葡萄糖生物传感器检测方法的研究进展

葡萄糖生物传感器以其灵敏度高、选择性好、反应速度快以及稳定性好等优点吸引了许多研究者的关注。 本文将已发表的一些葡萄糖检测方法分为两类：葡萄糖酶生物传感器检测方法与无酶葡萄糖生物传感器检测方法,简要介绍了这2种检测方法的一些研究进展,并对葡萄糖检测方法的发展前景进行了展望。     

Electrochemical synthesis of glycoconjugates of 3β-hydroxy-Δ-steroids by using non-activated sugars and steroidal thioethers

A new protocol for the electrochemical synthesis of glycoconjugates is presented. Thioether derivatives of cholesterol and other sterols were subjected to anodic oxidation in the presence of a sugar alcohol affording glycoconjugates with the sugar linked to a steroid moiety by an ether bond. The isomeric 6β-3α,5α-cyclo-steroidal thioethers proved to be better sterol donors than the normal 3β-Δ⁵-steroidal thioethers.     

A novel paper-based device coupled with a silver nanoparticle-modified boron-doped diamond electrode for cholesterol detection

A novel paper-based analytical device (PAD) coupled with a silver nanoparticle-modified boron-doped diamond (AgNP/BDD) electrode was first developed as a cholesterol sensor. The AgNP/BDD electrode was used as working electrode after modification by AgNPs using an electrodeposition method. Wax printing was used to define the hydrophilic and hydrophobic areas on filter paper, and then counter and reference electrodes were fabricated on the hydrophilic area by screen-printing in house. For the amperometric detection, cholesterol and cholesterol oxidase (ChOx) were directly drop-cast onto the hydrophilic area, and H₂O₂ produced from the enzymatic reaction was monitored. The fabricated device demonstrated a good linearity (0.39 mg dL⁻¹ to 270.69 mg dL⁻¹), low detection limit (0.25 mg dL⁻¹), and high sensitivity (49.61 μA mM⁻¹ cm⁻²). The precision value for ten replicates was 3.76% RSD for 1 mM H₂O₂. In addition, this biosensor exhibited very high selectivity for cholesterol detection and excellent recoveries for bovine serum analysis (in the range of 99.6–100.8%). The results showed that this new sensing platform will be an alternative tool for cholesterol detection in routine diagnosis and offers the advantages of low sample/reagent consumption, low cost, portability, and short analysis time.     

控制卷积量变化的电化学方法研究(Ⅰ)——简单电极反应

本文提出了一种控制卷积量变化的实验方法。对简单电极反应进行了理论处理,得到了恒半积分法、半积分扫描法、半微分扫描法的理论方程,并对3个体系进行了实验验证,结果与理论分析基本吻合。     

Interaction of cholesterol with artificial bilayer lipid membrane system and development of an electrochemical sensor

Interaction of Cholesterol with the bilayer arrangement of phospholipid molecules was studied using electrochemical impedance spectroscopy in Sodium Chloride (NaCl) bath solutions. The membrane resistance (R_m) was decreased from 3.35 GΩ in 1.0 M NaCl bath to 0.756 GΩ in 0.01 M NaCl bath. The cholesterol molecules were found to penetrate into Bilayer Lipid Membrane (BLM) and fluidized the BLM phase. Due to fluidization, the membrane resistance was decreased. The fluidization effect of cholesterol was dependent on the concentration of bath solutions. In 1.0 M NaCl bath solution, the membrane was stable up to 200 µM concentration of cholesterol. With the addition of cholesterol in NaCl bath solutions, the membrane capacitance was increased. An impedimetric sensor was developed based on the membrane resistance in the presence of cholesterol at various concentrations. The detection limit of cholesterol by impedimetric sensor was dependent on the concentration of NaCl in the bath.     

电化学法制备石墨烯及其导电特性

采用电化学方法将石墨层电解剥离, 得到分散于电解质溶液的结构较为完整的石墨烯. 用透射电子显微镜和拉曼光谱分析了石墨烯的形貌和结构, 利用四探针法测定了石墨烯导电特性. 实验数据和理论拟合结果表明, 当100 K相似文献   

Determination of clenbuterol in pig liver by high-performance liquid chromatography with a coulometric electrode array system

A method has been developed to determine clenbuterol in pig liver using HPLC with coulometric electrode array system, for this compound can be irreversibly oxidized at high potentials by ordinary methods. Investigation into the effect of the pH of mobile phase on the retention factor and peak height of clenbuterol was made. The electrochemical behavior of clenbuterol at graphite electrodes was taken into account. Optimization of different extract conditions was also performed. The samples were pretreated using liquid-liquid extraction based on diethyl ether and the organic layer was evaporated to dryness. The residue was dissolved in mobile phase and monitored by an ESA electrochemical detector. Four electrodes in series were used for quantitation and the potentials of electrodes were set at 450, 600, 650 and 680 mV, respectively. Calibration curve showed good linearity and the detection limit of clenbuterol was 1.2 ng/g. This method developed using HPLC-ECD is reproducible, and sensitive enough for the determination of clenbuterol in pig liver. It is easy to perform.     

酶法测定人尿中L-瓜氨酸含量

L-瓜氨酸是人体多种疾病的重要检测指标。利用鸟氨酸甲氨酰转移酶和氨甲酰激酶对L-瓜氨酸的专一性作用,建立了一种准确、简便、灵敏的L-瓜氨酸含量酶法测定方法。较为适宜的酶转化条件是:30℃~35℃,pH6~7。固定化酶有较高的稳定性,4℃保存60d后酶活回收率仍高达95%。该方法测定L-瓜氨酸的线性范围为2~10mg/L;工作曲线回归系数r=0.9987;样品回收率达99%以上。     

Sol–gel derived nanoporous cerium oxide film for application to cholesterol biosensor

Cholesterol oxidase (ChOx) has been immobilized onto sol–gel derived nano-structured cerium oxide (NS-CeO₂) film deposited on indium-tin-oxide (ITO) coated glass substrate. Phase identification of sol–gel NS-CeO₂ film carried out using X-ray diffraction (XRD) yields reflection peak at 29.4° corresponding to (1 1 1) plane with oriented crystallite (34 nm) along c-axis normal to the substrate. Electrochemical studies reveal that NS-CeO₂ provides electroactive surface for the loading of ChOx and enhances electron transfer rate in the ChOx/NS-CeO₂/ITO bioelectrode. The low value of Michaelis–Menten constant (K_m) obtained as 2.08 mM indicates enhanced ChOx affinity to cholesterol. The observed results show application of sol–gel derived NS-CeO₂ for biosensing without any functionalization.     

A fast and highly sensitive detection of cholesterol using polymer microfluidic devices and amperometric system

In this work, the rapid detection of cholesterol using poly(dimethylsiloxane) microchip capillary electrophoresis, based on the coupling of enzymatic assays and electrochemical detection, was developed. Direct amperometric detection for poly(dimethylsiloxane) (PDMS) microchip capillary electrophoresis was successfully applied to quantify cholesterol levels. Factors influencing the performance of the method (such as the concentration and pH value of buffer electrolyte, concentration of cholesterol oxidase enzyme (ChOx), effect of solvent on the cholesterol solubility, and interferences) were carefully investigated and optimized. The migration time of hydrogen peroxide, product of the reaction, was less than 100 s when using 40 mM phosphate buffer at pH 7.0 as the running buffer, a concentration of 0.68 U/mL of the ChOx, a separation voltage of +1.6 kV, an injection time of 20 s, and a detection potential of +0.5 V. PDMS microchip capillary electrophoresis showed linearity between 38.7 μg/dL (1 μM) and 270.6 mg/dL (7 mM) for the cholesterol standard; the detection limit was determined as 38.7 ng/dL (1 nM). To demonstrate the potential of this assay, the proposed method was applied to quantify cholesterol in bovine serum. The percentages of recoveries were assessed over the range of 98.9-101.8%. The sample throughput was found to be 60 samples per hour. Therefore, PDMS microchip capillary electrophoresis, based on the coupling of enzymatic assays and electrochemical detection, is very rapid, accurate and sensitive method for the determination of cholesterol levels.     

无酶葡萄糖电化学传感器的研究进展

随着各种新型材料的层出不穷及其在葡萄糖电化学传感器方面应用的发展,无酶葡萄糖电化学传感器的研制成为葡萄糖电化学传感器的另一个研究热点.本文综述了近年来无酶葡萄糖电化学传感器的研究进展,重点介绍了电流型无酶葡萄糖传感器所使用的各种电极材料,总结了最近五年各种新型结构材料在该类传感器研制方面的应用,并对无酶葡萄糖电化学传感器发展方向和趋势进行了展望.     

水中氨氮的酶法测定

利用谷氨酸脱氢酶（ＧＬＤＨ）催化ＮＨ４＾＋与α－酮戊二酸及ＮＡＤＨ反应的原理,通过测定ＮＡＤＨ吸光度的变化率得出其酶促反应速度,对不同ＮＨ４＾＋浓度而制得标准曲线,水样中氨氮含量测定值查标准曲线求得。结果表明,本方法具有简便,快速,灵敏,准确及干扰少等优点。     

控制卷积量变化的电化学方法研究：伴有后续均相催化反应的电极过程（Ⅰ）

采用控制卷积量的化学实验方法，对伴有后续均相催化反应的电极过程进行了处理，得到恒半积分法，半积分扫描法和半微分扫描法的理论曲线，并对亚铁氰化钾－抗坏血酸体系进行了实验验证，获得后续均相催化反应的动力学速率常数，与文献值吻合。