A Piezoelectric Quartz Crystal Biosensor as a Direct Affinity Sensor

Abstract

A microprocessor controlled piezoelectric detector as sensor was employed to monitor in real time protein adsorption and immunoreactions using piezoelectric quartz crystals (AT-cut) with a basic resonant frequency of 10 MHz. The adsorbed protein was an immunoglobulin (h-lg G); in the immunosensing a covalent immobilized molecule (the pesticide 2,4-D) formed the receptor for the immobilized ligand sample (Mab anti-2,4-D) in a competitive assay.     

Piezoelectric Crystal Biosensor System for Detection of Escherichia Coli

Abstract

A piezoelectric crystal biosensor system was applied to the detection of Escherichia coli. the system consists of an oscillator, a frequency counter, a flow cell and a modified piezoelectric crystal. Anti-E. coli antibody is immobilized on the surface of the crystal. It is used as an E. coli detection by measuring its resonant frequency shift due to a mass change caused by specific binding of the micro organisms to the surface. the frequency shift correlates with an E. coli concentration in the range of 10⁶?10⁸ cells·cm^?3. the resonant frequency shift is increased by further treatment to bind micro-particles modified with anti-E. coli antibody. This method allows us to improve the determination limit to 10⁵ cells · cm^?3.     

An Unexpected Frequency Response of A Piezoelectric Quartz Crystal Sensor to the Density and Viscosity of the Liquid

An unexpected frequency response for a piezoelectric quartz crystal (PQC) sensor to liquid density and viscosity was reported. For a PQC oscillating in a liquid phase, the frequency shifts (△f) show a wave-shape response to liquid density (p) and viscosity 03) in fine structure, ifthe longitudinal wave effect was not eliminated. This result is different from the well-knownlinear relationship between of Af and (ρη)1/2. An oscillating frequency-temperature curve of thesensor was observed and explained.     

压电免疫传感器用于B因子的测定

B因子是一种不耐热的球蛋白,它参与机体的防御,在炎症过程、细胞和组织损伤中均起重要作用.B因子的检测方法常用的有单扩散法、火箭电泳法和溶血法,前者灵敏度不高,重复性差;后两者操作较复杂^[1,2].     

一种用于测定尼古丁的新型压电石英晶体传感器的研制

本文将含有四苯硼钠的聚氯乙烯(PVC)敏感膜涂渍在压电石英晶体(PQC)表面,制成尼古丁传感器,该传感器在pH 5.0~7.5的范围内,对1.0×10-6~1.0×10-2mol/L的尼古丁水溶液有很好的线性响应,检出限为8.0×10-7mol/L。本法较紫外分光光度法有更宽的线性范围和更低的检出限。     

Optimisation of a Flow Injection System with a Piezoelectric Quartz Crystal Detector for the Determination of Inorganic Mercury

ABSTRACT

A new method combining flow injection methodology with quartz crystal microbalance (QCM) detection is proposed for inorganic mercury analysis. A modified simplex method is used in order to maximise the observed analytical signals (crystal frequency decrease). Six parameters were optimised: the concentration of the acidic carrier solution, the lengths of the sample loop and mixing coil, and the flow rates of the sample carrier, the reductant stream (SnCl₂), and the carrier of the mercury vapour (N₂). An increase of 18% in the signal of the centroid of the calibration line was achieved, as well as an increase in the sensitivity from 290 Hz μg^? to 313 Hz μg^?. Following the proposed procedure, detection limits of 47 μg L^? of inorganic mercury were found for sample volumes of 0.5 mL.     

A Piezoelectric Crystal Detector for Acetoin

Abstract

A piezoelectric quartz crystal coated with tetrabutyphosphoniun chloride was found to be a good detector for acetoin. The coating is sensitive in the ppb range and completely reversible. The response curve is linear over a concentration range of 8-120 ppb. The detector can be tuned to give a satisfactory response in 30 seconds.     

压电晶体传感器阵列用于含乙醇的蒸气检测

将多个表面涂有不同选择性吸附材料的压电晶体传感器组成阵列，用于混合有机溶剂蒸气中乙醇的检测。对阵列输出的数据，采用逐步判别法进行二类判别，可以检测混合蒸气中少量的乙醇，采用主成分回归法，可由阵列输出数据预测未知样品中乙醇的浓度。     

Piezoelectric Quartz Crystal Biosensors: Recent Immobilisation Schemes

ABSTRACT

A Mini Review on recent immobilisation techniques for the realisation of piezoelectric biosensors is presented. The reactions considered are affinity reactions such as DNA hybridisation and antigen/antibody systems. The immobilisation procedures considered are based on avidin-biotin interaction, adsorption and self-assembled monolayers.     

压电免疫传感器用于C2型葡萄球菌肠毒素的测定

报道了用蛋白Ａ－金电极法将抗体固化在３．５８ＭＨｚ和１０ＨｚＡＴ切割的石英晶体上，制作的可重复使用的压电免疫传感器，测定Ｃ２型葡萄球菌肠毒素。最适ＰＨ值为７，并用不同的方法测试了晶体片上的抗体固化情况。     

压电晶体传感器阵列测定装置及数据采集系统

研究了一种利用微机控制测量和采集压电晶体传感器阵列振荡频率的智能型仪器。介绍了其硬件及数据采集软件的功能，结构等。     

基于网状混合自组装膜的压电免疫传感器及其应用

结合纳米金及混合自组装技术, 制备了一种新型网状混合膜, 提出了一种新的生物分子固定化方法, 研制了一种用于检测人血清抗精子抗体的压电免疫传感器. 首先, 将纳米金溶胶、巯基丙酸和1,6-二巯基己烷按一定的比例混合制得网状混合自组装膜, 然后将此膜组装到压电石英晶振的金电极表面, 经EDC/NHS活化后, 再将抗原固定到电极上, 实现对抗精子抗体的检测. 结果表明, 该方法能明显提高抗体抗原结合效率, 从而提高传感器的灵敏度, 并降低传感界面的非特异性吸附. 将此传感器应用于人血清抗精子抗体的检测, 线性范围为10~800 mU/mL, 检出限为7 mU/mL. 此传感器为抗精子抗体的临床检测提供了新平台.     

Development of Piezoelectric Immunosensor for the Detection of Probiotic Bacteria

A Quartz Crystal Microbalance (QCM) based direct immunosensor was developed for real-time detection of probiotic bacteria. To optimize the immunosensor system, model measurements were carried out with bovine serum albumin (BSA) and anti-BSA IgG (a-BSA) antibody. During the model experiments, two kinds of self-assembled monolayers were created to compare their efficiency on antigen binding. Sulfosuccinimidyl 6-[3-(2-pyridyldithio)propionamido] hexanoate (sulfo-LC-SPDP) and 16-mercapto-hexadecanoic acid (MHDA) cross-linking agents were used for immobilizing anti-BSA antibody onto the gold surface of the AT-cut quartz wafer. Two different measuring procedures, flow-through and stopped-flow methods, were applied, and the frequency responses obtained by both analytical methods were compared.

After the model experiments probiotic bacteria, Bifidobacterium bifidum O1356 and Lactobacillus acidophilus O1132 serotypes were detected from buffer solution and from real samples (spiked milk samples, acidophilus, and bifidus milk samples).

Using the novel immunosensor, the target bacteria could be detected in the range of 10⁴–10⁷ colony-forming units (CFU)/ml within 60 minutes. The selectivity of a-Bifidobacterium bifidum and a-Lactobacillus acidophilus antibody coated sensors were also tested.     

Assay of Glomalin Using a Quartz Crystal Microbalance Biosensor

Glomalin is a soil protein abundantly occurring in the soil. In the current time, knowledge about glomalin is limited and there are also missing simple test for the determination of glomalin in the environment. This work is devoted to construction of a biosensor which is expected to be a simple device for the determination of glomalin in extracts from soil samples. The biosensor was constructed using an antibody against glomalin and piezoelectric quartz crystal microbalance (QCM) sensor platform allowing label free assay. Electrodes of QCM were activated using cysteamine and glutaraldehyde and finally, an antibody against glomalin was immobilized. Glomalin was acquired from various soil samples by extraction in an autoclave and its content was determined by a standard spectrophotometric test. Time necessary to bind sufficient amount of glomalin was discovered for the biosensor and four hours incubation interval corresponded with maximal efficacy. Limit of detection for the biosensor based assay was found to be equal to 3.40 μg/g which is enough to cover all the tested soil samples containing glomalin in a concentration from 291 μg/g to 3.47 mg/g. The assay also fully correlated with the standard tests. In a conclusion, the piezoelectric biosensor seems to be a suitable platform for the determination of glomalin in samples of environment origin. The method represents an improvement of the current analytical platforms that are based on measurement of total protein content in soil extract.     

增塑的PVC涂膜压电晶体传感器阵列用作香味传感系统

增塑的ＰＶＣ涂膜压电晶体传感器阵列用作香味传感系统曹忠，林辉概，王彬锋，王柯敏，陈泽忠，俞汝勤（湖南大学化学化工系，长沙，４１００８２）关键词阵列，压电晶体传感器，增塑的ＰＶＣ涂膜，香味传感系统吸附活性物质如类脂化合物等涂膜的压电晶体传感器（ＰＣＳ）...     

模式识别用于压电晶体传感器阵列识别可燃物质

用７个压电晶体组成传感器阵列,每个晶体上分别涂有不同种类的气相色谱固定液,通过测定各种可燃物质燃烧时放出的混合气体来识别所燃物质,在识别中分别应用了人工神经网络法（ＡＮＮ）和逐步判别分析法（ＳＤＡ）。讨论了解决神经网络开始训练时不收敛或产生麻痹现象的方法,提出了训练数据选取的新方法－训练集逐步扩展法,实验证明：人工神经网络对被测物质的识别准确率达１００％,高于逐步判别分析法（８３％）。     

塑料增强的新途径——热致液晶高聚物的增强作用

评价了热致液晶高聚物作为高性能成型材料的特点。综述了由增强性的热致液晶高聚物和热塑料聚合物基体组成的原位复合材料及其制备、结构和性能。也讨论了今后研究这一塑料增强新途径时要注意的诱导取向和相容性。     

检测硫化氢阳性菌属压电石英传感器的研制

针对硫化氢阳性菌属在新陈代谢过程中释放出H2S的特性,设计了双面镀银的压电石英晶体探头,构建新型的生物传感器模式。信号探针修饰的Ag可与生物代谢产物H2S结合,通过压电石英晶体经典的气相质量响应的原理,实现了对硫化氢阳性菌属的检测。结果表明,该传感器能很好地区分硫化氢阳性、阴性菌属,培养基中最佳的半胱氨酸浓度为0.05%。该传感器的设计避免了培养基与探头之间的直接接触,减少了液相质量响应存在的干扰,成功实现了硫化氢阳性菌属的自动培养和检测。     

Piezoelectric Nanogenerator Based on Electrospun Cellulose Acetate/Nanocellulose Crystal Composite Membranes for Energy Harvesting Application

Nanogenerators, as the typical conversion of mechanical energy to electrical energy devices, have great potential in the application of providing sustainable energy sources for powering miniature devices. In this work, cellulose acetate/cellulose nanocrystal(CA/CNC) composite nanofiber membranes were prepared by electrospinning method and then utilized to manufacture a flexible pressure-driven nanogenerator. The addition of CNC not only increased the content of piezoelectric cellulose I crystallization but also strengthened the mechanical deformation of the nanofiber membranes, which could greatly enhance the piezoelectric performance of CA/CNC composite membranes. The CA/CNC composite nanofiber membrane with 20%(mass fraction) of CNC(CA/CNC-20%) showed optimal piezoelectric conversion performance with the output voltage of 1.2 V under the force of 5 N(frequency of 2 Hz). Furthermore, the output voltage of the CA/CNC-20% nanogenerator device exhibited a linear relationship with applied impact force, indicating the great potential in pressure sensors.