Biosensors

R.D. Schmid

News

新闻

In health, metabolism is elegantly coordinated. Failure of an underlying process (as occurs in diabetes) disrupts the coordination and impacts on the global status of the affected individual. It takes a medical expert to intervene and restore order. Chaotic processes prevail at all times in biological systems and their behaviour in sickness degenerates between medical interventions. We have explored the use of an expert system to substitute for the physician between interventions and demonstrated its ability to maintain order and thus significantly improve control of blood glucose.

W.D. Lougheed

A. Schiffrin

A.M. Albisser

Stabilizing blood glucose with a novel medical expert system

新型医学专家系统稳定血糖

To allow for replacement and in situ cleaning and calibration of sensors in a fermenter, a probe calibrator was conceived, designed, developed and tested. The calibrator built functioned with a dissolved oxygen electrode but could, if somewhat modified, operate with many other types of sensors. The calibrator is operated by means of an accompanying control unit and is designed to be mounted on a fermenter headplate or through a sidewall penetration. Calibrator performance was tested during a series of fermentations.

Robert Kok

Pat Hogan

The development of an in situ fermentation electrode calibrator

原位发酵电极校准器的发展

Coimmobilized glucose oxidase and anti-T4 antiserum are employed in the construction of a biosensor for thyroxine measurements. The resulting enzyme-immunosensor yields an amplified response to T4 with a detection limit of 15 nM.

T. Yao

G.A. Rechnitz

Amperometric enzyme-immunosensor based on ferrocene-mediated amplification

基于铁氰化物介导放大的安培酶免疫传感器

Pyruvate oxidase from Pediococcus species was immobilized with gelatin and insolubilized in film form by tanning with glutaraldehyde. The film was fixed onto the tip of an oxygen electrode. The enzyme electrode was specific for pyruvate measurements. This electrode was sensitive to 0.1 mM and could be used up to a final pyruvate concentration of 2 mM. At each step of the enzymatic film preparation and assay 0.7 mM thiamine pyrophosphate, 10 μM flavin adenine dinucleotide, 5mM Mg2+ and 10 mM phosphate buffer were necessary. A computerized probe allowed successive measurements every 3 min for more than 20 h with the same enzymatic film. The reproducibillty for the same pyruvate concentration was 2% during 400 assays without special optimization. This enzyme electrode has many applications in basic (metabolism, enzymology) and applied (blood, yoghurt) research. Results obtained from assays carried out in yoghurt are presented.

A.M. Zapata-Bacri

C. Burstein

Enzyme electrode composed of the pyruvate oxidase from pediococcus species coupled to an oxygen electrode for measurements of pyruvate in biological media

由乳酸球菌属丙酮酸氧化酶与氧电极耦合构成的酶电极用于生物介质中丙酮酸的测定

Transient mode dissolved oxygen measurement has been studied using a specially constructed galvanic membrane electrode controlled by a microcomputer. A four-layer diffusion model was developed to describe the dynamic behavior of the electrode. The data interpretation method is based on on-line computer simulation and parameter estimation techniques. A user-friendly computer software package is also developed for calibration and measurement control. Both experimental and theoretical studies indicate that such measurement is less sensitive to fouling and changes in flow conditions than steady state operation of the electrode.

Henry Y. Wang

Xiang-Ming Li

Transient measurement of dissolved oxygen using membrane electrodes

膜电极法测定溶解氧的瞬态测量

Glucose oxidase (GOD) was covalently coupled to a cellulose acetate (CA) layer, using bovine serum albumin (BSA) and parabenzoquinone (PBQ) linkages. Prior to GOD coupling this CA layer was deposited on the platinum tip of a needle-type sensor and covered with an outer layer of polyurethane (PU). Such microsensors were found to be active, their GOD load reaching 1.6 to 3.0 μg mm−2 and their glucose response reaching 1 to 3 μA M−1 mm−2, even when the upper limit of their linear range reached 10–30 mM. Due to the multilayer structure and composition of these micro-sensors, small anions such as ascorbate were partially discriminated from neutral molecules such as hydrogen peroxide. When implanted subcutaneously in anaesthetized rats, sensor responses correlated correctly with blood glucose concentration but presented sensitivity coefficients significantly different to those determined in vitro: a 2 point calibration procedure was found necessary for in vivo experiments.

Robert Sternberg

Marie-Bernadette Barrau

Laurent Gangiotti

Daniel R. Thévenot

Dilbir S. Bindra

George S. Wilson

Gilberto Velho

Philippe Froguel

Gérard Reach

Study and development of multilayer needle-type enzyme-based glucose microsensors

多层针型酶基葡萄糖微传感器的研究与开发

Further development of a prototype receptor-based biosensor, or 'receptrode', utilizing the intact chemosensing structures of Callinectes sapidus is reported. Significant gains in lifetime extension of the system have been made. Also, an expansion of the list of analytes to which the receptrode responds is reported. Data are presented which indicate that the receptrode can be used to quantify some biologically important purine compounds, as well as the amino acids previously reported. The receptrode responds to stimuli concentrations over six orders of magnitude, with a high degree of specificity and a response time on the order of milliseconds. Approximately two minutes are required for the system to return to baseline, providing the limit for the analysis time. The rapid analysis time, large overall dynamic range of detection, and the high degree of specificity demonstrate the receptrode's potential as a powerful tool for chemical analysis in the future.

R.M. Buch

Intact chemoreceptor-based biosensors: responses and analytical limits

基于完整化学感受器的生物传感器：响应与分析极限

The major problems with existing amperometric enzyme electrodes for glucose sensing are oxygen sensitivity and output drift. The recently described miniature glucose sensors using immobilised ferrocene (dicyclo-pentadienyl iron) to mediate electron transfer from glucose oxidase to a base electrode are oxygen-independent but are often unstable. In this study, we test the hypothesis that the stability of ferrocene-based sensors can be markedly improved by better retention of the enzyme at the electrode. Sensors with graphite foil as the base electrode, dimethylferrocene as the mediator and carbodiimide/glutaraldehyde for enzyme immobilisation lost most of their activity when calibration curves were compared before and after 18 h operation in vitro at 37°C (mean current decrease at 20 mmollitre glucose was 91%). This sensor type with a covering cellulose membrane also lost activity (mean current decrease of 40% after 18 h). Electrodes in which the base sensor was platinum and the enzyme was covalently attached to agarose lost no activity when operated either at 700 mV without mediator (as a hydrogen peroxide detector) or at 160mV with mediator. We conclude that both ferrocene-mediated and hydrogen peroxide-detecting amperometric glucose sensors with a high density of covalently-linked enzyme have an operating stability in vitro which may render them suitable for clinical use as, for example, an overnight hypoglycaemla alarm.

John C. Pickup

Gill W. Shaw

Denzil J. Claremont

Potentially-implantable, amperometric glucose sensors with mediated electron transfer: Improving the operating stability

潜在可植入的安培型葡萄糖传感器与介导电子转移：提高操作稳定性

Solutions containing the electroactive species tris(2,2'-bipyridine)-ruthenium dication and ferrocene carboxylate as well as bovine serum albumin (BSA), gamma globulin (IgG) or human serum were ultrafiltered. Cyclic voltammetry at a glassy carbon electrode showed that the deleterious effects of BSA and IgG were eliminated by passing the solution through a 30 kdalton filter. This was insufficient filtration of serum, however. Ultrafiltration with 3 or 5 kdalton filters was required for good voltammetry. This indicates that the removal of the preponderant proteins is necessary, but not sufficient, to protect electrochemical surfaces.

Janean M. Elbicki

Stephen G. Weber

Ultrafiltration of human serum to determine the size of species that poison voltammetric electrodes

人血清超滤以确定毒害伏安电极的物种大小

出版信息	出版商: Elsevier B.V.，出版周期: ，期刊类型: journal，开源期刊: 否
基本数据	创刊年份: 1985，原创研究文献占比: ，自引率:， Gold OA占比:

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