Traditional methods of landmine detection, such as metal, acoustic and radar detections, are the most popular ways that are currently being used. These methods have many limitations: they are generally based on subjective judgment of the deminers, and, in most cases, deminers need to get into minefields with a high risk of their lives. Importantly, they cannot be used to detect the landmines made of new materials, such as ceramics and plastics. Other nonmetallic landmine detection technologies, such as pulse radar, infrared imaging, and neutron landmine detection approaches, are expensive and sensitive to false targets and electromagnetic field interference. Additional landmine detection methods using animals' senses of odors can also bring great uncertainty due to the uncontrollable nature of the animals.
In order to effectively avoid the impact of individuals’ subjective differences and improve the objective accuracy in landmine detection, we use synthetic biology to design an engineered bacterial strain as a biosensor, relying on a relatively simple device to detect landmine locations. In our system, the engineered bacteria are first used to sense the chemicals released by landmines, trigger EGFP expression in the engineered bacteria and then emit green fluorescence, which then activates a photoresistor, and its electrical signal is transmitted to a smartphone and processed by an app. The software can calculate the probability, determine landmine locations and intelligently propose the best routes to clear the landmines.
Firstly, to understand the current detection methods, the living conditions of people in landmine villages, the commonly used landmine detection tools, and the current status of landmine clearance, we interviewed officers and soldiers who had participated in frontline demining.
Secondly, we designed a questionnaire to publicize our project on the Internet to get suggestions for improvement, and to publicize synthetic biology knowledge to the public. In addition, we also introduced our project to high school students and provided them with basic knowledge of synthetic biology.
Finally, we used the network and self-media platforms to push the principles of our project and other synthetic biology knowledge, such as landmine detection technology and methods, landmine hazards, and related molecular biology experimental methods, as well as the stakeholder survey results.
1.Interviewing Landmine Clearance Officers and
In order to better understand the current living conditions of the people in the villages with landmines, the current status of mine clearance, and the actual process and methods of landmine detection, we interviewed a veteran of a former unit online at 2:00 p.m. on August 2, 2020. Through the communication and consultation with the expert, we have gained a lot of professional knowledge and valuable suggestions for the improvements on our project.
First of all, the officer explained some common used methods of landmine detection. Generally, with the rapidly changed battlefield conditions during combats, detection methods, such as rocket coverage and blasting tubes, are beginning to be used in combats, but their major disadvantage is the high cost.Manual detection methods, such as mine probes and metal detectors, were often used in the past. However, due to the need of personnel to get into the minefield for detection, the casualty rate is generally high.
Then, we described our project to the officer. He believed that our device should not have terrain restrictions, and neither required personnel to enter the minefield prior to detection. Thus, our device is relatively safe and suitable for daily demining tasks in complex terrains. If the detection sensitivity can be improved and the types of detectable chemicals can be expanded, the device may possibly be commonly used to equip individual soldiers. The officer also indicated that there was no perfect method in landmine detection to date. Thus, so as long as a method is effective, it is of great value and significance. At the same time, the officer also suggested that we should use shortwave or ultra-shortwave signals to improve the anti-interference capability of the device. In addition to mine detection, our system may also be extended to the investigation of explosives, especially those in urban and complex terrains. It will be helpful if it is feasible to place the device in unexpected places, such as walls, trees and rocks. Currently, the detection of such explosives is also a big problem to be conquered.
2. Suggestion Collection and Improvement
Conference of the China iGEMer Community
From August 28th to August 31st, the 7th CCiC (Conference of China iGEMer Community) was held online for four days with the participation of 60 teams. In the presentation section, we made a detailed introduction of our project ideas, experimental innovation, project impact and subsequent considerations. In the evening discussion, we got much profound ideas from the questions of the students and teachers in the meeting. For example, as for the model building of the DNT test, we had an energetic discussion with other teams on how to generate a model of detectable chemical concentrations due to different landmine burial time that may cause variable amounts of chemical volatilization.
In the poster section, we presented our poster. Many teams showed interests in our project but did not have a chance to discuss with us in the morning. Fortunately, we eventually communicated in the online virtual room in the evening. At the same time, we also got many professional suggestions. One of the teachers raised questions about our modeling construction building and gave us substantive advice. For example, we directly associated the fluorescence intensity with DNT concentrations in our modeling, but DNT can also be metabolized into THT through enzymatic routes.