Development of a low cost arsenate sensor

Lead Research Organisation: University College London
Department Name: Structural Molecular Biology

Abstract

Arsenic is an infamous toxin and the WHO has labelled drinking arsenic-contaminated water by hundreds of millions of people "The greatest mass poisoning of a population in human history". While arsenic remediation remains the answer to this problem, it needs to be combined with a quick, low-cost, simple to use and accurate method of determining the amount of both species of soluble arsenic in water. In the short term, this is essential to prevent people drinking water laden with arsenic and then to identify sources that need remediation and to confirm its effectiveness. In this project we will expand our arsenic sensor technology from detecting only one (the most toxic) of the two forms of soluble arsenic to both. Together with arsenite oxidase to measure arsenite concentrations we will develop an enzyme-electrochemical arsenate sensor using the enzyme arsenate reductase. Together the two enzymes will form the basis of this novel sensing system measuring both forms on a single strip.

Publications

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Glasser NR (2018) Structural and mechanistic analysis of the arsenate respiratory reductase provides insight into environmental arsenic transformations. in Proceedings of the National Academy of Sciences of the United States of America

 
Description 1. We have found that it is possible to express arsenate reductase using an aerobic expression system in E. coli. We found that the expression of arsenate reductase and the incorporation of its cofactors is highly dependent on the dissolved oxygen concentration in the growth media. Fine monitoring and control of the dissolved oxygen is required to establish optimum arsenate reductase expression. We subsequently optimised expression of the enzyme in a fermenter, which means the process is scalable.
2. We have identified two cheap mediators and two electrode materials that can be used in combination with arsenate reductase to detect arsenate. The arsenate reductase could also be used directly with one of the electrode materials and was found to operate in the presence of oxygen.
3. Assisted by BBSRC GCRF IAA funding, we were able to maximise the impact of BBSRC-funded research in Bangladesh by learning more about the water usage of rural inhabitants and the measures that will be needed to tackle the arsenic problem.
Exploitation Route With our shortlist of mediator-electrode combinations, we can move on to improve sensitivity of the arsenate-sensing system, and provide a cheap, point-of-use sensor for arsenate in resource limited markets (e.g. Bangladesh, India, Mexico).
Sectors Agriculture, Food and Drink,Communities and Social Services/Policy,Environment,Healthcare,Manufacturing, including Industrial Biotechology

 
Description GCRF-IAA
Amount £20,000 (GBP)
Funding ID BB/GCRF-IAA/17/21 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 11/2017 
End 02/2018