We've done an investigation about water pollution in the past few months. Through street interviews and online questionnaires,369 valid replies were collected from 9 countries. Here's the conclusion: Although different countries have varying degrees of water pollution, people are uniformly worried about this. Accordingly, there is support, and even demand for a method that is both cheap and convenient to tell them whether their water is safe to drink. And that's the reason for this project.

We had constructed 14 different parts. All of them, including several ion sensors, have ribB CDS. Our experiments confirmed that the expression degree of ribB can influence the riboflavin production. Then we took them into MFC and the voltage showed that our genetically engineered E.coli responded to the change of Cu²⁺ concentration. Thus we linked the concentration of metal ion to the electricity production.

Based on the wet lab results, we constructed the Micro Holmes concentration measurement system' which contained a Microbial Fuel Cell, a Microprogrammed Control Unit, a voltage magnification circuit board, an Analogue-to-Digital Conversion chip, a set of input and output devices and one or several kinds of bacteria.