Jeanne Moldenhauer - Excellent Pharma Consulting, Inc.
Introduction
For many years pharmaceutical companies have relied upon chemical methods to inactivate microorganisms and viruses present in their facilities. Over these same years we have found issues with the various chemicals used. For example, many disinfectants are considered oxidizing agents, which can harm the surfaces in the facility. Examples of oxidizing disinfectants include halogens, chlorine, iodine, bromine, and chlorine dioxide. There are also oxygen-releasing materials like peracetic acid and hydrogen peroxide that are considered with the oxidizing disinfectants. There are some non-oxidizing disinfectants like quaternary ammonium compounds, amphoterics, biguanides, and acid anionics. (Fisher, 1993) Most disinfectants inactivate bacteria, molds, and/or yeasts, but not bacterial spores. Additionally, there may be concerns with discarding these types of chemicals into wastewater. (Fisher, 1993)
Ions are defined as atoms or molecules that have gained or lost one or more electrons, resulting in them having an electrical charge. There are Ions formed naturally in the environment from such energy sources (e.g., UV light, frictional charging by the wind, water droplet breakup (waterfalls, sea waves), electrical discharge from lightning, and the like). (Trane, 2021)
Microorganisms are classified as Gram-negative or Gram-positive. Microorganisms with both types of Gram reaction contain peptidoglycans as part of their cell walls. In the Gram-negative organisms, the cell wall is thin and it is multi-layered (thick) in Grampositive cell walls. The peptidoglycans are interspersed by teichoic acids, which are anionic polymers yielding a negative charge on the microorganism. (Dubey, 2016)
Similarly, enveloped viruses have phospholipids on the cell surface which give them an overall negative charge. DHA has a negative charge because of the multiple phosphate groups. (Robb, et al., 2019)
Ions and their electrical charges are important when working with magnets. Figure 1 shows how a magnet works.
When ions of the same charge are exposed to magnetic fi elds of the same charge, the ions are repelled. When ions of a different charge are exposed to magnetic fields of the opposite charge, the ions are attracted to the opposite charges.
Using Polar Charges to Inactivate Microorganisms and Viruses
Scientist are using the understanding of the ionic charges of microorganisms and viruses along with knowledge of magnets (polar fields) to inactivate microorganisms and viruses. If the microbes and viruses are exposed to negative charged substances, they are repelled. If the microbes and viruses are exposed to positively charged substances, they are attracted (bound to the charged surface). The electrical charge from the opposite charges results in inactivation of the negatively charged microorganism or virus.
Alves, et al. (2009) utilized cationic charges to achieve microbial inactivation. They chose a cationic material that included a photosensitizer.
Another application of using polar charges for inactivation is bipolar ionization (BPI). While ionization has been studied for a long time, there are debates about the efficacy of the technology. Bipolar ionization uses ions as antimicrobial agents. BPI refers to technologies that use an artificial source of energy to produce both positively charged ions (cations) and negatively charged ions (anions). Often this is achieved by applying voltage to electrodes to create an electric field; as the air passes through the electric field, some atoms or molecules in the air stream may lose or gain electrons and become ions. Depending upon the electrical arrangement, different variants of bipolar ionization devices, e.g., corona discharge, dielectric barrier discharge, needlepoint bipolar ionization (NPBI®), and the like are made. They may be installed in air handling units, air ducts, or as free-standing units. (Trane, 2021)
Jewett and Weber (2021) reported on a study conducted by Boeing Airlines and the use of ionization technologies in airplanes. Several ionization technologies were adopted by schools to combat COVID-19. The intent was to determine whether they effectively killed germs on surfaces. Unfortunately, an appropriate level of effectiveness could not be established to justify implementation on commercial airlines. One should note that in the Boeing study, evaluations were conducted only on surface samples, not air samples.
Use of Charged Textiles and Filters
With the concerns about COVID-19, there has been an increased focus on personal protective equipment. One area of work is in the field of face masks. There has been an increase in research with nanoscale materials. They have utilized antimicrobial fabrics with charged copper nanoparticles that provided antimicrobial activity onto fabrics. The data generated by Redwanul (2018) showed this type of treatment to be effective against a variety of microorganisms. The copper ions provide a positive charge versus the negatively charged microorganisms to provide inactivation.
Several varieties of face masks are available that are infused with metals, which gives the perception that they are capable to prevent transmission of COVID-19. Usually, the infused masks are reusable. Many of these masks do not make medical claims and therefore were not submitted for regulatory approval. (Nicholas, 2020) According to Nicholas (2020) typical antimicrobials used on face masks include zinc, silver, and copper. There is also an emerging use of graphene/carbon. Depending upon the fabric used, some metal-based agents have not been as effective against viruses. Some of the metals chosen for use are inherently toxic to microorganisms. Effectiveness of these products is dependent upon the ability of the metal ion to remained fixed on the fabric. Many metal ions wear off when the fabric is machine washed. This can significantly reduce the antimicrobial effectiveness. There are also some health concerns associated with use of metal ions on fabrics in contact with humans. (Nicholas, 2020)
Current Technologies Using Charged Particles
The use of charged particles to inactivate microorganisms and viruses has been implemented in antimicrobial products. The benefits of using this type of product is that there are no chemicals added to the solution. The autoionization properties of water can be utilized in different ways to generate high levels of hydronium or hydroxyl ions which are capable of inactivating microorganisms and viruses. Data generated for these products are available on the affected product websites substantiating their kill claims. The special benefits of these products include: no chemicals added to the product, the product is antimicrobial and antiviral, and the product equally inactivated vegetative and spore forms of the organisms. Additionally, these types of products do not oxidize, corrode, or damage the surfaces on which it is used.
Another area of significant research and product development is in the field of air filtration. A variety of textiles have been treated with charged particles to capture and kill microorganisms and viruses.
A study conducted at the University of Michigan showed that dangerous viruses are rendered harmless when exposed to energetic, charged fragments of air molecules (cold plasma). (Univ. of Michigan, 2019) Sakudo, et al. (2019) Studies conducted by Sakudo, et al. (2019) showed that plasma is effective to inactivate microbial pathogens (bacteria, fungi and viruses). They also found the plasma effective in degrading toxins. Their studies were evaluated on medical and dental device surfaces.
Scientists have also been experimenting with the use of polymers on textile materials. These polymers can be charged and used in filter constructions to provide capture and inactivation of microorganisms and viruses. The textile materials are used as a single or double layer within the filter material. Ideally, the polymers used should not incorporate the use of metal particles or polymers that shed.
Conclusion
The use of physics and electrical charges in products to inactivate microorganisms and viruses can significantly improve modern contamination control programs. While air filters have historically been used to clean the air using particle size exclusion, use of the antiviral protection could provide significant health benefits to the personnel in the area.
Using cleaning and disinfectant agents based upon charged particles can reduce the likelihood of equipment damage and may be more effective (e.g., eliminating the need for separate sporicidal agents) than the chemical products on the market.
References
- Alves, E., Costa, L., Carvalho, C.M.B., Toméz, J.P.C., Faustino, M.A., Neves, M.G.P.M.S., Toméz, A.C., Cavleiro, J.A.S., Cunha, A., and Almedia, A. (2009) Charge Eff ect on the Photinactivation of Gram-negative and Gram-positive Bacteria by Cationic Meso substituted Porphyrins. BMC Microbiology. 9:70.
- Dubey, S. (2016) Does bacterial cell wall have any charge? If so, what is the charge? Downloaded from: Does bacterial cell wall have any charge? If so what is the charge? (researchgate.net) on November 18, 2021.
- Fisher, J. (1993) Types of Disinfectant. Encyclopedia of Food Science. Food and Nutrition. Academic Press. Downloaded From: https://www.ncrfsma.org › fi les › page › fi les › type on November 18, 2021.
- Gupta, D. and Bhaumik, S. (2007) Antimicrobial Treatments for Textiles. Indian Journal of Fibre and Textile Research. 32 (June): 254-263.
- Hasan, Redwanul. (2018). Production of Antimicrobial Textiles by Using Copper Oxide Nanoparticles. International Journal of Contemporary Research and Review. 9. 20195- 20202. 10.15520/ijcrr/2018/9/08/564.
- Jewett, C., and Weber, L. (2021) Do Air Purifi ers Protect Against COVID? Lawsuit Says Company Makes “false” Claims. Kaiser Health News. Downloaded from: Do air purifi ers protect against COVID? Lawsuit says company makes ‘false’ claims (nbcnews.com) on November 18, 2021.
- Nicholos, R. (2020) Are Face Masks Infused with Metals Eff ective, Safe and Ecofriendly? Medium. Downloaded from: Are Face Masks Infused with Metals Eff ective, Safe and Ecofriendly? | by Richard Nicholas | Medium on November 18, 2021.
- Redwanul, H. (2018). Production of Antimicrobial Textiles by Using Copper Oxide Nanoparticles. International Journal of Contemporary Research and Review. 9. 20195- 20202. 10.15520/ijcrr/2018/9/08/564. Downloaded from: Download citation of Production of Antimicrobial Textiles by Using Copper Oxide Nanoparticles (researchgate. net) on November 18, 2021.
- Robb, N.C., Taylor, J., Kent, A., Pambos, O.J., Gilboa, B., Evangelidou, M., Mentis, A-F., Kapanidis, A.N. (2019) Rapid functionalization and detection of viruses via a novel Ca2+- mediated virus-DNA interaction. Scientifi c Reports. Nature Research. Downloaded from: Rapid functionalisation and detection of viruses via a novel Ca2+-mediated virus-DNA interaction (nature.com) on November 18, 2021.
- Sakudo, A., Yaguy, Y., and Onodera, T. (2019) Disinfection and Sterilization Using Plasma Technology: Fundamentals and Future Perspectives for Biological Applications. International Journal of Molecular Science. 20(20); 5216. doi: 10.3390/ijms20205216
- Trane (2021) A Taxonomy of Air-Cleaning Technologies Featuring Bipolar Ionization. Downloaded from: Technology Whitepaper - Bipolar Ionization.pdf (trane.com) on November 18, 2021.
- Univ. of Michigan (2019) Cold Plasma can Kill 99.9% of Airborne Viruses. Science Daily. Downloaded from: Cold plasma can kill 99.9% of airborne viruses -- ScienceDaily on November 19, 2021.
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