一种安培型尿酸生物传感器的初步研究

利用铁氰化钾作为电化学反应的媒介体,将尿酸氧化酶固定在羧甲基纤维素处理的碳电极表面,制成了一种新型的尿酸安培传感器.该传感器在恒电位0.3 V和尿酸氧化酶的催化作用下,使被检测物--尿酸--氧化,铁氰化钾还原,在电极表面产生灵敏的氧化-还原峰,然后利用安培法即可对尿酸进行间接测定.10秒内即可达到输出稳态电流,尿酸的测定范围为1 mg/dL～20 mg/dL,线性范围较好,拟合系数为0.9723.同时该传感器对尿酸的测定避免了常规电化学传感器测定中样品所含大量的易氧化物质带来的干扰.     

基于碳纳米管修饰丝网印刷碳糊电极的葡萄糖和尿酸生物传感器

在丝网印刷碳糊电极上利用吸附法固定葡萄糖氧化酶或尿酸酶,并用碳纳米管进行修饰,铁氰化钾作为电子传递剂,制作用于测量人体血浆中葡萄糖和尿酸浓度的生物传感器.葡萄糖传感器的响应时间仅为5 s,响应电流范围为1.2～30μA,线性测量范围为1～33.3 mM,尿酸传感器响应时间为和电流范围分别为50 s,0.7～14μA,线形测量范围是2～20 mg/dL.用碳纳米管修饰酶电极,改善了电极表面条件,加快了电极反应速度,并提高了传感器的灵敏度.通过碳纳米管修饰电极,葡萄糖传感器的灵敏度从0.333 8μA/mM提高到0.843 2μA/mM,尿酸传感器的灵敏度从0.402 8μA/(mg/dL)提高到0.713 8μA/(mg/dL).     

用于血糖无创检测的葡萄糖传感器研究

研制一种新型葡萄糖传感器,初步实现用于反离子电渗透技术提取皮下组织液的葡萄糖的浓度测量。用铁氰化钾作为电子媒介体,固定在聚环氧乙烷凝胶里的葡萄糖氧化酶与溶液中的葡萄糖催化氧化生成葡萄糖酸和亚铁氰化钾,通过检测该反应产生的氧化还原电流的大小来计算葡萄糖溶液的浓度。新型葡萄糖传感器的检测浓度范围2～22 mmol/L内线性度较好,传感器的一致性测试表明:同一传感器多次测量的偏差不超过2%,反应时间较短,接近于1 s。     

基于有机-无机杂化材料和铂电极的葡萄糖氧化酶电极的研究

在制备由聚乙烯醇和二氧化硅溶胶凝胶掺杂而成的有机-无机杂化材料的基础上,将葡萄糖氧化酶用此杂化材料包埋固定在铂盘电极上,利用修饰电极对过氧化氢的电催化还原特性,制得了高性能的安培型葡萄糖氧化酶电极.此酶电极可以在0.05 V(vs SCE)下对葡萄糖进行测定,有效地消除了抗坏血酸和尿素的干扰.最适pH值为7.0,载酶量为6%.在选定的工作条件下,此酶电极的灵敏度和线性范围分别为211 nA/mmol·L-1和0.1～4.0 mmol·L-1,平均响应时间为2.8 s左右.     

锇聚合物修饰的低浓度葡萄糖传感器制备与响应特性研究

将锇氧化还原聚合物与辣根过氧化酶共价交联修饰薄膜金电极,使用戊二醛交联固定葡萄糖氧化酶制得葡萄糖传感器,对传感器的制备条件和其对低浓度葡萄糖的响应特性进行了研究.在-0.1 V(vs.Ag|AgCl)电位下,该传感器的背景电流小于1 nA,检出限为1 μM,小于400 μM范围内灵敏度为2900 nA μM-1 (相关系数R=0.998),且能够消除抗坏血酸对葡萄糖测定的干扰,实现了低浓度葡萄糖的测定,为实现血糖的无创监测奠定了基础.     

用于同时测定葡萄糖和半乳糖的多功能薄膜型生物传感器的研究

本文采用微电子薄膜技术制作了具有双铂工作基底电极的传感器芯片。用Ｎａｆｉｏｎ膜修饰电极表面,并用化学交联法分别固定上葡萄糖氧化酶、半乳糖氧化酶,即制成可同时测定葡萄糖、半乳糖的多功能生物传感器。该多功能生物传感器对葡萄糖、半乳糖测定的范围分别为０－８．０ｍｍｏｌ／Ｌ和０－６．０ｍｍｏｌ／Ｌ,响应时间分别为３０ｓ和４０ｓ左右。适宜的ＰＨ范围为７．０－８．０。同时测定葡萄糖,半乳糖双组分时无交叉干扰。     

基于碳纳米管固定葡萄糖氧化酶的ECL葡萄糖传感器的制备

将葡萄糖氧化酶(GOD)固定在多壁碳纳米管(MWCNTs)修饰电极(ME)上,GOD催化氧化葡萄糖生成过氧化氢,并使鲁米诺产生电致化学发光(ECL),据此构建了一种新型ECL葡萄糖传感器.结果表明:CNTs修饰的电极对鲁米诺和H2O2反应具有显著的电催化活性和增敏效果.该传感器对葡萄糖检测的线性范围为0.01～10.0...     

基于聚中性红和纳米银修饰的葡萄糖生物传感器

采用循环伏安法在铂金电极上电聚合一层聚中性红膜,将葡萄糖氧化酶和纳米银通过静电吸附交替固定于聚中性红修饰的铂金电极表面,最后用聚中性红包埋电极,从而制得葡萄糖生物传感器.中性红能够在电极表面形成一层性能稳定并对生物分子有较强的电催化作用复合膜,加入纳米银后,显著增加葡萄糖氧化酶固定量,提高传感器的响应灵敏度.电极在葡萄糖浓度为0.5×10-8～3.5×10-6mol/L的范围内,氧化峰峰电流值与葡萄糖呈良好的线性关系,检测下限为0125×10-8mol/L(S/N=3).该传感器制备方法简单、灵敏度高、稳定性好,并具有抗抗坏血酸、尿酸干扰的特点.     

金属铁卟啉纳米粒子修饰的生物传感器及其用于鼠脑中葡萄糖测定的研究

该文制备了金属铁卟啉的纳米粒子,将此纳米颗粒、葡萄糖氧化酶和Nafion依次修饰于光玻碳电极表面,得到了以金属铁卟啉纳米颗粒为电子媒介体的葡萄糖生物传感器.考察了该传感器在优化的实验条件下对葡萄糖的响应特性,实验结果表明该传感器在pH为6.9的磷酸缓冲溶液(PBS)条件下对葡萄糖的线性检测范围为1.0×10-6～2.0×10-3mol/L,检测下限为5.0×10-7mol/L.该传感器克服了传统传感器中介体易流失的缺点,延长了使用寿命,并提高了检测的灵敏度、稳定性和抗干扰性,用于S.D.大鼠脑中葡萄糖浓度的测定取得满意的结果.     

基于铂黑修饰金电极的葡萄糖传感器的研究

利用铂黑颗粒吸附能力强、比表面积大、电催化活性高等优良特性,与基于MEMS技术制备的基础电极相结合,通过物理吸附法固定葡萄糖氧化酶,从而制备出高性能的葡萄糖传感器.该传感器应用于血清中葡萄糖的测定,其灵敏度和线性范围分别为457 nA/mmol,1～30 mmol;线性相关系数为0.986.     

葡萄糖传感器保存稳定性的研究

利用丝网印刷方法,在碳电极上吸附固定氧化酶制备葡萄糖传感器。探讨了氧化酶固定化过程中氧化酶含量、铁氰化钾含量、缓冲液类型以及干燥过程对传感器保存稳定性的影响。结果发现,当氧化酶的质量分数为4%,铁氰化钾的质量分数为4%,邻苯二甲酸氢钾(pH=6)作为缓冲液,采用超干燥技术,在相对湿度为10%的空气中干燥传感器,制得传感器的表观米氏常数为6.06mmol/L,其保存6个月后的响应电流曲线与刚制作完成的传感器响应电流曲线基本符合。     

基于纳米金修饰丝网印刷电极的乙醇生物传感器

在丝网印刷电极上利用吸附法固定乙醇脱氢酶,并用纳米金进行修饰,以铁氰化钾为介体制作了用于酒精检测的一次性乙醇脱氢酶电极试纸.纳米金颗粒修饰酶电极,极大地改善了电极电流响应,提高了传感器的灵敏度.此乙醇传感器的响应时间仅为25 s,灵敏度为0.06 μA(mmol/L)~(-1),线性浓度测量范围为1.0 mmol/L至10 mmol/L.     

全血L􀀁乳酸􀀂生物传感器

全血L-广乳酸生物传感器适用于快速方便地测量全血中L-乳酸的浓度。它包括印有一对碳电极的基片，由L-乳酸氧化酶和作为电子传递剂的铁氰化钾构成的反应层和塑料薄膜形成的反应腔。将血样(2μL)滴在反应腔中，然后在电极两端施加一个300mV的恒电压，50s后读取电流值，即可得到对应的L-乳酸浓度。该传感器的线性范围为0-15mol。保存120d后，响应没有明显衰减。该传感器的测量结果和美国强生VITROS250 SYSTEM全自动干化学分析仪的测量结果有良好的相关性(r=0．9809)，该传感器适合大规模生产。     

An amperometric glucose biosensor based on layer-by-layer GOx-SWCNT conjugate/redox polymer multilayer on a screen-printed carbon electrode

An amperometric glucose biosensor based on a multilayer made by layer-by-layer assembly of single-walled carbon nanotubes modified with glucose oxidase (GOx-SWCNT conjugates) and redox polymer (PVI-Os) on a screen-printed carbon electrode (SPCE) surface was developed. The SPCE surface was functionalized with a cationic polymer by electrodeposition of the PVI-Os, followed by alternating immersions in anionic GOx-SWCNT conjugate solutions and cationic PVI-O solutions. The purpose is to build a multilayer structure which is further stabilized through the electrodeposition of PVI-Os on the multilayer film. The electrochemistry of the layer-by-layer assembly of the GOx-SWCNT conjugate/PVI-Os bilayer was followed by cyclic voltammetry. The resultant glucose biosensor provided stable and reproducible electrocatalytic responses to glucose, and the electrocatalytic current for glucose oxidation was enhanced with an increase in the number of bilayers. The glucose biosensor displayed a wide linear range from 0.5 to 8.0 mM, a high sensitivity of 32 μA mM⁻¹ cm⁻², and a response time of less than 5 s. The glucose biosensor proved to be promising amperometric detectors for the flow injection analysis of glucose.     

Molecularly imprinted self-assembled films with specificity to cholesterol

Molecularly imprinted hydrophobic monolayers have been fabricated by spontaneous self-assembly of hexadecyl mercaptan in the presence of cholesterol on gold surfaces. The lypophilic layer of long chain hexadecan have been formed around the template molecules adsorbed on gold surface. The extraction of cholesterol has resulted in formation of sites in the layer of hexadecyl mercaptan which could selectively re-bind the template molecules. The imprinting cavities have been used as channels for potassium ferricyanide which was reduced at the electrode surface. It has been shown, that the molecular recognition process running inside of these channels diminished the mass-transport of potassium ferricyanide to the electrode surface and consequently reduced an electrochemical signal. The change of potassium ferricyanide reduction peak has been related to the template concentration. The formation of the cholesterol-specific monolayers, their specificity and stability has been studied and the possibility of its application for sensor development has been discussed.     

In situ colorimetric detection and mixing of glucose–enzyme droplets in an open-surface platform via Marangoni effect

Precise detection of glucose concentration in blood is critical in health monitoring and medical research. This paper describes a novel approach for enzymatic glucose sensing (glucose oxidase based) using thermal gradient in an open-surface platform. In order to obtain glucose concentration, droplets of enzyme and glucose with various concentrations are dispensed on a thin layer of fluorinert oil. By engineering the location of the droplet on the fluid surface and controlling the surface temperature drop of the fluid, surface deformation is created with fluid recirculating due to Marangoni convection. The surface deformation allows the microliter droplets to collide and mix at the hot spot. Image processing of the colorimetric reaction of the glucose and enzyme allows accurate determination of glucose concentration. The designed biosensor offers high repeatability, and concentration is measured within ±9.5 % of standard absorptiometry method. Contact-free manipulation of droplets, in situ measurement of glucose concentration, fast response time and high sensitivity are the key advantages of this device.     

Comparing sensitivities of differently oriented multi-walled carbon nanotubes integrated on silicon wafer for electrochemical biosensors

In this study, we report on multi-walled carbon nanotubes fabricated on silicon substrate with four different orientations via chemical vapor deposition. It is well-known that chemical treatments improve the nanotube electrochemical reactivity by creating edge-like defects on their exposed sidewalls. Before use, we performed an acid treatment on carbon nanotubes. To prove the effect of the treatment on these nanostructured electrodes, contact angles were measured. Then, sensitivities and detection limits were evaluated performing cyclic voltammetry. Two target molecules were used: potassium ferricyanide, an inorganic electroactive molecule, and hydrogen peroxide that is a product of reactions catalyzed by many enzymes, such as oxidases and peroxidases. Carbon nanotubes with tilted tips become hydrophilic after the treatment showing a contact angle of 22° ± 2°. This kind of electrode has shown also the best electrochemical performance. Sensitivity and detection limit values are 110.0 ± 0.5 μA/(mM cm²) and 8 μM for potassium ferricyanide solutions and 16.4 ± 0.1 μA/(mM cm²) and 24 μM using hydrogen peroxide as target compound. Considering the results of wettability and voltammetric measurements, nanotubes with tilted tips-based electrodes are found to be the most promising for future biosensing applications.     

基于静电沉积壳聚糖铂纳米颗粒复合膜构建葡萄糖生物传感器

利用电沉积方法对壳聚糖/铂纳米颗粒复合膜进行组装,以戊二醛作为交联剂同定葡萄糖氧化酶,构建葡萄糖生物传感器.实验结果表明:制得的葡萄糖生物传感器响应时间仅为8 s,线性测量范围为1×10-5～1×10-3moL/L,检测限为1.4×10-5 mol/L(S/N=3.0).该传感器灵敏度高,稳定性好.