用于测定营养物质的通用生物传感器

报导了一种用于测定培养基中的养分的通用生物传感器.这种生物传感器以溶氧电极为基本传感器,在敏感膜上覆合上一种生物膜,用以测定一种假单孢菌培养液的醋酸铵的含量.其线性范围为:0~40mg/L;90%的响应时间为:15~20min;测定一个样品所需时间为40~60min;其测量精度为:±6%;使用寿命可达一年以上.     

谷氨酸生物传感器的研制及谷氨酸发酵液中谷氨酸含量的测定

本文以牛血清白蛋白-戊二醛为交联剂,将具有谷氨酸脱羧酶的大肠杆菌与二氧化碳气敏电极偶合制成谷氨酸生物传感器,并系统地研究了该传感器的电化学性能。该传感器在30℃测定谷氨酸的线性范围为8.0×10~(-4)～2.5×10~(-2)mol/L,响应时间为8～15min,回收率为97.0～102.9％,标准偏差<0.072,变异系数<1.8％。用该传感器测定味精中谷氨酸一钠含量,结果与旋光法一致;用于测定谷氨酸发酵液中谷氨酸含量,结果与华勃氏呼吸法无显著性差异。     

基于胱胺自组装金纳米线的第三代过氧化氢生物传感器的研制

以聚碳酸酯为模板,采用电沉积法制得金纳米线,并利用胱胺将金纳米线自组装到金电极上,然后通过金纳米线吸附辣根过氧化物酶(HRP)制得新型无电子媒介过氧化氢生物传感器.考察了pH、电位等条件对传感器测定过氧化氢的影响.结果表明在pH6.90,电位为-0.110 V条件下传感器检测过氧化氢的线性范围为2.0×10-4～2.8×10-2 mol/L,该传感器稳定性好,制作简单.可用于实际样品中过氧化氢的测定,为过氧化氢的测定提供了一种新的手段.     

碳纳米管修饰的尿酸传感器的研制及应用

利用碳纳米管对尿酸的电催化氧化作用,研制了一种新型的基于尿酸氧化酶的生物传感器.考察了pH、温度等条件对传感器测定尿酸的影响,结果表明在pH 6.9,25℃时该传感器检测尿酸的线性范围为5.0×10-6～1.0×10-3 mol@L-1,检出下限为2.5×10-6mol@L-1,响应时间为10 s.该传感器稳定性好,抗干扰能力强,可以用于实际尿样中尿酸的测定,为尿酸的测定提供了一种新的手段.     

应用组织基膜生物传感器测定脑脊液中谷氨酞胺

应用猪肾切片固定于氨气敏电极组装成谷氨酰胺生物传感器,已用此传感器完成了人脑脊液中谷氨酰胺浓度的测定.在临床上重要的浓度范围(10~(-4)～10~(-3)mol)内,其测量值较准确精密,实际样品结果的平均偏差为5.6%,平均回收率为101.4%.本文推荐的方法也与现行方法作了比较,表明两法所测得的结果无显著差异.     

用于无创检测皮下葡萄糖的新型生物传感器研究

以无创检测人体血糖为应用需求,采用高灵敏度锇氧化还原聚合物修饰在薄膜电极上,并通过戊二醛交联法固定酶分子制备成新型生物传感器。实验结果表明:在0~700μmol/L的葡萄糖标准浓度范围内,传感器灵敏度为23.955 nA/(μmol.L-1),最低检测限为0.3μmol/L,相关系数为0.999;在标准皮下葡萄糖浓度0~19mmol/L浓度范围内,被抽取出的葡萄糖电流响应值与皮下葡萄糖的浓度成线性关系,线性相关系数为0.994,灵敏度为4.03 nA/(mmol.L-1);单只传感器对100μmol/L葡萄糖检测的精度为4.07%(n=10),不同传感器之间对100μmol/L葡萄糖测量的精度为3.22%(n=10),在4℃条件下,传感器的寿命可达450 d。     

测定谷氨酰胺的组织传感器的研究

本文报道一种利用新鲜猪肾组织的薄片,经组织化学固相化后制成的生物在化膜,与氨气敏电极组成测定谷氨酸胺的新型生物传感器。此传感器具有制备简单,成本低廉,灵敏度高,使用寿命长等特点。此传感器的线性范围、斜率和检测下限分别为1×10~(-4)～5×10~(-3)M;49.8mv;5×10~(-5)M。使用寿命29天,150次分析。     

莴苣组织传感器及其动力学响应机理的研究

本文选用莴苣组织切片作为生物催化材料,与二氧化碳气敏电极组合,研制了对 L—组氨酸选择响应的新型的组织传感器。该传感器的线性范围为1.0×10~(-4)—1.0×10~(-3)mol·dm~(-3),检测下限为3.2×10~(-5)mol·dm~(-3),斜率为54.2mV·dec~(-1)。探讨了传感器组织膜中酶促反应的动力学机理。用该传感器测定了L—组氨酸脱羧酶的动力学参数Km和Vm。     

基于STC单片机的便携式快速血糖仪的设计与实现

介绍一种基于电流型生物传感器——葡萄糖氧化酶电极和STC单片机STC12C5410AD的微功耗便携式快速血糖测试仪。详细说明了血糖检测仪的工作原理、各模块的硬件电路及主程序工作流程,并给出了温度测量与实时时钟电路。仪器测试范围为1.1~33.3mmol/L;变异系数CV不大于3%;测试时间小于5 s;历史记录存储量180组;测试温度范围为10~45℃,具有自动温度补偿校正功能。     

二氧化碳传感器测定植物及其种子呼吸强度的研究

本文就 CO_2气敏传感器测定植物及其种子的呼吸强度进行了研究。在实验条件下,CO_2浓度在10~(-4)～10~(-2)mol/L 范围内时,传感器有很好的能斯特响应,检测下限为10~(-5)mol/L,此时传感器的响应时间 t≤8min。并且在 pH 值为3～4时,常见离子无干扰作用。实验表明,本法简便易行,分析速度快,精确度高,重现性好,结果准确可靠。已成功地应用于植物及其种子呼吸强度的测定。     

Computer-assisted diabetic management: a complex approach

This paper describes the architecture of, and the main reasoning methods involved in, a computer system developed to assist in diabetic management. The system integrates (i) a database module used for blood glucose monitoring, (ii) an interpreter module used to analyse the adequacy of diet and insulin treatment for diabetics, and (iii) an advisory module suggesting alterations in diet and/or insulin regimen in order to improve glycaemic control. The analysis of blood glucose profiles and hypoglycaemic episodes, as well as the suggestions for altered diet and insulin therapy, are based on qualitative and quantitative models of insulin effect and carbohydrate absorption using meal-time related glucose balance and distance from the preselected target (DFT) glucose values as focal concepts in the reasoning process. During the sequence of consultations with the system, a dynamic model of carbohydrate metabolism is gradually adjusted in order to constitute an appropriate simulation for the specific patient. This model is used to confirm the suggestions made by the ADVISOR program and to assist the health care professional in selecting the best control action by predicting the blood glucose profiles resulting from alternative control policies.     

A circulatory model for calculating non-steady-state glucose fluxes. Validation and comparison with compartmental models

This study presents a circulatory model of glucose kinetics for application to non-steady-state conditions, examines its ability to predict glucose appearance rates from a simulated oral glucose load, and compares its performance with compartmental models. A glucose tracer bolus was injected intravenously in rats to determine parameters of the circulatory and two-compartment models. A simulated oral glucose tolerance test was performed in another group of rats by infusing intravenously labeled glucose at variable rates. A primed continuous intravenous infusion of a second tracer was given to determine glucose clearance. The circulatory model gave the best estimate of glucose appearance, closely followed by the two-compartment model and a modified Steele one-compartment model with a larger total glucose volume. The standard one-compartment model provided the worst estimate. The average relative errors on the rate of glucose appearance were: circulatory, 10%; two-compartment, 13%; modified one-compartment, 11%; standard one-compartment, 16%. Recovery of the infused glucose dose was 93+/-2, 94+/-2, 92+/-2 and 85+/-2%, respectively. These results show that the circulatory model is an appropriate model for assessing glucose turnover during an oral glucose load.     

Application of an enteric coat increases the resistance to gastric juices for swallowable biosensors

This paper describes a biosensor with an immobilized-electron mediator that was covered with an enteric coat to generate a swallowable biosensor. Ferrocene-attached poly-l-lysine was crosslinked with glucose oxidase and bovine serum albumin by glutaraldehyde on a Au- or Pt-disc electrode, or a screen-printed electrode. The electrode was dip-coated to generate the enteric coat. The glucose sensor with enteric coat retained its activity under anaerobic conditions after 3 h of artificial gastric juice treatment. Mixing the enteric coat solution with plasticizer resulted in an enhanced stability of the coat. The proposed method is useful to construct the swallowable biosensor for non-invasive continuous glucose monitoring.     

Thin-film electrode based on TCNQ complex and immobilized enzyme for a glucose sensor

A thin film of TCNQ (tetracyanoquinodimethane) complex and immobilized glucose oxidase (GOD) has been prepared as a new type of enzyme electrode, and evaluated for an amperometric glucose-sensor application. This enzyme electrode is coated with two layers. The inner layer is TCNQ charge-transfer complex, which is prepared by the spontaneous electrolysis of Ag substrate in TCNQ solution. The outer layer consist of GOD and an electron mediator (dimethylferrocene) dispersed uniformly in the polymer matrix. Electron transfer from the outer layer to the inner layer take place with the aid of the mediator and the conducting charge-transfer complex. This enzyme electrode shows a rapid current response and is not affected by fluctuations of the dissolved oxygen concentration. Furthermore, a glucose-sensing system has been constructed by placing the counter electrode near the enzyme electrode. This system shows a rapid current response to a drop of glucose solution and a linear relationship between the response current and the glucose concentration on applying low potential. Therefore the system has been applied to human serum containing up to 25 mM glucose without preliminary treatment (diluting or mixing the sample).     

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.     

Free-living inferential modeling of blood glucose level using only noninvasive inputs

The goal of this work is to present a causation modeling methodology with the ability to accurately infer blood glucose levels using a large set of highly correlated noninvasive input variables over an extended period of time. These models can provide insight to improve glucose monitoring, and glucose regulation through advanced model-based control technologies. The efficacy of this approach is demonstrated using real data from a type 2 diabetic (T2D) subject collected under free-living conditions over a period of 25 consecutive days. The model was identified and tested using eleven variables that included three food variables as well as several activity and stress variables. The model was trained using 20 days of data and validated using 5 days of data. This gave a fitted correlation coefficient of 0.70 and an average absolute error (AAE) (i.e., the average of the absolute values for the measured glucose concentration minus modeled glucose concentration) of 13.3 mg/dL for the validation data. This AAE result was significantly better than the subject’s personal glucose meter AAE of 15.3 mg/dL for replicated measurements.     

Integral-based parameter identification for long-term dynamic verification of a glucose-insulin system model

Hyperglycaemia in critically ill patients increases the risk of further complications and mortality. This paper introduces a model capable of capturing the essential glucose and insulin kinetics in patients from retrospective data gathered in an intensive care unit (ICU). The model uses two time-varying patient specific parameters for glucose effectiveness and insulin sensitivity. The model is mathematically reformulated in terms of integrals to enable a novel method for identification of patient specific parameters. The method was tested on long-term blood glucose recordings from 17 ICU patients, producing 4% average error, which is within the sensor error. One-hour forward predictions of blood glucose data proved acceptable with an error of 2-11%. All identified parameter values were within reported physiological ranges. The parameter identification method is more accurate and significantly faster computationally than commonly used non-linear, non-convex methods. These results verify the model's ability to capture long-term observed glucose-insulin dynamics in hyperglycemic ICU patients, as well as the fitting method developed. Applications of the model and parameter identification method for automated control of blood glucose and medical decision support are discussed.     

基于CDMA和2.4G通信的无线远程血糖监护网络

目前,针对糖尿病的主要治疗方法为用血糖仪频繁测量患者体内的血糖含量,据此对患者的血糖代谢进行调节.借鉴无线传感器网络及体域网相关的技术与思想,利用CDMA蜂窝移动通信技术与2.4G射频通信技术设计了一个可用于监护个人及小区域内多人血糖情况的无线远程血糖监护网络系统.此血糖监护网络能够实现糖尿病的远程诊疗,拉近医患距离,减轻患者痛苦.重点介绍了血糖监护网络的网络架构,详细描述了网络节点CDMA和2.4G无线通信功能的设计与实现.     

MINMOD: a computer program to calculate insulin sensitivity and pancreatic responsivity from the frequently sampled intravenous glucose tolerance test

Insulin sensitivity and pancreatic responsivity are the two main factors controlling glucose tolerance. We have proposed a method for measuring these two factors, using computer analysis of a frequently-sampled intravenous glucose tolerance test (FSIGT). This 'minimal modelling approach' fits two mathematical models with FSIGT glucose and insulin data: one of glucose disappearance and one of insulin kinetics. MINMOD is the computer program which identifies the model parameters for each individual. A nonlinear least squares estimation technique is used, employing a gradient-type of estimation algorithm, and the first derivatives (not known analytically) are computed according to the 'sensitivity approach'. The program yields the parameter estimates and the precision of their estimation. From the model parameters, it is possible to extract four indices: SG, the ability of glucose per se to enhance its own disappearance at basal insulin, SI, the tissue insulin sensitivity index, phi 1, first phase pancreatic responsivity, and phi 2, second phase pancreatic responsivity. These four characteristic parameters have been shown to represent an integrated metabolic portrait of a single individual.     

计算机模拟优化的葡萄糖传感器阵列

介绍一种可植入的葡萄糖传感器阵列的设计和计算机模拟优化。葡萄糖传感器采用固定葡萄糖氧化酶层的氧电极和氧参比电极。考虑到葡萄糖传感器的使用寿命，本设计采用氧电极阵列。用计算机对氧电极阵列的氧电极排列的间距和相互影响进行了计算机模拟优化。考虑到葡萄糖传感器在体植入环境的氧浓度较低，而葡萄糖浓度较高，所以采用特殊的膜的结构，以提高葡萄糖传感器的测量范围，并用计算机模拟优化了膜的结构尺寸。