Metallophthalocyanine-based molecular materials as catalysts for electrochemical reactions

Screen printing is widely used to fabricate disposable and economical electrochemical sensors and has helped us to establish the route from ‘lab-to-market’ for a plethora of sensors We overview recent developments in the field where screen printed electrochemical sensors are utilised Starting with their fundamental understanding, through to highlighting new developments in bulk metal and mediator modified electrodes, as well as novel advantageous electrode designs, we demonstrate the wide and diverse range of applications that sensors based on this fabrication approach have achieved

New directions in screen printed electroanalytical sensors: an overview of recent developments.

This review summarizes scientific research activity on biosensors, especially screen-printed, electrode-based biosensors. The basic configurations of biosensors based on screen-printing technology are discussed and different procedures for immobilization of the biorecognition component are reviewed. Theoretical aspects are exemplified by practical environmental and food-analysis applications of screen-printed, electrode-based biosensors.

Biosensors based on screen-printing technology, and their applications in environmental and food analysis

This review article provides an overview of the most recent literature on biosensors for environmental pollutants and food contaminants. Due to the large number of publications, only papers published between 2000 and January 2003 were considered. Also, while not all of the published literature could be reviewed here, over 200 references are cited to provide a good overview of research undertaken in the last two years. Older publications are covered by a number of earlier review articles. This article provides an introduction into the field including specific consideration of the application areas, describes the typical biosensor assay format used, and is subsequently structured according to the biorecognition elements used (i.e., nucleic acids, enzymes, whole cells, tissue and whole organisms, antibodies and receptors, and biomimetic materials). In addition, a section on microbiosensing systems is provided. Since only very few microbiosensors with applications in environmental and food systems have been published, enabling technology is also covered in this article.

Biosensors for environmental pollutants and food contaminants.

Biosensors, combining a selective biological recognition element and a sensitive transducer, are versatile analytical tools applied more and more in different fields, such as medicine, food quality and safety control, and environment pollution monitoring. They are expected to play an increasingly important role in the improvement of life quality. In this context, the present work covers recent approaches in design and development of biosensors applied for analysis of real samples of medical, environmental or industrial relevance. The described sensors meet the sensitivity, selectivity, and response time required by their applications. Moreover, they are designed to avoid contamination of the monitored systems with undesirable components and to minimise the damage of living organisms (when it comes to in vivo monitoring). (C) 2004 Elsevier B.V. All rights reserved. (Less)

Biosensors for life quality. Design, development and applications

An amperometric biosensor for sulfite has been developed. The enzyme sulfite oxidase (SOD) and electron acceptor cytochrome c are mixed into the carbon ink that is deposited onto the working electrode of a screen-printed strip. A silver–silver chloride electrode is printed alongside the working electrode and serves as reference/counter electrode. The electrochemical behaviour of the biosensor surface in plain buffer has been investigated by cyclic voltammetry. In the voltage range −0.5 to +0.5 V, a well-defined anodic peak appeared at −0.15 V and a less well-defined anodic peak at about +0.2 V. In the presence of SO32−, the cyclic voltammogram obtained with the biosensor exhibited an increase in magnitude of the more positive peak; this was considered to result from the electrocatalytic oxidation of SO32− involving SOD and the heme (Fe2+/Fe3+) centre of cytochrome c. Amperometry in stirred solution was used to construct a hydrodynamic voltammogram for SO32− using the biosensor; this exhibited a single wave with a plateau beginning at +0.3 V. This wave corresponds to the electrocatalytic response observed by cyclic voltammetry. The pH and concentration of buffer components have been optimised for the determination of SO32− by amperometry in stirred solution. Using these conditions, a detection limit of 4 ppm was obtained. The stability of the biosensors was examined after storage in 0.05 M phosphate buffer pH 7.4 at 4°C; it was found that the initial response was retained for at least 45 days. The proposed biosensors were evaluated on samples of unspiked and spiked estuarine, river and tap waters. The recovery and precision data indicated that the devices could be expected to give reliable data in these waters.

Development of an amperometric sulfite biosensor based on sulfite oxidase with cytochrome c, as electron acceptor, and a screen-printed transducer

Development of disposable amperometric sulfur dioxide biosensors based on screen printed electrodes

Cyclic voltammetry was used to investigate the electrochemical reaction of propanethiol at a cobalt phthalocyanine modified screen printed carbon electrode coated with a hydrogel. Cyclic voltammograms exhibit one anodic peak at + 0.45 V in the potential range from 0 to + 0.7 V. The peak is considered to result from the electrocatalytic oxidation of propanethiol to produce the corresponding disulfide. Hydrodynamic votammetry revealed one well defined anodic wave, and the optimum potential for amperometric studies was found to be + 0.5 V. Calibration studies were performed for devices on exposure to propanethiol at different concentrations; a linear response was obtained over the range 6–22 vpm. A method is proposed to estimate the diffusion coefficient in gels based on the amperometric data and the free boundary model of diffusion. The diffusion coefficient of propanethiol in agarose gel was found to be ≈ 1.96 × 10 −5 cm 2 s −1 . The diffusion coefficient obtained at a gel free sensor was calculated to be ≈ 2.5 × 10 −5 cm 2 s −1 . The lower value obtained for the former may be due to obstruction by the polymer particles which constitute the gel.

Electrocatalytic, diffusional and analytical characteristics of a cobalt phthalocyanine modified, screen-printed, amperometric gas sensor for propanethiol

A.K. Abass

Papers

Development of an amperometric sulfite biosensor based on sulfite oxidase with cytochrome c, as electron acceptor, and a screen-printed transducer

Development of disposable amperometric sulfur dioxide biosensors based on screen printed electrodes

Electrocatalytic, diffusional and analytical characteristics of a cobalt phthalocyanine modified, screen-printed, amperometric gas sensor for propanethiol