菲涅耳反射型光纤生物传感器研究

构建了一种基于菲涅耳反射原理的光纤生物传感器,以生物素-链霉亲和素体系为模型验证了其进行生物传感的可行性.首先,利用硅烷偶联剂,在切平整的普通单模光纤端面修饰上生物素,将其作为吸附链霉亲和素的生物敏感膜.然后,将光纤端面浸入不同浓度的链霉亲和素溶液中,测量宽带光源经过光纤端面反射后的光谱.实验结果表明,反射光谱的相对功率与链霉亲和素溶液浓度之间呈线性关系,测量得到灵敏度为15.38 dB/(mg/mL).用牛血清白蛋白代替链霉亲和素,测量得到的反射光谱曲线与在之前浸入生物素后的反射光谱曲线基本重合,证明此生物传感器的选择性好.最后以人免疫球蛋白G与山羊抗人免疫球蛋白G体系验证了此结构进行生物传感的实用性.     

Acetylcholinesterase immobilised eggshell membrane-based optical biosensor for organophosphate detection

The development of an optical biosensor for the determination of malathion based on acetylcholinesterase (AChE) inhibition using Ellman’s reagent is reported. The AChE has been immobilised onto the eggshell membrane (ESM) using glutaraldehyde as a cross-linking agent. Scanning Electron Microscopic (SEM) studies and Fourier Transformed Infra-Red (FTIR) characterisations have been carried out to affirm the successful immobilisation of AChE onto the ESM. Under optimum conditions, the developed biosensor estimated the pesticide concentration in the range of 0.1–50 ng/mL with a limit of detection (LOD) of 0.1 ng/mL within 30 min. Parameters affecting the biosensor response such as concentration of enzyme, substrate and inhibition time were optimised. The stability and reusability of the AChE/ESM sensor have been observed as 31 days at 4°C and two times, respectively.     

Application of diazo-thiourea and gold nano-particles in the design of a highly sensitive and selective DNA biosensor

An effective procedure for constructing a DNA biosensor is developed based on covalent immobilization of NH_2 labeled,single strand DNA(NH_2-ssDNA) onto a self-assembled diazo-thiourea and gold nanoparticles modified Au electrode(diazo-thiourea/GNM/Au).Gold nano-particles expand the electrode surface area and increase the amount of immobilized thiourea and single stranded DNA(ssDNA) onto the electrode surface.Diazo-thiourea film provides a surface with high conductibility for electron transfer and a bed for the covalent coupling of NH_2-ssDNA onto the electrode surface.The immobilization and hybridization of the probe DNA on the modified electrode is studied by differential pulse voltammetry(DPV) using methylene blue(MB) as a well-known electrochemical hybridization indicator.The linear range for the determination of complementary target ssDNA is from 9.5(±0.1) × 10~(-13) mol/L to1.2(±0.2) x 10~(-9) mol/L with a detection limit of 1.2(±0.1) 10~(-13) mol/L.     

Comparative Study of Nanostructured Matrices Employed in the Development of Biosensors Based on HRP Enzyme for Determination of Phenolic Compounds

This paper made a comparative study of new matrices of nanostructured materials (multiwall carbon nanotube, fullerene and hydroxylated fullerene) aiming to compare them when employed in the process of immobilization of enzyme horseradish peroxidase (HRP) on the development of amperometric biosensors for the determination phenolic compounds. The results confirm that all the three nanostructured matrices used in the preparation of the biosensor show improvements when acting as a transducer stabilizer and immobilization matrix, comparing to the electrode of carbon paste. Regarding the performance of these matrices it is verified that the developed biosensor employed the multiwall carbon nanotube as matrix immobilized enzyme HRP has shown the best sensitivity for the molecule of phenol (33 nA cm^?2 µmol^?1 L), however, regarding the range of linear response, the elaborated biosensor containing the hydroxylated fullerene has shown the best response (5–200 µmol L^?1). In terms of operational stability, the biosensors maintained their responses around 95 % after more than 200 analyzes. It is also important to mention that in all the cases, the association with the graphite powder improves the answers of the biosensors around 10 to 15 %.     

Development of Silver Nanowires Based Highly Sensitive Amperometric Glucose Biosensor

The fabrication of a highly sensitive amperometric glucose biosensor based on silver nanowires (AgNWs) is presented. The electrochemical behavior of glassy carbon electrode modified by Ag NWs exhibits remarkable catalytic performance towards hydrogen peroxide (H₂O₂) and glucose detection. The biosensor could detect glucose in the linear range from 0.005 mM to 10 mM, with a detection limit of 50 µM (S/N=3). The glucose biosensor shows high and reproducible sensitivity of 175.49 µA cm^?2 mM and good stability. In addition, the biosensor exhibits a good anti‐interference ability and favorable stability over relatively long‐term storage (more than 21 days).     

MCM-41型介孔二氧化硅纳米颗粒的制备及其在DNA生物传感器中的应用

MCM-41型介孔二氧化硅纳米颗粒具有独特的结构特征和理化性质,能够与DNA、信号探针以及多种活性纳米颗粒结合,在DNA生物传感器中得到了广泛应用。其中,球形和薄膜形的MCM-41型介孔二氧化硅具有高负载量、孔口控释和高比表面积等优点,能有效装载各种信号探针、控制粒子的扩散以及固定大量活性纳米颗粒,可大大提高DNA生物传感器的灵敏度。本文就MCM-41型介孔二氧化硅在合成方式、模板剂去除、表面修饰及应用等三个方面的最新研究作了综述。首先依次介绍了球形和薄膜形MCM-41型介孔二氧化硅的常用合成方法和模板剂去除方法,并简要描述了各方法的优缺点。其次,大致介绍了其表面性质和功能化修饰的研究现状。再次介绍了现阶段将MCM-41型介孔二氧化硅作为信号探针的传递系统、分子筛和活性纳米材料的载体来提高检测灵敏度的DNA生物传感器。最后总结了目前研究中的不足之处并展望了其未来的进展方向。     

A Novel Amperometric Glucose Biosensor Based on Fe3O4-Chitosan-β-Cyclodextrin/MWCNTs Nanobiocomposite

A novel enzymatic biosensing platform toward glucose is achieved with nanocomposite of magnetic nanoparticles (Fe₃O₄−CS−CD) and multi-walled carbon nanotubes (MWCNTs). The synergistic effect of chitosan, β-cyclodextrin and MWCNTs can facilitate electron transfer between enzyme and electrode based on the promoting results of the cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The new biosensors exhibited direct electron transfer (DET) from enzyme to electrode after glucose oxidase (GOx) was immobilized on the modified electrode with the nanocomposite. Consequently, the enzymatic glucose biosensor displayed a considerably wide linear range (40 μM to 1.04 mM) with a high sensitivity of 23.59 μA mM⁻¹cm⁻², low detection limit of 19.30 μM, good selectivity, reproducibility and repeatability for detecting glucose. In addition, the current response still retained at 93.4 % after 25 days. Furthermore, the practical application of glucose biosensor was test in human serum samples with satisfactory accuracy, demonstrating promising and practical potential in biomedical diagnostics.     

基于锁核酸探针的传感器用于BCR/ABL融合基因检测的研究

基于慢性粒细胞白血病中BCR/ABL融合基因的碱基序列,设计了一种新型发夹结构锁核酸(locked nucleic acids, LNA)探针,把LNA探针通过Au-s键固定在金电极表面构建了特异的生物传感器.LNA探针与目标链DNA杂交,以自行合成的苯甲酸二聚铜配合物([Cu2(C7H5O2)4(C2H6O)2], 简称[Cu(R)2]2+)为杂交指示剂,应用差示脉冲伏安法进行检测,表现出良好的响应信号.该新型锁核酸传感器能较好的区分完全互补链DNA、单碱基错配链DNA.对互补链DNA检测的线性范围为1.0×10-8～1.0×10-6 mol•L-1,检出限为2.0×10-9 mol•L-1.     

纳米金颗粒增强信号的表面等离子体共振生物传感器用于甲氧檗因高灵敏检测的研究

报道了一种基于表面等离子体共振(SPR)生物传感器的高灵敏检测抗癌药物甲氧檗因的新方法. 分别在纳米金颗粒和金膜表面修饰富含腺嘌呤(A)的DNA链, 当存在甲氧檗因时, 由于一个甲氧檗因分子可与4个A碱基相结合, 从而使得修饰在纳米金颗粒和金膜表面的DNA形成稳定的双链结构, 进而将功能化纳米金颗粒捕获在金膜表面. 由于纳米金颗粒与金膜之间的电场耦合效应可增强SPR信号, 从而可实现对小分子甲氧檗因的高灵敏、特异性检测. 本方法的检测下限低至0.07 pmol/L, 相对比色法和荧光法而言, 降低了约5～6个数量级. 以4种药物(盐酸小檗碱、青霉素G、硫酸庆大霉素、5-氟尿嘧啶)作为对照考察了该传感器的选择性, 结果表明该传感器具有较好的选择性.     

溶胶-凝胶生物传感器

评述了溶胶－凝胶生物传感器这个领域已取得的成果,主要内容涉及溶胶－凝胶固定化方法的过程,优点与性质,溶胶－凝胶光学生物传感器和安培生物传感器的发展,并展望了其发展趋势。