Team:NTHU Taiwan/Implementation



Before we started to construct our topic, the very first things we considered were reality and pragmatic application. We wanted to conduct a project which can contribute to solving the recent problem or elevating our standard of living not just a fancy project with an abstract and unpractical core value. Our purpose was to strike the balance between reality and our imagination which we believed is one of the most important things iGEM treasured.

Nowadays, the quantum dot is a versatile and ubiquitous material in our daily life. From television screen to bio-imaging technique, the quantum dot is everywhere and provides us a better method in drug delivery, cancer cell diagnostics, and therapeutics. However, these kinds of applications require precise, uniform, and numerous quantum dots which is not an available target for us to achieve in one year. Thus, we found out another application of our project and also played an indispensable role in scientific, engineering, and environmental areas.


Initial stage:

Since our project is still in the embryonic stage of development, the quality of our quantum dots is not stable enough to be applied to bioimage. And our alternative way to utilize our product is by using quantum dots to detect mercury in the water[1]. Mercury detection of quantum dots is an effective method to determine the contamination of mercury in solution and does not need to overcome a high threshold of quality to implement the precise detection considering the detection is mainly based on the nuance of fluorescence intensity. The principle of this phenomenon is the mercury ion in solution will deconstruct the surface of quantum dots and results in a rough surface and poor fluorescence intensity.

Figure 1. (a) The fluorescence spectra of N, S-GQDs excited with various wavelengths ranging from 310 to 430 nm, (b) UV–vis spectra of N,S-GQDs and (c) photographs of N, S-GQDs under daylight (left) and UV light irradiation at 340 nm (right)[1].

Our initial trial will be conducted in our laboratory with the concentration of both cadmium and cysteine under control. The product is going to be used in a certain concentration of mercury and the decay of fluorescence intensity will be monitored and record as our database. With serial testing and modification, our goal is to establish a calibration line of our product and make sure the good reproducibility is accessible. After the accuracy of results matches our ideal, we will get start on the easy manipulation process in order to promote this technique and allow it to be available for everyone. This will lead to our medium-term goal.


Our medium-term goal is to apply our project in a real sewage treatment system. We not only deal with wastewater but also turn it into valuable products. The reason to add our project into the existing system is to reduce the carbon emission of setting our system and simplify the process of implementation. To complete such a tremendous objective, we have to combine each teammates’ major knowledge together. One of the factors is to scale-up our system and this requires the knowledge of chemical engineering in process design. Materials and membranes are in the area of material science and we have got all these members in our team which makes our ideal more feasible.


The long-term purpose of our project is to treat it as an education tool to propagate the issue of contamination in water and hope to attract people’s attention by introducing the easy and precise detection method. Not every water contamination is visible and we would like to emphasize protecting our environment by making the process of monitor easier and reachable for everyone even the students. Education is the best way to shape our society which is why we want to focus our promotion on the education part. People who are raised by exposing to environment conservation are more likely to care about our living planet and there is no better way to achieve our ultimate objective of raising people’s awareness of environment.

Figure 2.Education promotion of our project.

End User

In the end, our end user would be the companies and wastewater treatment factories. The former will introduce our system since the environmental awareness of the whole society is raised, they have to maintain people’s impression of their enterprises. The latter will introduce our system due to the additional income from the valuable.


Among all of our goals, there is the most important thing we need to mention. Safety is always the core of our project and we also conjure up a safety mechanism when we are going to implement our project in the real world. We are going to use the existing part in iGEM, KillerRed (Part: BBa_K1184000),to set our safety killing mechanism.

Figure 3.Crystal Structure of KillerRed (PDB ID: 3GB3) with the QYG chromophore shown

Once our bacteria get leaked into the environment, the external light will induce the killing mechanism and let our engineered bacteria commit suicide. This showcases that we did not just put effort into better results but also take care of environmental safety. Further detail will be demonstrated in our safety part.


  1. Anh, N.T.N., et al., Highly sensitive and selective detection of mercury ions using N, S-codoped graphene quantum dots and its paper strip based sensing application in wastewater.2017. 252: p. 1169-1178.