纳米TiO2管电化学生物传感器用于测定水体中微囊藻毒素

制作了辣根过氧化物酶和溶胶-凝胶结合Nafion-TiO2修饰石墨电化学传感器,用示差脉冲伏安法研究了该修饰电极的电化学性质,并优化了微囊藻毒素-LR(MC-LR)的测定条件.结果表明,在pH=6.5柠檬酸-NaOH-HCl缓冲溶液中,采用该修饰电极示差脉冲伏安法测定MC-LR,质量浓度在10-5～1μg/L范围内呈良好的线性关系,脉冲伏安法测定微囊藻毒素线性方程为100Δi=0.142 2logC+0.799 7,相关系数为0.995 0,最低检测限达10-6μg/L.电极的重现性及稳定性较好,连续测定10次,相对标准偏差为2.5%;4℃下储存28d后示差脉冲信号无明显变化;应用于饮用水中MC-LR的测定,样品的回收率为99.3%～102.9%.该传感器灵敏度高、稳定性好.     

Redox-flexible NADH oxidase biosensor: A platform for various dehydrogenase bioassays and biosensors

A generic amperometric bioassay based on the enzymatic oxidation catalysed by the stable NADH oxidase (NAox) from Thermus thermophilus has been developed for NADH measurements. The NAox uses O₂ as its natural electron acceptor and produces H₂O₂ in a two-electron process. Electrochemical and spectrophotometric experiments showed that the NAox used in this work, presents a very good activity towards its substrate and, in contrary to previously mentioned NADH oxidases, does not require the addition of any exogenous flavin cofactor neither to promote nor to maintain its activity. In addition, the NAox used also works with artificial electron acceptors like ferrocene derivatives. O₂ was successfully replaced by redox mediators such as hydroxymethyl ferrocene (FcCH₂OH) for the regeneration of the active enzyme. Combining the NAox with the mediator and the horseradish peroxidase we developed an original, high sensitive “redox-flexible” NADH amperometric bioassay working in a large window of applied potentials in both oxidation and reduction modes. The biosensor has a continuous and complementary linearity range permitting to measure NADH concentrations starting from 5 × 10⁻⁶ M in reduction until 2 × 10³ M in oxidation. This redox-flexibility allows choosing the applied potential in order to avoid electrochemical interferences. The association of the “redox-flexible” concept with NADH dependent enzymes opens a novel strategy for dehydrogenases based bioassays and biosensors. The great number of dehydrogenases available makes the concept applicable for numerous substrates to analyse. Moreover it allows the development of a wide range of biosensors on the basis of a generic platform. This gives several advantages over the previous manufacturing techniques and offers a general and flexible scheme for the fabrication of biosensors presenting high sensitivities, wide calibration ranges and less affected by electrochemical interferences.     

生物材料与生物传感器

论述了具有分子识别功能的生物材料的开发应用现状,生物材料的元件化,生物元件的改良,生物传感器的原理及电极式、热敏式、光敏式、声波检测器式生物传感器的研究开发动向,最新成果及未来展望.     

用于细胞外电信号测量的CMOS集成生物 传感芯片的研究

新型的细胞外电信号传感芯片是采用0.6 μm标准CMOS工艺设计制造,片上集成了6×6单元有源传感阵列、模拟多路选择器、输出缓冲器、参考源和数字控制电路.有源传感单元面积为60μm×60μm,包含15μm×15μm的传感电极和预处理电路,能够线性放大幅值范围100μV～25 mV的微小信号,电压增益为40dB.并采用相关二次采样工作模式降低固定模式噪声,提高传感器的精度.在标准CMOS工艺基础上,应用无电浸镀金改进传感电极的生物兼容性,并采用特殊封装技术提高芯片在溶液环境中的稳定性.溶液中模拟生物信号测量验证了该芯片的功能.     

生物传感器的研究进展综述

生物传感器是以固定化的生物成分(如,酶、蛋白质、DNA、抗体、抗原)或生物体本身(如,细胞、微生物、组织等)为敏感材料,与适当的化学换能器相结合,用于快速检测物理、化学、生物量的新型器件。最初,以酶电极的生物传感器开始,逐渐扩展到多种技术,如,离子敏场效应管、光纤、声表面波、石英晶体谐振器及表面等离子体谐振技术将生物传感器的发展推向一个新的阶段。生物传感器在环境监测、医学研究、食品工业、发酵工业等领域已得到广泛应用。     

纳米金与二茂铁在葡萄糖传感器中的相互作用

针对纳米金颗粒修饰的葡萄糖生物传感器对葡萄糖的响应电流随着工作电压的下降快速下降的问题,进一步利用电子媒介体二茂铁对其进行修饰,并选用丝网印刷电极研究了纳米金颗粒和二茂铁之间的相互作用。实验结果表明:二茂铁有效地降低了纳米金颗粒修饰的葡萄糖生物传感器响应电流的下降值,纳米金颗粒降低了电子媒介体二茂铁的氧化还原反应电位,并且,纳米金颗粒与电子媒介体二茂铁在葡萄糖生物传感器中表现协同增效效应。     

医用微型全量分析系统中的酶生物传感器研究

酶生物传感器由于其对被分析物具有高度的选择性,成为解决μTAS(微型全量分析系统)中,复杂体系下的多种组分同时测定问题一个有效方法.以基于葡萄糖氧化酶的葡萄糖传感器为例,研究了酶生物传感器对被分析物的选择特性,实验证明,酶生物传感器完全适用于μTAS 中多种组分同时测定的用途.     

基于苯丙氨酸解氨酶的生物传感器线性化研究

针对苯丙氨酸解氨酶生物传感器非线性特性，依据最小二乘法理论，采用最优化技术，建立了最佳拟合直线的数学模型，并给出基于可编程控制器的数据拟合程序，实际运行表明，该方法克服了生物传感器校正传统方法拟合准确度低的缺点，对生物传感器线性化研究提供了新思路。     

生物传感器及其在食品分析中的应用

论述了生物传感器的分类及其在食品分析中的应用，主要包括对食品成分、食品添加剂、农药和抗生素残留量、微生物和生物毒素、食品鲜度的分析检测。     

Biosensor Measurements on Diffusion Coefficients of Physiologically Active Substances in Brain Tissue

Three methods are proposed for determining the diffusion coefficient D for several substances in vivo. The results are discussed along with the prospects for using chemical biosensors for examining the variations in D produced by external physical factors (vortex magnetic fields).