微梁传感研究谷胱甘肽转硫酶抗原抗体特异结合

利用微梁传感器（MicroCantilever Sensor，MCS）对抗原抗体的反应进行检测。通过分子自组装方法将谷胱甘肽转硫酶（Glutathione S-transferase，GST）修饰到微悬臂梁的单侧镀金表面后，应用光杠杆原理监测在加入GsT抗体的过程中，微悬臂梁的实时弯曲过程。实验过程中的抗原抗体活性由酶联免疫吸附（enzyme linked immunosorbent assay，ELISA）实验得到了确认。结果表明：a．微悬臂梁传感技术可以对抗原抗体的结合过程进行实时的监测；b．为研究生物大分子间微观层次上相互作用提供了一种新型的实验手段。     

微梁传感研究谷胱甘肽转硫酶抗原抗体特异结合

利用微梁传感器(MicroCantilever Sensor, MCS)对抗原抗体的反应进行检测.通过分子自组装方法将谷胱甘肽转硫酶(Glutathione S-transferase,GST)修饰到微悬臂梁的单侧镀金表面后,应用光杠杆原理监测在加入GST抗体的过程中,微悬臂梁的实时弯曲过程.实验过程中的抗原抗体活性由酶联免疫吸附(enzyme linked immunosorbent assay, ELISA)实验得到了确认.结果表明: a.微悬臂梁传感技术可以对抗原抗体的结合过程进行实时的监测;b.为研究生物大分子间微观层次上相互作用提供了一种新型的实验手段.     

基于激光阵列的多通道微梁生化传感系统

针对单微悬臂梁生化检测系统中存在的温度漂移、溶液折射率变化等环境噪声影响和不能多目标检测等问题,设计制作了一种基于垂直腔面射型激光器阵列(VCSELs)的新型微悬臂梁阵列生化传感系统。利用双透镜组光路汇聚激光器阵列发出的激光束,依次照射到微悬臂梁阵列尖端进行精确定位扫描,实现了5根微悬臂梁变形信号的同步检测。该系统具有灵敏度高、一致性好、检测快速等优点。通过升降温动态实验测试,验证了该系统的稳定可靠性。上述结果为微悬臂梁阵列式生化传感技术的开展提供了一种新的方法和平台。     

一种新型微梁阵列传感器设计及实现

微悬臂梁传感技术是微纳传感技术研究的热点,仪器装置的研究也从单悬臂梁向微梁阵列的方向发展.本文针对间距为250μm的商品化微梁阵列,提出了一种实现对其弯曲变形的读出系统光路.利用高精度位移平台调节激光器空间位置,使光束实现微距离上平行,并分别照射在阵列梁的相邻微梁上.用位置敏感探测器对两个微悬臂梁尖端反射的激光信号进行...     

一种基于压电扫描的新型微梁阵列免疫传感器

微梁免疫传感技术是在原子力显微镜和微机电系统基础上发展起来的一项新兴传感技术,具有检测灵敏度高、无需标记、能实时原位再现生化反应过程等优点。本文针对单梁传感系统中存在的环境扰动和不能多通道检测等问题进行改进,设计制作了一种基于压电扫描的新型微梁阵列免疫传感器。利用商品化微梁阵列对传感器进行了温度测试实验,所得信号曲线稳定一致,且检测灵敏度达到2nm,实验结果验证了该微梁阵列传感系统在多通道信号检测中的可行性,为微梁阵列生化传感技术的实现提供了一种新的方案。     

基于微悬臂梁技术对固液界面间横向摩擦力的检测

研究固液界面上的力学行为对于界面科学和工程应用具有重要意义,如何检测液滴在材料表面的横向摩擦力一直是界面领域研究的难题之一.本文基于微悬臂梁传感技术和视觉图像分析技术,设计并搭建了一套固液横向摩擦力检测系统,将毛细管端部的弯曲程度与固液界面的相互作用力建立关系,实现对固液界面间横向摩擦力的精确测量;通过对水滴在疏水界面...     

碳纳米管应变传感器的性能分析:传感介质与制备工艺

利用碳纳米管拉曼特征峰位对其变形的灵敏特性,基于拉曼光谱的碳纳米管应变传感方法,已经实现了针对非拉曼活性固体材料表面微尺度范围内的平面应变分量非接触传感测量。本文侧重该方法在微尺度实验力学研究中的推广应用,从传感介质和制备工艺的选择出发,采用改进后的三种不同工艺,制备了碳纳米管/环氧树脂复合薄膜作为传感介质;综合零载标定实验和步进单轴拉伸标定实验的实测结果,对比分析了不同工艺获得传感介质的应变传感灵敏度、量程、稳定性和时间分辨率四个关键性能指标;最后对传感性能的影响因素进行了探讨。     

微梁传感研究大分子构象转变

通过表面修饰技术将大分子连接到微悬臂梁的单侧表面上,调节周围的物理、化学环境使大分子的构象发生转变,并用光杠杆法检测微梁变形.实验结果显示,大分子在微梁表面的构象转变过程会引起微梁的表面应力发生变化,并使之产生纳米量级的端部位移变形.此外,对于不同的大分子,促使微梁表面应力发生变化的机制是各不相同的.分析显示,氢键作用、静电作用和疏水作用分别在PNIPAM分子、PAA分子和胰蛋白酶分子的构象转变和微梁表面应力变化过程中起主要作用.微梁传感用于大分子的构象转变检测,提取的是分子间相互作用力的信息,它为从微观上理解大分子构象转变问题提供了一种新的实验手段.     

微梁传感研究大分子构象转变

通过表面修饰技术将大分子连接到微悬臂梁的单侧表面上，调节周围的物理、化学环境使大分子的构象发生转变，并用光杠杆法检测微梁变形。实验结果显示，大分子在微梁表面的构象转变过程会引起微梁的表面应力发生变化，并使之产生纳米量级的端部位移变形。此外，对于不同的大分子，促使微梁表面应力发生变化的机制是各不相同的。分析显示，氢键作用、静电作用和疏水作用分别在PNIPAM分子、PAA分子和胰蛋白酶分子的构象转变和微梁表面应力变化过程中起主要作用。微梁传感用于大分子的构象转变检测，提取的是分子间相互作用力的信息，它为从微观上理解大分子构象转变问题提供了一种新的实验手段。     

基于全场位移测量技术的微悬臂梁面内弯曲性能测试

基于自制的微力试验机和全场位移光学测量仪,建立了微尺度力学性能原位测试系统。其中微力试验机基于电磁驱动兼载荷计量原理设计,载荷量程和噪音分别为±1N和50μN。全场位移光学测量仪基于白光数字散斑相关方法研制。采用该系统对MEMS单晶硅(001)微悬臂梁进行了面内弯曲力学性能原位测试,获得了微悬臂梁末梢施力点的力-位移关系曲线,以及全场变形情况。结果显示,微悬臂梁表现出很好的弹性弯曲行为,最后在根部发生脆性断裂。根据弹性弯曲理论计算出单晶硅弹性模量为123.8GPa(±3.2%)。该技术为研究MEMS微构件的力学性能提供了一种有效的手段。     

Tailoring Beam Mechanics Towards Enhancing Detection of Hazardous Biological Species

Microcantilever based sensors have been widely employed for measuring or detecting various hazardous chemical agents and biological agents. Although they have been successful in detecting agents of interest, researchers desire to improve their performance by enhancing their mass sensitivity towards developing “detect to warn” detection capabilities. Moreover, there has been little work aimed at tailoring beam mechanics as a means to enhance mass sensitivity. In this paper, a numerical study is performed to assess the influence of microcantilever geometry on mass sensitivity in order to improve these devices for better detection of hazardous biological agents in liquid environments. Modal analysis was performed on microcantilevers of different geometries and shapes using ANSYS software and compared to the basic rectangular shaped microcantilever structures employed by most researchers. These structures all possessed a 50 μm length, 0.5 μm thickness and 25 μm width where the cantilever is clamped to the substrate, and were analyzed for their basic resonance frequency as well as the frequency shift for the attachment of a 0.285 pg of mass attached on their surfaces. These numerical results indicated that two parameters dominate their behavior, (1) the effective mass of the cantilever at the free end and (2) the clamping width at the fixed end. The ideal geometry was a triangular shape, which minimized effective mass and maximized clamping width, resulting in an order of magnitude increase in mass sensitivity (1,775 Hz/pg) over rectangular shaped cantilevers (172 Hz/pg) of identical length and clamping width. The most practical geometry was triangular shaped cantilever with a square pad at the free end for capturing the agent of interest. This geometry resulted in a mass sensitivity of 628 Hz/pg or nearly a 4-fold increase in performance over their rectangular counterparts.     

考虑中性层位置变化的微悬臂梁气体传感器静态模型的分析

微悬臂梁是一种高灵敏度的生化传感器。本文考虑吸附表面应力引起的中性层位置的变化,采用能量法建立了微悬臂梁在单层分子吸附稳定后的静态弯曲模型,并以表面吸附有水蒸汽分子的微悬臂梁为例,研究了微悬臂梁曲率半径随其厚度、杨氏模量及吸附分子间距的变化规律以及中性层位置变化对微悬臂梁传感器性能预测的影响,结果发现：1)微悬臂梁的曲率半径与其杨氏模量、厚度及吸附分子间距之间可以近似用一次、二次和八次函数关系表示;2）中性层变化导致的曲率半径计算误差,随着微悬臂梁厚度、杨氏模量的增加而减小,但影响较小,而吸附分子间距会对该相对误差产生明显影响;3）中性层位置变化会对微悬臂梁传感器灵敏度和表面应变预测产生明显的影响。     

光学读出微梁阵列红外成像性能分析与优化

系统响应率是光学读出微梁焦平面阵列(Focal Plane Array,FPA)红外成像的关键性能参数。在刀口滤波光学读出技术中,系统响应率的主要组成部分——光学读出灵敏度与微梁反光板的长度密切相关,并受到反光板弯曲变形的严重影响。由于残余应力在制作过程中不可避免地存在,微梁反光板都有弯曲变形,膜厚相同的反光板具有相同的变形曲率半径。本文利用傅里叶光学分析了反光板长度和弯曲变形对光学读出灵敏度的影响,构建并实验验证光学读出灵敏度理论模型。根据该模型,分析了系统响应率与反光板长度之间关系,理论分析与实验结果相符。结果表明,通过减薄SiNx厚度并使反光板处于该厚度下的最优长度,不仅能提高红外成像的系统响应率,而且能同时提高红外成像的空间分辨率。     

光机械式红外探测器中镜面弯曲对探测灵敏度的影响(英文)

光学读出式红外成像技术是近年来研究的热点,本文讨论了镜面弯曲对光学检测灵敏度的影响。由双材料微悬臂梁组成的非致冷焦平面阵列通过体刻蚀工艺加工而成,由于残余应力的影响,制成的焦平面阵列将会发生弯曲,应力导致的镜面弯曲将会降低光学探测灵敏度。本文通过傅立叶光学模拟了镜面弯曲对光学探测灵敏度的影响,并通过实验验证了该模型。实验和模拟结果表明,在镜面曲率为0 .1mm-1时,光学探测灵敏度将会降低到理想情况的40 %。最后我们用这个模型评价了通过表面修饰来提高光学性能的效果。     

光机械式红外探测器中镜面弯曲对探测灵敏度的影响

光学读出式红外成像技术是近年来研究的热点，本文讨论了镜面弯曲对光学检测灵敏度的影响。由双材料微悬臂梁组成的非致冷焦平面阵列通过体刻蚀工艺加工而成，由于残余应力的影响，制成的焦平面阵列将会发生弯曲，应力导致的镜面弯曲将会降低光学探测灵敏度。本文通过傅立叶光学模拟了镜面弯曲对光学探测灵敏度的影响，并通过实验验证了该模型。实验和模拟结果表明，在镜面曲率为0．1mm-1时，光学探测灵敏度将会降低到理想情况的40％。最后我们用这个模型评价了通过表面修饰来提高光学性能的效果。     

A novel inductive technique for microcantilever displacement detection

A novel inductive technique for the detection of microcantilever displacement for sensing applications was presented. We highlight the basic structure and evaluate its characteristics with the aid of modeling and simulation. Results generated by numerical simulations using ANSOFT are compared with those obtained from an equivalent circuit model using PSPICE. There are indications that the sensitivity of the inductive cantilever is about one order of magnitude higher as compared to piezoresistive silicon cantilevers of the same dimension under the same cantilever bending.     

Nanohybrid TiO2/carbon black sensor for NO2 gas

A nanohybrid sensor of nanosized TiO2-coated carbon black particles, prepared by sol-gel technology for the detection of NO2 gas, has been developed. The response of the electric resistance of the hybrid sensor to NO2 concentration is investigated, showing that the sensitivity of the hybrid sensor is raised as certain ratio of the TiO2 content in the sensor. Easy and cheap to fabricate, the hybrid TiO2/carbon black promises to be a practical sensor for detecting NO2 gas.     

微悬臂梁生化传感系统的性能分析

在基于光杠杆原理检测微悬臂梁变形的生化传感实验系统中,液体折射率的变化会导致PSD上光斑的位移,从而影响系统的检测信号。本文从理论上分析了在不同检测光束的入射角度、微梁的放置角度等参数条件下,液体折射率的变化对系统检测信号的影响。结果表明：在传统的光路下,液体折射率改变10-3引起的光斑位移与一般的生化反应引起的位移相当,即液体折射率的改变严重影响系统的检测信号。通过理论分析还发现在适合的参数配置下,可以忽略折射率变化对系统检测信号的影响。同时,参数的改变不影响系统的检测灵敏度。理论分析的结果得到了实验验证。     

Non-linear vibrations and frequency response analysis of piezoelectrically driven microcantilevers

Microcantilevers have recently received widespread attentions due to their extreme applicability and versatility in both biological and non-biological applications. Along this line, this paper undertakes the non-linear vibrations of a piezoelectrically driven microcantilever beam as a common configuration in many scanning probe microscopy and nanomechanical cantilever biosensor systems. A part of the microcantilever beam surface is covered by a piezoelectric layer (typically ZnO), which acts both as an actuator and sensor. The bending vibrations of the microcantilever beam are studied considering the inextensibility condition and the coupling between electrical and mechanical properties in the piezoelectric materials. The non-linear terms appear in the form of quadratic expression due to presence of piezoelectric layer, and cubic form due to geometrical non-linearities. The Galerkin approximation is then utilized to discretize the equations of motion. In addition, the method of multiple scales is applied to arrive at the closed form solution for the fundamental natural frequency of the system. An experimental setup consisting of a commercial piezoelectric microcantilever attached on the stand of a state-of-the-art microsystem analyzer for non-contact vibration measurement is utilized to verify the theoretical developments. It is found that the experimental results and theoretical findings are in good agreement, which demonstrates that the non-linear modeling framework could provide a better dynamic representation of the microcantilever than the previous linear models. Due to microscale nature of the system, excitation amplitude plays an important role since even a small change in the amplitude of excitation can lead to significant vibrations and frequency shift.