The engineers Hyo-Jick Choi and Ilaria Rubino at the University of Alberta developed salt-based masks that could neutralize viruses present in droplets within 5 minutes. From this concept, we thought it could be extrapolated to any kind of surface. Recent studies have shown that the virus can survive many days on surfaces like walls, metal parts of furniture and therefore become a viral transmitter. Consequently, a viral neutralizing surface coating could be very useful in a pandemic situation.
What it does
NaCl functionalization of medical face masks’ PP filters has proven to neutralize Influenza viruses embedded in aerosols. On contact with the salt crystals, the microscopic droplets absorb the NaCl and due to evaporation its concentration increases. The resulting strain on the virus originates both from the osmotic pressure, as well as the recrystallization of NaCl and signifies, therefore, the physical destruction by irreversible deformation of its envelope. As this physical destruction is not dependent on the chemical interaction of salt and influenza, it is supposed to work on a wide variety of viruses. The coating has shown to stay well present on the PP fibers for at least 15 days. This functionalization has shown to destroy viruses quickly and very reliably, resulting in a high level of protection.
How we are planning to build it
The easiest way to apply the coating is via spray deposition. Since on the masks the coating stays 15 days, we could imagine that on walls for the same amount of time so health workers in hospitals would have to apply a new layer frequently. Therefore the deposition has to be user-friendly. Further researches will be needed to determine if the materials can be similar but one can already say that the implementation will need some adjustment since big surfaces can be put in an oven.
Challenges we ran into
As the NaCl coating has been tested on the H1N1 influenza virus, the efficiency of this applied destruction method has to be further confirmed on Sars-CoV-2. As the salt induces physical destruction of the viral envelope, the hypothesis of being equally applicable to this virus has been judged as highly probable.
The coating method, as well as the deposition of NaCl on different surfaces, depends on the interaction of the materials. As NaCl is not highly reactive chemically, its compatibility with a wide variety of surfaces is given. The residence time, however, may depend on both the material and the atmospheric composition. Therefore also other salts can be considered to be more adept at the changing conditions. Another challenge is that NaCl is brittle and on surfaces frequently touched or rubbed such as gloves, tables or door handles, the surface coating has to be resistant or it can’t be applied on such objects. It is also important to mention that due to the current situation no experimental studies can be done.
What's next for Virus neutralizing salt-based solution surface coating
If possible we'd like to do some tests with the mix polymers and NaCl solution for the gloves and eventually design our own deposition nozzle to make it compatible with NaCl deposition and user-friendly. We will also compare NaCl with other salts like CuSO4. The aim of this hackathon was to established a plan for a bachelor project in material science which is what we've done.