基于微电极阵列的嗅球细胞网络传感器的研究

嗅球(OB)是嗅觉系统的第一中转站,在嗅觉信息的识别和处理中具有重要的作用.嗅球中具有多种类型的神经元,分别具有不同的生理特点和功能.本研究利用细胞培养技术,将嗅球神经元与微电极阵列(MEA)芯片耦合,构建一种细胞网络传感器,用于对多点的嗅球神经元电活动进行同步观察与分析.结果显示,MEA上培养的嗅球细胞生长良好,能够检测多个通道的嗅球神经元的自发电位以及谷氨酸作用下的诱发响应.研究表明,该嗅球细胞网络传感器能够实现信号的多通道同步检测及有效分辨神经元的自发信号和诱发响应,并且能够很好地捕捉不同通道神经元响应的特点.该研究对于进一步分析嗅觉信息在嗅球内的传导和编码具有重要的意义.     

细胞芯片的研究进展

细胞芯片技术是以活细胞作为研究对象的一种生物芯片技术。它是适应后基因组时代人类对生命科学探索的要求而产生的。作为细胞研究领域的一种新技术，其既保持传统的细胞研究方法的优点如原位检测等，又满足了高通量获取活细胞信息等方面的要求。本文中扼要介绍细胞芯片的概念以及几种已报道的细胞芯片，并对细胞免疫芯片进行了简述。     

基于细胞三维受控组装技术的细胞芯片构建

如何将细胞准确装配于细胞芯片的设计位置,是制约细胞芯片向组织和生理系统细胞芯片方向发展的关键问题之一。本研究用细胞组装技术将细胞装配到细胞芯片的设计位置并检测的理论和方法。首先设计构建了含多组传感器阵列的细胞芯片;选取输送和固定细胞的明胶-海藻酸钠复合水凝胶材料,探讨用细胞组装技术在芯片上精确装配细胞的方法;测试复合材料和多种电解溶液对电阻抗的影响,并用芯片对细胞增殖进行检测。结果显示:复合材料能输送并将细胞固定在芯片上超过4周;细胞组装技术可精确将细胞装配到指定传感器,组装的细胞/材料微丝直径100～120μm。复合材料对芯片基础电阻抗影响小,在大于103Hz的高频段,基础阻抗为小于102.6Ω;PBS和DMEM溶液在103.5～105Hz高频段可替代氰铁化钾溶液作为电解液;芯片上的传感器在103.5Hz可准确测出Hela细胞增殖引起的电阻抗变化。研究证明了用细胞组装技术构建复杂细胞芯片的可行性。     

多功能细胞传感器集成芯片的设计及实验研究

为了实现对细胞的生长凋亡等状态和电兴奋细胞的胞外电场及胞外离子代谢的同步检测,本研究提出了将具有对应功能的叉指电极(IDE)、微电极阵列(MEA)、光寻址电位传感器(LAPS)集成在单片硅基底上,设计了细胞多功能检测的集成芯片。在集成芯片的设计上,各功能模块采用多通道布局,并且优化了电极尺寸、电极间排布、电极表面特性处理等方面的设计,以减少电极之间干扰并提高性能。在加工方面利用SiO2层同时作为MEA、IDE的绝缘层和LAPS的保护层,采用微加工技术将三种传感器融合加工于同一硅基底上。器件的评估结果显示,3种传感器的性能和相应的单独设计芯片性能相近,且满足生物相容性的要求。本集成芯片成功弥补了传统细胞传感器检测参数单一的缺陷,建立了细胞多生理参数检测的细胞传感器平台。     

基于微电极阵列的多通道电生理检测系统的研制

设计并制备出一套低成本的微电极阵列及多通道电生理检测系统。通过基本的光刻、腐蚀对ITO导电玻璃进行加工,制备带有电极图形的导电玻璃,复合一层绝缘层后获得微电极阵列。利用软件设计PCB电路图并委托公司加工,获得相关系统的硬件部分。在labVIEW平台下进行编程,满足对数据采集卡的操作。我们成功制备了一套低成本的微电极阵列及相关检测系统。该系统用于不同类型神经细胞组成的神经网络自发放电检测,可在体外培养的神经网络中检测到5μV的神经信号,并在神经网络发育14 d检测到密集的同步簇发动作电位。我们研发的微电极阵列及多通道电生理检测系统具有良好的性能,可用于不同类型神经细胞的神经网络微弱信号的检测与神经网络发育研究。     

嗅觉和味觉电生理及其芯片技术的研究进展

评述了当前国际上嗅觉和味觉组织、细胞电生理及其芯片技术的研究状况。介绍了细胞胞内记录技术在嗅觉和味觉的电生理研究中应用，分析该技术在实现组织一细胞以及胞间信号传导过程的实时动态检测中面临的问题。在此基础上，进一步介绍细胞阵列和单细胞芯片技术的特点及目前的发展，指出了芯片技术应用于嗅觉和味觉组织的发展前景。最后结合我们的工作，提出嗅觉和味觉细胞芯片的研究和发展方向。     

纳米传感器芯片让药物开发提速

据Gaster RS[Nat Nanotechnol,2011,6(5):314-320]报道,美国斯坦福大学的研究人员开发出一种新型的传感器芯片,可以大大加快药物开发过程。这种由高度敏感的纳米传感器构成的微芯片,可以分析蛋白质如何相互结合,在评估药物的有效性及可能带来的副作用方面迈出了关键一步。     

基于BIOMEMS技术的细胞电阻抗传感器的研究进展

细胞一电阻抗传感器是基于BIOMEMS技术的研究细胞电生理和临床药理研究的新兴工具,主要应用于细胞等微生物体的形态和功能研究.近年来,它以其新颖简单的设计和长时程的无损测试等优点一直受到国内外学者和企业的广泛关注.首先分析细胞一电极阻抗界面模型并加以细化,然后介绍生物阻抗传感器在国际上研究的最新进展.在此基础上,结合实验室当前的研究工作,介绍了自制的基于叉指型细胞电阻抗传感器,最后提出了未来主要发展方向.     

传感器阵列数据采集和处理的虚拟仪器设计

设计了基于LabVIEW的传感器阵列数据采集和处理的虚拟仪器.使用LabVIEW编程软件,通过微机化数据采集系统和通用虚拟仪器对传感器阵列数据采集和信号处理.采用分析折线补偿法,有效减少传感器的非线性误差,提高了传感器的测量准确性.通过对每个传感器进行校正和补偿,使各个传感器的特性归一化.只要修改软件,就可以增减此虚拟仪器系统的功能.     

一种基于阵列传感器设计和双曲定位模型的心尖搏动信号获取技术

目的针对传统单一传感器采集心尖搏动信号时因传感器位置不易确定,信号可靠性受质疑的问题,提出一种新的心尖搏动信号获取技术。方法采用阵列传感器设计,将3片完全相同的压电传感器设计成等边三角形结构,同步采集3路心尖搏动信号,同时对心尖搏动信号在胸腔传播过程中衰减的幅值特性和频率特性进行分析,建立心尖搏动信号的双曲定位模型,然后依据该模型重建出真实的心尖搏动信号。同步采集20例受试者的3路心尖搏动信号,以传感器A为基准信号,统计分析传感器B和C信号的3个特征点（C点、E点和0点）与基准信号的偏差有无显著性差异,进而说明单一传感器信号的可靠性。结果t检验结果显示传感器B和C信号的3个特征点与基准信号的偏差均有显著的统计学差异,提示心尖搏动信号易受传感器放置位置的影响,信号可靠性不高。结论本文提出的心尖搏动信号获取技术解决了单一传感器放置位置不易确定的缺陷,利用双曲定位模型重建出可靠性更高的信号波形。     

Integrated wireless neural interface based on the Utah electrode array

This report presents results from research towards a fully integrated, wireless neural interface consisting of a 100-channel microelectrode array, a custom-designed signal processing and telemetry IC, an inductive power receiving coil, and SMD capacitors. An integration concept for such a device was developed, and the materials and methods used to implement this concept were investigated. We developed a multi-level hybrid assembly process that used the Utah Electrode Array (UEA) as a circuit board. The signal processing IC was flip-chip bonded to the UEA using Au/Sn reflow soldering, and included amplifiers for up to 100 channels, signal processing units, an RF transmitter, and a power receiving and clock recovery module. An under bump metallization (UBM) using potentially biocompatible materials was developed and optimized, which consisted of a sputter deposited Ti/Pt/Au thin film stack with layer thicknesses of 50/150/150 nm, respectively. After flip-chip bonding, an underfiller was applied between the IC and the UEA to improve mechanical stability and prevent fluid ingress in in vivo conditions. A planar power receiving coil fabricated by patterning electroplated gold films on polyimide substrates was connected to the IC by using a custom metallized ceramic spacer and SnCu reflow soldering. The SnCu soldering was also used to assemble SMD capacitors on the UEA. The mechanical properties and stability of the optimized interconnections between the UEA and the IC and SMD components were measured. Measurements included the tape tests to evaluate UBM adhesion, shear testing between the Au/Sn solder bumps and the substrate, and accelerated lifetime testing of the long-term stability for the underfiller material coated with a a-SiC_x:H by PECVD, which was intended as a device encapsulation layer. The materials and processes used to generate the integrated neural interface device were found to yield a robust and reliable integrated package.     

Application of a PDMS microstencil as a replaceable insulator toward a single-use planar microelectrode array

Here we present a novel idea for a replaceable insulator, and thus advance toward the goal of a single-use planar microelectrode array (MEA) for the study of electrogenic tissues. The concept of a replaceable insulator is motivated by insulator degradation after repeated usage of an MEA. Instead of fabricating a more durable insulator for repeated MEA usage, we propose replacing the insulator and effectively producing a fresh MEA for each experiment. We chose a polydimethylsiloxane (PDMS) microstencil as a candidate for the replaceable insulator as it is biocompatible, shows reversible adhesion to surfaces, and can be easily and controllably fabricated. As a proof-of-concept, we demonstrate two applications using microstencils: the rejuvenation of an old MEA and the fabrication of a single-use MEA. These MEAs were tested with dissociated neural cell cultures and neural recordings were performed at 14 days in vitro. Inexpensive and quick supply of insulators with micrometer-sized holes provides a way of constructing an MEA that can be treated as a disposable component in high throughput cell-based biosensor applications.     

A transparent oxygen sensor array

The development of a transparent array of independently connected oxygen sensors is described. With an appropriate sensor pattern, this device may be useful to monitor the distribution of oxygen on the surface of tissues, while permitting simultaneous tissue visualization. The electrochemical characteristics of individual oxygen sensors are examined and models are proposed for the distribution of oxygen in the vicinity of individual sensors.     

Fabrication and testing of high-performance detection sensor for capillary electrophoresis microchips

This study presents a new approach for high-performance detection sensors for MEMS-based capillary electrophoresis chips to substitute laser induced fluorescence (LIF) detection systems. The developed sensors easily integrate with well-known microfabrication techniques for glass-based microfluidic devices. Three-dimensional gold electrodes are structured in enveloping side channels by sputtering and patterned using a standard “lift-off” process. The variations in the capacitance between the electrodes in the side channels are measured as different samples and ions pass through the detection region of the capillary electrophoresis separation channel. Samples of beer, white wine and milk are each mixed in different buffer solutions, then successfully separated and detected using the developed device. The proposed high-performance detection sensors have microscale dimensions and provide a critical step towards the realization of the lab-on-a-chip concept.     

微电极技术与脑运动性信息传导的研究

在生理和病理状态下 ,研究脑运动性信息在运动回路中的传递 ,一直是神经科学中的重要课题。近年来 ,作为现代神经电生理学的重要技术之一 ,微电极技术在运动回路中脑运动性信息的研究应用日益增多。本文就这一领域的应用情况进行综述。     

Active microelectrode array to record from the mammalian central nervous systemin vitro

The detection of extracellular potentials in nervous tissue with conventional microelectrodes has many limitations. The number of sites at which activity can be detected in one experiment is small, and the noise performance of the system is frequently poor. A monolithic integrated circuit array of microelectrodes and buffer amplifiers has been built, enabling potentials to be detected simultaneously at nine sites, and substantially reducing the noise caused by electrostatic pick-up. The electrodes and buffer amplifiers were made on a silicon substrate using a fabrication process based on standard i.c. processing techniques. With an off-chip multiplexer, the potentials at each electrode have been displayed simultaneously on a normal oscilloscope in experiments on slices of rat brain tissue. Initial results have shown that an informative display which would be almost impossible to obtain with conventional electrodes can readily be produced, and that the long-term stability of the device is good.     

双绞微电极制作装置设计与验证

微电极作为外部电子设备与内部神经核团之间的接口,在动物机器人、深度脑刺激、神经假体等方面都起着重要的作用。针对现有微电极制作装置价格高昂且制作工艺复杂等问题,本文提出了一种基于开源电子原型平台(Arduino)和三维打印技术的双绞微电极制作装置,并验证了其电极制作性能及神经刺激性能。实验结果表明,在微电极制作过程中,电极丝的正向绞合圈数一般应设置为其长度的1.8倍左右较适宜,逆向绞合圈数与长度无关,一般为5左右。与同类产品相比,本文所提装置不仅价格低廉、制作简单并具有较好的扩展性,对于微电极制作的个性化、普及化以及降低实验成本都有着积极的促进意义。