Team:NTU-Singapore/Implementation

Introduction

SARS-CoV-2 is a contagious virus that spreads easily. The virus was first discovered on 31st December 2019 and it caused a worldwide pandemic. To control the spread of the virus, rapid detection plays a vital role in allowing doctors to diagnose patients accordingly. In Singapore, we currently have 2 methods of diagnosis for SARS-CoV-2, the RT-qPCR test and the Antigen Rapid Test (ART). RT-qPCR is the gold standard for SARS-CoV-2 diagnosis as it is able to accurately detect the presence of the virus, however the process takes a few hours to complete. On the other hand, the ART is able to produce results in a few minutes. However, this method has its downside which is its poor accuracy. Our team has identified that the diagnostic methods available may not be the most optimal in managing the pandemic and has decided to build a diagnostic device that is able to produce accurate results in less than an hour.

After achieving a few promising results to identify one variant for SARS-CoV-2, we decided to take a step further by brainstorming ideas to integrate this in the real world.

End Users

SARS-CoV-2 has impacted the working environment as people are no longer allowed to gather in large groups. This has made the working environment difficult as people are split into different teams and have to work remotely. This might affect the productivity of the team.

Office workers can benefit greatly from our device as it provides a fast and accurate diagnosis. Civil servants such as military personnel can also benefit greatly as operations have to continue despite the pandemic. Students will also find it useful as they have to attend classes and intermingle with different groups of students. The elderly who have difficulty understanding how to carry out the test will be able to do it by themselves as the device is user friendly and requires minimal steps.

With this device, our end-users will be able to continue their daily activities without the fear of contracting the virus if everyone around them tested negative. The test can be conducted daily and multiple tests can be done with the same device as the long chemical reagents are available.

Safety

One of the safety concerns that we had was making it portable. Portable devices require batteries, and it may cause leakage if the circuit in the device is not properly designed. Other problems may also occur such as overheating of the device and causing it to catch fire, injuring the user. To eradicate these issues, some of the members, working with the device attended some workshops and went through courses that are available in NTU. This ensures that the members are aware of the risks and dangers of using batteries and design circuits.

Besides that, we realised that the type of material is important to prevent any melting when the heater is at 65°C. For the prototyping stage, we will be using polylactic acid (PLA) as the filament for 3D printing. 3D printing is used to develop multiple pieces of the device rapidly. Besides that, it has a melting temperature of between 170°C and 180°C which will not melt at 65°C. However, for the actual device, we are planning to use Polytetrafluoroethylene (Teflon) to house all the components. In addition, to prevent inefficient heating, material with a high heat capacity will be considered.

Challenges

Some challenges that we thought about was the storage of the reaction mix for individuals to do a test using the device. The reaction mix has to be stored below 4°C when not in use. Instead of issuing the reaction mix with the device, we proposed that these reaction mix can be sold separately, and it can be stored in the refrigerator at pharmacies or nearby vending machines.

Besides that, maintaining the block temperature at 65°C is a challenge as there are many factors that have to be considered when designing the closed loop system. Some considerations are the electronic components such as the resistors, sensors and heating element. Some calculations have to be done to ensure that the voltage and current are within the appropriate range and to prevent any safety issues.

Survey

To further ensure that we are tackling the needs of our target end user, we have sent out a short survey to gather feedback on what features people would like to see in our diagnostic device. Based on the responses, a large number of respondents feel that it is important for our device to be able to test multiple samples per device.

Figure 1: Survey results

We will design our device where it can be reusable as long as the chemical reagents are available. This allows the end users to test multiple samples with the same device.