Arsenic Biosensor Background
From 2006.igem.org
Revision as of 16:23, 29 June 2006
The worst mass poisoning the world has ever known
It is estimated that at this very moment up to 100 million people across the world are being poisoned due to the presence of arsenic in their drinking water. One in a hundred of these people will develop a fatal cancer as a result, and countless others will get ill and suffer as the poison slowly damages their bodies.
This problem is greatest in one of the world’s poorest countries – Bangladesh. Because of the combination of regular yearly floods and poor sanitation, the available fresh water is swarming with harmful diseases. In an attempt to alleviate this problem, a large number of tube-wells were dug all across the country in order to provide people with clean water. However, in a cruel twist of fate, a lot of these wells were dug through a layer of arsenic – out of the estimated 10 million wells dug by now, at least 1 in 4, and possibly almost as many as a half of these wells contain water with harmful levels of arsenic.
So the choice facing a poor rural family in Bangladesh is basically between a quick death from disease if they drink the water from the rivers, or the potential of slow death from poisoning if they drink the water from the wells. The problem is that they don’t know which wells are poisoned, and because the effects of arsenic are slow and cumulative, by the time they find out, it’s already too late.
1 in 4 wells. Would you play Russian roulette with your children’s lives?
The project
Scientists around the world have been working to change this. The distribution of arsenic in the wells is quite irregular, so if a cheap, easy-to-use arsenic detector was to become available, all the wells could be tested, and safe ones could be found – something that is currently financially unfeasible because of the instruments and expertise required.
A lot of research has been done into arsenic biosensors already, and some have already been created, mostly using fluorescence. The components are available, there are gene promoters that respond to the presence of arsenic, and various different outputs are possible. The next stage is really more of an engineering question: how do you come up with an optimal design that’s easy to use in the field?
Our suggested project uses a pH change as a signal for the presence of arsenic, improving upon previous designs because the change is easily detectable using a pH meter, or even just a couple of drops of indicator. It is also potentially possible to make the system detect a large range of arsenic concentrations, because the change in pH is gradual.
Not only is such a device both practical and marketable, it is ethically imperative to produce it. Using the cutting edge of modern science, it really is possible to change the world.
