Implementation
Overview
Studies show that not only is heavy metal pollution a severe issue, it is also prevalent around the world, especially in water sources. Furthermore, water contamination may accumulate in soils and sediments. In China, around 16.1% of arable land is potentially contaminated by heavy metals. According to statistics, heavy metal contamination has led to an annual reduction of more than 10 million tons of grain production in China, and more than 1200 tons of grain are contaminated by heavy metals each year, resulting in a cumulative economic loss of 20 billion yuan.
However, the detection instruments and equipment are usually expensive and difficult to operate. Therefore, most of the population it still difficult to detect heavy metals by themselves. To provide a more convenient and cheaper approach to address this problem, our team designs a whole-cell biosensor kit that can test heavy metal content conveniently and readily.
Target Users
Our product aims to provide sustainable biosensors for consumers who are potentially exposed to heavy metal pollutants, Per our investigation, huge amounts of heavy metal pollutants are released into the environment, contaminating the earth which means our testing equipment is available for all aspects of society for very wide target groups, mainly including those people living around factories or people relying on underground water that may be contaminated. For some individual fishermen's fast water testing and living environment may contain heavy metals, most of the general public is not willing to spend a lot of money to test the water source or food for heavy metals, not to mention some of them might be not aware of or not pay attention to heavy metal pollution.
Since the current heavy metal testing process in the market is complicated and expensive, our product is a portable detection kit with quite a lower price that can quickly and easily detect the presence of heavy metals. Thus, our product will be more attractive to those individual aquaculture farmers and the general public who have a requirement for drinking water. By utilizing our heavy metal detection kit, our customers could easily and rapidly detect the presence of heavy metal pollution in food or water to avoid further harm to health.
Product
Engineering Principle
Our project's aim is to create a biosensor in order to detect the heavy metal cadmium, zinc, and arsenic. For cadmium and zinc, we utilize the operon CadA to express reporter feruloyl esterase in Bacillus subtilis. Specifically, the CadA functions as an energy-dependent cadmium efflux ATPase and a metal-induced protein. The repressor CzrA inhibited CadA. However, Cd2+ competitively binds to CzrA, thus enabling the reporter feruloyl esterase to be expressed.
The principle of the pET28a-Biosensor Function
Product Concept
Operation procedure of our biosensor
As shown above, follow the below steps to use our biosensor:
- Take out the bottle of our biosensor E.coli and the supplementary;
- Collect the water sample and add it to the biosensor bottle;
- Add the supplementary (4-NPB);
- 4ix the solution and wait for around 2 hours: no change means negative, otherwise positive (blue for Cd presence; green for As presence);
- Heat or use chemical disinfectant to disinfect the solution;
- Dispose of the solution and throw the tube into the container
Compared to current heavy metal detection instruments, our product has below features and advantages:
- Direct detection
- Portability
- Biodegradability
- Easy operation
- Affordability
- General Accessibility (no specific license required)
Safety Concerns
Safety is the most regarded issue for H-Metal Silence throughout the entire project.
The whole process of our experiment adheres to the principle of safety, which not only meets the ethical requirements of scientific research, but also ensures the guarantee of the experimental personnel and the experimental environment during the entire experimental process. All the designs and operations strictly follow the lab procedures and official guidelines. While we ensure biological, chemical, and general lab safety, the heavy metal samples were disposed of correctly.
Finally, our final product will be the biosensor for heavy metal detection which includes our live engineered bacteria and its supplementary. To avoid any leak by improper operation, we will require every user to read our operation procedure before purchasing our product. However, we still have safety risks for current version of our product.
Challenges
Technically
Recombinant bacteria containing our vector hold the risk of spreading antibiotic resistance via horizontal gene transfer if the product is not disposed of correctly (if left undisinfected or improperly operated).
Due to the potential complexity of the sample, it may be necessary to perform a pre-treatment of the sample to ensure the accuracy of the test. This is one of the problems we need to solve to make our products more convenient for users.
So far we have not settled down on the method to quantify our detection results and further make them visualized which will make our detection results more rigorous and reliable.
Marketing
Nowadays actually there are many research groups and technology companies working on the related biosensor development, thus we need to speed up our product development so as to enter the market earlier and further quickly establish a brand and upstream and downstream supply chains.
In addition, although we are aware of the serious heavy metal pollution issue, there still exist a lot of people not aware of this according to our survey. A major challenge we are facing is how to improve everyone's awareness of the prevention and control of heavy metals and start to pay attention to the harm of heavy metals to the body and the environment. Only in this way can our products be recognized by the public.
Future Plan
To overcome those challenges listed above, we also addressed future plans accordingly as follows:
Technically
To avoid the leak of our engineered bacteria due to being undisinfected or improperly operated, firstly we will consult with more experts to establish a Cell-Free Expression System that requires no live bacteria so as to deal with the root risk.
To make the operation more user-friendly, we will modify the detection kit set, like adding another easy part for preprocessing samples.
Besides, we will conduct more performance tests and further figure out the relation between heavy metal concentration and other variables, like fluorescence intensity. This might help us to develop the method to quantify the detection results in the future.
Marketing
The purpose of raising awareness of heavy metals through publicity is to increase the demand and popularity of our products and expand the scale of the market. At a time when Chinese society is increasingly concerned about the health and environmental safety, we will first improve our awareness through the popularization of knowledge and publicity by spokespersons. In addition, we will spread the concept and attributes of our products to them through some promotional strategies, such as advertisements, so as to expand the market as much as possible.
Through our investigation, we found that most of the popular products in the market are heavy metal treatment facilities, and they are usually large machines. The price of these products is relatively high and the throughput is large. Compared with their products, our advantage is cheap and portable. We are expected to enter the market with our simple operation and low price as the testing market grows year by year. We could predict the rapid growth of our product in some specific areas where we could take initiative to capture the market.
Reference
[1]Ali, M. M. , Hossain, D., Al-Imran, A., Khan, M. S. , Begum, M., & Osman, M. H. (2021). Environmental Pollution with Heavy Metals: A Public Health Concern. In M. K. Nazal, & H. Zhao (Eds.), Heavy Metals - Their Environmental Impacts and Mitigation. IntechOpen.
[2]Chung, J. Y., Yu, S. D., & Hong, Y. S. (2014). Environmental source of arsenic exposure. Journal of preventive medicine and public health = Yebang Uihakhoe chi, 47(5), 253–257.
[3]Kubier, A., Wilkin, R. T., & Pichler, T. (2019). Cadmium in soils and groundwater: A review. Applied geochemistry: journal of the International Association of Geochemistry and Cosmochemistry, 108, 1– 16.
