平面波导型荧光免疫传感器的制备与应用

研究了一种基于全内反射荧光和免疫检测原理的传感器系统,它可用于检测水环境中的有机污染物,如2,4-D、藻毒素等.本系统采用长波长的荧光染料Cy 5.5,以氦氖激光器作为激发光源,结合流动注射分析系统,能够快速方便地对传感基片上发生的免疫反应进行测定.本研究介绍了平面波导型荧光免疫传感器的检测原理、系统结构设计、传感基片的修饰、小分子配基的固定和系统测试结果.实验结果表明,系统具有很高的稳定性,对荧光染料的响应灵敏度可达1nmol/L;修饰后的传感基片基本不对蛋白产生非特异性吸附,而对不同浓度小分子配基抗体的响应符合Logistic方程;传感基片重复使用20个周期后,性能没有明显的下降.     

基于硬币的简易气体传感实验装置设计

设计并构建了一种简易的气体传感实验装置。由于硬币中含有多种金属元素,在空气中加热后会在表面形成一层氧化物,基于氧化物的气体敏感原理,可以对多种气体进行检测。本实验中,利用金属和酸的反应产生氢气,通过测量氧化硬币的电阻,发现其电阻的变化量线性正比于所产生氢气的量。这是一个紧密联系科学原理和传感技术的实验案例,有利于学生对气体传感器的学习和科学思维的培养。     

基于微纳结构的高灵敏度柔性压力传感器

近年来,随着互联网和人工智能的发展和普及,轻薄便捷、电子性能优异的柔性压力传感器作为可穿戴电子设备的核心器件,拥有了越来越广阔的市场。柔性压力传感器具有灵活柔韧、可折叠、传感性能优异等优点,因而在电子皮肤、运动检测、医疗监测和人机界面等方面已引起广泛的关注。构筑微纳结构是提高压力传感器灵敏度和传感性能的关键。基于此,本文首先总结了高灵敏度压力传感器的传感机制(压阻式、电容式、压电式和摩擦电式)和关键性能参数(灵敏度、压力检测范围、检测限、响应/恢复时间、循环稳定性和线性度等),然后归纳了利用基材构建表面微纳结构(微凸结构、荆棘结构和褶皱结构)和利用导电材料构建微纳结构(微球结构、海胆状结构、蜂窝状结构)的柔性压力传感器的研究进展及其优缺点,总结了基于微纳结构的高灵敏度柔性压力传感器在脉搏监测、电子皮肤、运动检测和人机界面等方面的应用现状。最后,从今后应用的角度出发,概述了高灵敏度柔性压力传感器即将面临的挑战及未来发展方向。     

光子晶体生化传感器的构建及应用

光子晶体生化传感分析是基于光子晶体的结构特性将生化信号放大或转换为光电可读信号,并通过仪器或肉眼进行定量或半定量分析的方法.本文围绕着光子晶体生化传感器的材料选择与构建、传感机理、设计及应用三方面进行综述.在材料选择与构建上,本文从单分散胶体颗粒、电磁复合胶体颗粒、纳米线、金属-有机框架等方面进行综述;在传感机理上,本...     

基于酶催化银沉积质量放大的血吸虫压电免疫传感器的研究

发展了一种基于酶催化金属银沉积信号放大的新型高灵敏气相压电免疫传感检测技术.先将血吸虫抗原(SjAg)共价固定在石英晶体表面,制备得到血吸虫压电免疫传感器.检测时,在晶振上滴加不同浓度的待测血吸虫抗体,再将碱性磷酸酶标记的二抗通过夹心方式结合到传感器表面.然后利用碱性磷酸酶催化磷酸化的抗坏血酸酯水解从而还原硝酸银,使金属银沉积在晶振表面上,放大传感器的质量响应信号.实验结果表明该传感检测方法可显著提高气相压电免疫传感器的检测灵敏度,传感器对血吸虫抗体的响应线性范围在1～225 ng/mL,检测下限为1 ng/mL.     

消耗型化学发光传感器的研究

本文首次发展了多种消耗型化学发光传感器, 方法基于发光试剂通过电价键全部固定在阴、阳离子交换树脂上, 在不添加外来发光试剂的情况下, 可直接对待测物进行传感。该类型传感器固定化方法简单, 灵敏度高, 还可通过控制洗脱剂的浓度精确控制发光试剂的释放量, 进而控制固定化试剂柱的使用寿命。所设计的六种类型的传感器均已成功地应用于样品中待测物的测定。     

荧光传感器阵列

传感器阵列是基于对动物嗅觉系统的认识发展起来的一种有力的分子识别手段,其由一系列传感单元组成,通过各传感单元对样品响应后产生的特征图谱实现对特定物质的识别检测,尤其对混合样品的鉴定具有突出优势。其中,荧光传感器阵列由于具有灵敏度高、无需参照体系、输出信号丰富、能够成像等优点,已成为近年来传感器阵列发展的重点。本综述根据荧光传感单元形式的不同,分别介绍了溶液型、颗粒型、薄膜型荧光传感器阵列的发展情况,并重点阐述了荧光传感器阵列的设计方法、传感机理及其在对金属离子、有机化合物和生物分子识别中的应用。     

新型微梁阵列生化传感器的研制

为了消除单微梁生化传感系统中存在的温度漂移、溶液折射率变化等环境噪声影响,同时实现多种靶标分子的快速并行检测,设计制作了新型微梁阵列生化传感器.利用压电驱动激光束扫描微梁阵列,并通过光杠杆法实时读出微梁弯曲信号,即可得到在微梁表面发生的特异性生化反应的动力学曲线.对250 μm间距的两定点的9h扫描实验数据验证了系统光路的稳定性;同时进行了温度激励测试,升温6℃后微梁阵列弯曲信号基本保持一致(误差6.5％),验证了系统检测的可靠性.最后,利用自制毛细管阵列套合修饰装置,成功将克伦特罗抗体修饰到微梁阵列一侧的金表面上,对待测液中10μg/L克伦特罗标样进行了准确检测,验证了此传感系统在生化检测中的实际可行性.     

用于接近-压力感知的全纸基智能传感器

近年来,伴随可穿戴电子设备与日俱增的需求,成本低廉、绿色环保、可批量生产的纸基传感器得以快速发展.然而,目前的纸基传感器仍有两大挑战亟待解决:(1)广泛使用金属电极,极大地削弱了纸的本征优势.(2)传感机理受限于单一触觉感知功能,难以满足多重刺激感知的需求.本文报道了一种基于聚吡咯(PPy)的电容-电阻双模式全纸基传感器.该器件能够感知接近和压力刺激,从而能够应用于人体运动的监测、接近物体的感知.此外,我们还借助该传感器实现了接触式和非接触式摩斯电码输入,并能实现两种模式下的准确区分.该接近-压力全纸基传感器结构简单,容易制造,在可穿戴设备和绿色电子等领域有着巨大潜力.     

电化学发光和电化学生物传感器的研究

本研究小组近年来在电化学发光DNA和适体传感器研究和无标记以及阵列电化学DNA和适体传感器方面进行了一些工作,重点介绍如何提高生物传感器灵敏度进行传感界面设计的一些思路.利用纳米粒子提高灵敏度和再现性的途径主要有三种,一是用纳米材料修饰电极上,提高待测物或探针在电极表面的固定量;二是用纳米材料作为信号分子的载体或信号粒子, 以提高检测信号的强度~([1]);三是纳米材料直接作为信号物质~([2]).     

Robust High Temperature Sensor Probe Based on a Ni-coated Fiber Bragg Grating

A robust high temperature sensor probe based on a Ni-coated fiber Bragg grating（FBG） was fabricated by Ni electroplating of femtosecond laser written FBG. The probe can resist high temperature up to 800℃ with a high sensitivity of 32.2 pm/℃. It also has a good mechanical strength even after high temperature annealing. The thermal strain of the probe was simulated by the finite element method（FEM）. The Bragg resonant wavelength shift with temperature and its sensitivity change with the thickness of the Ni-coated layer were also calculated.     

Electroless Nickel Plating and Electroplating on FBG Temperature Sensor

Metal-coated fiber Bragg grating（FBG）temperature sensors were prepared via electroless nickel（EN）plating and tin electroplating methods on the surface of normal bare FBG.The surface morphologies of the metal-coated layers were observed under a metallographic microscope.The effects of pretreatment sequence,pH value of EN plating solution and current density of electroplating on the performance of the metal-coated layers were analyzed.Meanwhile, the Bragg wavelength shift induced by temperature was monitored by an optical spectrum analyzer.Sensitivity of the metal-coated FBG（MFBG）sensor was almost two times that of normal bare FBG sensor.The measuring temperature of the MFBG sensor could be up to 280℃,which was much better than that of conventional FBG sensor.     

Investigations of flow field designs in direct methanol fuel cell

An experimental and simulation research had been performed to investigate the performance as well as the flow distribution in the cathode flow field in the case of direct methanol fuel cells (DMFCs). The gas was well distributed in serpentine flow field, whereas stagnation of the gas was observed in parallel flow field. These would contribute to the cell performance greatly due to mass transfer effect when the cells start operating. In addition, the durability test of DMFC was drastically affected in parallel flow field due to poor ability to drain flooded water produced electrochemically at cathode and crossover from anode. In addition, pressure drops of different flow fields were also investigated to evaluate their contribution and feasibility as an economic application for DMFC. DMFC with serpentine flow field featuring higher pressure difference resulted in a larger parasitic energy demand. However, the optimal flow field designs are needed to balance the performance and pressure loss to achieve a uniform fluid distribution and simultaneously minimize energy demand for mass transport. Consequently, flow field with grid pattern appears to be the optimal design for the DMFC cathode.     

Multiparameter Sensor Chip with Barium Strontium Titanate as Multipurpose Material

It is well known that biochemical and biotechnological processes are strongly dependent and affected by a variety of physico‐chemical parameters such as pH value, temperature, pressure and electrolyte conductivity. Therefore, these quantities have to be monitored or controlled in order to guarantee a stable process operation, optimization and high yield. In this work, a sensor chip for the multiparameter detection of three physico‐chemical parameters such as electrolyte conductivity, pH and temperature is realized using barium strontium titanate (BST) as multipurpose material. The chip integrates a capacitively coupled four‐electrode electrolyte‐conductivity sensor, a capacitive field‐effect pH sensor and a thin‐film Pt‐temperature sensor. Due to the multifunctional properties of BST, it is utilized as final outermost coating layer of the processed sensor chip and serves as passivation and protection layer as well as pH‐sensitive transducer material at the same time. The results of testing of the individual sensors of the developed multiparameter sensor chip are presented. In addition, a quasi‐simultaneous multiparameter characterization of the sensor chip in buffer solutions with different pH value and electrolyte conductivity is performed. To study the sensor behavior and the suitability of BST as multifunctional material under harsh environmental conditions, the sensor chip was exemplarily tested in a biogas digestate.     

Development of a modified grating coupler in application to geosciences

A grating coupler system has been developed to measure refractive index gradients with high spatial (6.7 μm) and temporal (milliseconds) resolution. The system was applied to two-phase model systems consisting of water and non-aqueous pollution liquids. Refractive index gradients at the interfaces between the aqueous and organic phase of 1-butanol, hexane, and 1-heptanol were monitored under steady-state conditions. The temporal resolution was utilized in diffusion experiments with glycerol and sodium chloride in water, where the formation of a concentration gradient was studied. In a further application, the grating coupler system was modified to monitor low-level concentrations of aqueous pollution profiles as are caused by bacterial degradation in the aqueous phase. Toluene was selected as contaminant. The sensor sensitivity was improved by coating the sensor with the pre-concentrating polymers polydimethylsiloxane and Teflon® AF-2400. With the grating coupler setup, a multi-purpose instrument was created to measure high-resolution refractive index gradients with high temporal and spatial resolution in different fields of application. The new sensor system can be used to measure absolute refractive indices by covering parts of the sensing area with cover media of known refractive index. Coatings can be used for sensitivity improvement by pre-concentrating the sample, for selectivity by utilizing filtering properties of the coating, and as calibration standard for absolute refractive index measurements.     

Theory of operation for differential ion mobility spectrometry without alpha

Using the Langevin equation for ion motion in the presence of a variable electric field, and expressing the collision frequency in a manner that conforms to scattering a polyatomic ion with an equivalent hard-sphere core, a relationship is derived for the compensation and dispersion fields in a differential ion mobility spectrometer (DIMS). For a conservative collision (no clustering or ion-neutral dissociation or rearrangement interactions), the compensation field depends on both even and odd powers of the dispersion field, and the relationship between both fields is independent of pressure when the fields are divided by the drift gas density. Because the first and most important approximation for the compensation field is proportional to the square of ion mobility under zero field conditions, the compensation field increases with the temperature of the drift gas, but the functional form for the temperature dependence involves higher order terms and requires additional knowledge of the temperature dependence for the collision cross section. Duty cycle curves for long-chain secondary ketones compare favorably to experiments using an asymmetric rectangular waveform for excitation.     

Effects of pressure on the behavior of (hydroxypropyl)cellulose in aqueous solution

The effects of pressure and temperature on the phase behavior of aqueous solutions of (hydroxypropyl)cellulose (HPC) were in¶vestigated at low and high concentrations. In dilute solutions, the transition temperature (T _t) as measured by apparent light scattering increased with an increase in pressure at lower pressures, but decreased with increasing pressure above 100?MPa. At lower temperatures, the transition pressure (P _t) increased slightly with increasing temperature, but decreased with at temperatures above 10–15?°C. Both T _t and P _t showed a moderate polymer-concentration dependence and they also showed strong concentration dependence on salt; T _t and P _t decreased with increasing concentrations of KCl and K₂SO₄, whereas the addition of KI or KSCN increased T _t and P _t. The apparent absorbance of concentrated solutions (62.5%) of HPC, in a cholesteric (chiral nematic) mesophase, was also measured. The spectrum shifted to a longer wavelength under high pressure. These results could be explained by assuming that the helicoidal pitch was increased under elevated pressure, probably due to a decrease in the angle between the two semiflexible and twisted HPC molecules in adjacent planes under high pressure.     

Systematic investigation of the effects of temperature and pressure on gas transport through polyurethane/poly(methylmethacrylate) phase-separated blends

Polyurethane (PU) and polyurethane–poly(methylmethacrylate) (PMMA) blend membranes were used in gas separation studies. The effects of blend composition, temperature, and pressure on the permeability, diffusivity, and solubility of CO₂, H₂, O₂, CH₄, and N₂ were investigated. The separation factors of some gas pairs were also evaluated. Positron annihilation lifetime spectroscopy was applied to assess free volume changes as a function of blend composition and temperature. Free volume size increases by approximately 30% with increasing temperature from 10 to 40 °C for all blends studied. The permeability of all gases decreases by approximately 55% with the addition of 30 wt% of PMMA. The permeation process is governed by diffusion, except that of CO₂. In relation to the behavior of gas transport as a function of temperature, some important observations are (i) CO₂ presents the lowest permeation activation energy value (28 kJ/mol), and (ii) gas pair selectivity increases at low temperatures and is high for gas pairs that present differences in permeation activation energies as high as 15 kJ/mol for the CO₂/CH₄ gas pair. Furthermore, the study with pressure variations shows that: (i) at elevated pressure, the PU and the blend membrane permeability to CO₂ and H₂ increases by approximately 35%, and (ii) oxygen-to-nitrogen selectivity increases with pressure as a consequence of the decrease in the permeability to nitrogen in the case of the 30%-PMMA blend.     

Recent advances in organic pressure-responsive luminescent materials

Pressure is a powerful tool to regulate the molecule aggregation and intermolecular interactions. Organic luminescent materials under high pressure can produce rich phenomena,which have many potential applications.     

Recent advances in organic pressure-responsive luminescent materials

Organic luminescent materials are very sensitive to external stimuli,such as pressure,temperature,and electric field.The luminescent properties of some organic luminescent materials significantly change under high pressure.Some materials may show luminescence discoloration,whereas some may exhibit luminescence enhancement.These properties have many potential applications in anticounterfeiting,force sensor,data recording and storage,and luminescent devices,thereby greatly attracting the attention of scientists.In this review,the progress of research on these materials at high pressure in recent years is summarized.