Can you imagine? Just spray it lightly and you can "wear" a layer of "mask" in your nose. Researchers from the Institute of Process Engineering of the Chinese Academy of Sciences (hereinafter referred to as the Institute of Process Engineering) have created an "intranasal mask" that can intercept and inactivate viruses, which can greatly reduce the risk of viral infection. Research shows that "intranasal masks" have shown significant protective effects in the verification of mice, human nasal cavity digital models, and human respiratory tract simulation models.

  What is an "intranasal mask", what is its protective principle, and what are its advantages compared with ordinary masks? Science and Technology Daily reporters interviewed relevant experts on these issues.

Set up a "checkpoint" in the nasal cavity

  Aerosols are the main mode of transmission of viral respiratory infectious diseases. Given that viral aerosols can invade the human body through the nasal cavity, researchers wondered whether a "gateway" or "shield" could be set up in the nasal cavity, that is, a coating that could effectively intercept or even inactivate the virus? Based on years of research on biological dosage form engineering, the team of Ma Guanghui, an academician of the Chinese Academy of Sciences and a researcher at the Institute of Process Engineering, and Wei Wei, a researcher at the Institute of Process Engineering, created an "intranasal mask".

  In fact, the "intranasal mask" is a temperature-sensitive gel made of chimeric cell vesicles. It consists of micron-sized cellular vesicles with highly expressed viral receptors on their surfaces, embedded in a temperature-sensitive hydrogel carrying positive charges. It is liquid at room temperature and can be sprayed into the nasal cavity. When the liquid "intranasal mask" enters the nasal cavity, it can quickly transform from liquid to gel state under the action of human body temperature, thereby forming a gel protective layer in the nasal cavity.

  "This protective layer can prevent viral aerosols from entering the lungs through interception and trapping, and can make the viruses in the viral aerosols lose their ability to infect." said Wang Shuang, co-first author of the paper and associate researcher at the Institute of Process Engineering , when the virus aerosol is inhaled into the nasal cavity, the positively charged gel in the gel protective layer can intercept and adsorb the negatively charged virus aerosol particles, thereby blocking its spread to the downstream trachea and lungs; while chimeric The micron-sized cell vesicles in the gel can further rely on highly expressed virus receptors on the surface to trap viruses into the interior of the vesicles and inactivate them, thus protecting nasal epithelial cells from virus infection. The above two functions work together to reduce the risk of viral infection.

  "During the research process, we prepared a variety of hydrogels with different concentrations and ratios. By examining their spray performance, temperature-sensitive performance, aerosol adsorption performance, etc., we finally selected a hydrogel with good performance in many aspects. performance of the gel formulation." said Hu Xiaoming, co-first author of the paper and a doctoral student in the Institute of Process Engineering.

  Through experiments on virus infection models and virus transmission models in mice, researchers found that "intranasal masks" can effectively protect the nasal cavity and lungs of mice from virus aerosol infection.

  In addition, the research team also used 3D printing technology to obtain a physical model of the human nasal cavity, and connected it with the human lung organoid module (simulating lung tissue) and the airflow duct module (simulating respiratory airflow) to build an integrated human respiratory tract simulation model . On this basis, the team proved that "intranasal masks" can effectively reduce the infection rate of lung organoids by different virus aerosols.

Masking of viral infectious proteins by internalization

  Unlike previous studies that mainly focused on viral infections, this study mainly focused on viral aerosols. "Our research provides a new idea to intercept viral aerosols and trap viruses, thereby preventing viral aerosol infection. This adds a new piece of the puzzle to the field of viral aerosol protection," Wang Shuang said.

  In previous studies, researchers mainly used nanoscale cellular vesicles or host cell membrane-modified nanoparticles as virus "baits." This viral "bait" can bind to the virus with the help of viral receptors carried on its surface. However, because its internal size is too small or has no internal space, it cannot internalize the virus and can only cover part of the virus's infectious proteins, making it possible for the virus to infect cells.

  Wang Shuang introduced that in this study, the team prepared micron-sized cellular vesicles as virus "baits". It has a large space inside, which can shield the viral infection protein through internalization, greatly reducing the risk of viral infection. More importantly, the viral receptors on the surface of micron-sized cell vesicles come entirely from the host cell of the virus, and the process of virus infection of cells must rely on viral receptors on the surface of the host cell membrane. Therefore, this binding is not lost due to mutations in the virus. This means that the ability of micron-sized cellular vesicles to internalize viruses and inactivate them will not be lost due to virus mutations, and can be applied to different mutant strains of the virus.

  This study innovatively applies computational fluid dynamics-discrete particle simulation (CFD-DPS) technology and 3D reconstruction technology based on computed tomography (CT) data to research in the field of intranasal protection against viral aerosols. The research also constructed a human respiratory tract simulation model for the first time to simulate the process of inhaling viral aerosols by a real human body under respiration. At the same time, the study used a combination of computer simulation and experimental verification to provide strong evidence for the applicability and effectiveness of "intranasal masks" on the human body from multiple perspectives. Wei Wei believes that innovative models such as computer simulation technology and human respiratory tract simulation model used in the study have provided some new ideas for researchers in the field of virus protection.

Bring extra protection to specific groups of people

  Compared with ordinary masks, "intranasal masks" have some obvious advantages. Hu Xiaoming introduced that in terms of use parts, ordinary masks are worn on the face; "intranasal masks" are applied inside the nasal cavity. In terms of protective mechanism, ordinary masks mainly play a physical barrier role, intercepting viruses outside the respiratory tract, but cannot inactivate viruses adhering to the mask; "intranasal masks" can not only intercept viruses, but also further inactivate the intercepted viruses. Viruses in aerosols lose their ability to infect, reducing the possibility of viruses infecting cells. In real life, "intranasal masks" can be used in conjunction with ordinary masks. Ordinary masks are used to physically block most virus aerosol particles, while "intranasal masks" can further intercept, capture and inactivate viruses inhaled through the gaps in the mask.

  "It must be emphasized that this result is still in the preclinical research stage, and the actual clinical efficacy has yet to be further verified." Wang Shuang said that if the clinical efficacy of the "intranasal mask" is verified well, its promotion in the future can provide Asthma patients and other people who are not suitable or accustomed to wearing masks provide an additional option, which can increase the public's willingness to protect and reduce the incidence of viral respiratory infectious diseases.

  At the same time, "intranasal masks" used in conjunction with ordinary masks can also provide additional protection for medical staff and other people who often enter and leave areas with high concentrations of virus aerosols. It is expected to significantly reduce the risk of infection caused by virus aerosols to them and improve their health. Provides additional protection.

  More importantly, given the versatility, flexibility and safety of this system, when dealing with new viral respiratory infectious diseases in the future, researchers will be able to use gene editing and other means to make existing engineered cells express the virus's corresponding of viral receptors. In this way, "intranasal masks" for new viral aerosols can be quickly prepared to quickly respond to emerging viral respiratory infectious diseases, reduce the transmission rate of these infectious diseases, and reduce their threat to public health safety. (Science and Technology Daily reporter Lu Chengkuan)