压电生物传感器

虽然压电效应在上一世纪业已发现,但是压电石英晶体在化学传感器中的应用却是1995年Sauerbrey导出了频率-质量关系式之后才实现的.1964年King报道了第一个压电石英晶体检测器.至今,压电石英传感器已广泛用于气体、液体试样分析.我国姚守拙等人在压电石英晶体的分析应用领域率先进行了大量的研究工作.根据Sauerbrey方程,结合生物体中某些高选择反应,通过对石英晶体表面进行修饰,使其能选择性地与被检测物质作用,便可制成压电生物敏感元件(或压电生物传感器).1972年Shons首次用抗原涂膜压电晶体来检测溶液中的抗体,由于当时技术的限制及人们对该类传感器认识不足,未能得到较好地发展,直到本世纪80年代中期才为人们所重视.目前国外对此新领域的研究非常活跃,但国内尚未见压电生物传感器方面的研究报道.现对     

压电传感器在线监测蛋白质在自组装膜上的吸附

在压电石英晶体传感器的金电极表面化学修饰烷基硫醇（ＨＳ（ＣＨ２）１５ＣＨ３）的自组装单层膜（ＳＡＭ）,并利用该传感器在线监测纤维蛋白原在ＳＡＭ表面的吸附过程。该方法给出有关蛋白质吸附的动力学、可逆性,吸附等温线等方面的信息。     

压电石英晶体生物传感器应用研究进展

压电石英晶体生物传感器是利用压电石英晶体振荡频率对晶体表面质量负载和表面性状如密度、粘度、电导、介电常数等的高度敏感性与生物识别分子的高度特异性相结合发展起来的一种新型传感器。它具有灵敏度高、特异性好 ;操作简单 ,不需任何标记 ;检测速度快 ,成本低廉 ;能实时检测等特点。近年来 ,压电石英晶体生物传感器在医学实验诊断、军事监控、环境监测、食品卫生检验、工业生产实时监测等野外流动作业和在线检测等领域得到广泛应用。     

压电传感器在线监测自组装膜的成膜过程

在压电石英晶体表面真空喷镀金电极，当金电极与长链烷基硫醇（ＨＳ（ＣＨ２）１５ＣＨ３）接触时，硫醇分子自发地在金电极表面发生化学吸附，并形成紧密堆积、高度有序的自组装单层膜（ＳＡＭ），本文利用压电石英晶体传感器在线监测ＳＡＭ形成过程中的质量变化量，给出有关ＳＡＭ的成膜动力学方面的信息。     

压电石英晶体传感器在单链及乙肝病毒检测中的应用

建立压电石英晶体传感器检测乙肝血液样品的方法。在石英晶体表面固定单链DNA,构建压电晶体DNA生物传感器,然后,分别与乙肝病毒的特异性片段和处理过的乙肝血液样品进行杂交反应。DNA传感器能较好地诊断出血清中的HBV病毒基因。压电石英晶体传感器操作方便、省时,且具有较好的准确度,在临床诊断中有很好的前景。     

提高液体中石英晶体传感器频率稳定度的方法

石英晶体传感器的动态阻抗显著增大,品质因数下降是液体阻尼负载作用的主要效果。本文从分析液体中石英晶体谐振器的相位平衡条件出发,研究了影响传感器频率稳定度的因素;由石英晶体谐振器的能量局部化效应,分析了传感器液体测头设计中的问题,并由此设计出在液体中工作的石英晶体传感器。实验结果表明,此传感器在液体中具有较高的频率稳定度。     

提高液体中石英晶体传感器频率稳定度的方祛

石英晶体传感器的动态阻抗显著增大, 品质因数下降是液体阻尼负载作用的主要效 果# 本文从分析液体中石英晶体谐振器的相位平衡条件出发, 研究了影响传感器频率稳定度 的因素) 由石英晶体谐振器的能量局部化效应, 分析了传感器液体测头设计中的问题, 并由 此设计出在液体中工作的石英晶体传感器 # 实验结果表明, 此传感器在液体中具有较高的频 率稳定度.     

提高液体中石英晶体传器频率稳定度的方法

石英晶体传感器的动态阻抗显著增大，品质因数下降是液体阻尼负载作用的主要效果。本文从分析液体中石英晶体谐振器的相位平衡条件出发，研究了影响传感器频率稳定度的因素；由石英晶体谐振器的能量局部化效应，分析了传器液体测头设计中的问题，并由此设计在液体中工作的石英晶体传感器，实验结果表明，此传感器在液体中具有较高的频率稳定度。     

本期摘要

钢水成分传感器及其应用进展，厚膜压力传感器的温度补偿与调理方法研究，一种新型高精度压电谐振式石英晶体温度传感器，动态血糖连续测定系统，几种较新的纳米聚合物传感器     

基于薄膜体声波谐振器的免疫球蛋白传感器制备

研制了一种基于薄膜体声波谐振器（ FBAR）的生物免疫球蛋白传感器,该FBAR采用AlN作为压电层,3对Ti/W金属层作为布拉格声学反射层,工作频率为2.047 GHz,回波损耗为－32 dB。利用自组装膜法修饰顶部金电极敏感区域。测试了免疫球蛋白G抗体和抗原的特异性结合前后传感器的指标变化。结果得到传感器的Q值和灵敏度分别达到846,3.38 kHz·cm2/ng,远高于广泛使用的石英晶体微天平（ QCM）,具有广阔的应用前景。     

硅酸镧镓压电传感器监测离子液体膜的粘度

以硅酸镧镓晶体为压电材料,研制的微天平传感器不仅对质量变化高度敏感,也可用于液体粘度传感,并能在高粘性介质中使用.随传感器所接触的液体粘度增加,它的谐振频率下降,而动态电阻增加.基于粘度响应模式,该传感器应用于实时检测溴代1-甲基-3-正己基咪唑膜吸附乙醇过程中的粘度及乙醇吸附量的动态变化,为研究离子液体粘度及其吸附性能提供了一种新的测量方法.     

Comparison of FBAR and QCM-D sensitivity dependence on adlayer thickness and viscosity

Unlike the quartz crystal microbalance, which has been used extensively for the analysis of biochemical interactions, only few measurements with biochemical adsorbent have been done with film bulk acoustic resonators (FBAR). In this paper, the FBAR behaviour on exposure to a lipid vesicle solution and the formation of a polyelectrolyte multilayer structure is investigated and compared with the results obtained with the quartz crystal microbalance. Differences in the resonator response were found between the two techniques and depending on the resonators resonance frequency ranging from the MHz to the GHz regime. As an explanation, we suggest that the penetration depth and the influence on viscoelastic properties, which are both known to be frequency dependent, cause the variations in the results. As a consequence, the higher operating resonance frequencies of the FBAR increase the sensitivity to changes in the viscoelasticity of the adsorbent and also decrease the sensing length of the device.     

Polyaniline–TiO2 nano-composite-based trimethylamine QCM sensor and its thermal behavior studies

Inorganic/organic composites are very attractive due to synergetic behavior and a wide range of potential use. A polyaniline–TiO₂ nano-composite, obtained by combination of chemical polymerization and a sol–gel method, was deposited on the electrode of quartz crystal to implement a quartz crystal microbalance (QCM) chemical sensor. The morphology of the composite film was studied by scanning electron microscopy (SEM) measurements. The coated quartz crystal and a non-coated quartz crystal were mounted in a sealed chamber, and their frequency difference was monitored. When analyte vapor was injected into the chamber, gas absorption decreased the frequency of the coated quartz crystal and thereby caused an increase of the frequency difference between the two crystals. The frequency difference change response towards trimethylamine was evident and could be recovered by N₂ purgation easily. The calibration curve towards trimethylamine, its long-term stability and selectivity were investigated. The thermal behavior of the sensing characteristics was compared with that of a polyaniline QCM sensor. Fourier transform infrared (FTIR) spectra of polyaniline and polyaniline–TiO₂ nano-composite and QCM data under various conditions were used to study the effect of thermal treatment.     

蛋白质在硅烷膜表面吸附特性的压电传感监测

在压电石英晶片表面自组装修饰末端为胺基的硅烷膜,该膜在酸性和中性pH条件下带正电荷,可通过静电引力吸附带负电荷的牛血清白蛋白(BSA),吸附过程中的质量变化可通过石英晶片的谐振频率变化实时监测。结果表明:该吸附过程虽然为部分不可逆,但吸附等温线符合Langmuir方程,吸附速率常数为0.0117 L.g-1.s-1,吸附平衡常数为2.87 L.g-1,表观饱和吸附量Γ∞=0.954μg.cm-2。     

A piezoelectric micro-cantilever bio-sensor using the mass-micro-balancing technique with self-excitation

A biosensor was developed for using in a Lab-On-a-Chip (LOC). The sensor detects the change in the resonance frequency of a micro-cantilever with a piezoelectric film. This is the mass micro-balancing technique, which has been successfully used for detecting bio-materials in the quartz crystal microbalance (QCM). The PZT film, a piezoelectric film, is designed to act as both sensor and actuator. The geometry of the micro cantilever is optimized to maximize the sensitivity and minimize the environmental effects such as viscous damping and added mass effect in liquid. The fabricated sensor is composed of a 100 μm long, 30 μm wide, and 5 μm thick cantilever with a 2.5 μm thick piezoelectric (PZT) layer on it. The ratio of thickness to length of the micro cantilever is very high compared to others in micro cantilever-based studies. This high aspect ratio is the key to maximize the sensitivity and minimize the environmental effects. The fabricated micro sensor was tested by detecting the mussel gluing protein, the insulin-anti insulin binding protein and the poly T-sequence DNA.     

Out-of-plane vibrations of quartz resonators used in quartz crystal microbalance measurements in gas phase

The article reveals that shear-mode quartz crystal resonators, currently used in quartz crystal microbalance (QCM) measurements, exhibit an out-of-plane vibration without being in contact with a liquid. Laser assisted CVD was used to deposit carbon-nanoparticles on the surface of a quartz resonator. The in-plane, shear vibration of the quartz resonator, produces a mega-gravity acceleration which induces a sedimentation of the carbon-nanoparticles, while the out-of-plane vibration produces a mega-gravity acceleration, normal to the crystal surface, which induces an expelling of the deposited carbon-nanoparticles. The two opposite effects reveal a complex situation on the quartz resonator surface in QCM measurements.     

Uncooled IR imaging array based on quartz microresonators

A quartz crystal resonator's resonance frequency is sensitive to temperature. This sensitivity has been exploited in the past in thermometers made of single, macroscopic quartz resonators that can accurately detect temperature changes of μK. Using semiconductor microfabrication techniques, it is now possible to fabricate a large number of microresonators from a single quartz wafer. It is shown that combining the small thermal mass and high thermal isolation capability of such microresonators, the steep frequency versus temperature characteristics of resonators made of certain cuts of quartz and the low-noise characteristics of quartz crystal oscillators can result in high-performance infrared (IR) sensors and sensor arrays. In a microresonator sensor, the temperature change produced by the absorption of IR energy results in a frequency change that can be measured with a resolution that corresponds to a change in the resonator's temperature of less than a μK. Calculation shows that an array of microresonators in the 200 MHz-1 GHz range can be the basis of an uncooled IR imaging system with a noise equivalent temperature difference, NETD, of <0.01 K. The design and fabrication problems to be overcome before such microresonator arrays can be realized are discussed     

Application of quartz tuning forks and extensional microresonators for viscosity and density measurements in oil/fuel mixtures

Real time monitoring of the physical properties of liquids is of great concern in the automotive industry. For example, tracking the viscosity of lubricating oils is of great importance because they are exposed to dilution with diesel fuel as result of late-injection processes, which are essential for regenerating diesel particulate filters. Here we describe two in-plane movement based resonators and their capability to assess oil dilution with diesel and biodiesel fuels. One of the resonators is a state-of-the-art micron-sized AlN-based rectangular plate, actuated in the first extensional mode in the MHz range. The second resonator is a commercially available millimeter-sized quartz tuning fork, working at 32.7 kHz. Electrical impedance measurements were performed to characterize the performance of both resonators in various liquid media over a wide range of viscosities. These measurements were compared with the results obtained with low-cost electronic circuits also developed in this work. In order to track density and viscosity of different fluids we have measured two parameters by various techniques: the resonance frequency and the quality factor.     

QCM振荡频率检测平台的建立及其稳定性探讨

压电石英晶体振荡器谐振频率的稳定性是构建晶体微天平检测平台的前提,环境温度是导致稳定的石英晶体振荡器的频率漂移的主要因素。本文通过理论分析,选用合适晶片、采用差频技术构建特殊的振荡电路,消除了检验检测平台由于环境温度引起的频率漂移,从而提高了微天平的稳定性,使传感器的性能得到明显提高。