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There are a population of 884 million still drink water without the previous purification all over the world. There are about 3 billion to 4 billion families lack of drinkable water. Each year about 3.5 million people's deaths are associated with insufficient water supply and sanitation condition, which occurs mainly in developing countries.

According to all above, the matter of water quality is a great matter of human beings’ life quality. It has always been crucial to many researchers engaging in improving and making breakthroughs on the approaches towards water quality detection. Currently chemical detection methods are more complex and time consuming; besides ,on the way of bringing the samples to the laboratory, some of the indicators may probably be changed. Another thing we may acknowledge is that chemical detection apparatus cost too much money.

Based on the matters above, this year we intended to look for a new way using biotechnology. Here come the ideas, through two kinds of approaches we may achieve rapid water quality detection. One of the approaches is so called comprehensive detection, here we mainly rely on LuxAB ,which encodes a kind of luciferase. Because anything toxic within the water may have a negative impact on the activity of luciferase, the luminescence is likely to be decreased. The other is specific detection, because only in this way can we successfully quantify specific metal ions like Hg(II). One sequence of MerR operon occupies a significant position along with quorum sensing system. In addition, we use gfp as reporter.

Besides the two biosensors we built, the joint uses of microfluidic chips, automatic detection devices, photoelectric detection technology and micro total analysis systems will extremely promote biological detection method. This device can also be linked to the computer and has the ability of offline CNC screen operation, which improves the detection efficiency. What’s more, little device is convenient to carry and free from limitation of experimental conditions.

Biological method not only has the priority of concise operations and less consumption, but also has the advantages of high accuracy, specificity, and security.

Further Application

When it comes to the further application about the project, we can also explore the deeper meaning of the biological methods and the combination with micfluidics. Mostly, biotechnology applied in our project is supposed to be engineered. We have tried severe approaches to conduct recombinant plasmids to achieve specific goals, for instance, a sequence specialized to a very narrow group of metal ions can be integrated to a chassis cell, hence the chassis can obtain some new functions. Just as what we had intended to achieve, when we transmit particular sequence identifying specialized metal ions by varies plasmids, we shall find the way on engineering. Furthermore, our matched devices which will do some detections through the usage of micro fluidics can also be engineered. The chips we used can be reformed to match with desired purposes as identify different ions toxic in water relying on specific sequences. Another thing we should pay more attention to is that the devices can be more general and popular. Because of the advantages as portable, automatic and inexpensive. So it is not so hard to popularize the devices to the public, for example people who are interested in field survival activities. Anyway, there is more possible to encounter difficulties , that you need to detect the water quality to make true whether it is drinkable or not. In other circumstance, water being polluted when catastrophe happened, like earth quake. In this case, the correct and portable method to detect water source quality is really vital. Our devices can be considered absolutely. Concluded, we can still make further application on the devices.