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【Editor's Note】
In half a month, the 2022 Beijing Winter Olympics will be held soon. The Winter Olympics is not only an arena for athletes, but also a showcase for China's scientific and technological innovation. Since the success of the bid for the Winter Olympics, a series of innovative achievements have gushed out around the "Winter Olympics of Science and Technology". Science and technology empower the Winter Olympics, not only decorating this ice and snow event more excitingly, but also laying a solid foundation for the future sharing of the results of the Winter Olympics.
Nanfang Daily and Nanfang + launched a series of reports on "Winter Olympic Black Technology" from today to introduce the achievements of scientific and technological innovation inside and outside the arena.
Aerosols are colloidal systems consisting of droplets or solid phase particles suspended in the air that can be inhaled directly into the lungs. In the spread of outbreaks caused by the importation of cases from abroad, transmission through the environment such as aerosols and surfaces is a very important route of transmission. Research has also proven that the outbreak of the 2021 Guangzhou Liwan epidemic is mainly transmitted through aerosols.
On the basis of China's effective control of the local epidemic situation, it is very important to effectively prevent and control the imported epidemic from abroad. Monitoring the aerosol coronavirus is an important part of preventing and controlling the environmental spread of the epidemic.
Since October 2020, researchers from Tsinghua University and other units have carried out emergency research and developed a public space bioaerosol new coronavirus monitoring system in 8 months, successfully solving the problem of aerosol detection. The system is capable of collecting and detecting bioaerosols present in the air with up to 10 times the sensitivity of conventional methods.
During the Beijing Winter Olympics test match, the system has been sampling and testing aerosols at competition venues such as the Capital Gymnasium and the National Speed Skating Hall. Through the application and verification of the test match, the system has been optimized accordingly, which is more in line with the requirements of the Winter Olympic games. In the upcoming Winter Olympics, the system will provide comprehensive aerosol COVID-19 testing guarantees.
8 months of emergency research
In order to solve the problem of aerosol detection, in October 2020, under the deployment of the Beijing Municipal Party Committee and the Beijing Municipal Government and the direct leadership of the Beijing Municipal Science and Technology Commission, Liu Peng, a researcher at the Department of Biomedical Engineering of Tsinghua University School of Medicine, joined hands with Changping Laboratory, Peking University and other units to carry out emergency research, and completed the public space bioaerosol new coronavirus nucleic acid monitoring system in 8 months.
Liu Peng introduced that the bioaerosol new coronavirus monitoring system for public space is divided into two parts: the portable bioaerosol sampler as a front-end collection device will work in the place where testing is required to carry out air sample sampling; the automated fully integrated high-sensitivity virus nucleic acid detection system is set up in the laboratory to analyze the collected samples and generate test reports. The system enables true "sample-in-result" highly sensitive detection.
The front-end "aerosol collector" was developed by the team of Professor Yao Maosheng of Peking University, and then improved and upgraded many times to make it more portable and easy to use. In the middle of the aerosol sampler is a specially designed cavity in which the inhaled air forms a whirlwind. After the instrument is started, the amount of air collected per minute can reach 400-500 liters, and the aerosol particles within 12 cubic meters can be collected in 30 minutes and enriched into the virus inactivation solution.
It is understood that the virus enrichment efficiency of this collector is the highest in domestic similar products.
At the testing end, Liu Peng and his team have completed the emergency development of "integrated high-sensitivity new coronavirus nucleic acid detector" after more than half a year of research. The system uses a microfluidic platform combined with new nucleic acid extraction and amplification technology, and the core is a tape-sized nucleic acid capture and in situ amplification detection chip.
The chip adopts a fully enclosed design, and after the sample is collected, the nucleic acid capture and in situ amplification filter membrane can capture more than 80% of the viral nucleic acid from 1 ml of sample. Subsequently, the experimenter only needs to neatly insert the chip into the molecular diagnosis and control integrated machine, and the instrument can automatically amplify and analyze the nucleic acid, directly generating the detection results, without manual participation in the whole process.
The sensitivity and detection speed are greatly improved, which can cope with various mutant strains
"It's much more difficult to test air than traditional methods like throat swabs." Liu Peng said that because the virus content in the air is much lower than the content in the human body, and the new crown virus is an RNA virus, the stability is poor, and the air is always flowing, if it is delayed for too long, it will lose the significance of detection, which requires that sample collection must be efficient and the detection must be sensitive."
Liu Peng introduced that the aerosol nucleic acid detection system can achieve a sensitivity of 20 copies per milliliter, while conventional methods require 200 copies to 500 copies per milliliter to detect, "It can be said that the detection sensitivity is an order of magnitude higher than the existing technology."
Li Shanglin, a member of the R & D team and a postdoctoral fellow at the School of Medicine of Tsinghua University, also introduced that the same type of automation machine in foreign countries has a sensitivity of 60-80 copies per milliliter, "We have 20 (copies) in 1 ml that can be detected." From the point of view of the all-in-one machine, our sensitivity is very high. ”
"In addition, our testing time is very short." Li Shanglin added, "Pure automation abroad takes about an hour, and we only need 30-40 minutes." ”
In addition, Li Shanglin also mentioned that the detection system can detect 8 samples at a time, while ordinary fully integrated instruments can only detect one sample at a time. This can further improve efficiency.
Conservative calculations, each collector in the field to collect 30 minutes, and then after 45 minutes of automated integrated detection, you can draw a test conclusion. From the beginning of sampling to the feedback of the final results to the epidemic prevention department, the whole process will not exceed 4 hours.
Liu Peng introduced that this system can deal with mutant strains including Omicron.
"We need to design primers to amplify a certain segment of the virus to determine whether the virus is present. The primers we designed used a conservative sequence of the virus, that is, this sequence of viruses does not mutate, which ensures that our method can detect a variety of different strains. Liu Peng said.
But Liu Peng also added that this method can only determine whether there is a new crown virus, and to know which strain it is, other methods are needed.
Beijing Ditan Hospital Combat Test: The virus can be detected by the patient exhaling
"From April to August last year, we have been making real samples at Ditan Hospital to test the effectiveness of our system." Liu Peng said.
Ditan Hospital is the designated hospital for medical treatment of new crown pneumonia in Beijing and the main battlefield to face the new crown virus. At Ditan Hospital, the team collected nasopharyngeal swabs, saliva, exhaled gas, and aerosol samples from the ward, and divided the samples into two for simultaneous aerosol testing and routine testing. The results showed that the coincidence of the two detection methods was very high, and the detection rate of the aerosol system was 3 times that of the existing PCR system.
"Some patients are undetectable with conventional methods, but our methods can be detected. Using our method, the patient's exhaled ha qi condenses into a solution, and the new crown virus can also be detected inside, so the sensitivity is very high. Clinically small-scale tests demonstrate the effectiveness of our approach. Liu Peng said.
Completed the test in the Winter Olympic Test Match and will appear at the Winter Olympic Games
Before it was officially put into use, the aerosol nucleic acid detection system was verified by experts to confirm that the virus collected through the aerosol would be rapidly inactivated in the collection tube to ensure the safety of the subsequent detection process.
From October to December 2021, the system has carried out aerosol sampling and testing in 5 Olympic venues, including the Capital Gymnasium, the National Speed Skating Hall, the Ice Cube, the Wukesong Ice Center, the National Stadium, the Main Media Center, the Xiyuan Hotel, and the Ziyu Hotel. A total of 348 specimens were collected and tested during the test match, and the success rate of detection was 100%. The detection system has been widely used and verified in the Winter Olympic Test Match, and has been optimized accordingly for the epidemic prevention conditions during the Game, which meets the requirements of the Winter Olympic Games.
It is reported that this project has been identified as one of the projects implemented by all venues of the "Science and Technology Winter Olympics", and the Winter Olympic Organizing Committee has issued the "Monitoring and Response Plan for The New Coronavirus of Bioaerosols during the Beijing 2022 Winter Olympic and Paralympic Games" to officially promote aerosol detection during the Winter Olympics. According to the plan, the project team will arrange aerosol collectors in multiple venues of the Winter Olympic Games, and set up temporary testing stations in Changping Laboratory and main media center to provide comprehensive aerosol new coronavirus testing guarantee for the Winter Olympics.
Liu Peng also stressed that aerosol detection is only a part of the entire epidemic prevention system, "which can only be said to play an early warning and supplementary role." For example, he said, even if infected with the new crown virus, if the mask is worn correctly, then the virus is difficult to transmit.
Liu Peng said that the epidemic prevention system includes a series of monitoring methods such as daily prevention and control, sampling and testing, and environmental disinfection, and air environmental testing is part of the overall epidemic prevention system. If there is an abnormality in the test, the laboratory will communicate with the epidemic prevention department in time and take a series of follow-up measures.
Liu Peng said that the Winter Olympics is a very good demonstration application scenario. In the future, the monitoring of the new crown virus will inevitably be a long-term process, and he hopes that this system can land in crowded places such as hospitals, stations, and airports in the future to find clues to the epidemic in a timely manner.
【Planner】Huang Can, Chen Zhi
【Coordinator】 Hu Nianfei Liu Jiangtao
[Reporter] Wang Shikun, Liu Changxin, intern Xi Congcong
【Video Shooting】Liu Changxin
【Editing】Intern Chen Yan Longyu
【Author】 Wang Shikun; Liu Changxin
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Source: South+ - Create more value