Implantable Electrochemical Microsensors for In Vivo Monitoring of Animal Physiological Information

In vivo monitoring of animal physiological information plays a crucial role in promptly alerting humans to potential diseases in animals and aiding in the exploration of mechanisms underlying human diseases.Currently,implantable electrochemical microsensors have emerged as a prominent area of research.These microsensors not only fulfill the technical requirements for monitoring animal physiological information but also offer an ideal platform for integration.They have been extensively studied for their ability to monitor animal physiological information in a minimally invasive manner,characterized by their bloodless,painless features,and exceptional performance.The development of implantable electrochemical microsensors for in vivo monitoring of animal physiological information has witnessed significant scientific and technological advancements through dedicated efforts.This review commenced with a comprehensive discussion of the construction of microsensors,including the materials utilized and the methods employed for fabrication.Following this,we proceeded to explore the various implantation technologies employed for electrochemical microsensors.In addition,a comprehensive overview was provided of the various applications of implantable electrochemical microsensors,specifically in the monitoring of diseases and the investigation of disease mechanisms.Lastly,a concise conclusion was conducted on the recent advancements and significant obstacles pertaining to the practical implementation of implantable electrochemical microsensors.

Meso-Scale VOC-Mixture Analyzer with Tunable Separation and Microsensor Array Detection

A novel portable instrument developed for field determinations of complex mixtures of volatile organic compounds (VOCs) is described.The key features of the instrument are a miniature multi-stage adsorbent preconcentrator/focuser,two series-coupled separation columns with pressure and temperature tunable retention control,and an integrated array of four chemiresistor (CR) sensors coated with Au-thiolate monolayer-protected nanoparticles (MPN).MPN-CR array response patterns are used with retention times to identify eluting vapors.Air is used as the carrier gas.Calibrations of 20 common indoor air contaminants gave LODs in the range of 0.05 ng/g～0.53 ng/g for a 1 L sample volume.Results of preliminary analyses of characteristic VOCs generated from U.S.currency as well as vapor-phase markers of environmental tobacco smoke (ETS) at low-or sub-ng/g levels are presented.

A band-gap voltage reference for interface circuit of microsensor

A high performance CMOS band-gap voltage reference circuit that can be used in interface integrated circuit of microsensor and compatible with 0. 6 μm ( double poly) mix process is proposed in this paper. The circuit can be employed in the range of 1. 8 - 8 V and carry out the first-order PTAT ( proportional to absolute temperature) temperature compensation. Through using a two-stage op-amp with a NMOS input pair as a negative feedback op-amp,the PSRR ( power supply rejection ratio) of the entire circuit is increased,and the temperature coefficient of reference voltage is decreased. Results from HSPICE simulation show that the PSRR is - 72. 76 dB in the condition of low-frequency,the temperature coefficient is 2. 4 × 10 -6 in the temperature range from - 10 ℃ to 90 ℃ and the power dissipation is only 14 μW when the supply voltage is 1. 8 V.

AN ANALYSIS ON CHARACTERISTIC OF MAGNETOELASTICITY OF A MAGNETIC FIELD MICROSENSOR MADE OF CANTILEVERED PLATES WITH FERROMAGNETIC FILMS

The purpose of this paper is to study the magnetomechanicalcharacteristic of a microsensor which is composed of a cantileveredbeam-plate with ferromagnetic films in order to measure the magneticfield from the deformation of plate when the microsensor is locatedin the magnetic field. To this end, a nu- merical approach made up ofthe finite element method for magnetic field and the finitedifference method for deflection of the microsensor is proposed toperform the numerical analysis of deflection under magnetoelasticinteraction. Some quantitative results of a case study for themagnetoelastic characteristic between the mag- netic field anddeflection of the microsensor in the magnetic field are given. Theresults show that this mi- crosensor can be used not only to measurethe magnitude of magnetic intensity, but also to possibly monitor thedirection of the vector of the magnetic field.

An interdigitated impedance microsensor for detection of moisture content in engine oil

To address the need for the on-site measurement of aging oil, in this paper, we propose an impedance-based microsensor for analyzing the moisture content in engine oil. Using a microfabrication process, we fabricated an interdigitated microelectrode and integrated it with a 3 D-printed microcontainer to produce a microsensor that can detect changes in the permittivity of oil. When the moisture content in oil increases, this sensor can detect the resulting change in the oil impedance, which is related to its permittivity, and then determine the degree to which the oil has aged. The test results show that the proposed microsensor has the advantages of being small and having high sensitivity, good accuracy, and the ability to be combined with hand-held instruments.The proposed method is expected to be used for the rapid, low cost, on-site determination of oil aging.

ELECTRIC FIELD MICROSENSOR BASED ON THE STRUCTURE OF PIEZOELECTRIC INTERDIGITATED CANTILEVER BEAMS

This paper presents the design, fabrication, and preliminary experimental result of an electric field microsensor based on the structure of piezoelectric interdigitated cantilevers with staggered vertical vibration mode. The working principle of this electric field microsensor is demonstrated, and the induced charges and structural parameters of this microsensor are simulated by the finite element method. The electric field microsensor was fabricated by Micro-Electro Mechanical Systems(MEMS) technique. Each cantilever is a multilayer compound structure(Al/Si3N4/ Pt/PZT/Pt/ Ti/SiO 2/Si), and Piezoelectric, PieZ oelectric ceramic Transducer(PZT)(PbZ rxTi(1–x)O3) layer, prepared by sol-gel method, is used as the piezoelectric material to drive the cantilevers vibrating. This electric field microsensor was tested under the DC electric field with the field intensity from 0 to 5×104 V/m. The output voltage signal of the electric field microsensor has a good linear relationship to the intensity of applied electric field. The performance could be improved with the optimized design of structure, and reformative fabrication processes of PZT material.

Interdigital MnO_(2)/PEDOT Alternating Stacked Microelectrodes for High-Performance On-Chip Microsupercapacitor and Humidity Sensing

For microelectronic devices,the on-chip microsupercapacitors with facile construction and high performance,are attracting researchers'prior consideration due to their high compatibility with modern microsystems.Herein,we proposed interchanging interdigital Au-/MnO_(2)/polyethylene dioxythiophene stacked microsupercapacitor based on a microfabrication process followed by successive electrochemical deposition.The stacked configuration of two pseudocapacitive active microelectrodes meritoriously leads to an enhanced contact area between MnO_(2)and the conductive and electroactive layer of polyethylene dioxythiophene,hence providing excellent electron transport and diffusion pathways of electrolyte ions,resulting in increased pseudocapacitance of MnO_(2)and polyethylene dioxythiophene.The stacked quasi-solid-state microsupercapacitors delivered the maximum specific capacitance of 43 mF cm^(-2)(211.9 F cm^(-3)),an energy density of 3.8μWh cm^(-2)(at a voltage window of 0.8 V)and 5.1μWh cm^(-2)(at a voltage window of 1.0 V)with excellent rate capability(96.6%at 2 mA cm^(-2))and cycling performance of 85.3%retention of initial capacitance after 10000 consecutive cycles at a current density of 5 mA cm^(-2),higher than those of ever reported polyethylene dioxythiophene and MnO_(2)-based planar microsupercapacitors.Benefiting from the favorable morphology,bilayer microsupercapacitor is utilized as a flexible humidity sensor with a response/relaxation time superior to those of some commercially available integrated microsensors.This strategy will be of significance in developing high-performance on-chip integrated microsupercapacitors/microsensors at low cost and environment-friendly routes.

Single-chip 3D electric field microsensor

This paper presents a single-chip 3D electric field microsensor, in which a sensing element is set at the center to detect the Z-axis component of an electrostatic field. Two pairs of sensing elements with the same structure are arranged in a cross-like configuration to measure the X- and Y-axis electrostatic field components. An in-plane rotary mechanism is used in the microsensor to detect the X-, Y-, and Z-axis electrostatic field components simultaneously. The proposed microsensor is compact and presents high integration. The microsensor is fabricated through a MetalMUMPS process. Experimental results show that in the range of 0-50 kV/m, the linearity errors of the microsensor are within 5.5%, and the total measure- ment errors of the three electrostatic field components are less than 14.04%.

Sulfate reducing bacterial community and in situ activity in mature fine tailings analyzed by real time qPCR and microsensor

Sulfate reducing bacteria（SRB） play significant roles in anaerobic environments in oil sands mature fine tailings（MFTs）. Hydrogen sulfide（H2S） is produced during the biological sulfate reduction process. The production of toxic H2S is one of the concerns because it may hinder the landscape remediation efficiency of oil sands tailing ponds. In present study, the in situ activity and the community structure of SRB in MFT and gypsum amended MFT in two settling columns were investigated. Combined techniques of H2S microsensor and dissimilatory sulfite reductase β-subunit（dsrB） genes-based real time quantitative polymerase chain reaction（qPCR） were applied to detect the in situ H2S and the abundance of SRB. A higher diversity of SRB and more H2S were observed in gypsum amended MFT than that in MFT, indicating a higher sulfate reduction activity in gypsum amended MFT; in addition, the activity of SRB varied as depth in both MFT and gypsum amended MFT： the deeper the more H2S produced. Long-term plans for tailings management can be assessed more wisely with the information provided in this study.

Design and implementation of a low-pass filter for microsensor signal processing

A novel low-pass filter that consists of a switched capacitor filter （SCF） and its antialiasing prefilter and smoothing postfilter is proposed for a microsensor signal processing system, which is used in separation point detection on the surface of micro air vehicles. In the system, the filter is not only applied to finish the function of filtering but also used as the front end antialiasing filter of the over sampling analog-to-digital converter. This proposed implementation mostly relies on the design of a high-precision SCF employing a correlated double sampling technique and optimisation switches. Simultaneously, the multiple-loop feedback low pass filter with good high frequency attenuation characteristics is applied as the pre- and postfilter. The design is implemented in the Central Semiconductor Manufacturing Corporation （CSMC） 0.5 μm double-poly three-metal （2P3M） 3 chip die area occupies only 0.39 mm2 and dissipatesl.53 mW. 3 V CMOS technology, with satisfactory results, The

RhIr@MoS2 nanohybrids based disposable microsensor for the point-of-care testing of NADH in real human serum

Dihydronicotinamide adenine dinucleotide(NADH)is an important enzyme in all living cells,which is found to be abnormally expressed in cancer cells.Since it is redox-active,an electrochemical detection method would be suitable for monitoring its concentration in biological fluids.Here we present a strategy for specific determination of NADH in real human serum by using RhIr@MoS2 nanohybrids based microsensor.To implement the protocol,RhIr nanocrysrals are in-situ grown onto MoS2 interlayers forming a nanohybrid structure(RhIr@MoS2).After being locally deposited on an electrochemical microsensor,it could be used for the analysis of NADH.The developed RhIr@MoS2 nanohybrids based microsensor possesses the ability for analyzing NADH at the applied potential of 0.07 V(much lower than most reported values).The detection limit is evaluated as low as 1 nmol/L even in bovine serum albumin(BSA)media.In addition,the sampling analysis of human serum from cancer patients and health controls shows that the microsensor displays good diagnostic sensitivity and specificity,illustrating that this developed detection technique is a relatively accurate method for measuring NADH in biological fluids.The proposed electrochemical microsensor assay also owns the benefits of convenience,disposable and easy processing,which make it a great possibility for future point-of-care cancer diagnosis.

静电力驱动的悬臂梁微型电场传感器件

随着智能电网和能源互联网的发展,大规模实时电压/电场监测成为电力系统的迫切需求,这依赖于先进传感器件的大规模布置。电场测量在电力系统中具有重要意义。一方面,基于电场测量的电压反演可以实现高电压的非接触式测量,替代传统高压互感器,从而减少测量设备绝缘成本和安装难度;另一方面,电场测量还可以被应用于设备故障诊断、雷电预警、电磁环境测量等应用场景。传统的电场测量设备,如场磨等,往往体积大、成本高,无法大规模灵活布置。本文提出了一种静电力驱动的压阻式微型电场传感器。传感器被设计为四悬臂结构,悬臂在静电力的驱动下产生位移和应变,通过压阻材料转化为可测信号。所提出的传感器具有尺寸小、成本低、功耗低、易于批量生产的优点。同时,该传感器该具有高信噪比、高分辨率及宽电场测量范围。实验结果表明,所提出的传感器具有1.1~1100.0kV·m^(-1)的线性测量范围、112 V·m^(-1)·Hz^(-1/2)的交流电场分辨率以及496 Hz的截止频率。这一微型电场传感器将在智能电网及能源互联网中具有广泛的应用价值。

磁组装辅助乳滴模板聚合法制备pH响应光子晶体微传感器

为了解决响应性光子晶体微传感器响应时间长、检测精度不稳定的问题,采用磁组装辅助乳滴模板聚合法制备一种可快速可视化监测局部微环境pH的响应光子晶体微传感器,采用场发射扫描电子显微镜、透射电子显微镜、傅里叶转换红外光谱仪和光纤光谱仪等对制得的pH响应光子晶体微传感器进行结构与性能表征,研究该微传感器在不同pH溶液中的响应变色性能、响应时间和循环稳定性。结果表明:该微传感器直径约为8μm,微观结构为嵌有周期性组装磁性胶体粒子链的响应性凝胶微球;当介质环境pH由3.6变化到7.8时,该微传感器衍射光波长从443 nm红移到641 nm,结构色从蓝色变成红色;该微传感器响应快,响应时间为3 s,具有良好的循环稳定性,并在保存30 d后仍保持良好的检测性能。

A High Precision CMOS Opamp Suitable for ISFET Readout

This paper presents a high precision CMOS opamp suitable for ISFET readout. The opamp is tailored to provide a constant bias condition for ISFET as part of the readout circuits and,hence,is compatible for single chip integration with the sensor. A continuous time auto-zero stabilization technique is studied and employed, with the aim of suppressing the low frequency noises, including the offset voltage, 1/f noise, and temperature drift. The design is based on a 0.35μm CMOS process. With a 3.3V power supply,it maintains a DC open loop gain of more than 100dB and an offset voltage of around 11μV,while the overall power dissipation is only 1.48mW. With this opamp, a pH microsensor is constructed, of which the functionality is verified by experimental tests.

Nafion/Au溶胶自组装微铂传感器的研究及其在心肌细胞中NO水平测定中的应用

制备了一种新型的 Nafion/ Au溶胶修饰微铂传感器 ( Au溶胶颗粒的直径为 7～ 1 4 nm) ,并将该传感器应用于心肌细胞中 NO水平的研究 .实验结果表明 ,自组装制备的 Nafion/ Au溶胶修饰微传感器对 NO有较高的灵敏度和良好的选择性 ,在 1 .0× 1 0 - 7～ 4 .0× 1 0 - 5mol/ L浓度范围内 ,NO的催化氧化电流与其浓度呈良好线性关系 ,检测限为 5 .0× 1 0 - 8mol/ L.探讨了该修饰微传感器对 NO的催化机理 ,研究了在L-精氨酸和乙酰胆碱刺激下心肌细胞内的 NO释放 .

湖泊沉积物-水界面氧气交换速率的测定及影响因素

水流启动-停止法可有效获取体积式氧气交换速率(O2(t)),且该速率与沉积物柱样培养法获得的总氧气交换速率(TOE)之间具显著相关性;与由一维溶解氧剖面计算获得的氧气在扩散界面层中的扩散速率和氧气在沉积物中的扩散速率相比,O2(t)与TOE不仅能代表氧气扩散速率,而且还包括沉积物中生物呼吸以及生物扰动引起的界面氧气交换速率信息.此外,通过比较太湖及南四湖多位点不同沉积物性质条件下界面氧气交换速率,结果表明界面氧气交换速率在空间尺度上的差异性,除与生物因素有关外,还与沉积物有机物质含量显著相关.

聚四氨基酞菁铜微型传感器及其在一氧化氮测定中的应用

利用电化学聚合的方法制备了聚四氨基酞菁酮[Cu(TAPc)]微型传感器,并探讨了微型传感器对一氧化氮(NO)的电化学响应.结果表明,电化学聚合Cu(TAPc)微型传感器对NO具有良好的催化氧化作用.示差脉冲伏安法(DPV)和示差脉冲安培法(DPA)的结果表明,该传感器对NO的响应具有较低的检测限和较高的灵敏度.NO的浓度在1.20×10^(-8)～1.00×10^(-6)mol/L范围内与传感器的电流响应呈线性关系,相关系数为0.9998;检出限为6.00×10^(-9)mol/L.生物体内常见共存物质如抗坏血酸、儿茶酚胺类神经递质及其代谢产物、NO的降解产物NO_2^-等不干扰NO的测定.所研制的微型传感器可以满足NO的活体分析的要求.

SOI微型电场传感器的设计与测试

该文研制了一种新型的基于SOI(Silicon-On-Insulator)微机械加工技术的高性能电场传感器敏感结构。为提高传感器的灵敏度和信噪比,该器件采用侧面屏蔽感应电极的独特设计方案,降低了传感器屏蔽电极的边缘效应;并基于有限元仿真,进一步优化了传感器敏感结构参数。在室温和室内大气压条件下,测试表明,测试量程0～50kV/m,传感器总不确定度优于2%,分辨率为50 V/m。

微机电系统的发展及其应用

微机电系统是在微电子技术基础上产生和发展起来的多学科交叉的前沿科学研究领域 ,是面向 2 1世纪的高新科技 .介绍了微机电系统产生的背景影响、组成特征和基础研究内容 ,综述了微机电系统技术基础所涉及的材料、微机械设计和模、微细加工技术以及微封装与测试等领域 ,并对微机电系统的应用、典型的微器件、国内外的发展现状及前景进行全面分析 .在此基础上 。

基于MEMS技术的微型传感器

和传统的传感器相比,微型传感器具有许多新特性,它们能够弥补传统传感器的不足,具有广泛的应用前景,越来越受到重视。文中详细介绍了一些微型传感器件的结构和原理,说明了微型传感器的基本性能特点和微型传感器的发展趋势。