基于咪唑盐离子液体固定GO_x于Au/石墨烯复合材料电极表面的葡萄糖酶传感器研究

利用长链离子液体特殊的性质,用其固定葡萄糖氧化酶(GOx)于Au/石墨烯电极表面组装成Nafion/GOx/[C10-mim+]Br-/Au/Gr修饰电极,然后用其测定葡萄糖。用透射电镜表征氧化石墨烯和Au/氧化石墨烯的形貌发现,金纳米颗粒很均匀的分散在石墨烯表面,并不存在团聚现象。电化学数据显示,Nafion/GOx/[C10-mim+]Br-/Au/Gr修饰电极对葡萄糖具有很好的催化作用,葡萄糖浓度在6.0×10-5~2×10-3mol/L范围内呈良好的线性关系(R=0.997),检出限为1.6×10-5mol/L。     

层层自组装制备基于多壁碳纳米管的胆碱生物传感器

以经混酸处理的多壁碳纳米管(MWCNTs)修饰铂(Pt)电极,在此基础上固定(PAA/PVS)3复合膜,采用层层自组装技术将高分子聚电解质PDDA与胆碱氧化酶交替组装在已修饰的电极上,构建了电流型胆碱生物传感器。实验结果表明,MWCNTs的引入使电极对H2O2的催化电流明显增大,制成的酶电极可以有效控制酶量的使用,酶膜组装层数为8时最优,对胆碱的线性响应范围为5×10-7～1×10-4mol/L;灵敏度为12.53μA/mmol;响应时间为7.60s;检出限为2×10-7mol/L(S/N=3)。传感器的抗干扰能力强,稳定性好,30d时的响应电流值仍保持最初的89.5%。3次平行实验的RSD为3.64%。     

维生素B_1自组装膜修饰金电极对多巴胺、尿酸的电催化作用

用维生素B1(VB1)在金电极上进行自组装,制备了VB1自组装膜修饰金电极(VB1-Au/SAMs/CME).利用循环伏安法初步研究了此自组装单分子膜修饰电极的电化学行为.结果表明: VB1在金电极表面具有特性吸附.以\3-/ 4-氧化还原电对为探针,考察了VB1自组装膜修饰金电极的电化学性质, VB1自组装膜的存在对\3-/4-的电子转移具有明显的阻碍作用.研究了多巴胺(DA)和尿酸(UA)在此电极上的电化学行为.实验结果表明, DA和UA在此电极上均可被电催化氧化.差分脉冲伏安(DPV)氧化峰电流与DA浓度在2.0×10-5～4.0×10-4 mol/L范围内呈线性关系;测定UA的线性范围为6.0×10-5～2.2×10-4 mol/L,而且可实现这两种物质的同时测定.     

硫代乙醇酸与半胱氨酸铜共固定自组装过氧化氢传感器的研制

将半胱氨酸铜(CuCysh)络合物共价键合到自组装在Au电极表面的硫代乙醇酸(TAA)单分子层上,获得了衍生化自组装CuCysh-TAA单分子膜传感器。采用扫描电镜(SEM),X射线光电子能谱(XPS)对电极表面进行了表征。固定在电极表面的CuCysh在(pH 5.5)0.2 mol/L NaAc-HAc中对H2O2的还原显示出较好的电催化响应,测定线性范围在5.0×10-7~3.0×10-4mol/L之间,H2O2在12 s内达到95%的稳态电流,检出限为1.6×10-7mol/L(S/N=3)。在较大的H2O2浓度范围内,该传感器表现出M ichaelis-M enten行为。表观M ichaelis-M enten常数为0.34 mmol/L。较小的值表明固定在金电极表面的半胱氨酸铜络合物对H2O2具有较高的亲和性。同时,该电极具有较好的稳定性和重现性。     

四羧基酞菁钴-半胱胺自组装修饰金电极对烟酰胺腺嘌呤二核苷酸的电催化研究

本文将(4,4′,4,″4)四羧基酞菁钴(CoTcPc)共价键合到自组装在Au电极表面的半胱胺单分子层上,获得了自组装单分子膜修饰电极(CoTcPc-Cys CME),研究了它的电化学性质,并对电极表面进行了表征。电极表面覆盖度为3.7×10-10mol/cm2,电子转移速率常数Ks为1.21 s-1。实验表明,在pH 7.0的磷酸盐缓冲溶液(PBS)中,CoTcPc/Au对烟酰胺嘌呤二核苷酸(NADH)的氧化具有良好的电催化作用,使NADH在裸金电极上的氧化电位降低了近300 mV,催化电流与cNADH在5.0×10-6~3.2×10-3mol/L范围有线性关系,检出限为2.8μmol/L。测定了电极催化NADH的米氏催化常数KMapp和催化反应速率常数K。     

多肽自组装膜用于凝血酶的检测

利用自组装膜技术在石英片表面构建了多肽自组装膜。考察了组装液浓度和组装时间对多肽自组装膜组装效果的影响,并用紫外可见吸收光谱仪和扫描电镜对该膜进行了表征。研究结果表明,当γ-氨基丙基三乙氧基硅烷水溶液浓度为1%(V/V),组装时间为3 h;金纳米浓度为2.4×10-4mol/L,组装时间为12 h;多肽浓度为1×10-4mol/L,组装时间为12 h时,组装效果最好。基于凝血酶可特异性酶切多肽中精氨酸和甘氨酸之间的肽键,建立了一种测定微量凝血酶的新方法,方法的线性响应范围为2.8×10-12~9.9×10-10mol/L,检出限为1.4×10-12mol/L。此膜用于血清样品中凝血酶的测定,回收率为91.6%~107.6%。     

去甲肾上腺素在3-氨基-5-巯基-1,2,4-三唑修饰金电极上的电化学行为及研究

本文通过自组装的方法制备了3-氨基-5-巯基-1,2,4-三唑(TA)修饰金电极。X射线光电子能谱表明,3-氨基-5-巯基-1,2,4-三唑是通过形成S-Au键而组装到Au电极表面。研究了去甲肾上腺素在该自组装膜电极上的电化学行为。实验结果表明:在pH 4.5的0.1 mol/L BR缓冲溶液中,膜电极对去甲肾上腺素的电化学氧化具有明显的催化作用,其氧化峰电流与去甲肾上腺素的浓度在2.0×10-6~1.9×10-4mol/L范围内呈良好线性关系。方法检出限为4.0×10-7mol/L。     

L-半胱氨酸自组装电极循环伏安法测定多巴胺

建立了痕量多巴胺(DA)电化学分析方法.在pH 7.6的0.2 mol/L Na2HPO4-NaH2PO4 0.1 mol/L KCl底液中,L-半胱氨酸(L-Cys)自组装金电极对多巴胺有明显的电催化氧化作用,考察了该电极作为DA传感器的实验条件.结果表明:DA在L-Cys/Au电极上的氧化峰电流与多巴胺的浓度在一定范围内成线性关系,线性范围为6.7×10-5～4.6×10-3 mol/L,检出限为8.4×10-6 mol/L,平行测定8次,相对标准偏差为3.2%,用于盐酸多巴胺注射液中DA的测定,回收率为94%～96%.     

血红蛋白-Fe3O4-CaCO3三维生物纳米复合材料的特性及在生物传感中的应用

通过层层自组装的方法,在中性条件下利用静电作用将Fe3O4纳米粒子组装到修饰了高分子聚电解质的CaCO3多孔微米球上。该复合材料具有好的生物相容性、导电性、磁性和稳定性。将血红蛋白酶固定到该复合材料上,进而制备得到血红蛋白(Hb)-Fe3O4-CaO3复合物修饰玻碳电极,并在该修饰电极上实现了Hb与电极之间的直接电化学。该生物传感器对H2O2的还原具有较好的响应,线性范围为3.0×10-6~5.3×10-5 mol/L,检测限为8.9×10-7 mol/L。     

巯基丁二胺镍(Ⅱ)自组装单分子层H2O2传感器研究

采用巯基丁二胺镍(Ⅱ)(NiL-SH)自组装单分子层修饰金电极,制得测定H2O2的电流型生物传感器.NiL-SH在电极表面有一对可逆的氧化还原峰.传感器对H2O2的还原显示出快速电催化响应(＜10 s),采用电子扫描电镜(SEM)和光电子能谱(XPS)对电极表面进行了表征,且计算了其自身电化学反应性质.研究了各种因素如pH、工作电位等对传感器响应电流的影响.循环伏安法测定H2O2的线性范围为5.0×10-6～3.0×10-3 mol/L(r=0.999),检出限为2.0×10-6 mol/L.该电极显示出模拟酶特性,测定米氏常数KMapp＝2.78 mmol/L.对传感器的稳定性,灵敏度和选择性进行研究,并应用于实际样品测定.     

酶-离子色谱法检测葡萄糖

应用酶反应催化性能高，反应选择性好以及离子色谱法快速，灵敏、准确的特点，率先提出酶、离子色谱法检测葡萄糖的新方法，在含葡萄糖样品溶液中加入一定量的葡萄糖氧化酶（GOD），在葡萄糖氧化酶的催化下，被测葡萄糖被氧化产生H2O2，生成的H2O2与加入的NO2^-进一步反应，生成的NO3^-用离子色谱定性和定量测定，因为被测的葡萄糖与生成的NO3^-存在定量关系，从而可以由NO3^-的浓度计算出葡萄糖的含量，测定葡萄糖的线性范围在5－100mg/L，测定了市售葡萄糖和蜂蜜中葡萄糖的含量，回收率分别为94％和94．5％。     

Glucose Biosensor Based on Carbon/PVC-COOH/Ferrocene Composite with Covalently Immobilized Enzyme

A carbon/PVC-COOH/ferrocene composite electrode used for the determination of glucose has been prepared. The ferrocene acted as mediator was incorporated into the PVC-COOH polymer and the leakage could be prevented. The presence of carboxyl groups on the electrode surface allowed immobilizing enzyme via EDC and NHS. The ratio of PVC-COOH to graphite powder （w/w） has been studied. Amperometric determination of glucose has been performed at potential of 0.30 V vs SCE. The response time was 〈 15 s. The linear response range was of 0.1-20 mmol/L with a detection limit of 48μmol/L.     

电化学葡萄糖传感器

作为电化学生物传感器中最重要的研究内容之一,葡萄糖生物传感器在数十年的发展中取得了巨大进展。本文综述了近年来利用纳米技术设计的新型电化学葡萄糖传感器的主要研究进展,并从纳米材料维度分类进行了讨论。其中,零维纳米材料主要讨论了包括金纳米颗粒、银纳米颗粒以及铜、铂等金属纳米颗粒材料; 一维纳米材料主要讨论了通过模板法制备的金属或金属氧化物纳米线以及单臂或者多壁纳米管材料; 二维纳米材料主要总结了以碳为基础的石墨烯材料和一些片状的金属材料。纳米材料对电化学葡萄糖传感器的影响主要集中在生物相容性、增强检测灵敏度、酶的固定等方面。此外,本文也对电化学葡萄糖传感器的今后发展做了展望。     

Nafion-二茂铁-双酶修饰的葡萄糖传感器

用二茂铁作为过氧化物酶与玻碳电极的电子传递体,通过牛血清白蛋白-戊二醛交联剂把葡萄糖氧化酶和过氧化物酶固定在Nafion-二茂铁修饰玻碳电极上,制备成葡萄糖传感器。由于工作电位低,电活性物质如抗坏血酸、尿酸等对测定无干扰。该传感器的线性范围为5.0×10～(-4)～2.5×10～(-2)mol/L,响应时间小于30s.     

Determination of Glucose in Diluted Blood with a Thermal Flow Injection Analysis Biosensor

Abstract

The glucose concentration in diluted whole blood has been measured, using a miniaturized thermal biosensor based on the enzyme thermistor principle. The biosensor is a small flow injection system. A sample volume of 20μl is injected into a flow of 50μl/min. The heat produced when the sample passes the enzyme column is measured with a thermistor connected to a Wheatstone bridge. The enzyme column contains glucose oxidase and catalase co-immobilized on a solid support material. Samples of whole blood usually cause problems in flow-systems. The blood cells tend to block the enzyme column and the back pressure increases. We have tested a superporous agarose material as enzyme support material using tenfold diluted samples of whole human blood. The blood was collected from the finger-tip and diluted with buffer containing an anticoagulant and sodium fluoride. The number of samples possible to inject and the accuracy compared to the Boehringer Mannheim Reflolux have been determined. At least 100 ten-fold diluted blood samples could be injected on a micro-column of superporous agarose. The obtained glucose concentration correlated well with the one obtained with the reference instrument.     

Biological Glucose Metabolism Regulated Peptide Self‐Assembly as a Simple Visual Biosensor for Glucose Detection

A glucose oxidase (GOx)‐mediated glucose metabolism was in vitro mimicked and employed to regulate the self‐assembly of peptide‐based building blocks. In this new stimuli‐responsive self‐assembly system, two peptide‐based building blocks, respectively, having aspartic acid (gelator 1 ) and lysine (gelator 2 ) residues were designed and prepared. When adding glucose and GOx to the aqueous solution of gelator 1 or the self‐assembled fibrillar hydrogel of gelator 2 to construct glucose metabolism system, the metabolic product (gluconic acid) can trigger the protonation of the peptide molecules and induce the phase transitions of gelators 1 (sol‐gel) and 2 (gel‐sol). Because this glucose metabolism regulated peptide self‐assembly is built on the oxidation of glucose, it can be used as a simple visual biosensor for glucose detection.     

N-[3-(4-乙氧基苄基)-4-氯苯基]-1-脱氧野尻霉素的合成及其降血糖作用

以具有降血糖活性的达格列净、卡格列净和脱氧野尻霉素为参照,设计合成了新化合物N-[3-(4-乙氧基苄基)-4-氯苯基]-1-脱氧野尻霉素(A)。以2-氯-5-硝基苯甲酸为原料,先将羧酸转化为酰氯、再经Friedel-Crafts酰基化、羰基还原及硝基还原,合成了中间体2-氯-5-氨基-4'-乙氧基二苯基甲烷;另一方面,以单丙酮葡萄糖为原料,经选择性氧化和水解反应得到5-氧化-D-葡萄糖。该化合物和2-氯-5-氨基-4'-乙氧基二苯基甲烷发生双还原胺化反应得到化合物A的粗品。将粗品A与乙酸酐反应,经柱色谱分离得到高纯度的四乙酰基-N-[3-(4-乙氧基苄基)-4-氯苯基]-1-脱氧野尻霉素(B),再将其水解制得纯的化合物A。将化合物A口服给药SD大鼠后,发现该化合物可以降低SD大鼠血糖,增加尿量和葡萄糖从尿液中的排出。     

一种基于壳聚糖固定葡萄糖氧化酶的葡萄糖生物传感器的研究

本文选用生物相容性好的壳聚糖作为基体材料，使其与戊二醛交联成网状结构包埋葡萄糖氧化酶制成电化学传感器。这种壳聚糖膜不仅可以减小葡萄糖氧化酶的流失，而且能为酶提供了适宜的微环境。用红外光谱、紫外光谱及透射电镜对膜的形态和性质进行了表征。实验结果表明该传感器具有很快的响应速度，很好的稳定性和重现性，能选择性地催化葡萄糖并测定其浓度。该传感器的制备方法简单，成本低，于冰箱中放置两周信号保持在90％以上，对葡萄糖测量的线性范围为1×10^-5 - 3.4×10^-3mol•L^-1，当信噪比为3:1时检测限为5×10^-6mol•L^-1。     

Glucose Biosensor Based on the Fabrication of Glucose Oxidase in the Bio-Inspired Polydopamine-Gold Nanoparticle Composite Film

A highly efficient enzyme immobilization method has been developed for electrochemical biosensors using polydopamine films with gold nanoparticles (AuNPs) embedded. This simple enzyme fabrication method can be performed in very mild conditions and stored in a long time with high bioactivity. The fabricated amperometric glucose biosensor exhibited a high and reproducible sensitivity, wide linear dynamic range and low limit of detection (LOD) (0.1 μmol·L^?1). A low value of 1.5 mmol·L^?1 for the apparent Michaelis‐Menten constant K^app_M was obtained. The high sensitivity, wide linear range, good reproducibility and stability make this biosensor a promising candidate for portable amperometric glucose biosensor.     

Effect of Hydrolyzable Tannins on Glucose-Transporter Expression and Their Bioavailability in Pig Small-Intestinal 3D Cell Model

Intestinal transepithelial transport of glucose is mediated by glucose transporters, and affects postprandial blood-glucose levels. This study investigates the effect of wood extracts rich in hydrolyzable tannins (HTs) that originated from sweet chestnut (Castanea sativa Mill.) and oak (Quercus petraea) on the expression of glucose transporter genes and the uptake of glucose and HT constituents in a 3D porcine-small-intestine epithelial-cell model. The viability of epithelial cells CLAB and PSI exposed to different HTs was determined using alamarBlue^®. qPCR was used to analyze the gene expression of SGLT1, GLUT2, GLUT4, and POLR2A. Glucose uptake was confirmed by assay, and LC–MS/ MS was used for the analysis of HT bioavailability. HTs at 37 µg/mL were found to adversely affect cell viability and downregulate POLR2A expression. HT from wood extract Tanex at concentrations of 4 µg/mL upregulated the expression of GLUT2, as well as glucose uptake at 1 µg/mL. The time-dependent passage of gallic acid through enterocytes was influenced by all wood extracts compared to gallic acid itself as a control. These results suggest that HTs could modulate glucose uptake and gallic acid passage in the 3D cell model.