Jeffrey D. Newman

Ink-jet printing for the fabrication of amperometric glucose biosensors

Ink-jet printing has been demonstrated as a manufacturing technique that facilitates the rapid, reproducible and economical production of amperometric glucose biosensors. Glucose was chosen as the ...

Development of a mass-producible glucose biosensor and flow-injection analysis system suitable for on-line monitoring during fermentations

Screen printed amperometric glucose biosensors were constructed and optimised for use in a flow injection analysis (FIA) system. The sensors were fabricated using a catalytic metallised carbon based ink, allowing a working potential of +350 mV (Ag/AgCl). Overall the sensors displayed a high degree of reliability and robustness. A linear response was obtained over the range 0.1 to 25 mM glucose with a slope of 1.35 ± 0.20 μA/mM. The within electrode coefficient of variation at each concentration tested (n = 10) was less than 2% (or 0.1 mM for concentrations below 5 mM). In addition, it was demonstrated that a single sensor can be used in the FIA system over a seven day period indicating a high level of operational stability. These sensors fulfil the criteria necessary for a mass produced device, which would be suitable for the on-line monitoring of glucose consumption during microbial fermentation.

BIOSENSORS FOR PROCESS-CONTROL

Biosensors have been extensively studied during the last 20 years, and a myriad of laboratory biosensors have been developed. Improvements are required in biosensor design and performance before they become widely accepted in industrial process monitoring. However, as the biotechnology industry expands, biosensors may become more acceptable because, despite their limitations, they are the only devices capable of delivering the information required.

TTF-Modified Biosensors for Hydrogen Peroxide

Abstract Amperometric biosensors for hydrogen peroxide were produced, based on TTF-modified graphite disc electrodes, incorporating immobilised peroxidase. At the optimum operating potential (−200 mV vs. calomel electrode), a linear response to hydrogen peroxide was obtained in the range 0–2 mM (Km value = 1.98 mM). Low sensitivity to pH fluctuations and good stability at room temperature were exhibited.

Investigating pipeline and state of the art blood glucose biosensors to formulate next steps

Ten years on from a review in the twentieth issue of this journal, this contribution assess the direction research in the field of glucose sensing for diabetes is headed and various technologies to be seen in the future. The emphasis of this review was placed on the home blood glucose testing market. After an introduction to diabetes and glucose sensing, this review analyses state of the art and pipeline devices; in particular their user friendliness and technological advancement. This review complements conventional reviews based on scholarly published papers in journals.

Monitoring of the glucose concentration during microbial fermentation using a novel mass-producible biosensor suitable for on-line use

A flow-injection analysis system was combined with a mass producible, disposable biosensor and was used to monitor glucose concentrations during several microbial fermentations. The biosensor was m ...

Monitoring the Effect of Metal Ions on the Mobility of Artemia salina Nauplii

This study aims to measure the effect of toxic aqueous solutions of metals on the mobility of Artemia salina nauplii by using digital image processing. The instrument consists of a camera with a macro lens, a dark chamber, a light source and a laptop computer. Four nauplii were inserted into a macro cuvette, which contained copper, cadmium, iron and zinc ions at various concentrations. The nauplii were then filmed inside the dark chamber for two minutes and the video sequence was processed by a motion tracking algorithm that estimated their mobility. The results obtained by this system were compared to the mortality assay of the Artemia salina nauplii. Despite the small number of tested organisms, this system demonstrates great sensitivity in quantifying the mobility of the nauplii, which leads to significantly lower EC50 values than those of the mortality assay. Furthermore, concentrations of parts per trillion of toxic compounds could be detected for some of the metals. The main novelty of this instrument relies in the sub-pixel accuracy of the tracking algorithm that enables robust measurement of the deterioration of the mobility of Artemia salina even at very low concentrations of toxic metals.

Developing Novel Prognostic Biomarkers for Multivariate Fracture Risk Prediction Algorithms

Multivariate prediction algorithms such as FRAX® and QFractureScores provide an opportunity for new prognostic biomarkers to be developed and incorporated, potentially leading to better fracture prediction. As more research is conducted into these novel biomarkers, a number of factors need to be considered for their successful development for inclusion in these algorithms. In this review, we describe two well-known multivariate prediction algorithms for osteoporosis fracture risk applicable to the UK population, FRAX and QFractureScores, and comment on the current prognostic tools available for fracture risk; dual X-ray assessment, quantitative ultrasonography, and genomic/biochemical markers. We also highlight the factors that need to be considered in the development of new biomarkers. These factors include the requirement for prospective data, collected in new cohort studies or using archived samples; the need for adequate stability data to be provided; and the need for appropriate storage methods to be used when retrospective data are required. Area under the receiver operating characteristic curve measures have been found to have limited utility in assessing the impact of the addition of new risk factors on the predictive performance of multivariate algorithms. New performance evaluation measures, such as net reclassification index and integrated discrimination improvement, are increasingly important in the evaluation of the impact of the addition of new markers to multivariate algorithms, and these are also discussed.

Welcome to Biosensors: A New Open-Access Journal

The journal Biosensors has been started as a peer-reviewed, open access journal. As editors, we believe that it will fulfill an important role in the community of researchers and developers in the field of biosensors. The addition of a “free access” journal to the existing, high quality publications in this field is something that we believe is very important in a field which is now so entwined with commercial activity and where researchers aim, not only at academic research, but on the development of products at a potentially massive scale. For these researchers, it is important that they can publish their results in a journal that guarantees quality that comes from peer-review, but that at the same time breaks the traditional boundaries of academic journals which need a subscription or a pay-per-view option to access the published data.

Novel fabrication technique for development of polymer-based microsensor arrays for molecular diagnostics

An innovative production technique is described for the low-cost production of arrays of interdigitated electrode (IDE) structures. The resulting polymer chips form the basis of a new type of diagnostic device allowing for the impedimetric detection of either hybridisation or immuno-affinity binding of antibody-antigen combinations. Sensitivity of the IDEs is maximised by focusing the field of sensitivity to the molecules of interest by lowering the electrode dimensions and spacing to the sub-micron region. This has been achieved using a unique combination of state-of-the-art micro-structuring of polymers and the directionality of metal-deposition by evaporation. Subsequently, polymer based arrays of IDEs with micron to sub-micron electrode widths can be realised using a single metallisation step, completely omitting any sophisticated photolithography.