植物组织基膜生物传感器的研制

应用微生物及动、植物组织的生物催化材料作传感器已越益引起人们的注意,已有用植物的叶、果、花等研制植物组织电极的报道。 香蕉皮中含有草酸盐氧化酶,苹果中含有L-天冬酸脱羧酶。我们选择了香蕉皮和苹果作为生物催化材料,以二氧化碳气敏电极为基础电极,研制了两种植物组织电极。     

马铃薯组织过氧化氢生物传感器的研究

以马铃薯组织作为生物催化材料与氧电极结合研制成过氧化氢传感器，具有灵敏度高、选择性好和寿命长等特点．响应时间５ｍｉｎ，过氧化氢浓度在２×１０－４－４×１０－３ｍｏｌ／Ｌ之间与响应有线性关系，检出限５×１０－５ｍｏｌ／Ｌ．     

香蕉组织膜草酸电极的研究

将香焦组织与氧电极偶合,制成了草酸生物组织电极。在静态和流动条件下,测得电极的线性响应范围分别为8.8×10~(-5)～6.3×10~(-4)mol/L和5.0×10~(-5)～1.8×10~(-3)mol/L,二者的相关系数均为0.9998。研究了介质条件、pH、温度、流速、取样量和固定化等条件的影响。测定了电极的选择性和使用寿命等性能。计算了该实验条件下酶反应的米氏常数。采用静态法和流动注射法测得7份草酸标液的平均回收率分别为98.4％和98.9％。电极已用于一些食品中草酸的测定,所得结果与文献报道基本一致。     

生物传感器的研究.V.尿素—石竹花组结电极的研究

尿素—石竹花组织电极是一种植物组织传感器。文中叙述了一种完整石竹花瓣的固定新方法,改善了此类生物传感器的性能:线性范围7.6×10~(-(?))～1.0×10~(-3)mol·L~(-1),斜率47mv·decade~(-1),检测上下限分别为3.2×10~(-3)mol·L~(-1)和4.6×10~(-6)mol·L~(-1),响应时间15～20min,寿命14天.该电极已初步用于实际样品的测定,结果与凯氏法吻合。对尿素含量为3.0×10~(-4)mol·L~(-1)的样品,本法分析结果偏差≤0.2×10~(-4)mol·L~(-1),平均回收率为101.5%(M=3,n=3),表明该传感器具有一定的实用价值。     

L—谷氨酰胺植物组织电极的研究

选择草莓，萝卜，西红柿等植物组织作为生物功能材料，结合氨电极研制成３种用于测定Ｌ－谷氨酰胺的组织传感器，考察了工作条件和性能，此类电极制作简单、价格低，寿命４－６天。     

动物组织切片L-赖氨酸电极研究

本文首次使用鸡肾组织切片作为L-赖氨酸氧化酶的来源并与氧电极偶合制作成测定L-赖氨酸的组织电极。该电极在5.0×10~(-5)～7.0×10~(-3)mol/L浓度范围内电极输出讯号与L-赖氨酸的浓度呈线性关系。电极响应时间为5～8min。除L-亮氨酸外,其它17种氨基酸均无明显干扰。电极寿命可达14天。实验并发现维生素B_2对L-赖氨酸氧化酶有较大的激活作用。     

丝氨酸织组膜电极的研究

利用猪肝组织膜配合氨气敏电极,研制了丝氨酸生物催化传感电极。丝氨酸浓度的测定范围为5.1×10~(-5)～3.2×10~(-3)mol/L,检出限为3.1×10~(-5)mol/L。研究和讨论了电极的最佳工作条件,并测定了实验条件下酶催化反应的米氏常数Km。该电极用于合成样品分析,效果满意。     

Biosensors Based on the Tissue of Plant as Catalytic Material for Amino Acids

Two tissue electrodes are described in this paper. It is shown that a portion of intact tissue from apple or cactus can be coupled with potentiometric ammonia gas sensing electrode to prepare sensors for some amino acids with good response properties. Their optimum operating conditions and properties with respect to buffer sort, pH of the bulk solution, selectivity, linearity, stability, sensitivity and response time are studied and discussed. At the same time, the dynamic parameters, such as Km and Km, of L-glutamine deaminasc and L-as-paragine deamlnase have been obtained by means of these tissue electrodes.     

Nitric Oxide Biosensors Based on the Immobilization of Hemoglobin on Mesoporous Titania Electrodes

A nanocrystalline TiO₂ film is an electrode material with large surface area which allows high levels of protein adsorption without loss of protein structure or activity. As an optically transparent semiconductor, titania can be used to carry out direct spectroelectrochemistry of proteins such as hemoglobin. We demonstrate that the high protein loading and the optical transparency and electrical conductivity of the Hb/TiO₂ films allow the optical and/or electrochemical sensing of nitric oxide. In particular we demonstrate the nitric oxide cycle of oxyhemoglobin immobilized on TiO₂ films and use it to electrochemically measure micromolar levels of nitric oxide.     

Disposable Horseradish Peroxidase Biosensors for the Selective Determination of Tyramine

This work reports the development of horseradish peroxidase based biosensors using screen‐printed carbon electrodes for the determination of tyramine (tyr). A novel procedure based on the insertion of the enzyme in the screen‐printing process (SPC_HRPEs) has been compared with the cross‐linked immobilization into the carbon working electrode (HRP/SPCEs). Both biosensors were characterized obtaining good capability of detection (2.1±0.2 and 0.2±0.01 µM for SPC_HRPEs and HRP/SPCEs, respectively). The reproducibility was 3.4 % and 6.8 % for SPC_HRPEs and HRP/SPCEs, respectively. The repeatability was 2.2 % and 7.1 % for SPC_HRPEs and HRP/SPCEs, respectively. The specificity towards different biogenic amines was analyzed. The developed biosensors were applied to the determination of tyr content in cheese samples.     

Electrochemical Nucleic Acid Biosensors for the Detection of Interaction Between Peroxynitrite and DNA

We studied the reactivity of peroxynitrite and different nucleic acid molecules using DNA electrochemical biosensors. SIN‐1 (3‐morpholinosydnonimine) has been used for the simultaneous generation of NO?and superoxide, i.e., as a peroxynitrite (ONOO^?) donor. Double strand DNA (dsDNA), single strand DNA (ssDNA) and 15 guanine bases oligonucleotide (Oligo(dG)₁₅) were immobilized on a carbon paste electrode to generate the biosensor and DPV was selected as the electroanalytical technique. Results showed that electrochemical biosensors were very sensitive for detecting interaction between ONOO^? and DNA. A down/up effect was observed, i.e., at low ONOO^? concentrations the guanine oxidation signal decreased while at high ONOO^? concentrations the guanine oxidation current increased. Oligo(dG)₁₅ exhibited greater interaction at low ONOO^? concentrations than the other DNA molecules. The reactivity between ONOO^? and DNA was also evaluated in solution phase, showing the same down/up effect. Finally, the capacity of DNA to hybridize was prevented after interaction with ONOO^?.     

Substantial Influence of Temperature on Anchoring of Gold‐Nanoparticle Monolayer for Performance of DNA Biosensors

This paper presents a way of modification of crystalline gold surface with a high quality layer of gold nanoparticles (Au NPs) via self‐assembled dithiol. The application of additional Au NPs monolayer prepared at various temperatures was tested with three types of biosensors previously described in the literature. The examined DNA biosensors differed by the detection method and the way of the immobilization of DNA probe at the modified gold electrode surface. For the immobilization of DNA probe in the sensing layer either the formation of SAM or the affinity binding (biotin – sterptavidin) or covalent attachment were used. The necessary condition of successful preparation of a perfect such monolayer is the preparation temperature of 4 °C. The preparation of Au NPs layers at higher than 4 °C temperatures leads to poor repeatability and unsatisfactory precision of the measurements. The application of the perfect Au monolayer lowers the detection limit (circa by 10 to 100 times) for all tested DNA biosensors.     

Electrochemical Biosensors Based on Micro-fabricated Devices for Point-of-Care Testing: A Review

Point-of-care testing (POCT) is becoming a hot research topic that allows rapid, on-site, and non-professional measurements outside the central laboratory. The micro-fabricated devices prepared by various micro-machining technologies have shown the advantages of low reagent consumption, high-throughput samples, and wearability. This review presents the recent progress of electrochemical biosensors based on various micro-fabricated devices for POCT and the corresponding electrochemical techniques. Signal amplification strategies based on enzyme and nanotechnology are also illustrated for the more sensitive POCT applications of these micro-fabricated devices. Consequently, the trends and challenges of electrochemical biosensors based on micro-fabricated devices in POCT diagnosis are discussed.     

Application of the Ugi reaction for the preparation of enzyme electrodes

Glucose oxidase and catalase were immobilized via the Ugi reaction by means of cyclohexyl isocyanide and glutaraldehyde on a nylon net partially hydrolysed by hydrochloric acid. A specific enzyme sensor for D-glucose was made by fixing the nylon net with immobilized enzymes on the tip of a Clark-type oxygen sensor. For comparison purposes glucose oxidase and catalase were also co-immobilized in the absence of cyclohexyl isocyanide or only glucose oxidase was immobilized with and without cyclohexyl isocyanide. The prepared biosensors were characterized by the specific activity of glucose oxidase and its dependence on Ph and temperature and by the apparent Michaelis constant. The linear range of the biosensor response to the substrate concentration and the stability of the biosensor were determined. The long-term stabilities of the enzyme electrodes were compared and the advangtage of the developed method was demonstrated.     

乙醇酸菠菜组织电极和马兰组织电极的研究

分别以菠菜和马兰叶为生物催化材料，将其叶浆组织与氧电极相结合，首次制成乙醇酸电极，本研究了这两种电极的响应性能。菠菜组织电极线性范围为５．０×１０＾－６－１．０＾１０＾－４ｍｏｌ／Ｌ；响应时间为３ｍｉｎ；寿命为１０天，马兰组织电极线性范围为２．０×１０＾－６－１．０×１０＾－４ｍｏｌ／Ｌ；响应时间为３ｍｉｎ；寿命至少３０天。这两种电极对底物乙醇酸钠皆有良好的选择性。     

Fabrication and Properties of Redox Ion Doped Few Monolayer Thick Polyelectrolyte Film for Electrochemical Biosensors at High Sensitivity and Specificity

Redox ions are deposited on a polyelectrolyte‐coated gold electrode by an electric field to fabricate an ion‐selective thin film electrode. The Fe(CN)${{{4- \hfill \atop 6\hfill}}}$ ions are deposited on a few monolayer‐coated polyelectrolyte gold electrode by a slow periodic potential cycle. The deposition process and electrode properties are quantitatively and simultaneously monitored by cyclic voltammetry and a novel technique, using a Scanning Electrometer for Electrical Double‐layers (SEED). No redox properties are obtained without the electric‐field‐deposition. Owing to the redox mediation and net charge due to the redox ion, the electrode is ion‐selective. We demonstrate the principle to detect 1 µM of dopamine in a mixture with 1 mM of ascorbic acid.     

普鲁士蓝修饰生物传感器的研究进展

文中叙述了普鲁士蓝(PB)结构特征和电化学特性,PB在过氧化氢传感器中的应用。综述了PB葡萄糖传感器及其他基于PB的生物氧化酶传感器的研究进展。引用文献52篇。