共查询到19条相似文献,搜索用时 15 毫秒
1.
石英晶体微天平实时监测亲和素对低密度脂蛋白的吸附 总被引:1,自引:0,他引:1
利用石英晶体微天平(QCM)实时监测低密度脂蛋白(LDL)在亲和素(Avid in)上的吸附,并探讨二者的作用机理。实验结果表明:Avid in与LDL之间的相互作用方式主要是静电吸附,即中性环境下带正电的Avid in可与LDL分子表面的带负电的磷脂分子发生静电吸引,当LDL浓度为0.049 5 g/L时,最大吸附量达到3.54×10-7g/cm2,吸附率为59.68%,NaC l溶液的洗脱效果达到了86%。研究证实:Avid in具有较大的吸附量和较高的吸附率,有望作为新型吸附LDL的吸附剂配基。 相似文献
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Weili HuAuthor VitaeShiyan ChenAuthor Vitae Bihui ZhouAuthor VitaeLuting LiuAuthor Vitae Bin DingAuthor Vitae Huaping WangAuthor Vitae 《Sensors and actuators. B, Chemical》2011,159(1):301-306
A novel highly stable and sensitive humidity sensor based on bacterial cellulose (BC) coated quartz crystal microbalance (QCM) has been successfully fabricated. The results showed that the sensors possessed good sensing characteristics by increasing more than two orders of magnitude with increasing relative humidity (RH) from 5 to 97%, and the Log(Δf) showed good linearity (20-97% RH). The sensitivity of sensors coated with BC membranes was four times higher than that of the corresponding cellulose membranes at 97% RH. In addition, the sensor sensitivity is greatly enhanced by increasing the coating load of the BC membranes with more absorption sites in the sensing membranes. Moreover, the experimental results prove that the resultant sensors exhibited a good reversible behavior and good long term stability. Herein, not only a novel and low-cost humidity sensor material was exploited, but also a new application area for BC nanofibrous membranes was opened up. 相似文献
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Comparison of surface plasmon resonance spectroscopy and quartz crystal microbalance for human IgE quantification 总被引:2,自引:0,他引:2
Surface plasmon resonance (SPR) and quartz crystal microbalance (QCM) have been known independently as surface sensitive analytical devices capable of label-free and in situ bioassays. In this study a SPR device and a 10 MHz QCM sensor are employed for the study of human IgE and anti-human IgE-binding reactions upon immobilizing the latter on the gold electrodes. The SPR and QCM response curves to the antibody immobilization and antigen binding are similar in shape but different in time scale, reflecting different resonation principles. Through optimization of the anti-human IgE coating, both the SPR and QCM sensors could detect IgE in a linear range from 5 to 300 IU/ml. Although the intrinsic sensitivity of the SPR device is five times of the 10 MHz QCM, the IgE detection sensitivity of the two methods is, however, different only in a factor of 2. The acceptable QCM sensitivity for the IgE detection is attributed to the fact that QCM measures the sum of molar mass of a protein layer and the entrapped water. Although both the devices use open, stand still liquid cell, and all the measurements are performed at room temperature, the SPR reproducibility and reliability are better than QCM, as the QCM frequency is more sensitive to temperature fluctuations, press changes and mechanical disturbances. 相似文献
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Quartz resonators coated with three kinds of poly(acrylamide) derivatives were studied for simply but accurately detecting HCl gas in air. The exposure of the resonator to HCl gas reversibly decreased the oscillation frequencies. The sensitivity, response time, and reversibility were found to depend on the structure of the amide group. Among the polymers used, poly(N,N-dimethylacrylamide) (PDMAA) showed the most relevant data for the HCl sensor. The HCl sensitivity obtained for PDMAA was ca. 250 ppb/Hz. On the other hand, the irreversible response toward NO2 gas was considerably high, and great interference was also produced by changes in the test gas humidity. 相似文献
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Monolithic sensor array based on a quartz microbalance transducer with enhanced sensitivity for monitoring agricultural emissions 总被引:2,自引:0,他引:2
A low-cost sensor array system for agricultural applications is presented. The sensor array is based on a quartz crystal microbalance (QMB) transducer with a novel heating structure. Selective host molecules are used as gas-sensitive layers. The gas-sensitive layers were optimized for the selective detection of ammonia at varying humidity concentrations. A mode of operation is presented which allows on-line monitoring of ammonia without a reference gas (RG). In addition, this temperature modulation (TM) mode improves the signal-to-noise ratio of the sensors compared to the usually applied RG mode. Multivariate regression models are applied on the sensor array data to selectively predict the ammonia concentration in agricultural emissions. 相似文献
7.
Styrene-co-chloromethyl styrene copolymers chemically modified with various kinds of monoamines or diamines were synthesized. Their sensing properties based on toluene vapor sorption/desorption behaviors were measured using a quartz crystal microbalance (QCM) technique. Introduction of aliphatic diamine compounds having a proper chain length (e.g., N,N-dimethyl-1,3-propanediamine (DMPDA)) into the structure of the copolymer realized improvements to the toluene vapor sorption capacity, the response time, and reversibility compared to the conventional polymer coatings. FTIR analysis suggests the formation of a loosely cross-linked structure, resulting in the promotion of toluene vapor diffusion into the film. 相似文献
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研究了ZSM5分子筛膜对神经类毒剂沙林的相似物甲基磷酸二甲脂的敏感特性,并结合高灵敏的石英谐振微天平(QCM)研制了甲基磷酸二甲脂气体传感器。测试甲基磷酸二甲脂气体的体积分数分别为10-6,5×10-6,20×10-6的气体。研究表明:基于ZSM5纳米分子筛膜的传感器的检测灵敏度高,对气体体积分数为10-6甲基磷酸二甲脂气体的检测灵敏度为60Hz/10-6,比半致死浓时积低;传感器的响应与脱附时间较快,对气体体积分数为10-6甲基磷酸二甲脂气体的响应与脱附时间均为100s;对同体积分数丙酮气体进行了频率响应测试,对传感器的选择性进行验证。还研究了ZSM5分子筛对甲基磷酸二甲脂气体的脱附再生条件,发现经过200℃脱附,分子筛的再生能力可以得到较好的恢复. 相似文献
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A microcantilever device has been used as a miniaturized sensor for the determination of total carbonate in soil samples. The method is based on the selective generation of CO2 (g) from samples and the measure of the pressure effect on the microcantilever sensor located in a closed system. The experimental set-up uses a manifold including the sample reaction minichamber and a dedicated flow-cell designed and built for housing the microcantilever. The response of this sensor was electronically and analytically characterized by using conductance signals. The analytical performance of the sensor was compared to that provided by the conventional quartz crystal microbalance (QCM), demonstrating advantages in terms of sensitivity, linear range of response and resolution. After the optimization of the method, it was validated for its use for direct determination of carbonate in soil samples. The method allowed the determination of carbonate in the 3–75 mg range, with a precision of 1.7%, expressed as relative standard deviation. It was applied to the analysis of different soil samples, obtaining results in agreement with those produced by the official method. 相似文献
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对基于石英晶体微天平(QCM)生物传感器的两种检测核酸适体与蛋白质解离常数方法进行了比较,提出来一种更加精确合理的检测流程。以凝血酶和凝血酶适体 TBA15为模型,耗散型石英晶体微天平(QCM-D)为传感器,实时检测末端修饰巯基适体的固定、表面封闭剂对非特异性结合位点封闭以及两种不同的蛋白进样方式引起的频率响应,实验数据拟合得到解离常数。不同蛋白的进样方式得到的解离常数不同,非特异性位点的封闭也同样影响解离常数的检测。从低浓度到高浓度依次通入固定体积蛋白的进样方式,实验重复性高且消耗样品量小于1μg,是较为理想的检测方式。 相似文献
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Chunyan ZhangAuthor Vitae Xianfeng WangAuthor Vitae Jinyou LinAuthor Vitae Bin DingAuthor Vitae Jianyong YuAuthor VitaeNing PanAuthor Vitae 《Sensors and actuators. B, Chemical》2011,152(2):316-323
Here we report a novel fabrication approach to highly sensitive formaldehyde sensors by the surface modification of the electrospun nanofibrous membranes. The three-dimensional fibrous membranes comprising nanoporous polystyrene (PS) fibers were electrospun deposition on quartz crystal microbalance (QCM), followed by the functionalization of the sensing polyethyleneimine (PEI) on the membranes. The morphology and Brunauer-Emmett-Teller (BET) surface area of the fibrous PS membranes with fiber diameter of 110-870 nm were controllable by tuning the concentrations of PS solutions. After PEI modification, PEI particles in clusters of varying sizes (50 nm to 1.2 μm) were immobilized onto the surface of the bead-on-string structured nanoporous fibers. The developed formaldehyde-selective sensors exhibited fast response and low detection limit (3 ppm) at room temperature. This high sensitivity is attributed to the high surface-area-to-volume ratio (∼47.25 m2/g) of the electrospun porous PS membranes and efficient nucleophilic addition reaction between formaldehyde molecules and primary amine groups of PEI. 相似文献
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Pi-Guey SuAuthor Vitae Chuen-Chi ShiuAuthor Vitae 《Sensors and actuators. B, Chemical》2011,157(1):275-281
A novel flexible H2 gas sensor was fabricated by the layer-by-layer (LBL) self-assembly of a polypyrrole (PPy) thin film on a polyester (PET) substrate. A Pt-based complex was self-assembled in situ on the as-prepared PPy thin film, which was reduced to form a Pt-PPy thin film. Microstructural observations revealed that Pt nanoparticles formed on the surface of the PPy film. The sensitivity of the PPy thin film was improved by the Pt nanoparticles, providing catalytically active sites for H2 gas molecules. The interfering gas NH3 affected the limit of detection (LOD) of a targeted H2 gas in a real-world binary gas mixture. A plausible H2 gas sensing mechanism involves catalytic effects of Pt particles and the formation of charge carriers in the PPy thin film. The flexible H2 gas sensor exhibited a strong sensitivity that was greater than that of sensors that were made of Pd-MWCNTs at room temperature. 相似文献
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D. Çayc?Author VitaeS.G. StanciuAuthor Vitae ?. ÇapanAuthor Vitae M. Erdo?anAuthor VitaeB. GünerAuthor Vitae R. HristuAuthor VitaeG.A. StanciuAuthor Vitae 《Sensors and actuators. B, Chemical》2011,158(1):62-68
In this work, 2,3,7,8,12,13,17,18-Octaethyl-21H,23H-porphine (OEP) in its free base form and metalated with iron (III) chloride (FeOEP), magnesium(II) (MgOEP) and cobalt(II) (CoOEP) have been used to fabricate Langmuir-Blodgett (LB) thin films. Using the surface pressure-surface area (Π-A) isotherm graphs optimum conditions for thin film deposition have been determined and by changing the deposition parameters various thin films have been deposited. Quartz Crystal Microbalance (QCM) system was used to investigate their gas sensing performances during exposure to Volatile Organic Compounds (VOCs) including chloroform, benzene and toluene. The surface properties have been investigated using Atomic Force Microscopy (AFM) and analyzed together with the QCM results to understand the effect of the surface properties on gas sensing mechanism. It is observed that larger surface area leads to higher response in gas sensing applications in terms of resonance frequency change. 相似文献
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The piezoelectric quartz crystal microbalance (QCM) was used to monitor the adhesion of mammalian cells on a chitosan (CS)/multiwalled carbon nanotubes (MWCNTs) composite modified gold electrode. The morphology and chemical properties of the CS/MWCNTs film were characterized with scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. The human breast cancer cells (MCF-7) were adhered to and grown on the CS/MWCNTs film modified gold surface or a net CS film modified gold surface, and the process of which was continuously monitored and displayed by changes of the resonant frequency (Δf0) and the motional resistance (ΔR1) of the QCM. The attachment/spreading process of the MCF-7 cells on the QCM Au electrode decreased the Δf0 and increased the ΔR1 simultaneously, implying rather complicated effects (simultaneous mass, viscoelasticity and probable surface-stress load) on the sensor surface. The attachment rate and viability of the cells when proliferating on the two surfaces were detected by the MTT assay. The presence and state of cells on the electrode surface were confirmed by the fluorescent microscopy. Cyclic voltammetry and electrochemical impedance spectroscopy of the ferricyanide/ferrocyanide couple were examined before and after the cell adhesion. All data showed that the cell adhesion and proliferation processes were more efficient on the biocompatiable nanocomposite surfaces. The cell-based biosensor has potential for identification and screening of biologically active drugs and other biomolecules affecting cellular shape and attachment. 相似文献
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《Displays》2019
In this paper, we propose an effective real-time image enhancing technology for transparent displays based on polymer-dispersed liquid crystal (PDLC). The image enhancing technology consists of both global and local enhancement functions. It not only removes the affected haze but also sharpens the edge regions for transparent PDLC displays. This technology can improve the image quality such as contrast, brightness, color saturation, and gamma correction for transparent PDLC displays. The experimental results indicated that our proposed method can effectively enhance the visibility and remove the affected haze in the transparent PDLC display. 相似文献
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基于ZigBee技术的连栋温室低功耗环境监测系统设计 总被引:1,自引:0,他引:1
针对连栋温室环境监测系统布线困难、监测低效、部署不灵活等问题,设计了一种基于无线传感器网络的低功耗监测系统.以CC2530为核心构建传感器节点,以ZigBee技术构建树状无线传感器网络覆盖整个温室范围,搭配现场PC构建现场自动化监测系统,24h监测环境变化;在传感器节点中进行硬件和软件的低功耗优化设计,降低建造和维护成本,添加时间同步管理和电源管理,增加系统可靠性.初步试验表明:系统能以较低的功耗(提高96.3%)实现数据的准确采集,符合科研和精细化生产的应用要求. 相似文献
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基于能量高效的无线传感器网络LEACH协议改进 总被引:4,自引:0,他引:4
针对无线传感器网络节能问题,详细分析了经典分簇协议——LEACH,在其基础上针对LEACH的不足进行改进,提出了一种能量高效的分簇路由协议。该协议在簇头选举的算法中纳入节点剩余能量作为参数,提出各簇独立进行的簇头轮换机制,控制簇头在簇中的分布和各簇成员节点数目,并采用基于阈值的单跳与多跳相结合的簇间通信方式。仿真结果表明,改进后的协议较LEACH能够有效节约节点能量,均衡网络各节点消耗,显著延长了网络生存周期。 相似文献