DEFINE CURRENT ISSUES
Identify the recent problem - Visit Yakult Production Factory
To acquire more information about food testing in the food industry, we visited Guangzhou Yakult Dairy Co., LTD. Together with SZPT-CHINA. Yakult is also a company that uses active lactic acid bacteria to manufacture milk drinks. After visiting the exhibition of fermentation with SZPT-CHINA, Yakult staff introduced the necessary food testing in the production process. When the Yakult is produced and sent for food security testing, various procedures are needed to ensure the quality of the product. Although we are all pursuing the freshness of food and drinks, the latest Yakult drinks on the market are two days old due to the long-time period of food testing.
Therefore, there is great demand for rapid testing in the food industry. Since our project aims to detect the nitrite concentration inside food, it is essential to ensure that time for testing should be finished in a short period. In addition, fast-testing speed should be one of the considerable characteristics of our device.
Explore the social needs - Visit School Testing Hygiene Lab
For the purpose of understanding the social needs for nitrite detection devices, we visited the School Testing Hygiene Lab in CUHKSZ, which was attached to Sino Assessment Group (SAG). During the discussion, we asked for the evaluation of the current nitrite testing method from their point of view, to investigate their expectations for new monitoring approach. They illustrated that the process of applying test paper for detecting whether nitrite is excess in nitrite in Hygiene Lab. Usually, this approach needs additional reagents, and later after reaction, the result should be measured by the naked eye to compare with the standard color set. They have raised the concern that naked eyes could cause uncertainty during the measurement. It is expected that our Nitrisensor would eliminate such probable mistakes involved.
BUILD ON OUR SOLUTION
Understand the current solution’s drawbacks - Interview with Prof. Jia Zhijian
We approached Professor Jia Zhijian, a current Chemistry professor at the Ningbo University of Technology, to know the pros and cons of the current method of detecting nitrite in the laboratory. At first, he explained that chronography, which was the primary way of testing nitrite in the laboratory, has high accuracy and precision. However, the test sample did need some pre-treatments to do with, and the measurement required complex instruments, which indicated that such a method is complicated for people to use in daily life.
Then, we expressed our concern about food safety in the current and shared our idea of fast, convenient testing for nitrite. He pointed out that food safety should be attached importance to human beings.More importantly, faster speed is one of the most significant factors that the food testing industry should chase. Therefore, a simple, convenient method of testing nitrite become the core objective of our project.
Practical Method defined - Interview with Prof. Gan Ning
After ensuring that we would use engineered E. coli to express the nitrite reductase and use an electrochemical approach to measure the concentration of nitrite before and after reaction with nitrite reductase, we approached Professor Gan Ning, who is working at Ningbo University and specializes in Analytical Chemistry. He helped us define Cyclic Voltammetry as a suitable method for detecting the chemical concentration in our hardware design as such an approach needed a simple instrument and was easy to handle. More importantly, Prof. Gan pointed out that the resulting graph of CV method is straightforward and can be analyzed in a simple way.
IDEATE OUR SOLUTION
Professional Support - Sensor design assisted by Prof. Liu Guozhen
From the previous iHP works, it is clear that applying an electrochemical method for detecting nitrite concentration has higher feasibility, and such a detection approach has higher commercial value. Then we approached Professor Liu Guozhen, who is specialized in biosensors at CUHKSZ. Prof. Liu has given us systematic guidance on the whole design of the point-of-care nitrite detection sensor, especially the detection principle part. More importantly, the idea of using printed electrodes to perform point-of-care detection raised by Prof. Liu has significantly improved our hardware design. She also helped us to verify that our biosensor is viable theoretically. With respect to the enzymatic reaction, she suggested that the current response of the electrochemical reaction could be in a linear relationship with the nitrite concentration in the environment. Furthermore, she raised a few possible challenges in our design, including improving the sensitivity and selectivity of our biosensor.
She and her ID2 (integrated diagnostic lab) ² team also provided us with the equipment, materials, and technical support. More specifically, Doctor Long Yi gave us systematic training on lab safety. Graduate student Huang Ziyang offered us technical guidance in the practical operation of electrochemical detection, including using the electrochemical station to perform the cyclic voltammetry method.
Longer Storage for Bacteria - Freeze-dried Powder Instruction
After we first learned about the idea of dried-freeze powder from SZPT-CHINA, we contacted Doctor ChenJie, whose degree was in Pharmaceutical Science. She explained why the dried-freeze powder could be stored for longer than other methods and instructed our team to operate the dried-freeze powder machine.As SZU-China has similar requirements for knowing more about the freeze-dried powder, we also filmed a video introducing how to use the manufacturing machine for SZU-China and even subsequent users who aimed to study it.
EVALUATION
MED Research Day
Our team also participated in the MED Research Day, a research forum for young scientists held by the School of Medicine, The Chinese University of Hong Kong, Shenzhen. This forum required an academic poster containing a series of elements of a published paper, which directed us to complement and present our project more systematically. We further delivered an oral presentation to a group of experienced professors and graduate students, to whom we exchanged the latest research outcomes and received a significant amount of guidance and help.
Specifically, a professor pointed out the latent interference of detection brought by the complicated internal environment of cells, promoting us to improve our sensor's selectivity for nitrite. Another senior appreciated the innovation of directly immobilizing bacterial cells but showed concerns about maintaining cell viability. Our team was then inspired to combine hydrogel and the freezing-drying method to achieve long-term storage. Moreover, we shared the spirit of iGEM and its impact on undergraduate researchers with the audience, winning us second place in the best presentation and the best poster prizes. It is also worth noting that the keynote speaker of this event shared his latest research progress in the field of quantitative synthetic biology. He also shared his thoughts on the future of synthetic biology, from the white box paradigm to the black box paradigm led by artificial intelligence.
By attending such a seminar, our team got in touch with the advanced knowledge and researchers in synthetic biology and developed a more profound understanding of our project.
Questionnaire from the Public
To understand how the public comprehends our project Nitrisensor and the current hot field of synthetic biology, our team designed a short questionnaire. The education level of the respondents was high school or above.
In the Nitrisensor part, the questionnaire first introduced our project, which aims to design a test strip based on E. coli that can quickly detect the nitrite content of the tested substance. The first question in this part investigated the public attitude towards nitrite poisoning events in recent years.
Over 75 percent of respondents were worried about the problem of undetected excessive nitrite in daily food. While about 23 percent of respondents considered that people poisoning from nitrite overdose was a rare event, and they did not need to pay too much attention.
Then we investigated the attitude of the public towards our project Nitrisensor. About 80 percent of respondents were willing to utilize our device to detect the nitrite level in daily food. They considered that applying this product could ensure the security of food and life to some extent. About 20 percent of respondents conceded that our project has an optimistic starting point. At the same time, they doubted the safety and accuracy of the technology. Only one respondent regarded this project as superfluous.
For the acceptance of more sensors which include but are not limited to food and agriculture for different components in the future, about 95 percent of respondents were willing to accept. In contrast, three respondents held an unsure attitude. In conclusion, the majority of the respondents were willing to apply our test strip to practical detection. In addition, almost all the respondents held an optimistic attitude toward the sensor technology, which can be applied to quality inspection.
Considering the attitude toward the application of synthetic biology at the environmental and ecological level, about 80 percent of respondents considered that synthetic biology was worth being carried forward. The discipline illustrated that synthetic biology is connected with the optimal solution's moral rules and natural law. Five respondents considered that synthetic biology was still a theory. The discipline was valid in an experiment but did not guarantee its validity in reality. Another five respondents held a relatively pessimistic viewpoint. They suggested that there is a risk of biological leakage. Thus, it is necessary to strengthen corresponding biosafety supervision. The rest respondents did not have certain degrees of understanding of this aspect.
It is worth mentioning that 97 percent of respondents are willing to understand synthetic biology further.