基于脱乙酰基魔芋葡甘聚糖固定酶的H2O2生物传感器

对魔芋葡甘聚糖进行了脱乙酰基改性处理,并用红外光谱表征了其脱乙酰基前后的结构变化.探讨了脱乙酰基魔芋葡甘聚糖溶胶-凝胶的制备条件对其成膜性能及酶固定化的影响.将脱乙酰基魔芋葡甘聚糖用于辣根过氧化物酶的固定,制备出了H2O2生物传感器.传感器在优化的工作条件下线性范围为1.0×10-6 ～6.0×10-4 mol/L,检出限为8×10-7 mol/L,稳定性良好.实验表明脱乙酰基魔芋葡甘聚糖是一种适用于生物传感器领域酶固定化的优良材料.     

普鲁士蓝修饰电极结合硅溶胶-凝胶技术制备高灵敏葡萄糖传感器

基于普鲁士蓝修饰玻碳电极结合二氧化硅溶胶 凝胶固定化酶技术构造具有“三明治”式结构的酶电极。考察了酶电极对葡萄糖的电化学响应以及操作条件。结果表明 :所制备的传感器在pH 6 .5 ,电位为- 0 .0 5V条件下对葡萄糖在 0～ 5mmol/L呈线性响应 ,响应时间为 12s ,检出限为 0 .0 2mmol/L ,灵敏度高达1 182 μA/ (mmol·L-1)。传感器的稳定性好 ,4 5d其响应值仍保持 90 %。     

高取代度魔芋葡甘聚糖醋酸酯的制备及其热塑性和流变性研究

以魔芋葡甘聚糖(KGM)为原料,浓硫酸为催化剂,乙酸酐为改性剂,制备了KGM醋酸酯.研究了反应条件对KGM醋酸酯取代度(DS)的影响,KGM醋酸酯制备的最佳反应条件是乙醇∶水量比5∶5,反应时间2h,反应温度75℃,催化剂浓硫酸的浓度0.1mol/L,KGM与乙酸酐的量比5∶40(g/mL),取代度高达2.93,其分子量与KGM相比,则明显降低.运用傅立叶红外光谱仪(FTIR)、X射线衍射仪(XRD)、扫描电镜(SEM)、热重分析仪(TGA)、示差扫描量热仪(DSC)和旋转流变仪对KGM和高取代度KGM醋酸酯进行了表征.结果表明,KGM醋酸酯的羰基(CO)特征吸收峰较KGM明显增强,其表观形貌大部分为疏松絮状,KGM及其醋酸酯均为非晶态结构.与KGM相比,KGM醋酸酯的热稳定性下降,分解温度(Td)由KGM的261.10℃降低至KGM醋酸酯的204.56℃,KGM醋酸酯出现了明显的玻璃化转变,其玻璃化转变温度(Tg)为128.49℃.KGM醋酸酯是典型的黏弹性材料,其弹性比率占21.27%,其剪切黏度η对温度变化非常敏感,可通过温度的改变来调节KGM醋酸酯的加工流动性.KGM醋酸酯具有较好的热塑性.     

硅溶胶-凝胶包埋纳米金和酶的葡萄糖生物传感器

采用溶胶-凝胶技术将金纳米粒子和葡萄糖氧化酶一次性固定于硅溶胶-凝胶的网络结构中,制备了葡萄糖生物电化学传感器并优化了传感器的制备条件。酶电极对葡萄糖具有良好的电化学响应,葡萄糖浓度在0.02~2.0 mmol/L范围内和催化电流呈线性关系,检出限为0.005 mmol/L。酶电极在4 ℃下贮存100 d后对葡萄糖的响应仅下降8%。该酶电极灵敏度高、响应快、稳定性好。     

SiO_2/Nafion杂化膜固定酶的过氧化氢生物传感器

通过溶胶-凝胶技术制备SiO2/Nafion杂化膜并固定辣根过氧化物酶,以杂化膜中Nafion固定的亚甲基蓝为辣根过氧化物酶和玻碳电极间的电子传递介体,制成了电流型过氧化氢生物传感器。探讨了杂化膜的制备条件、工作电位、pH值、温度、干扰物质等对生物传感器的影响。该生物传感器的线性响应范围为1.0×10-6～1.6×10-4mol/L,检出限(S/N=3)为6.0×10-7mol/L,达到95%稳态响应电流用时少于15s。固定化酶对过氧化氢催化反应的米氏常数为1.129 mmol/L。     

掺杂固定化酶柱的次黄嘌呤液滴光化学传感器研究

研制了一种基于掺杂的溶胶-凝胶固定化酶柱的次黄嘌呤液滴光化学传感器。在凝胶形成过程中添加肌氨酸和山梨醇,由于两种添加剂的模板作用,可形成大而有序的凝胶网格,使得酶与底物能充分接触,从而达到提高传感器响应速度和灵敏度的目的。基于这一方法固定了黄嘌呤氧化酶,并结合液滴光化学传感装置,用于次黄嘌呤的测定。在pH值为8.74的Tris-HC l缓冲液中,该传感器对2.0×10-7~8.0×10-6mol/L的次黄嘌呤呈线性响应,检出限为5.0×10-8mol/L。本实验固定化黄嘌呤氧化酶的催化效率是普通溶胶-凝胶法固定化酶的2.54倍。     

有机锆交联魔芋葡甘聚糖凝胶的制备及性能

以正丁醇锆为中心离子试剂,分别以3-氨基-1,2-丙二醇(APG)和N-甲基二乙醇胺(MDEA)为有机配体制备两种正丁醇锆交联剂,用魔芋葡甘聚糖(KGM)溶液与正丁醇锆交联剂制备了一系列水基压裂液。通过傅里叶变换红外光谱仪(FT-IR)、核磁共振波谱(NMR)、高分辨质谱(HRMS)、流变仪、扫描电子显微镜(SEM)和差示扫描量热仪(DSC)系统地表征了压裂液的结构、形貌以及性能。讨论了锆酸盐与植物胶发生交联的反应途径,并运用Winter-Chambon公式准确确定溶胶-凝胶转变点。研究了反应物浓度、配体种类对储能模量(G′)、损耗模量(G″)和溶胶-凝胶转变时间(tcr)的影响。结果表明,相较于APG配体,以MDEA为配体的有机锆/KGM凝胶体系的延迟交联性能、耐温耐剪切性能更好,其tcr随KGM质量浓度的增大呈先减小后增大的趋势,并且随配体浓度和交联剂质量分数的增加呈减小趋势,KGM质量浓度控制在4.0 g/L时,凝胶体系的常温延时交联时间在7～45 min内可调节,溶胶-凝胶转变温度(T_sol-gel)为71.4℃,其耐温性能高达120℃,在170 s-1剪...     

固定化辣根过氧化酶的壳聚糖/二氧化硅杂化膜的制备及表征

利用生物相容性良好的天然高分子聚合物壳聚糖(C5)与四乙氧基硅烷(TEOS)通过原位溶胶-凝胶法制备壳聚糖／二氧化硅有机无机杂化复合膜,用杂化膜对辣根过氧化酶进行固定,用红外光谱法、扫描电镜法对膜进行了表征。以金电极和固定化酶膜构建过氧化氢生物传感器,并用循环伏安法和计时电流法对传感器的特性进行了研究。结果表明,用于研制固定化酶生物传感器时．杂化膜不仅对底物的响应时间快(小于10s）,而且能较好地保持酶的催化活性。求得酶促催化反应的表观米氏常数为0．87mmol／L。     

魔芋葡甘聚糖DEAE阴离子交换介质的制备及表征

以交联的魔芋葡甘聚糖微球(KGM)为基质,制备了DEAE型的阴离子交换层析介质,考察了反应物浓度、温度、时间等反应因素对魔芋葡甘聚糖层析介质离子交换容量的影响,确定最优反应参数.结果表明,层析介质的离子交换容量达到3.42mmol/g,蛋白吸附容量高达126.84mg/mL,蛋白洗脱率为90.42%.     

自组装碳纳米管-氯洁霉素分子印迹溶胶-凝胶电化学传感器研究

结合自组装技术, 采用电聚合方法在碳纳米管修饰金电极表面制备对氯洁霉素具有特异性识别位点的分子印迹溶胶-凝胶薄膜, 成功构建了一种新型印迹溶胶-凝胶电化学传感器. 通过循环伏安法(CV)、示差脉冲法(DPV)、安培计时法(I-t)和扫描电镜(SEM)表征了该印迹溶胶-凝胶膜的电化学性能和表面形貌. 结果表明, 该传感器具有良好的选择性和灵敏度, 氯洁霉素在多壁碳纳米管修饰的印迹溶胶-凝胶传感器上的响应明显提高. 该印迹溶胶-凝胶传感器对氯洁霉素的浓度响应线性范围为5.0×10^-7~8.0×10^-5 mol/L, 检出限为2.44×10^-8 mol/L. 该传感器被成功地用于人体尿液中氯洁霉素的分析测定.     

Multianalyte Biosensors for the Simultaneous Determination of Glucose and Galactose Based on Thin Film Electrodes

A multianalyte biosensor for the simultaneous determination of glucose and galactose was developed by immobilizing glucose oxidase (GOD) and galactose oxidase (GAO) on Nation-modified thin film platinum disk electrodes. The dual Pt working electrodes with disk shape and the surrounding ring shaped counter electrode were fabricated by thin film technology,which were integrated onto the same microchip. The response of the designed biosensor for glucose and galactose were linear up to 6.0mmol/L and 3.5mmol/L with sensitivities of 0.3μA/mmol/L and 0.12μA/mmol/L, respectively. No cross-talking effect was observed.     

聚多巴胺包埋G-四联体/血红素DNA酶制备过氧化氢生物传感器

利用多巴胺的氧化自聚实现对G-四联体/血红素DNA酶的包埋,成功构建了H2O2电化学生物传感器。DNA和血红素混合得到G-四联体/血红素复合物;DNA酶物理吸附在玻碳电极上后,将10μL 5 g/L多巴胺的磷酸盐缓冲液(pH 8.0)滴在表面,空气中的氧气氧化多巴胺形成聚多巴胺膜,实现DNA酶的固定。考察了不同DNA序列对传感器性能的影响,表明电化学与光学传感过程具有不同序列响应。此传感器对H2O2的检出限为2.2μmol/L;线性范围为0.01～1.5 mmol/L。本研究证实了利用聚多巴胺固定酶和用DNA酶代替天然酶构筑传感器的可行性。     

基于Dy_2(MoO_4)_3-AuNPs复合纳米材料的葡萄糖生物传感器

采用水热法合成了纳米材料钼酸镝[Dy_2(MoO_4)_3],并制备了Dy_2(MoO_4)_3-AuNPs复合材料,利用该复合材料固定葡萄糖氧化酶(GOD)构建了葡萄糖生物传感器.通过透射电子显微镜(TEM)、紫外-可见光谱(UV-Vis)和能谱分析(EDS)等手段对所制备的材料进行了表征,并利用电化学阻抗谱(EIS)和循环伏安(CV)曲线研究了该传感器的电化学性能.结果表明,Dy_2(MoO_4)_3-AuNPs复合材料具有较好的生物相容性,能增强固定化的GOD的生物活性,并促进GOD在电极表面的电子传递速率;该传感器在葡萄糖浓度为0.01~1.0 mmol/L范围内葡萄糖浓度与响应电流呈较好的线性关系,最低检出限为3.33μmol/L(S/N=3),该生物传感器还具有较好的稳定性和重现性.     

鱼鳔膜为基质的生物传感器测定葡萄糖的研究

以鱼鳔膜为基质同定葡萄糖氧化酶,偶联氧电极,构建了葡萄糖生物传感器,通过测定溶解氧浓度的变化定量测定葡萄糖.考察了酶浓度、pH值、缓冲液浓度对传感器的影响,优化了实验条件:即酶浓度为1 mg,pH 7.0,缓冲液浓度为100 mmol/L.此传感器具有较宽的线性范围(0.016～1.2 mmol/L),较短的响应时间(...     

An optical fiber biosensor for chlorpyrifos using a single sol-gel film containing acetylcholinesterase and bromothymol blue

An optical fiber biosensor consisting of acetylcholinesterase (AChE) and bromothymol blue (BTB) doped sol-gel film was employed to detect organophosphate pesticide chlorpyrifos. The main advantage of this optical biosensor is the use of a single sol-gel film with immobilized AChE and BTB. The compatibility of this mixture (AChE and BTB) with the sol-gel matrix has prevented leaching of the film. The immobilization of the enzyme and indicator was simple without chemical modification. The biosensing element on single sol-gel film has been placed inside the flow-cell for flow system. In the presence of a constant AChE, a color change of the BTB and the measured reflected signal at wavelength 622nm could be related to the pesticide concentration in the sample solutions. The performance of optical biosensor in the flow system has been optimized, including chemical and physical parameters. The response time of the biosensor is 8min. A linear calibration curve of chlorpyrifos against the percentage inhibition of AChE was obtained from 0.05 to 2.0mg/L of chlorpyrifos (18-80% inhibition, R(2)=0.9869, n=6). The detection limit for chlorpyrifos was 0.04mg/L. The results of the analysis of 0.5-1.5mg/L of chlorpyrifos using this optical biosensor agreed well with chromatographic method.     

Detection of NADH and ethanol at a graphite electrode modified with titania sol-gel/Meldola’s Blue/MWCNT/Nafion nanocomposite film

For electrocatalytic determination of NADH, a graphite electrode modified with titania sol-gel/Meldola’s Blue/MWCNT/Nafion nanocomposite was proposed. The composition of the matrix film was optimised in terms of the content of carbon nanotubes and Nafion. Incorporation of a redox mediator, Meldola’s Blue, into the nanocomposite film enabled electrocatalytic determination of NADH at a low potential, −50 mV. For determination of ethanol, alcohol dehydrogenase (ADH) was immobilized into the matrix layer. Experimental conditions affecting the biosensor response were examined, including enzyme loading, temperature of measurement and pH of background electrolyte. Assessments of the analytical characteristics of the biosensor were performed with respect to sensitivity, limit of detection, operational stability, repeatability and reproducibility. The proposed biosensor showed electrocatalytic activity toward oxidation of ethanol with sensitivity of 2.24 μA L mmol⁻¹, linear range from 0.05 to 1.1 mmol L⁻¹, and limit of detection of 25 μmol L⁻¹. The apparent Michaelis-Menten constant was 1.24 mmol L⁻¹, indicating a high biological affinity of ADH/titania sol-gel/Meldola’s Blue/MWCNT/Nafion electrode for ethanol. The developed biosensor was tested in determinations of ethanol content in alcoholic beverages.     

High-Sensitive Glucose Biosensor Based on Ionic Liquid Doped Polyaniline/Prussian Blue Composite Film

The Prussian blue/ionic liquid-polyaniline/multiwall carbon nanotubes (PB/IL-PANI/MWNTs) composite film was fabricated by using cyclic voltammetry. The ion liquid acting as a lubricating agent, could enhance the electron delocalization degree and reduce the struc-tural defects of the polyaniline. The surface morphology of the composite film revealed that the PB nanoparticles have smaller size than that in pure PB film. Due to the introduction of ion liquid, the PB/IL-PANI/MWNTs composite film showed wonderful synergistic effect which can remarkably enhance sensitivity, expand linear range and broaden acidic adapt-ability for hydrogen peroxide detection. The composite film demonstrated good stability in neutral solution contrast to pure PB film, with a linear range from 2.5 μmol/L to 0.5 mmol/Land a high sensitivity of 736.8 μA·(mmol/L)^-1·cm^-2 for H₂O₂ detection. Based on the com-posite film, an amperometric glucose biosensor was then fabricated by immobilizing glucose oxidase. Under the optimal conditions, the biosensor also exhibits excellent response to glucose with the linear range from 12.5 μmol/L to 1.75 mmol/L and a high sensitivity of 94.79 μA (mmol/L)^-1·cm^-2 for H₂O₂. The detection limit was estimated 1.1 μmol/L. The resulting biosensor was applied to detect the blood sugar in human serum samples without any pretreatment, and the results were comparatively in agreement with the clinical assay.     

壳聚糖固定化葡萄糖氧化酶生物传感器测定葡萄糖的含量

应用壳聚糖将葡萄糖氧化酶固定于鸡蛋膜上,结合氧电极制得葡萄糖传感器.实验表明,壳聚糖比戊二醛能更好地固定葡萄糖氧化酶,最佳条件为壳聚糖浓度0.3%、固定化酶量0.8 mg、 pH 7.0、缓冲溶液浓度300 mmol/L和温度25 ℃.本葡萄糖传感器的线性范围为0.016～1.10 mmol/L;检出限为8.0 μmol/L(S/N=3), 响应时间<60 s,有很好的稳定性,寿命>3个月.同一个传感器重复使用以及同方法制作的不同传感器之间都有很好的重现性,RSD分别为2.5%(n=10)和4.7%(n=4).实际样品中可能存在的烟酰胺、 VB6、 VB12、 VE、Ca2+、 Mg2+、 K+和Zn2+等对葡萄糖的测定不产生干扰.本传感器已成功地应用于市售饮料中葡萄糖含量的测定.     

辣根过氧化酶在纳米金／氧化锌球腔微电极阵列上的直接电化学研究

利用Langmuir - Blodgett技术和溶胶-凝胶(sol -gel)法在氧化铟锡(ITO)电极表面制备了有序的纳米金／氧化锌(nano-Au/ZnO)球腔阵列,并采用扫描电镜表征了nano-Au/ZnO球腔阵列的形貌.该阵列的循环伏安曲线具有微电极特性.将辣根过氧化酶(HRP)直接固定于nano-Au/ZnO...