Team:Shanghai United/Implementation
Implementation
Background information
Arsenic is a microelement that is omnipresent in the environment. However, it is this common microelement that could be harmful to human body. If we take in more than 50 µg/L of arsenic, the function of our body will be disrupted. Also, the level of arsenic throughout the world is gradually increasing every year, and has already exceeded the level that human body can metabolize.
Areas close to factories whose product involves arsenic usually have a high arsenic concentration. Thus, we need arsenic detectors to ensure the security of people who work in these factories. According to the questionnaires and street research we did, although the general public did not know much about arsenic, most people believed that having an inexpensive and accurate sensor to detect arsenic is necessary. In addition, environmental and market scientists also considered that the current testing methods in the market are too cumbersome, so equipment that can detect arsenic levels easily and efficiently is required.
Purpose
The purpose of our product is to reduce individuals’ exposure to arsenic and prevent the harmful impact it might bring through accurately detecting the arsenic in people’s surroundings.
Customers
Our main target customer are companies, factories, and government departments that being involved with arsenic detection. The main reason is that this detecting equipment can detect arsenic in a more efficient, convenient, and most importantly, more economical way. It is true to say that, the only conceivable drawback might be the accuracy of the result. However, the result is comparatively accurate enough to support our target clients to make basic decisions. Besides, we also take into account that some families with high pursuit of life quality, who worry about arsenic’s harmfulness and might become our potential customers, because these groups are usually educated to know the necessity of protecting their health, while purchasing specialized equipment is also affordable for them.
Product design
Design
Figure 1. Design Drawing of the product - Arsenic Biosensor
Basic information
Inner tube diameter: 7.5 mm
Outer tube diameter: 15 mm
Inner tube length: 27 mm
Outer tube length: 30 mm
Radius difference: 2.5 mm
Arsenic testing solution: 6 µL
Maximum sample volume: 6 µL
NaClO bleach: 2 mL
-Liquid seal cap
-Outer container uses soft, transparent plastics, 1mm
-Inner container uses glass/acrylic, 1mm
Reaction mechanism
E. coli will naturally react when arsenic is present in the environment. Using this mechanism, genetically engineered E. coli have been used in the testing solution. When exposed to arsenic, these genetically engineered E. colu will synthesize a green fluorescent protein that will emit green fluorescence when exposed to blue light. Thus, the presence of arsenic may be detected by inspecting the presence of green fluorescence in the testing tube.
User manual
- Open the lid of the tube.
- If the sample is a solid, grind the sample into smaller piece that fit the input hole of the test tube.
- Insert the sample into the test tube though the input hole.
- Mix the sample and the testing liquid thoroughly. Wait for the test tube to react with the sample.
- Apply blue flashlight to the tube and inspect for any sign of green fluorescence.
- If green fluorescence is present, then arsenic is detected in the sample. Compare the strength of the fluorescence to the reference card to determine the concentration of arsenic in the sample.
- Apply force to break the inner wall of the tube to release bleach to neutralize the test solution. Note: test solution must be neutralized before disposal of the tube.
Storage conditions
Store the test tubes in dark, refrigerated conditions. Ideal storage temperature should be below 0 ˚C.
Product Principal Analysis
Arsenic in the environment can pass through the cell membrane of E. coli (Escherichia coli) and enter the interior of E. coli. When arsenic enters the interior of E. coli, it binds to ArsA, ArsD and ArsR proteins. In an arsenic-free environment, Ars proteins that are not bound to arsenic repress genes downstream of the ARS gene. When bound to arsenic, the Ars protein then no longer represses genes downstream of ARS, and subsequently activates the expression of genes downstream of the ARSA gene, ARSD gene and ARSR gene. In the genetically modified E. coli used for the assay, the green fluorescent protein is implanted downstream of the ARS gene. Thus, green fluorescent protein, which emits green fluorescence, is synthesized when arsenic is present in the environment in which E. coli is exposed. The presence of arsenic and its concentration can be measured by detecting the green fluorescent protein, i.e., its intensity.
Figure 2. Fluorescence Intensity curve of the strain changes by the concentration of the arsenic salt
According to our test results, our strain could respond to a certain range of concentration of cacodylic acid sodium salt trihydrate (C2H12AsNaO5) by glowing itself. In the future, more function tests regarding other arsenic would be conducted to further analyze the performance of our biosensors.
Challenges for the future of the product
STRENGTH
- Convenient to use
- Steady production
- Short detection time
- Portable to transport
CHALLENGES
- The strain can only be used once
- The different colors for different detection results can hardly be differentiated from each other
- Can’t be used by people who are color blind and can’t see colors clearly
- Very high concentrations of arsenic cannot be detected
- The machine can only detect the concentration level of arsenic
Promotion
- Package
We will use glow stick’s design as our product’s packaging idea. The package is similar to ampoule bottle and at the same time, we will add cartoon rubber protective containment to attract customers.
- Arsenic popularization
When popularizing, we will use different platforms like WeChat, BiliBili and Weibo to send posters and tweets about arsenic, and also, we will communicate with some educational institutes and schools. We will give their students lectures about arsenic regularly. We also sign agreementss with companies which produces environment monitors. They will add our advertisements to their products’ packages. Besides, we will design some peripheral products which can help us attract the publics. In that way, they will gain more knowledge about arsenic pollution.
- Events
In the social research, most of the people are concerned about the price of the instruments. For our instruments and equipment, it is a disposable product, so we make a breakthrough on the sales strategy and come up with a new way to attract customers to buy more products by reducing the cost that they will spend on the product under the condition of covering our cost. For example, for factories and environmental monitoring departments we decide to adopt a 20% discount if you buy more than 500 products at one time, and for home users we introduce a free set of products when you buy three sets to increase the purchase desire of the customer base.
- Combination
We will offer different packages, different product combinations so that customers can have a variety of different choices. Customers can purchase the products based on their own needs and the sets with the function of multielement detectors will be available for selling. For example, if a customer wants to test for formaldehyde and arsenic, we could offer a package with arsenic biosensor as a bundle.
- Streaming
We can make use of the current popular publicity method to promote our sales, that is, using online publicity for sales. We can cooperate with professional experts and weblebrities in this field, and let them inform the harmful effects of arsenic to our customers when selling products, so as to achieve the effect of multi-selling.
- Collaboration
We will cooperate with environmental protection organizations. All interests will be donated to them in order to help developing techniques that can help decreasing arsenic pollution in the environment.
