Team:ZJUT China B/Implementation
Implementation
Traditional detection relies on a variety of expensive large equipment, which limits its application scope to the laboratory level. The collection, transportation, recovery and storage of samples are in the charge of special institutions, and the samples are be centralized analysed and treated by specific labs. The new innovative technology makes the diagnosis and detection gradually breaking away from the laboratory restrictions, and transferring to the patient care scene (known as point-of-care testing,POCT). This makes the detection safer and more efficient.
With advantages such as portability, high efficiency, visualization, and wide target spectrum, our device can be applied to a variety of scenarios, which is the perfect application of virus detector in POCT.
Application scenarios
Household detector
The portable virus detector has the advantages of small size, portability and high sensitivity. It is fast and easy to operate from sample processing to result display. A preliminary diagnosis of diseases caused by common RNA viruses can be achieved, and timely treatment and isolation also can be achieved in the early stage of the disease.
Pandemic
The outbreak of this epidemic has highlighted the dangers of the virus. Because many small and medium-sized medical institutions do not have the ability to detect viruses, the spread of the disease is out of control. The detector we designed is small, portable and highly sensitive, making it the best choice for small and medium-sized medical institutions. With the detector, more people can be diagnosed, isolated, and the epidemic can be effectively controlled.
Potential multi virus epidemic
With the evolution of viruses, their infectious ability has become stronger and more serious. In the near future, it is likely that multiple severe viruses will break out in one area at the same time. In that case, a multi-virus detection device is of importance. It can detect the positive status of multiple targets in a sample, detect patients infected with different viruses, which can improve the efficiency of disease prevention and control.
Applied design
Lyophilized chip
In order to preserve the protein, we lyophilize Cas13 proteins and add TDPs to reduce lyophilization effect on the activity of the proteins. The chip contains probes, crRNA and lyophilized proteins. They are stored in vacuum and dark. It does not require complicated operation before use which is simple and portable for most users. The chip is small in size, tough, easy to carry, and can be compatible with the device.
Device
Regarding the application in the real world, we designed a portable and multivirus detecting device. It uses swabs to sample, puts the sample on the sample processing microfluidic chip, and automatically controls it through our device. The microfluidic chip will amplify the nucleic acid signal of the sample through nucleic acid amplification. The processed liquid will be introduced into the detection chip through the microtube. At this time, we only need to insert the detection chip into the detection device, and we can judge the positive condition of the virus through the image returned by the device.
Our detector device will detect the concentration of different fluorescein within a few seconds and return a four-channel kinetic curve, which can analyze the presence of various viruses based on the maximum value of the fluorescein concentration. We can also revise the results based on the data obtained from the experiment to help us get more accurate results.
WeChat applet
We have designed a WeChat applet for ordinary users. In the design process, we follow the principles of strict protection of user privacy and user autonomy. We hope that the small program can read the data in the detection device and query the information at the same time, although we still cannot achieve data synchronization with the device due to the limitation of time. Users can learn basic information about the virus by directly retrieving the name of the virus or the corresponding symptoms. The basic information includes susceptible population, protection, treatment, vaccine status, etc which shows users a comprehensive viral information gallery so that the users could understand the virus better and take measures to protect themselves.
The virus database
In order to facilitate professional users to query virus crRNA for virus detection, we constructed a virus database to store virus crRNA information. The sequences of four Cas13 proteins : LwaCas13a, PsmCas13a, LbaCas13a and CcaCas13a , DR sequence and spacer sequences of several viruses are stored in the database. Users can select the corresponding Cas13 protein and input the virus name they want to query, and the database will automatically synthesize the corresponding crRNA.
Testing waste recovery
Our detecting device is divided into the reactor part and the detector part. Since the biochemical reagents are sealed in both parts, we plan to recover the reactor part after the use of the device and the disposable gloves and swabs used in the product in order to ensure that the product will not be littered or abused after use. These issues are related to the recycling of medical waste. Due to the low popularity of POCT, a comprehensive waste recovery mechanism has not yet been established.So we intended to take actions to promote the comprehensive establishment processing of waste recovery mechanism.
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