铂黑/二茂铁修饰MEMS电极的葡萄糖传感器

利用MEMS技术小批量加工了薄膜金电极。采用电化学沉积法在金电极表面修饰纳米铂黑颗粒,以有机功能性材料二茂铁作为电子媒介体,通过戊二醛-牛血清白蛋白共价交联固定葡萄糖氧化酶制得葡萄糖生物传感器。考察了不同修饰电极的电化学行为以及酶固定量和戊二醛浓度对传感器响应特性的影响。实验结果表明:该传感器响应时间仅为5s,在0.29V的低工作电压下,线性测量范围可达到0.5～22mmol/L,灵敏度为50.35μA/(cm2.mmol.L-1),相关系数为0.9925,差异系数为4.28%。     

检测三磷酸腺苷的交流阻抗型适体传感器

将一端标记具有可逆电化学行为的电活性基团二茂铁、另一端标记巯基的三磷酸腺苷(ATP)适体ss-DNA组装到薄膜金电极上,构筑了一种可灵敏检测ATP浓度的交流阻抗型适体传感器。首先研究了适体传感器的自组装方法,然后利用交流阻抗法研究了适体传感器在铁氰化钾(K3Fe(CN)6)和亚铁氰化钾(K4Fe(CN)6)混合溶液中的电极表面电子传递阻抗和被测物ATP浓度之间的关系,最后对自组装的阻抗型适体传感器的电化学特性进行了分析。实验表明:利用自组装的适体传感器检测ATP浓度时,适体传感器检出限低,线性检测范围宽,重复性好,其中检出限为0.5μmol/L,线性检测范围为0.5~100μmol/L,线性度为0.998 9,连续5次测量的相对标准差为1.5%。     

聚苯胺功能化的塑料光纤传感器用于黄曲霉毒素B1浓度检测

为开发低成本高灵敏度黄曲霉毒素B₁(AFB₁)检测设备,研制了一种将聚苯胺(PAni)与塑料光纤(POF)相结合的增敏光纤免疫传感器。传感器功能化设计采用两步法,首先将PAni涂层修饰至光纤传感区,然后通过戊二醛的交联作用,将AFB₁抗体分子固定于传感区。由于测量过程中抗原和抗体的免疫反应会导致POF表面折射率发生变化,从而引起探测光子数的波动,以此实现对AFB₁浓度的检测。实验研究了PAni涂层对传感器的增敏效果,结果表明PAni功能化的POF传感器增敏效果明显,且在0.01～10μg/L AFB₁浓度范围内,传感器的光子数变化量与AFB₁浓度间具有线性关系,检测限为0.53μg/L,加标回收率为95.97%～113.13%,且传感器对AFB₁的特异性和抗干扰性良好,满足AFB₁精量化检测的需要。     

硒化镍纳米片阵列的合成及其在非酶葡萄糖传感器的应用

采用一步水热法成功合成泡沫镍支撑的蜂窝状硒化镍(Ni_(0.85)Se)纳米片阵列,利用X射线粉末衍射仪、能量色散谱仪、扫描电子显微镜、透射电子显微镜对其结构、组成、形貌和晶格进行了表征。结果显示,所得蜂窝状Ni_(0.85)Se纳米片阵列属于六方相结构,其纳米片的厚度约为15 nm。通过循环伏安法和计时电流法来检测Ni_(0.85)Se纳米片阵列对葡萄糖传感器的电催化性能。实验结果表明,Ni_(0.85)Se纳米片阵列对葡萄糖有较好的安培响应(响应电流达到10~(–3)A)、较低的检出限(0.002 mmol/L(S/N=3))、宽的线性范围(0.0022μmol/L~1.022 mmol/L)、较高的灵敏度[1600μA/(mmol·L~(–1)·cm~2)]以及良好的选择性。以上结果表明蜂窝状Ni_(0.85)Se纳米片阵列在非酶葡萄糖传感方面具有良好的应用前景。     

用于重金属离子电化学传感器的TiO2NT/AuNP纳米复合材料

采用水热合成法将金纳米颗粒(AuNP)修饰到TiO₂纳米管(TiO₂NT)表面。用X射线衍射仪(XRD)和场发射扫描电子显微镜(FESEM)对制备的纳米复合材料进行表征。采用电化学阻抗谱(EIS)和循环伏安法分析了TiO₂NT/AuNP纳米复合材料修饰的玻碳电极(GCE)。通过方波阳极溶出伏安法(SWASV)分析了纳米复合材料检测重金属离子的可行性。纳米复合材料对Pb(Ⅱ)、Cd(Ⅱ)、Hg(Ⅱ)和Cu(Ⅱ)具有较高的电分析活性和灵敏度,对Pb(Ⅱ)、Cd(Ⅱ)、Hg(Ⅱ)和Cu(Ⅱ)的灵敏度分别为15.63、213.19、287.86和72.75μA·μM^-1(1 M=1 mol/L),检出限分别为0.052、0.004、0.003和0.011μmol/L。采用TiO₂NT/AuNP纳米复合材料对多种重金属离子进行了检测。此外,TiO₂NT/AuNP/GCE具有抗干扰性能和稳定性。因此,TiO₂NT/AuNP纳米复合材料可适用于电化学传感器来检测多种重金属离子。     

修饰掺硼金刚石电极循环伏安法检测尿酸

用直流等离子体喷射化学气相沉积(CVD)法制备掺 硼金刚石(BDD)薄膜电极。通过扫描电镜(SEM)观察到薄膜表面分布均匀致密;霍尔测 试仪检测薄膜的电阻率为0.023Ω·cm,载流子浓度为6.423×10¹⁹ cm－3;循环伏安法(CVa)测得其电极电势窗为 3.4V;分析了浓度为10μmol/L的 尿酸(UA)溶液在BDD电极表面的电化学响应,表明扫描速率的平方根与氧化峰电流呈线性关 系。通过对比茜素黄、牛磺酸和L-半胱氨酸3种物质对BDD电极进行修饰,表明由L-半胱氨 酸修饰BDD电极的电催化氧化能力最强;在浓度为1×10－7～1×10－4 mol/L范围内,浓度的对数与氧化峰电流呈线性关系,且检测限为 1×10－8 mol/L。实验结果表明,20倍浓度的葡萄糖和抗坏血酸对UA的 检测不构成影响。     

集成Ti/TiO2敏感电极和液接式Ag/AgCl参比电极的pH微纳传感器

常见的pH传感器大多采用电位法进行检测,基于电位法进行检测的传感器由敏感电极和参比电极组成.在尺寸仅为5 mm×5 mm的传感器芯片上制备了钛电极、银电极和铂电阻丝.采用电化学氧化的方法对钛电极进行阳极氧化制成Ti/TiO2敏感电极.采用电化学氯化的方法对银电极进行阳极氯化,再将饱和KC1溶液(3 mol/L)注入参比...     

组蛋白乙酰化/去乙酰化在冬凌草甲素诱导Molt-4细胞凋亡中的作用

目的:探讨组蛋白乙酰化/去乙酰化在冬凌草甲素(oridonin,Ori)诱导Molt-4细胞凋亡中的作用.方法不同浓度Ori(2.5μmol/L、5μmol/L、10μmol/L、20μmol/L、40μmol/L)作用于Molt-4细胞,MTT法检测细胞增殖;瑞氏染色光镜下观察细胞形态学变化;Western blot检测Caspase-3、组蛋白去乙酰化酶1(histone deacetylase inhibitor,HDAC1)及组蛋白H3乙酰化水平.结果:Ori抑制Molt-4细胞增殖,诱导细胞凋亡,呈时间-剂量依赖性;光镜下Molt-4细胞染色质固缩,凋亡小体出现.Ori活化Caspase-3,下调HDAC1表达,使组蛋白H3乙酰化水平上调.结论:Orr可能通过提高组蛋白H3乙酰化水平,抑制HDAC1活性诱导Molt-4细胞凋亡.     

TNF-α对3T3-L1脂肪细胞胰岛素敏感性的影响及罗格列酮的干预作用

目的观察肿瘤坏死因子-α(TNF-α)对3T3-L1脂肪细胞胰岛素敏感性的影响及罗格列酮的干预作用。方法采用不同浓度TNF-α(5μg/ml、10μg/ml、20μg/ml)处理3T3-L1脂肪细胞48h、采用20μg/ml TNF-α处理不同时间(6h、12h、24h、48h)及罗格列酮(10μmol/ml)预处理6h的3T3-L1脂肪细胞与20μg/mlTNF-α作用48h;以2-DG摄入法检测细胞对葡萄糖的摄取率。结果与对照组比较,5μg/L、10μg/L和20μg/LTNF-α作用各组分别使葡萄糖摄取率减少了25%(P<0.01)、43%(P<0.01)、58%(P<0.01);20μg/L TNF-α处理3T3-L1脂肪细胞6h、12h、24h、48h使葡萄糖的摄取率分别减少10%(P<0.05)、28%(P<0.01)、40%(P<0.01)、57%(P<0.01),罗格列酮预处理能使20μg/ml TNF-α组脂肪细胞对葡萄糖的摄取率增加37%(P<0.01)。结论TNF-α以浓度和剂量依赖方式导致脂肪细胞胰岛素抵抗;罗格列酮能明显改善此作用。     

基于折射率调制原理的光纤生物传感器的研制

根据光纤内光强损耗与芯外的环境有效折射率之间的关系,设计了一种结构简单、易于操作、成本低廉、灵敏度较高的折射率调制型的光纤生物传感器.文中对该传感器的结构进行了理论分析,通过对不同浓度葡萄糖溶液的检测,研究了该传感器的传感特性.结果表明:该传感器的检测灵敏度可以达到μmol/L量级,并具有较好的线性特性.     

传感器法检测甲萘威残留的研究

利用固定化的乙酰胆碱酯酶(AChE)制作了一种可用于农药残留检测的快捷灵敏的传感器,并探讨了AChE的固定化技术。酶固定化实验确定:固定化载体为孔径0.45μm硝酸纤维素膜、保护剂牛血清白蛋白(BSA)浓度为1.0%、交联剂戊二醛浓度为5.0%时,固定化酶传感器具有较高的灵敏度和稳定性。用氨基甲酸酯类农药甲奈威为抑制剂,与GC法(GB14877-94)进行对比,当喷洒量为10.0mg.L-1时,GC法测定的结果为9.03mg.L-1,生物传感器法测定的结果为6.56mg.L-1,可以满足对甲萘威农药残留的快速检测要求。     

Nanostructuring Platinum Nanoparticles on Multilayered Graphene Petal Nanosheets for Electrochemical Biosensing

Hybridization of nanoscale metals and carbon nanotubes into composite nanomaterials has produced some of the best‐performing sensors to date. The challenge remains to develop scalable nanofabrication methods that are amenable to the development of sensors with broad sensing ranges. A scalable nanostructured biosensor based on multilayered graphene petal nanosheets (MGPNs), Pt nanoparticles, and a biorecognition element (glucose oxidase) is presented. The combination of zero‐dimensional nanoparticles on a two‐dimensional support that is arrayed in the third dimension creates a sensor platform with exceptional characteristics. The versatility of the biosensor platform is demonstrated by altering biosensor performance (i.e., sensitivity, detection limit, and linear sensing range) through changing the size, density, and morphology of electrodeposited Pt nanoparticles on the MGPNs. This work enables a robust sensor design that demonstrates exceptional performance with enhanced glucose sensitivity (0.3 µM detection limit, 0.01–50 mM linear sensing range), a long stable shelf‐life (>1 month), and a high selectivity over electroactive, interfering species commonly found in human serum samples.     

二茂铁及其衍生物修饰电极的研究

二茂铁及其衍生物修饰电极在电催化、电分析和生物传感器等方面具有重要的应用前景。本文对二茂铁及其衍生物修饰电极分类、制备、特点及其应用等方面的研究现状作了归纳和评述。提出了今后研究工作的方向。     

Phase fluorometric glucose biosensor using oxygen as transducer and enzyme-doped xerogels

The development of a glucose biosensor based on co-immobilisation of oxygen (O₂) responsive luminophore and glucose oxidase (GOx) within nanoporous solgel-derived xerogels is described. The biosensor operates in the frequency domain and exploits the effect of glucose and O₂ consumption by GOx on the luminophore excited-state lifetime (i.e. phase angle). The biosensor consists of a modulated light emitting diode as the excitation source and a silicon photodiode as the detector. This sensing methodology establishes the viability for low-cost and accurate biosensors that operate at a low modulation frequency (tens of kHz). The biosensor is stable, reproducible, and provides an analytically reliable response from 0.5 to 15 mM glucose     

A Highly Efficient Electrochemical Biosensing Platform by Employing Conductive Nanocomposite Entrapping Magnetic Nanoparticles and Oxidase in Mesoporous Carbon Foam

A conductive multi‐catalyst system consisting of Fe₃O₄ magnetic nanoparticles (MNPs) and oxidative enzymes co‐entrapped in the pores of mesoporous carbon is developed as an efficient and robust electrochemical biosensing platform. The construction of the nanocomposite begins with the incorporation of MNPs by impregnating Fe(NO₃)₃ on a wall of mesoporous carbon followed by heat treatment under an Ar/H₂ atmosphere, which results in the formation of magnetic mesoporous carbon (MMC). Glucose oxidase (GOx) is subsequently immobilized in the remaining pore spaces of the MMC by using glutaraldehyde crosslinking to prevent enzyme leaching from the matrix. H₂O₂ generated by the catalytic action of GOx in proportion to the amount of target glucose is subsequently reduced into H₂O by the peroxidase mimetic activity of MNPs generating cathodic current, which can be detected through the conductive carbon matrix. To develop a robust and easy‐to‐use electrocatalytic biosensing platform, a carbon paste electrode is prepared by mechanically mixing the nanocomposite or MMCs and mineral oil. Using this strategy, H₂O₂ and several phenolic compounds are amperometrically determined employing MMCs as peroxidase mimetics, and target glucose was successfully detected over a wide range of 0.5 × 10^?3 to 10 × 10^?3 M , which covers the actual range of glucose concentration in human blood, with excellent storage stability of over two months at room temperature. Sensitivities of the biosensor (19 to 36 nA mM ^?1) are about 7–14 times higher than that of the biosensor using immobilized GOx in mesoporous carbon without MNPs under optimized condition. The biosensor is of considerable interest because of its potential for expansion to any oxidases, which will be beneficial for use in practical applications by replacing unstable organic peroxidase with immobilized MNPs in a conductive carbon matrix.     

Integrated multi-biosensors based on an ion-sensitive field-effecttransistor using photolithographic techniques

Two kinds of multifunctional biosensors, one sensitive to glucose and triolein and the other to glucose and urea, have been constructed using semiconductor fabrication techniques. An integrated ISFET (ion-sensitive field-effect transistor) with three hydrogen-ion-sensitive FET elements on one chip was used as a transducer for the biosensor. A photolithographic technique with a water-soluble photocrosslinkable polymer made possible the deposition of patterned enzyme membranes (glucose oxidase, lipase, and urease membranes) and bovine serum albumin membrane around each gate surface of ISFET elements. The multibiosensor for measuring glucose and triolein concentrations determined both glucose concentrations up to 5 mM and triolein concentrations up to 3 mM simultaneously. The biosensor for glucose and urea has a detection range of 0.03 to 3 mM for glucose and 0.1 to 20 mM for urea. Some multibiosensors showed a cross-sensitivity problem due to enzyme contamination. An improved membrane fabrication method to prevent the enzyme contamination is described     

Highly Ordered Platinum‐Nanotubule Arrays for Amperometric Glucose Sensing

Direct glucose sensing on highly ordered platinum‐nanotubule array electrodes (NTAEs) is systematically investigated. The NTAEs are fabricated by electrochemical deposition of platinum in a 3‐aminopropyltrimethoxysilane‐modified anodic alumina membrane. Their structures and morphologies are then characterized using X‐ray diffraction and scanning electron microscopy, respectively. Electrochemical results show that NTAEs with different real surface areas could be achieved by controlling the deposition time or by using anodic alumina membranes with different pore size. Electrochemical responses of the as‐synthesized NTAEs to glucose in a solutions of either 0.5 M H₂SO₄, or phosphate‐buffered saline (PBS, pH 7.4) containing 0.1 M KCl are discussed. Based on the different electrochemical reaction mechanisms of glucose and interferents such as p‐acetamedophenol and ascorbic acid, their high roughness factor makes NTAEs sensitive, selective, and stable enough to be a kind of biosensor for the non‐enzymatic detection of glucose. Such a glucose sensor allows the determination of glucose in the linear range 2–14 mM, with a sensitivity of 0.1 μA cm^–2 mM^–1 (correlation coefficient 0.999), and a detection limit of 1.0 μM glucose, with neglectable interference from physiological levels of 0.1 mM p‐acetamedophenol, 0.1 mM ascorbic acid, and 0.02 mM uric acid.     

The Synergistic Effect of Prussian‐Blue‐Grafted Carbon Nanotube/Poly(4‐vinylpyridine) Composites for Amperometric Sensing

Because of its high activity and selectivity toward the reduction of hydrogen peroxide and oxygen, Prussian blue (PB) is usually considered as an “artificial enzyme peroxidase” and has been extensively used in the construction of electrochemical biosensors. In this study, we report on the construction of amperometric biosensors via grafting PB nanoparticles on the polymeric matrix of multiwalled carbon nanotubes (MWCNTs) and poly(4‐vinylpyridine) (PVP). The MWCNT/PVP/PB composite films were synthesized by casting films of MWCNTs wrapped with PVP on gold electrodes followed by electrochemical deposition of PB on the MWCNT/PVP matrix. The electrode modified with the MWCNT/PVP/PB composite film shows prominent electrocatalytic activity toward the reduction of hydrogen peroxide, which can be explained by the remarkable synergistic effect of the MWCNTs and PB. Therefore, fast amperometric response of this sensor to hydrogen peroxide was observed with a detection sensitivity of 1.3 μA μM ^–1 of H₂O₂ per square centimeter area and a detection limit of 25 nM . These results are much better than those reported for PB‐based amperometric sensors. In addition, a glucose biosensor fabricated by casting an additional glucose oxidase (GOD) containing Nafion film above the MWCNT/PVP/PB composite film shows promise for the sensitive and fast detection of glucose. The observed high stability, high sensitivity, and high reproducibility of the MWCNT/PVP/PB composite films make them promising for the reliable and durable detection of hydrogen peroxide and glucose.