Experiment demonstration

We constructed several parts ( )in the project, including parts related to nicotine detection (BBa_K2827005, BBa_K2827006). We tested and compared the two versions of detection systems, making sure that it could be used as the nicotine detector ( ). We also built mathematic models for the two detection systems, and calculated the optimal concentration and time of detection ( ). Based on these findings, we designed two products for nicotine detecting.

Product demonstration

According to the results of the survey and interview, we designed two versions of products for nicotine detecting. Due to limited time, we only made physical model for the first version. The second version was improved upon the first version.

Version one: Stationary Nicotine Detector

The first generation product was a stationary nicotine-testing device (for more details: The instrument is divided into three parts: an air inlet pipe, a chamber, and an air outlet pipe(Figure1-Figure3). When it works, the chamber is filled with bacteria transformed with BBa_K2827005 or BBa_K2827006. We will install an electric fan under the air outlet pipe to extract gas from the chamber to form a low-pressure area in the chamber. Then the air from outside will be pumped into the chamber through the inlet pipe by the atmospheric pressure. The air inlet pipe is bent down and close to the bottom of the device, so that the air can fully contact with the liquid in the chamber,and the nicotine in the air can dissolve sufficiently. After about 4 hours, the GFP expression of the bacteria is induced by nicotine.We collect the bacteria and measure the fluorescence intensity, and calculated the nicotine concentration.

We used 3D printing technology to transform our product design into a physical model. The main body of the product model is a cuboid of 15cm in length, 7cm in width and 7cm in height (Figure1, Figure2, Figure3). The diameter of the inlet and outlet is 2 cm.

As soon as we got this physical model, we ran a simulation experiment. We found that this device had many disadvantages such as imprecise measurement, poor safety, and insensitivity, so we made a further improvement.

Second version: Portable nicotine detector

Compared with the first version, the second version of the detector has a smaller size (Figure4, Figure5) ( for more details : ) The size of the model is 7cm×5cm×5cm. The actual internal bottom area was about 16cm squared, so less amount of bacteria is needed to work(Figure6, Figure7). The equipment also adopts the pump type piston pumping way, which enable filters device to reduce the possible bacteria leakage properly. Because the piston is used to pump air, the gas is a fixed column of air volume when the piston pumps back and forth, bringing great convenience for us to exactly extract the volume we want.

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