测信号.     

一种高密度基因芯片设计的新方法

基因芯片是一种由高密度寡核苷酸探针所形成的微阵列.本文首先提出一种基因芯片上寡核苷酸探针设计的新思想,即变长变覆盖探针优化设计方法,通过该方法设计的寡核苷酸探针的杂交解链温度最大程度地保持一致,可有效地减少碱基杂交错配,提高基因芯片检测结果的可靠性.根据上述核心思想,本文提出具体的检测目标核酸序列及其突变的基因芯片设计方法.     

微波QFN芯片的SMT技术研究

QFN封装的微波芯片采用一种较新的封装形式,这种封装体积很小,特别适合高密度印刷电路板组装.着重介绍微波QFN芯片的表面组装技术,从QFN的封装形式、PCB的焊盘设计、组装工艺、QFN焊点检测及QFN器件的返修等方面加以详细论述,并对针QFN芯片总结出一套完整的组装技术.     

Pareto-Optimal Methods for Gene Ranking

The massive scale and variability of microarray gene data creates new and challenging problems of signal extraction, gene clustering, and data mining, especially for temporal gene profiles. Many data mining methods for finding interesting gene expression patterns are based on thresholding single discriminants, e.g. the ratio of between-class to within-class variation or correlation to a template. Here a different approach is introduced for extracting information from gene microarrays. The approach is based on multiple objective optimization and we call it Pareto front analysis (PFA). This method establishes a ranking of genes according to estimated probabilities that each gene is Pareto-optimal, i.e., that it lies on the Pareto front of the multiple objective scattergram. Both a model-driven Bayesian Pareto method and a data-driven non-parametric Pareto method, based on rank-order statistics, are presented. The methods are illustrated for two gene microarray experiments.     

基于倏逝波的生物芯片检测方法研究

报道了基于倏逝波原理的生物芯片检测平台。利用光波全反射时产生的倏逝波场，用倏逝波激发荧光物质，搭建了简单的检测平台，实现了对荧光标记的核酸（DNA）芯片进行检测。芯片被激发产生的荧光信号通过光学系统成像在CCD器件上并被转换成数字图像，通过对图像分析得出生物芯片上生物分子反应的定量结果。结果表明，该检测系统具有较高的灵敏度；与商品化生物芯片扫描仪的检测结果相比，具有良好的一致性。     

Study of the electrolyte-insulator-semiconductor field-effect transistor (EISFET) with applications in biosensor design

This paper presents a comprehensive review of the ion-sensitive field-effect transistor (ISFET) and its applications in biomolecular sensing and characterization of electrochemical interfaces. An introduction to the physics of field-effect transistors is presented, followed by a study of the properties of electrolytic solutions and electrolyte interface surface effects. Full modeling of the ion-sensitive transistor is given, followed by a survey of the different uses of the ISFET in biomedical and environmental applications. Particular attention is given to the use of the ion-sensitive transistors as replacements for microarrays in DNA gene expression analysis.     

Control and Implementation of a Real-Time Liquid Spotting System for Microarray Applications

This paper discusses the control and implementation of a real-time spotting system. It is intended for high-density high-yield microarray fabrication to facilitate diagnostic and research effort in genomics and proteomics. The method is based on a self-sensing fully automated aspiring/dispensing pin. System performance is evaluated by several batch runs with deionized water solutions of 0.3% fluorescent Cy-3 dye, which has similar physical properties to the deoxyribonucleic acid (DNA) probe materials. Experimental results show that this system is capable of fast and robust DNA/protein microarray fabrication in high volume while keeping spot size as small as 60 $muhbox{m}$ consistently. Based on the laser scanned images and experimental data of the spotted microarrays, it is also verified that this system can recognize and prevent the formation of abnormal spots.      

Fabrication of Robust Biomolecular Patterns by Reactive Microcontact Printing on N‐Hydroxysuccinimide Ester‐Containing Polymer Films

The fabrication of robust biomolecule microarrays by reactive microcontact printing (μCP) on spin‐coated thin films of poly(N‐hydroxysuccinimidyl methacrylate) (PNHSMA) on oxidized silicon and glass is described. The approach combines the advantages of activated polymer thin films as coupling layers, characterized by high reactivity and high molecular loading, with the versatility and flexibility of soft lithography. The transfer of amino end‐functionalized poly(ethylene glycol) (PEG) from oxidized poly(dimethylsiloxane) elastomer stamps to PNHSMA films is shown by Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, fluorescence microscopy, and ellipsometry measurements to result in covalent coupling and identical grafting densities, as found previously for coupling from solution. The PEG‐protected areas effectively inhibit the adsorption of fluoresceinamine, bovine serum albumin, as well as 25‐mer DNA, while the unreacted N‐hydroxysuccinimidyl methacrylate ester groups retain their reactivity towards primary amino groups. Biomolecule microarrays have been thus conveniently fabricated in a two‐step procedure. The hybridization of target DNA to immobilized probe DNA in micropatterns proves the concept of reactive μCP on activated polymer films for obtaining robust platforms for biomolecule immobilization and screening.     

Identification of Shared Components and Sparse Networks in Gene Expression Time-Course Data

High-throughput gene expression technologies such as microarrays have been utilized in a variety of scientific applications. In this article, we develop multivariate techniques for visualizing gene regulatory networks using independent components analysis (ICA) techniques. A desirable feature of the ICA method is that it approximates a biological model for the gene expression. The methods are outlined and illustrated with application to yeast gene expression data.     

TMABoost: an integrated system for comprehensive management of tissue microarray data.

In the last decade, high-throughput technologies such as DNA and tissue microarrays (TMAs) have become a means of large-scale investigation of gene expression, providing a plethora of new biomedical data in a relatively short time. Data collection and organization are critical aspects in this process to ensure the quality and reliability of future data interpretation. In this work, we propose a comprehensive approach to handle TMA data with the aim of supporting and promoting biomarker development. We describe a web-based system for the complete management of tissue microarray data in the field of pathology. The system has been in use since June, 2003. Our approach includes automatic localization and identification of tissue microarray samples, and quantitative image analysis that allows high-throughput screening of TMAs by ensuring nonsubjective measures and novel prognosis associations. In this paper, we present the architecture and the components of this system.     

ELB-Q: a new method for improving the robustness in DNA microarray image quantification.

Reliable and robust quantification of signal intensities is a critical step in microarray-based biomedical studies. However, traditional techniques for microarray image processing would face significant challenges if the number of pixels used for the quantification of the local background and the foreground decreases dramatically. We have developed a new method, ELB-Q, which, by design, is well suited for the image quantification of microarrays with very high density of spot layout (large number of spots arranged in unit area). In ELB-Q, a large extended local background (ELB) interspot region excluding those "noise of the background" pixels is used for estimating the local background, and the quantification of spot intensities (mean and median) in the putative target spot regions is performed after further excluding background pixels in these areas based on the cutoff values established during the ELB calculation. ELB-Q takes advantage of the abundant spatial information around each spot of interest, makes no assumption of the shape and size of the spots, and needs no sophisticated adjustment. We show results of image processing using ELB-Q on both the simulated data and real DNA microarrays, which compare favorably in robustness and accuracy against those obtained with GenePix Pro 6.0 (Axon Instruments, 1999) and the Markov random field (MRF) modeling approach. The ELB-Q software is developed in Matlab, and is available upon request.