대학신문방송국

How COVID-19 Vaccines Differ from Traditional Vaccines

By Kim Min-joong Reporter, Senior of Mechanical Engineering

Do you still think vaccines involve injecting weakened or dead pathogens into the body? The emergence of the sudden pandemic, COVID-19, has brought about a paradigm shift in the concept of vaccines. Unlike traditional vaccines, COVID-19 vaccines, which belong to a different category, were developed rapidly with worldwide attention within just one year of the outbreak. Therefore, public confidence in vaccines was initially low. Despite many people’s concerns, messenger RNA (mRNA)-based COVID-19 vaccines have been validated for their safety and scientific superiority, and have enabled many people to become protected against COVID-19 through this new type of vaccine. As a novel concept, mRNA-based COVID-19 vaccines cannot be explained solely by previously used vaccine methods because they do not involve the injection of pathogens into the body. Unlike previous methods, mRNA vaccines only contain genetic information required to create a portion of the pathogen. In the case of COVID-19 vaccines, mRNA that creates spike proteins is delivered into the body. Then Our body’s cells use this mRNA to create spike proteins, which can recognize and prevent infection of COVID-19 virus. Therefore, the reason why we have received repeated doses of the COVID-19 vaccine is to strengthen the immune response and provide ongoing protection, since initially generated antibodies via mRNA may not be enough.

The reason mRNA vaccines were able to be developed is due to the key technology of microchannels. Microchannels are, literally, micro-sized channels, and although they were not originally used in vaccine technology, they became the key point in the development of mRNA vaccines. After mRNA enters the cell, two problems must be solved to produce spike proteins that trigger an immune response to the disease. The first problem is the innate immune response. When mRNA enters our body, our body recognizes it as an invader and produces mRNA-degrading enzymes to protect itself. The second problem is the instability of RNA. mRNA cannot enter the cell because its molecular size is too large and it is disassembled outside the cell. Therefore, scientists applied Lipid Nano Particle (LNP) technology to mRNA to solve these problems. By wrapping the mRNA with LNP, innate immune response and RNA instability can be overcome, and mRNA can be safely transported to target tissues and cells. Microchannels play a crucial role in maximizing the possibility of wrapping mRNA with LNP to solve the aforementioned problems.

Microchannel is a key technology that achieves short mixing length, fast time, and high efficiency, a lot of research on microchannel development is going on. Professor Joachim Frank’s group, a world-renowned researcher, has utilized butterfly-shaped channels to conduct research. This microchannel shows high mixing efficiency at a short mixing length, where one fluid flow separates and repeatedly rejoins. This method is one of the techniques mainly used to improve the mixing efficiency of passive microchannels. Additionally, this microchannel shows close to 100 percent efficiency when the fluid reaches a short length of about 400 µm at a specific flow rate.

The reason for the high efficiency of microchannels can be confirmed through the analysis based on fluid mechanics. Due to the structural characteristics of the butterfly channel, the vortex is formed in a specific plane of the channel as shown in the figure and repeated in all elements. The vortex generated solely by these structural characteristics it has a significant effect on mixing even without external forces such as pressure, electricity, magnetism, and sound waves.

In the past, microchannels were primarily used in the fields of chemistry, aerospace, and heat transfer, but now they have helped save humanity from COVID-19. mRNA vaccines, with their rapid and flexible inherent properties, are not limited to COVID-19 vaccines. Once the genetic information of the pathogen is known, mRNA can be quickly designed and produced to provide solutions for cancer and infectious diseases. Although microchannels were used in the production of vaccines, their high mixing efficiency and fast mixing characteristics, which are inherent in microchannel technology, will be applied to many fields in the future. Ultimately, just as we used existing technology to develop mRNA vaccines, we do nott always need to look far for answers. The important thing is to realize that the answers are close at hand and to figure out how to utilize them.

[reference]

[1] Passive microfluidic device for submillisecond mixing, Zonghuan Lu, et al. Sensors and Actuators B 144 (2010) 301–309

[ Fig1. Configuration of the Micromixer, with the Detailed Dimensions Labeled ]

[ Fig3. Velocity Vectors at Different Planes Normal to the Flow Path of the First Butterfly Mixing Element (from plane (a) to plane (f)). Flow rate was set at 6.0 L/s ]

[ Fig2. Mixing Index of Simulation Results Along the Mixer Channel at Various Flow Rates ]