2010 Pittcon会议(Ⅲ)

电分析化学学会组织的特邀报告(电化学与材料)组有:(1)A Bralter-Toth等,微电极的傅里叶转换伏安法——原理与应用;(2)N Kim,单壁碳纳米管的扫描电化学显微术;(3)P J Kalesza等,高效率生物电催化集成系统的研发与特性鉴定;(4)B J Marguis等,暴露在可变物理性能的贵金属纳米材料下,进行塔电池的改变的衰减功函数的电化学分析;(5)A Karomerich等,可能应用于神经刺激与传感的、导电聚合物改性的电极;(6)Y SSingh等,活体伏安法的长期稳定性与准确性的因素——碳纤维微电极涂层;(7)J G Roberts等,碳纤维微电极电化学预处理引起的表面改变的研究;(8)A Polpke等,碳纳米管阵列的提高功能化的处理。     

脑死亡过程中谷氨酸与场电位的同步检测微电极阵列研究

高浓度胞外K+会引起神经元的去极化、谷氨酸释放、甚至细胞死亡。为研究高浓度K+对在体神经元的影响,采用微机电系统( MEMS)方法制作了一种植入式微电极阵列( MEA),其上包含形状、位置固定的电化学(50伊150μm)和电生理(直径为15μm)检测位点,可同时进行脑内神经递质谷氨酸、局部场电位信号( LFP)双模检测。将这种MEA植入到大鼠纹状体后,给大鼠皮层施加高浓度K+刺激,结果表明,高钾刺激增加了纹状体内谷氨酸浓度,同时抑制了神经电生理活动。这是首次采用双模MEA研究神经元在体死亡过程,结果验证了双模微电极阵列在体检测的可行性,可用于研究脑内神经电化学、电生理的时空关系。     

非电活性分子的活体电化学分析进展

发展非电活性分子的活体电化学分析方法,对于解析这些物质在生理过程和病理过程中的作用具有重要研究意义. 本综述从三种分析策略出发,简要介绍了最近活体电化学传感器的研究进展：1）设计和筛选高选择性配体,通过将特异性的化学反应转换成电化学信号,发展了新型的非电活性分子的活体分析;2）利用微型孔道里的整流效应,结合特异性配体,建立了非电活性分子的新型分析平台;3）结合微电极阵列技术及同时分析多种输出信号的新型分析模式,实现活体中的多种非电活性物质的同时分析.     

微电极制备、表面修饰及活体/单细胞电分析应用

微电极是指至少在一维尺度上不大于25μm的电极。微电极由于尺寸小而具有一些常规电极无法比拟的性质,如具有电流密度高、响应速度快、欧姆压降(iR降)小、信噪比高等特点。微电极特殊的性质使其在电化学测试中具有独特的优点和重要性,并在分析化学、生物学及医学等方面得到了广泛应用,尤其在生命分析领域如在单细胞检测和活体分析中具有众多重要的应用。微电极的设计制备是微电极电化学发展应用的关键,目前涌现出的制备微电极的技术有电化学刻蚀法、电沉积法、自组装技术、化学镀层技术等,这些制备方法为快速制备微电极提供了可能性。本文综述了近年来微电极的研究进展,包括微电极的特点、分类、制备方法及其单细胞检测和活体分析方面的应用,最后提出了微电极面临的挑战与发展方向。     

基于无机电致变色材料的变色储能器件

电致变色和电化学储能的原理均是基于电荷在电极中的嵌入或脱出而发生的氧化还原反应,具有相同的电化学本质。将电致变色和电化学储能功能集成在一起的电化学器件即电致变色储能器件。以锂离子电池为代表的电化学储能器件已广泛商业化,单一功能的电致变色器件也已被广泛报道并有商业化应用,但有关电致变色储能器件的研究仍然停留在实验阶段。该类器件在电化学储能的同时,可以改变其在可见光甚至红外波段的透射率,并可用颜色指示器件的荷电状态,为电化学器件提供新的应用前景。电致变色储能器件主要包括电致变色超级电容器、电致变色电池和光驱动电致变色智能窗等。电致变色超级电容器和电致变色电池以同时具有电致变色效应和电荷存储性质的材料为正负电极,光驱动电致变色智能窗则还包括将光能转化为电能的光电转换部分。这些器件可用于建筑节能智能窗、静态显示、智能传感等。此外,在柔性基底上制备的可穿戴电致变色储能器件在智能服装、植入显示器和电子皮肤等方面具有应用潜力。本文从基本原理、研究进展和应用领域等方面对无机电致变色储能材料与器件进行综述,并提出未来的研究展望。     

用于细胞检测的微电极传感器设计及传感分析

本文针对肿瘤细胞的活性检测、神经细胞的神经递质检测与巨噬细胞等的氧化损伤检测等细胞检测中的核心问题,简要介绍电化学生化传感器和传感方法在细胞检测领域的应用和发展,重点对不同微电极结构的电化学传感器的设计制作、细胞检测方法及应用进展进行了综述。电化学生化传感器从单一检测电极向集成多功能和阵列式电极发展,从单个电极传感检测模式向芯片集成微电极式传感系统发展,而在其生物相容性、检测限和检测效率等方面尚需进一步提升和拓展。基于微机电系统(MEMS)技术制作的微电极研制,电极表面的多种化学和生物修饰的敏感膜研究,从硅基到聚合物柔性基底电极的材料拓展,小体积、植入式、可穿戴式的电化学生化传感器研制等是目前发展的方向,其在临床检验、精准医疗、运动健康监测、老年健康服务等诸多领域中显示出巨大的应用前景。     

三维立体结构微纳电极研究

基于体硅加工工艺和纳米材料技术,研制微电机系统(MEMS)尺度敏感微结构与纳米铂颗粒的复合结构,提高微电极电化学性能,制备具有三维立体微结构的安培型微电极传感器.利用硅的各向异性湿法腐蚀技术在毫米级的工作电极表面实现微米级的锥体形微池阵列,以H2O2为检测对象考察立体电极结构对传感器性能的改进效果,实验证明,立体结构的设计使传感器具有更低的检出限(8 μmol/L)及更高的灵敏度(在 0～200 μmol/L浓度范围内检测灵敏度提高约85%),且具有较好的线性和重复性.利用电化学方法在电极表面沉积铂黑,通过微观形貌分析和电化学特性考察,比较了在平面微电极和立体微电极上修饰纳米材料的效果.立体结构为电沉积铂纳米颗粒提供了更为理想的微环境,改善了纳米材料修饰的效果;立体结构微电极与纳米颗粒的尺寸效应相结合,进一步提高了电极的催化效率和电化学特性.     

石墨烯基平面微型超级电容器的研究进展

便携式电子器件的快速发展极大地刺激了现代社会对多功能化、小型化的电化学储能器件的强烈需求.其中,微型超级电容器正逐渐成为芯片储能器件研究领域中一个新兴的、前沿的研究方向.它可作为微型功率源与微电子器件互相兼容,具有极大的应用前景.最近,以石墨烯为代表的二维材料为设计和发展新型平面化微型超级电容器提供了许多关键参数,引起了大家的关注.鉴于此,本文综述了石墨烯基平面微型超级电容器的最新进展,包括其发展历史、典型的石墨烯材料(如石墨烯、石墨烯量子点、活化石墨烯、石墨烯/碳纳米管、石墨烯/金属氧化物、石墨烯/聚合物)的制备、微型电极的构筑与加工(如光刻、电化学沉积、激光刻绘、喷涂印刷等)、电解液(如水系、有机系、离子液体和固态式)、微型器件构型组装(对称的、非对称的)和微型器件的评测方法.最后,展望了石墨烯基微型超级电容器未来的发展趋势和面临的挑战.     

电极/碱性聚电解质界面的微分电容曲线和零电荷电位测定（英文）

碱性聚合物电解质作为现代碱性氢氧燃料电池的核心组成部分,其单离子导体的特性使得“电极/碱性聚电解质”界面的性质与“电极/溶液”界面有所不同。本文使用微电极,运用循环伏安、电化学交流阻抗以及浸入法等方法,测定了电极/碱性聚电解质界面的微分电容曲线和零电荷电位。该界面的微分电容曲线呈“U”状,且存在局域极小值,该极小值所对应的电位与浸入法测得的零电荷电位数值一致。单离子导体的特性使得“电极/碱性聚电解质”界面在零电荷电位两侧表现出不同的电化学极化行为。     

电化学电容器储能机理的原位表征技术研究进展

电化学电容器是一种在高比表面积多孔电极表面通过电吸附离子或快速法拉第反应来存储电荷的储能器件.近十年来,通过对电极材料纳米尺度的调控,超级电容器的各项性能指标得到了大幅度提升.深入理解电荷存储机制对进一步提升超级电容器的性能至关重要.本文介绍了近年来国际上采用原位核磁共振技术(in-situ NMR spectroscopy)、电化学石英晶体微天平(EQCM)、原位红外光谱(in-situ infrared(IR) spectroscopy)和原位小角散射技术(in-situ scattering approaches)等电化学原位技术研究超级电容器储能机理方面的进展,并探讨了原位表征技术在构建高性能超级电容器方面所面临的挑战.     

基于高黏附可拉伸高分子材料的人机交互界面

随着柔性电子技术和人工智能的蓬勃发展, 将柔性传感器与人工智能、 大数据和5G通讯有机结合, 能够构建以人为中心的智能人机交互系统, 在智能健康监测和生物医疗等领域发挥越来越重要的作用. 作为连接人体信号与网络空间的人机交互界面, 皮肤电极的力学性能直接影响监测信号的灵敏度和稳定性. 从材料的角度出发, 如何同时实现电极的可拉伸性和高黏附性, 让其稳定地贴敷于皮肤表面, 成为皮肤电极进一步应用亟待解决的科学难题和技术挑战. 本文综合评述了近年来高黏附可拉伸高分子材料的研究进展及在人机交互界面的各种应用, 并展望了下一代智能人机交互界面的发展趋势.     

Biofuel Cell Operating in Vivo in Rat

Biocatalytic electrodes made of buckypaper were modified with PQQ‐dependent glucose dehydrogenase on the anode and with laccase on the cathode. The enzyme modified electrodes were assembled in a biofuel cell which was first characterized in human serum solution and then the electrodes were placed onto exposed rat cremaster tissue. Glucose and oxygen dissolved in blood were used as the fuel and oxidizer, respectively, for the implanted biofuel cell operation. The steady‐state open circuitry voltage of 140±30 mV and short circuitry current of 10±3 µA (current density ca. 5 µA cm^?2 based on the geometrical electrode area of 2 cm²) were achieved in the in vivo operating biofuel cell. Future applications of implanted biofuel cells for powering of biomedical and sensor devices are discussed.     

On the cyclic deformation behavior,fracture properties and cytotoxicity of silicone-based elastomers for biomedical applications

This paper provides results from a comprehensive experimental characterization on five silicone-based elastomers used as substrates for mechanobiological studies or in soft biomedical implants. A previous paper was recently published which focused on the large strain deformation behavior of these materials. This second part analyzes their reliability for biomedical applications in terms of changes of deformation behavior with the history of loading (long term cyclic behavior), ability to resist loads in the presence of defects (fracture properties), and cytotoxicity. For the latter, all materials are confirmed to be non-toxic which is a prerequisite for their use in mechanobiological studies or as part of implants and biomedical devices. The response in long term uniaxial tests over 220′000 cycles was characterized and the results indicate general stability of the mechanical response with, for some conditions, softening mechanisms active mainly in the initial phase of the test (50′000 cycles). A critical aspect of elastomer performance and their suitability for application in biomedical devices concerns their fracture properties. The tearing energy varies in a range from brittle (with approximately 80 J/m² for PDMS Sylgard 184) to tough (with approximately 900 J/m² for SMI G/G 0.020).     

Nanofibers for Biomedical and Healthcare Applications

Unique features of nanofibers provide enormous potential in the field of biomedical and healthcare applications. Many studies have proven the extreme potential of nanofibers in front of current challenges in the medical and healthcare field. This review highlights the nanofiber technologies, unique properties, fabrication techniques (i.e., physical, chemical, and biological methods), and emerging applications in biomedical and healthcare fields. It summarizes the recent researches on nanofibers for drug delivery systems and controlled drug release, tissue‐engineered scaffolds, dressings for wound healing, biosensors, biomedical devices, medical implants, skin care, as well as air, water, and blood purification systems. Attention is given to different types of fibers (e.g., mesoporous, hollow, core‐shell nanofibers) fabricated from various materials and their potential biomedical applications.     

Effects of dielectrophoresis on thrombogenesis in human whole blood

Thrombogenesis (blood clot formation) is a major barrier to the development of biomedical devices that interface with blood. Although state‐of‐the‐art chemically and pharmacologically mediated clot mitigation strategies are effective, some limitations of such approaches include depletion of active agents, or adverse reactions in patients. Increased clotting protein adsorption and platelet adhesion, which occur when artificial surfaces are exposed to blood result in enhanced clot formation on artificial surfaces. It is hypothesized that repelling proteins and platelets using dielectrophoresis (DEP), a contact‐free particle manipulation technique, will reduce clot formation in biomedical devices. In this paper, the effect of DEP on thrombogenesis in human blood is investigated. Undiluted whole blood from human donors is pumped through microchannels at a physiological shear rate (400 s ⁻¹). Experiments are performed by applying 0 V, 0.5 V_rms , 2 V_rms , and 3 V_rms to electrodes in the channel. Clot formation is observed to decrease in experiments in which DEP electrodes are active (average of 6% coverage @ 0V reduced to 0.08% coverage @ 3 V_rms ). Repulsion is more effective at higher voltages. DEP causes a quantifiable reduction in microscopic and macroscopic clot formation in PDMS microchannels.     

Surface patterning and modification of polyurethane biomaterials using silsesquioxane-gelatin additives for improved endothelial affinity

Polyurethanes (PUs) are well-known for their biocompatibility but their intrinsic inert property hampers cell-matrix interactions. Surface modifications are thus necessary to widen their use for biomedical applications. In this work, surface modifications of PU were achieved first by incorporating polyhedral oligomeric silsesquioxane (POSS), followed by alteration of the surface topography via the breath figures method. Subsequently, surface chemistry was also modified by immobilization of gelatin molecules through grafting, for the enhancement of the surface cytocompatibility. Scanning electron microscopy (SEM) was used to verify the formation of highly ordered microstructures while static contact angle, FTIR and XPS confirmed the successful grafting of gelatin molecules onto the surfaces. In vitro culture of human umbilical vein endothelial cells (HUVECs) revealed that endothelial cell adhesion and proliferation were significantly enhanced on the gelatin-modified surfaces, as shown by live/dead staining and WST-1 proliferation assay. The results indicated that the combination of the strategies yielded an interface that improves cell attachment and subsequent growth. This enhancement is important for the development of higher quality biomedical implants such as vascular grafts.     

Host Responses to Biomaterials and Anti‐Inflammatory Design—a Brief Review

Host responses toward foreign implants that lead to chronic inflammation and fibrosis may result in failure of the biomedical device. To solve these problems, first a better understanding of the biomaterial‐induced host reactions including protein adsorption, leukocyte activation, inflammatory and fibrotic responses to biomaterials is required; second an improved design of biomaterial surfaces is needed that results in an appropriate host response, causing less inflammatory response, and supporting tissue regeneration. Hence, this review provides a brief overview on the host response to implants, as well as in vitro models to study inflammatory and fibrotic responses to biomaterials to predict the clinical outcome of implantation. Moreover, the review highlights anti‐inflammatory strategies to improve the biocompatibility of implants, which contain the modification of physicochemical surface properties of materials as well as the immobilization of anti‐inflammatory reagents and bioactive molecules on biomaterials.     

Atmospheric Pressure Plasma Surface Treatment of Polymers and Influence on Cell Cultivation

Atmospheric plasma treatment is an effective and economical surface treatment technique. The main advantage of this technique is that the bulk properties of the material remain unchanged while the surface properties and biocompatibility are enhanced. Polymers are used in many biomedical applications; such as implants, because of their variable bulk properties. On the other hand, their surface properties are inadequate which demands certain surface treatments including atmospheric pressure plasma treatment. In biomedical applications, surface treatment is important to promote good cell adhesion, proliferation, and growth. This article aim is to give an overview of different atmospheric pressure plasma treatments of polymer surface, and their influence on cell-material interaction with different cell lines.     

Coated film electrodes

Summary The construction of coated-film electrodes is described. It is shown that they are miniaturizable, inexpensive, simple sensors for various cations and anions. They are similar to the coated-wire electrodes, but instead of a metal wire an extremely thin conductive metal layer manufactured in thin-film technology is used. Potassium and sodium electrodes studied so far show excellent electrode properties, i. e. near Nernst response over a wide concentration range, sometimes better than commercial ion-selective electrodes. Two film electrodes are used to develop a low cost sensor for the determination of the activity of ions in a simple way by potentiometric difference measurement; this solid-state sensor can be applied to biomedical measurements, especially for blood analysis.

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Dedicated to Prof. Dr. G. Tölg on the occasion of his 60th birthday     

表面抗菌功能涂层的构建及在生物医用材料中的应用研究

近年来,生物医用材料在使用过程中产生的医源性感染问题层出不穷,对人们健康和生命造成严重威胁.表面抗菌涂层构建是解决该类医源性感染问题最有效的策略之一.目前,按照作用机制和功能不同将表面抗菌涂层分为接触式抗菌涂层、抗黏附抑菌涂层、抗黏附杀菌涂层以及智能抗菌涂层.表面抗菌涂层的构建不仅赋予了生物医用材料抗菌性能,有效解决了...