基于柔性衬底的三维生物刺激微电极阵列研究

设计了一种基于聚酰亚胺薄膜的三维生物刺激微电极阵列,用于植入式人造视网膜应用.采用非硅MEMS技术,在柔性衬底上制备出具有生物相容性和化学稳定性,电极高度为80 μm的生物刺激电极阵列,通过PDMS牺牲层实现器件从基底的完整释放.实验中器件以聚酰亚胺和PDMS封装,电极柱和焊盘均镀金,从而提高电极的生物相容性.采用三电极法对微电极进行了电化学性能测试,在10-1～105Hz频率范围内,其阻抗为1.5～0.3 kΩ.制造出的器件尺寸小,质量轻,可靠性高,机械柔性好,符合生物电刺激要求.     

基于柔性微电极的高灵敏度MEMS电化学地震检波器

为了进一步降低微机电系统(MEMS)电化学地震检波器敏感电极的加工成本,提升传感器的灵敏度,推动其在地球物理勘探等领域的发展,提出了一种基于柔性微电极结构的新型MEMS电化学地震检波器.与基于硅衬底制作敏感电极相比,敏感电极的制作方法可以通过有效减小电极间距,大幅度提升传感器的灵敏度,大幅降低工艺成本.介绍了柔性微电极的加工工艺流程,并对传感器的性能进行了测试.结果表明:提出的地震检波器较基于硅衬底微电极器件灵敏度提高了一个数量级.     

石墨烯复合修饰电极的电化学应用

石墨烯作为一种二维结构的新型材料,其优异性能得到了人们的广泛关注.该文分析了石墨烯和功能化石墨烯的优异性质,总结了石墨烯作为新型传感材料的应用优势,并介绍了石墨烯对于酶电极的电子传导促进和检测优化以及石墨烯与其它有机物修饰后的复合电极对各种生物小分子的检测分析.同时对各种基于石墨烯材料的电化学传感器进行了简单介绍.展望了石墨烯修饰电极在生物检测与环境监测等方面的电化学应用前景.     

微阵列电极电化学生物传感器

以微阵列电极为基础的电化学生物传感器近几年来发展迅速,是实现生物传感器微型化和集成化的一个重要途径。介绍了微阵列电极以及作为信号转换器在电化学生物传感器中应用的有关进展情况,特别是在基因研究中的应用。     

基于微电子技术的微型化学与生物传感器

近二十年来,电极尺寸相当于或小于微米级的微电极技术已有了长足的发展,并显示了有别于常规电极的优越性能。以迅速发展着的微电子技术制作的微电极也为微型化学传感器和生物传感器的批量制作及商品化展现了引人注目的前景。以厚膜和薄膜技术制作的微电极已在微型传感器领域中得到了相当成功的应用,某些微型气体传感器和生物传感器已实现商品化。近年来,基于硅片各相异性三维刻蚀的微机械加工技术也已用于微型传感器的制作。作者在长期从事电流型化学与生物传感器研究工作的基础上,自90年代初起即依托中科院上海冶金所国家传感技术重点实验室,开展了以开发适合于批量制作的微型化学及生物传感器为目标的合作研究项目。与此同时,也对微电极的电化学特性及生物活性分子的表面修饰技术进行了较深入的探索。本文将对作者所在的联合课题组多年来的研究工作作     

三维泡沫石墨烯在抗坏血酸的干扰下检测尿酸

该文采用化学气相沉积法在泡沫镍上生长石墨烯,通过扫描电镜、X射线衍射、拉曼光谱对生成产物的形貌和结构分别进行了表征。结果表明：所制得的石墨烯为具有三维网状结构且层数较少的石墨烯。将三维泡沫石墨烯转移到ITO玻璃上制成生物传感器的工作电极,利用电化学工作站对尿酸和抗坏血酸进行检测．电化学测试结果表明：三维泡沫石墨烯修饰电极在抗坏血酸的干扰下可以准确的检测尿酸,其灵敏度为0．274μA／（μmol／L）,线性范围为10-100μmol／L。     

基于微电子的微型化学与生物传感器

近二十年来,电极尺寸相当于或小于微米极的微电极技术已有了长足的发展,并显示了有别于常规电极的优越性能。以迅速发展着的微电子技术制作的微电极也为微型化学传感器和生物传感器的批量制作及商品化展现了引人注目的前景。以厚膜和薄膜技术制作的微电极已在微型传感器领域中得到了相当成功的应用,某些微型气体传感器和生物传感器已实现商品化。近年来,基于硅片各相异性三维刻蚀的微机械加工技术也已用于微型传感器的制作。     

新型电化学CO气体传感器的研制

研制了一种用于测定CO的新型电化学式气体传感器,即把多壁碳纳米管自组装到铂微电极上,制备多壁碳纳米管粉末微电极,其电极在氧化过电位为+700mV时,对CO具有显著的电化学催化效应。以其电极为工作电极,Ag/AgCl为参比电极,Pt丝为对比电极,多孔聚四氟乙烯膜作为透气膜制成传感器。其传感器响应时间短、重复性好,能用于环境监测和控制。     

基于氧化石墨烯/聚吡咯-铟锡氧化物微电极的细胞阻抗生物传感器构建及细胞粘附增殖行为检测

构建一种基于氧化石墨烯/聚吡咯-铟锡氧化物GO/PPy-ITO（Graphene Oxide/Polypyrrole-Indium Tin Oxide）微电极的细胞阻抗生物传感器并用于细胞粘附增殖行为学检测。ITO微电极采用光刻技术对感光干膜绝缘层蚀刻而成,通过一步法电聚合技术在ITO微电极表面沉积GO/PPy纳米复合膜制备GO/PPy-ITO微电极;形状测量激光显微镜和扫描电子显微镜分别对GO/PPy表面粗糙度和拓扑形貌进行表征;电化学循环伏安法及阻抗谱表征GO/PPy-ITO微电极的电化学性质;人肺癌细胞株A549粘附、铺展和增殖实验考察GO/PPy界面的生物相容性;以GO/PPy-ITO微电极作为传感电极,利用电化学阻抗谱技术对A549细胞的粘附增殖行为进行检测。结果显示,ITO微电极表面上电沉积的GO/PPy纳米复合物表面平整,分布大量的微孔结构;电化————————————学实验结果显示GO/PPy-ITO微电极比裸ITO微电极具有更低的阻抗特征和更高的电化学活性;GO/PPy比纯PPy膜更能促进A549细胞粘附、铺展和增殖;GO/PPy-ITO微电极表面A549细胞的粘附增殖行为改变电极系统的阻抗谱特征,通过对阻抗谱数据进行等效电路拟合分析获得细胞粘附增殖行为学信息。本文发展的GO/PPy-ITO微电极兼具优良的电化学性质和细胞生物相容性,基于该电极系统构建的细胞阻抗生物传感器可用于细胞病理生理学行为、药物筛选等研究领域。     

基于纳米材料的辣根过氧化物酶电化学传感器的构建

酶生物传感器具有高选择性是由于酶对底物高选择性和反应产物指示无干扰性.这为在大量常规分析中进行快速实时分析提供了可能.自从Clark等首次报道了可以将酶固定在电化学检测器表面制成酶电极以来,电化学生物传感器得到了迅速地发展,电化学传感器被认为是21世纪最具有前途的研究领域之一.     

利用电化学生物传感器进行无创血糖检测技术研究

研制了一种新型的基于反离子电渗透原理无创检测血糖的电化学生物传感器,利用此生物传感器在自行搭建的实验装置上进行了裸鼠离体皮肤的葡萄糖透皮抽取和检测实验,研究了化学促渗剂和电流切换技术对无创血糖检测的影响.实验结果显示,使用化学促渗剂后葡萄糖的渗透量是不使用促渗剂情况下的2.29倍,采用电流切换技术,能减缓长时间通电对皮肤的刺激,在皮下葡萄糖浓度0～18 mmol/L范围内,生物传感器的响应电流与皮下葡萄糖浓度具有较好的相关性(R=0.9886,n=7).此外,还进行了与生物传感器配合使用的腕式仪表的研制,为实现糖尿病人血糖闭环控制奠定技术基础.     

石墨烯电化学研究进展

该文简要综述了石墨烯电化学研究的最新进展,包括石墨烯与电分析、石墨烯与能源电化学以及基于石墨烯的光透电极等内容,引用文献88篇。     

Flexible biomedical microdevices with double-sided electrode arrangements for neural applications

Micromachined devices with substrate-integrated electrodes are the key components in implantable microsystems for recording of neural signals or electrical stimulation of nerves. So far, electrodes have been located on only one side of the microsystems. In this paper, a technology has been developed to fabricate multichannel microelectrodes that are located on the top side and the back side of a flexible device. The process technology for polyimide-based devices is described. Prototypes of implantable microdevices with double-sided electrodes, called flexible nerve plates, have been fabricated. Results are discussed on scanning electron microscopy, cross-sections, and first electrochemical characterizations of the electrodes.     

Electrochemical deposition of polypyrrole/graphene oxide composite on microelectrodes towards tuning the electrochemical properties of neural probes

By exploiting the electrostatic interaction between positively charged pyrrole cation radicals and negatively charged graphene oxide (GO) sheets, we prepared polypyrrole/graphene oxide (PPy/GO) composite films by a one-step electrochemical process. We studied the effects of the polymerization current density and the GO content in electrolyte on the formation of PPy/GO coatings onto platinum neural microelectrode sites. As compared with pure PPy film, PPy/GO coatings show a rougher surface feature with micrometer-scale bulges. The impedance of the PPy/GO coated Pt electrode is only about 10% of the bare Pt electrode at the biological relevant 1 kHz, while the charge capacity density is more than two orders of the magnitude of the bare Pt electrode. Moreover, the PPy/GO coated Pt electrodes show higher performance than the PPy coated electrodes for the application of neural probe.     

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。     

Characteristics of electroactive polymer actuators using graphene electrodes

As alternatives to precious gold/platinum electrodes, graphene-based ionic polymer-metal composite actuators were successfully demonstrated by reduced graphene oxide and direct grown graphene on both sides of the perfluorinated sulfonic acid polymer layer using electronic spray coating and wet transfer methods. In addition, a platinum electrode was prepared as a reference. We characterized the electrical and structural properties of the graphene electrodes using a four-point probe system and atomic force microscopy. The static actuation ranges were analyzed, and a modeling procedure was carried out to obtain the linear curvature–voltage relations. Furthermore, the periodic actuation range was dynamically tested to evaluate the changes in the actuation performance over time. The experimental results showed that the reduced graphene oxide electrodes are a good alternative to platinum electrode that provide better flexibility and restoration of the original shape. And also direct grown graphene electrode is also valuable to access the stacked actuator owing to the hydrophobic sub-nanometer electrode.     

Polyimide micro-channel arrays for peripheral nerve regenerative implants

Mechanical guidance is one way in which regenerating axons can be directed towards an appropriate target. In this paper, we present the design and fabrication process of a three-dimensional (3D) device comprising a bundle of parallel micro-channels, which can be used as a 3D regenerative implant for peripheral nerve repair. The skeleton of the device is entirely made of flexible polyimide films. Gold micro-electrodes and micro-channels of photosensitive polyimide are patterned directly on polyimide substrates. After fabrication, the 2D electrode channel array is rolled into a 3D channel bundle fitting the peripheral nerve.The efficiency with which axons enter the 2D channel array was evaluated in vitro as a function of channel width, spacing and pitch. Axon outgrowth is maximised when micro-channels are wide (>30 μm), and when the array transparency (the channel width to pitch ratio) is at least 50%. To ensure the metallic electrodes remain functional in the rolled device, substrate thickness and micro-channel height must also be optimized to position the metal film in the neutral plane of the rolled structure. Electrodes embedded in the implant polyimide structure are robust to rolling. Their impedance at 1 kHz in Ringer solution is of the order of 1 MΩ on flat samples, and changes little when the same samples are rolled and inserted into 1.5 mm inner diameter tube. Such 3D, electrode channel devices on polymer not only provides a novel technological approach to physical guidance of regenerating neurons in vivo but also enables the fabrication of an electrode implant with direct electrical communication with multiple groups of nerve fibres in a regenerating peripheral nerve.     

A novel, electrically protein-manipulated microcantilever biosensor for enhancement of capture antibody immobilization

This study demonstrated a microcantilever biosensor for enhancement of capture antibody immobilization. The electrically protein-manipulated, microcantilever biosensor is featured with enhanced capture antibody immobilization, miniaturization, and high sensitivity. Thanks to the electric property of biological substances in a real environment, given charged proteins can be manipulated with attraction in solution under an electric field. It is evident that higher amount of capture antibody molecules immobilized onto sensing surfaces captures or detects specific molecules, indicating greater deflection and stresses as well. This however leads to significant cost in biosensors. With the merit of MEMS technique that allows highly fabrication-compatible integration into microcantilever biosensors, sparsely distributed antibody molecules in solution are attracted in focus onto a sensing solid surface under electric fields. As the sensing element of the gold-coated, V-shaped silicon nitride microcantilever also serves as an electrode, the electric fields are applied in a channel of flowing microfluidics by locally in-plane electrodes or by a top electrode arranged for three-dimensional fields. As expected, most charged proteins distributed in solution are effectively attracted onto the sensing area within the electric fields. This improves the efficiency of capture antibody immobilization and achieves an eight-fold reduction over the necessary amount of capture antibodies without applying electric fields. With such a successful manipulation of charged proteins, the novel microcantilever biosensor exhibits efficient use of capture antibodies in solution.     

碳纳米复合材料在电化学生物传感器中的研究进展

碳纳米材料以其优异的导电特性和机械性能及极佳的生物相容性在构建电化学生物传感器中备受关注,为电化学生物传感器的开发和研究开辟了一片广阔天地。将碳纳米材料与其它纳米材料复合,是一种拓展和增强其应用的有效方法。碳纳米材料在电化学生物传感器方面的应用主要是作为传感器界面的修饰材料、生物分子的固载基质以及信号标记物等。该文综述了碳纳米复合材料在电化学生物传感器中的应用,包括碳纳米管纳米复合物、石墨烯纳米复合物、富勒烯及碳量子点纳米复合物。并展望了未来基于碳纳米材料的电化学生物传感器的研究方向。     

电容式湿度传感器多孔上电极受力可靠性分析

电容式湿度传感器不断发展的同时上电极的制造工艺也在不断进行着技术更新,为了使湿度传感器的透水性更加优越,上电极在不断地被做薄,同时在多孔研究方面也在不断地进行着优化,但凡关于多孔上电极受力可靠性的问题,总是涉及到制作栅条过程中因为过度腐蚀而断裂的现象。利用ANSYS针对传统的条栅形多孔上电极以及自行设计的环形多孔上电极进行模拟受力分析,通过对多孔上电极内壁面进行压力加载,来模拟光刻过程中过度腐蚀的状况,观察比较两种上电极的模拟受力情况。从得到的受力形变图,等效塑性应变图以及等效应力图分析得出,环形多孔上电极具备比条栅形多孔上电极更可靠的受力响应。