基于ISFET的幽门螺杆菌传感器的研制

阐述了传感器的基本结构和工作原理,重点介绍了生物敏感膜的制备方法并给出了用该传感器和快速尿素酶药盒对感染了幽门螺杆菌的13例患者进行临床试验的比较结果.     

Performance evaluation of ISFETs and other ISE sensors for whole blood ion assay

Performance evaluations of ion-selective field-effect transistors (ISFETs) have been carried out using both quality-control materials and whole arterial blood samples. Comparison of the results from these evaluations suggests that the whole blood evaluation may be more useful when assessing the value of particular sensors for clinical applications. The effect of outliers on the imprecision estimates is demonstrated for ISFETs and ISEs, both graphically and in the calculation of the estimates with an without the outliers present. Estimates of constant and proportional bias, against an alternative sensor, determined from the intercept and slope of the linear regression vary according to the regression method used. The bias estimates obtained for the K+ISFET against the Radiometer KNA1 using ordinary least squares regression are compared with the Deming/Mandel method and the three-group resistant line method of Tukey. The Thorn EMI ISFETs are demonstrated to have acceptable imprecision and only a small bias compared with direct ISE instruments for whole blood assay and can be considered suitable for incorporation into clinical instrumentation.     

A decrease of intracellular ATP is compensated by increased respiration and acidification at sub-lethal parathion concentrations in murine embryonic neuronal cells: measurements in metabolic cell-culture chips

We present a label-free in vitro method for testing the toxic potentials of chemical substances using primary neuronal cells. The cells were prepared from 16-day-old NMRI mouse embryos and cultured on silicon chips (www.bionas.de) under the influence of different parathion concentrations with sensors for respiration (Clark-type oxygen electrodes), acidification (pH-ISFETs) and cell adhesion (interdigitated electrode structures, IDES). After 12 days in vitro, the sensor readouts were simultaneously recorded for 350 min in the presence of parathion applying a serial 1:3 dilution. The parathion-dependent data was fitted by logistic functions. IC₅₀ values of approximately 105 μM, 65 μM, and 54 μM were found for respiration, acidification, and adhesion, respectively. An IC₅₀ value of approximately 36 μM was determined from the intracellular ATP-levels of cells, which were detected by an ATP-luminescence assay using micro-well plates. While the intracellular ATP level and cell adhesion showed no deviation from a simple logistic decay, increases of approximately 29% in the respiration and 15% in the acidification rates above the control values were found at low parathion concentrations, indicating hormesis. These increases could be fitted by a modified logistic function. We believe that the label-free, continuous, multi-parametric monitoring of cell-metabolic processes may have applications in systems-biology and biomedical research, as well as in environmental monitoring. The parallel characterization of IC₅₀ values and hormetic effects may provide new insights into the metabolic mechanisms of toxic challenges to the cell.     

Diagnostic System for Helicobacter pylori Urease Based on a pHsensitive Field Effect Transistor

A rapid diagnostic system for Helicobacter pylori (H. pylori) was developed based on an urease analyser using a pH-sensitive field effect transistor (pH-FET). The system is composed of a solid-phase capillary-tube and a pH-measuring cell. The solid-phase tube, with an inner diameter 0.55 mm and coated with a monoclonal antibody against H. pylori's urease, was used to selectively capture the urease in endoscopically collected gastric mucus. The urease activity on the inner surface of the solid-phase tube was measured by coupling it with ph-FET in a pH measuring cell containing urea solution. Before immuno reaction in the solid-phase, gastric mucus was diluted with a phosphate buffered saline containing 1% n-octylglucoside, which was effective for accelerating the release of active urease from H. pylori's cells suspended in the sample solution. As a result of preliminary evaluations, it was found that the clinical sensitivity and specificity were 100 and 86%, respectively, using a bacteriological test as a reference.     

Development of a transcutaneous blood-constituent monitoring method using a suction effusion fluid collection technique and an ion-sensitive field-effect transistor glucose sensor

The paper describes a method for the transcutaneous monitoring of blood constituents. It combines the use of a suction effusion fluid (SEF) collecting technique with a silicon on sapphire/ion-sensitive field-effect transistor (SOS/ISFET) biosensor. SEF is directly collected by a weak evacuation through skin from which the stratum corneum has been removed. An SEF collecting cell with a stainless-steel mesh at the bottom is kept in a weak vacuum condition, and SEF is sucked up through the mesh and deposited in a reservoir above. An ISFET glucose sensor is able to detect glucose concentrations in very small SEF samples through the use of two small ISFETs and an immobilised enzyme membrane. The reliability of transcutaneously obtained SEF was first confirmed in an experiment using rabbits. A clinical analyser was used to determine levels of glucose, urea nitrogen and creatinine in SEF obtained transcutaneously; these results are compared with results obtained by the same analyser directly from sera. The ISFET glucose sensor was successfully tested on human subjects for the monitoring of blood glucose levels. During these tests, glucose level changes in the SEF followed acutal blood glucose level changes with a slight time delay. Results suggest the feasibility of non-invasive, transcutaneous monitoring of low molecular weight substances in the blood without the use of ordinary blood sampling.     

TRAIL受体微阵列生物传感器检测系统的初步应用

目的：肿瘤坏死因子相关凋亡诱导配体（TNF-related Apoptosis-induced Ligand，TRAIL）受体微阵列生物传感器检测系统为离子敏场效应型（Ion sensitive field effect transistor，ISFET）免疫生物传感器，利用此检测系统检测细胞表面的TRAIL受体。方法：将1：10稀释的4种TRAIL受体的抗体吸附在此型免疫生物传感器上，对正常血管内皮细胞株EVC9611、肺癌细胞株AS49-DDP、舌癌细胞株Tca8113以及白血病人来源的白细胞进行检测。结果：这种微阵列传感器检测系统可以同时检测细胞表面的4种TRAIL受体，并发现正常血管内皮细胞株EVC9611和舌癌细胞株Tca8113的细胞表面没有4种TRAIL受体的表达，而肺癌细胞株AS49-DDP细胞表面的TRAILR2表达较多，白血病人来源的白细胞4种受体都有表达。结论：研制的TRAIL受体微阵列生物传感器检测系统可以有效地同时检测各种细胞表面的4种TRAIL受体，为进一步使用TRAIL治疗肿瘤提供基础资料。     

Performance of pH monitoring systemin vivo

In vivo tests were performed on a pH monitoring system. For this purpose 12 catheters were introduced into the arterial bloodstream of dogs. In the tip of the catheters (6F) a pH-sensitive ISFET sensor and an Ag/AgCl reference electrode were incorporated. Blood pH was varied by ventilation changes and injection of acidic and basic solutions into the animal’s blood. After stabilisation and in vivo calibration the output of the microprocessor-controlled pH monitor was compared with that of an in vitro pH/blood-gas analyser. The average deviation of the monitor output was 0·016 pH over a measurement period of 4 h. The maximum deviation observed was 0·06 pH. The system’s response is fast enough for monitoring changes in blood pH in clinical conditions.     

Effect of Left Ventricular Assist Device (LVAD) on Myocardial pH Change after Regional Coronary Occlusion

To evaluate the effect of an assist pump on the metabolic viability of the ischemic myocardium, myocardial pH was continuously monitored using an ion-sensitive field-effect transistor (ISFET) pH sensor in 14 dogs after coronary occlusion. In seven dogs (control group), coronary occlusion (10-20 min) and successive reperfusion (30-60 min) were performed several times. In seven dogs [left ventricular assist device (LVAD) group], the LVAD was implanted between the left atrium and the aorta. Occlusion and reperfusion were performed first with the pump on and then with the pump off. In both groups, myocardial pH fell after occlusion, and increased after reperfusion. In the control group, the fall rate of pH in the later coronary occlusion decreased to 66 +/- 7% (mean +/- SEM) of that in the previous occlusion. Contrarily, in the LVAD group, the fall rate under LVAD-off increased to 174 +/- 32% of that under the preceding LVAD-on. This indicates that progressive cellular damage occurred in the control group, while the myocardium was preserved by the assist pump in the LVAD group. LVAD is effective for preserving the metabolic viability of the ischemic myocardium.     

A Review of Implantable Sensors

Les capteurs biologiques en cours de developpement offrent: bonne performance, petite taille, cout réduit et compatibilité avec des circuits integrés, Ľétal actuel de ces capteurs en ce qui concerne le milieu biologique est presenlé, Des capleurs physiques peuvent mésurer la pression, les débits, ľaccéleration etc. Des capteurs chimiques peuvent mesurer les ions H+, K+, Na+, etc. La recherche nécessaire pour ľimplantalion chez ľhomme est envisagée.
Solid state sensors offer high performance, small size, lower cost, and compatibility with computing circuits. The current status of these sensors for biomedi-cal applications is reviewed. Physical transducers may be used to measure pressure, flow, acceleration, velocity, etc. Chemical transducers may measure H+, K+, Na+, etc. Research required for their implantation is suggested.