光纤型微流控电泳芯片的研制

介绍了一种光纤型微流控电泳芯片,该芯片主要由两部分组成:多模光纤,PDMS基片和盖片.利用二次曝光技术制作出芯片的模具;通过浇注的方法制成电泳芯片;实现了在PDMS上制作深度不同的微流控沟道和光纤沟道,使光纤与微流控沟道能够方便地对准;利用异硫氰酸酯荧光素考察了系统的性能,最小检测浓度达到1.3×10-7mol/L,信噪比S/N=5.     

细胞计数分析传感器芯片的研究

细胞计数分析在医疗和科学研究方面有着广泛的应用,本论文叙述了一种有效结合了微流控分析和细胞传感器技术,并能够进行细胞计数分析的传感器芯片.通过微加工技术制备的聚二甲基硅氧烷(polydimethylsiloxane,PDMS)微通道,并将PDMS芯片键合在光寻址电位传感器(light-addressable potentiometric sensor,LAPS)的芯片表面,使其在硅基底上形成十字形、100 μm宽、30μm深的微流控通道,通过LAPS光生电流的传感测量,对重力驱动的大鼠血细胞进行了计数分析.该研究将微流控技术引入细胞传感器的研究,有利于后续通过细胞芯片实现细胞计数分析仪器的微型化和多功能化.     

一种低成本压电无阀微泵的研制

提出了一种低成本的由压电材料驱动的平面扩张/收缩管无阀微泵的制作工艺.通过数值模拟确定了扩张/收缩管扩张角的最优值,在此基础上,采用光刻和湿法刻蚀工艺,刻蚀了300μm深的泵腔基片和100 μm深的盖片;使用等离子体清洗技术将其与PDMS薄膜键合,完成了可以实现单向泵送的压电无阀微泵样机制作.研究了该压电无阀微泵样机的...     

基于声表面波实现数字微流体的产生

数字微流体的产生是压电材料为基片的微流控芯片进行微流分析的前提,报道了在压电基片上应用声表面波技术产生数字微流体的方法.在128°旋转Y切割X传播方向的LiNbO3基片上集成PDMS微通道,在微通道出口一侧为经疏水处理的铝薄片,注射泵产生恒定流量的微流体经PDMS微通道到达铝薄片并聚集,当聚集的微流体体积足够大时,微流体克服表面张力作用下滑到达压电基片,并在中心频率为27.7 MHz叉指换能器激发的声表面波作用下输运,实现微流体的数字化.同时,理论分析了微流体在铝薄片表面上受力状况,并以水为实验对象,进行微流体数字化实验.结果表明,声表面波作用下能精确产生微升量级数字微流体,为压电微流控芯片提供了一种新的微流体引入方法.     

一种基于微流控芯片技术的流式细胞计数系统

采用聚二甲基硅氧烷（PDMS）材料制作微流控流式细胞计数芯片,利用负压驱动与鞘液夹流技术实现样品的水力聚焦,达到了10μm的样品聚焦宽度。基于激光诱导荧光技术,制作了小型化的检测装置。以488nm固体激光器为光源,激光束以45°方向穿过一个水平狭缝,以线光源形式汇聚到微流控芯片的检测区域,并与微通道垂直交叉,细胞样品的荧光信号通过光电倍增管收集。整个分析系统结构简单,操作方便,灵敏度高,可初步实现细胞的计数。     

玻璃-PDMS薄膜-玻璃夹心微流控芯片制作

聚二甲基硅氧烷(PDMS)是目前微流控芯片中应用的最广泛的基质材料,但基于PDMS材料的微流控芯片在应用中存在溶剂易挥发、难以进行较长时间检测分析的问题.针对这些问题,发展了一种简便高效的“玻璃-PDMS薄膜-玻璃”(G-P-G)夹心式微流控芯片的制作方法.该方法巧妙利用聚酯(PET)胶片作为载体转移处理脆弱的结构化PDMS膜,然后通过等离子体处理将结构化PDMS膜夹在两个玻璃基板的中间,形成“玻璃-PDMS薄膜-玻璃”夹心结构芯片,由于玻璃材料的低通透性,使得芯片具有低溶剂挥发特性.该夹心式芯片的低溶剂挥发特性通过蛋白质结晶实验得到了验证.     

基于微流控芯片的尿酸和抗坏血酸并行电化学检测研究

尿样和血样中的尿酸水平是诊断痛风等疾病的重要指标,传统检测方法存在时间长、需要其他辅助试剂等不足,开展了在微流控芯片上对尿酸进行电化学检测的研究：以碳纳米管修饰的丝网印刷电极片为检测单元,构建了PDMS微流控芯片。以微流控芯片为平台,采用微分脉冲伏安法（DPV）对尿酸和抗坏血酸分别进行检测,确定其原始峰值电位。最后,实验测试和分析比较了不同浓度尿酸和抗坏血酸对电化学检测信号的影响。研究结果表明：用DPV法分别检测尿酸和抗坏血酸,测得峰电流与样品浓度均有较好的线性度;从并行检测信号中能够分辨出尿酸和抗坏血酸的氧化峰位;尿酸和抗坏血酸对彼此的DPV峰位无明显影响,但对DPV电流峰值有一定抑制作用。     

PDMS用加窗方式快速复制微结构

提出了一种微流控芯片中的制作方法,此方法可以复制现有芯片的任意结构,可用于实验室原有芯片的修复和整合.用窗口的方法提取结构,可排除芯片上相邻结构的干扰,得到表面光滑整齐的新芯片.特别适用于复制目前软光刻工艺尚未达到的特微结构和三维结构芯片.实验制作出的聚二甲基硅氧烷(PDMS)芯片沟道长30μm,宽5μm,深5μm,显微镜下观察芯片表面光滑,窗口内沟道性质复制良好,窗口边缘与表面之间具有明显的陡变.     

单泵控制聚焦流形态的微流控芯片的研制

研究一种单动力源、聚焦流形态可控的用于细胞排队的微流控芯片。建立了样品沟道与鞘流沟道不同长度比例、不同夹角的模型并进行了不同负压条件下聚焦流形态仿真,运用SPSS软件进行了回归分析并进行了模型优化。在芯片的微加工过程中,利用印刷电路板(PCB)制作了母板,以聚二甲基硅氧烷(PDMS)为芯片主要材料,制作了PDMS—PDMS,PDMS—玻璃及PCB—PDMS三种芯片。制作的芯片能够在单个动力源条件下控制聚焦流宽度,使不同大小的微粒及细胞呈单个排列流动。研究结果为分析不同尺寸的细胞而选择合适的样品流沟道与鞘流沟道长度、夹角等条件提供了依据,所制作的芯片也达到了廉价且实用的目的。     

采用SU—8胶制作模具的工艺研究

主要描述了SU—8胶制造微流体芯片用模具的工艺研究。讨论了各工艺流程主要包括有前烘、中烘、光刻、显影等因素对模具的影响。提出了一个可供参考的模具制作工艺流程,对抗粘层工艺进行了讨论。另外,在模具制造过程中加入反应离子刻蚀(RIE)来提高SU—8与硅基底的粘附性。最终通过上述的工艺研究,成功制作出了应用于流体的模具,并制造成了微流控芯片。     

微电子细胞传感器在抗肿瘤药物分析中的应用研究

研究采用微机械加工技术制备了生物电阻抗检测用的细胞传感器芯片。传感器各通道为50μm的微电极,以交错的方式间隔50μm排列。配以相应的药物微进样系统与控制系统后,将人肺腺癌细胞系A549细胞接种培养于芯片电极表面,研究了人参皂苷Rh2对细胞的作用。阻抗测试结果显示:人参皂苷Rh2具有良好的抑制肿瘤细胞生长作用,表明细胞微电子芯片为抗肿瘤药物的分析与筛选提供了一个良好微传感器测试平台。     

新型快速准分子激光微加工方法制备毛细管电泳芯片的研究

选用聚合材料聚甲基丙烯酸甲酯(PMMA)代替玻璃,石英等作为毛细管电泳芯片的基片材料.在19 kV,5 Hz及5mm/min的加工参数下,采用新型快速准分子激光微加工方法完成了毛细管电泳芯片的制备.实验结果表明该方法加工过程简单,耗时短,自动化程度高,有效提高了芯片成品率和加工质量.芯片与相同尺寸的盖片在105℃、160 N、恒温20 min条件下通过热压键合在一起,得到密闭性好的整体芯片.最后在芯片上应用激光诱导荧光检测法对Cy5染料完成了分离检测,获得了重复性很好的检测信息.     

An analog CMOS chip set for neural networks with arbitrarytopologies

An analog CMOS chip set for implementations of artificial neural networks (ANNs) has been fabricated and tested. The chip set consists of two cascadable chips: a neuron chip and a synapse chip. Neurons on the neuron chips can be interconnected at random via synapses on the synapse chips thus implementing an ANN with arbitrary topology. The neuron test chip contains an array of 4 neurons with well defined hyperbolic tangent activation functions which is implemented by using parasitic lateral bipolar transistors. The synapse test chip is a cascadable 4x4 matrix-vector multiplier with variable, 10-b resolution matrix elements. The propagation delay of the test chips was measured to 2.6 mus per layer.     

Monolithic fabrication of electro-fluidic polymer microchips

Integration of electronic wiring with microfluidic chips is an important process as it allows electrical interactions with the fluidic media, for example required for resistive and capacitive sensing. It is also necessary in order to implement various actuation and control mechanisms such as pumping, electrophoresis and temperature control. Typically electrical wire traces are added to microfabricated fluidic chips using metal deposition processes that are carried out after the fluidic chip has been fabricated. The process for adding the wiring is complicated and is limited to select metals that can be deposited by evaporation or sputtering. We present a single step method for integrating electrical wires into polymer microfluidic chips that are fabricated by a hot embossing process. This process can flexibly embed any kind of commercially available metal wire with a microfluidic chip and the wiring may be integrated to come into surface contact with the fluid or may be embedded in close proximity to (but insulated from)the fluid paths for example for local heating purposes. This method significantly reduces total processing time and is thus a valuable method for wire integration into polymer chips. We demonstrate two applications—a microelectrolysis chip and a heater chip that were fabricated using this methodology. The design, fabrication process and the initial test results are presented.     

MEMS中Ni-W合金薄膜力学性能的研究

研究了柠檬酸胺-1-羟基乙烷二膦酸（HEDP）镀液体系中Ni-W的力学性能。通过紫外曝光的光刻、电铸和注塑（UV—LIGA）技术制备出微拉伸试样和单轴微拉伸测试系统进行拉伸试验。结果表明：在Ni-W薄膜试样尺寸为5μm×50μm×100μm条件下,其杨氏模量约为100．4GPa,抗拉强度为1．96GPa,应变约为3．6％。     

An analog silicon retina with multichip configuration

The neuromorphic silicon retina is a novel analog very large scale integrated circuit that emulates the structure and the function of the retinal neuronal circuit. We fabricated a neuromorphic silicon retina, in which sample/hold circuits were embedded to generate fluctuation-suppressed outputs in the previous study . The applications of this silicon retina, however, are limited because of a low spatial resolution and computational variability. In this paper, we have fabricated a multichip silicon retina in which the functional network circuits are divided into two chips: the photoreceptor network chip (P chip) and the horizontal cell network chip (H chip). The output images of the P chip are transferred to the H chip with analog voltages through the line-parallel transfer bus. The sample/hold circuits embedded in the P and H chips compensate for the pattern noise generated on the circuits, including the analog communication pathway. Using the multichip silicon retina together with an off-chip differential amplifier, spatial filtering of the image with an odd- and an even-symmetric orientation selective receptive fields was carried out in real time. The analog data transfer method in the present multichip silicon retina is useful to design analog neuromorphic multichip systems that mimic the hierarchical structure of neuronal networks in the visual system.     

General-purpose vision chip architecture for real-time machine vision

To solve the I/O bottleneck problem in existing vision systems and to realize versatile processing adaptive to various and changing environments, we propose a new vision chip architecture for applications such as robot vision. The chip has general-purpose processing elements (PEs) with each PE being directly connected to a photo detector (PD) and can implement various visual processing algorithms. We developed and simulated some sample programs for the chip and proved that they can be processed within 1 ms/frame, a rate that is high enough for high-speed visual feedback for robot control. Aiming to complete the chip, we are now developing test chips based on the architecture. The latest design has 8 x 8 PEs and PDs in an area 3.3 mm x 3.0 mm using a 0.8 μm CMOS process.     

Fabrication of SU-8 photoresist micro–nanofluidic chips by thermal imprinting and thermal bonding

Micro–nanofluidic chips have been widely applied in biological and medical fields. In this paper, a simple and low-cost fabrication method for micro–nano fluidic chips is proposed. The nano-channels are fabricated by thermal nano-imprinting on an SU-8 photoresist layer followed by thermal bonding with a second SU-8 photoresist layer. The micro-channels are produced on the second layer by UV exposure and then thermal bonded by a third layer of SU-8 photoresist. The final micro–nano fluidic chip consists of micro-channels (width of 200.0 ± 0.1 μm and, depth of 8.0 ± 0.1 μm) connected by nano-channels (width of 533 ± 6 nm and, depth of 372 ± 6 nm), which has great potential in molecular filtering and detection.

     

A CMOS binary pattern classifier based on Parzen''s method

Biological circuitry in the brain that has been associated with the Parzen method of classification inspired an analog CMOS binary pattern classifier. The circuitry resides on three separate chips. The first chip computes the closeness of a test vector to each training vector stored on the chip where "vector closeness" is defined as the number of bits two vectors have in common above some thresholds. The second chip computes the closeness of the test vector to each possible category where "category closeness" is defined as the sum of the closenesses of the test vector to each training vector in a particular category. Category closenesses are coded by currents which feed into an "early bird" winner-take-all circuit on the third chip that selects the category closest to the test vector. Parzen classifiers offer superior classification accuracy than the common nearest neighbor Hamming networks. A high degree of parallelism allows for O(1) time complexity and the chips are tillable for increased training vector storage capacity. Proof-of-concept chips were fabricated through the MOSIS chip prototyping service and successfully tested.