Trends in the chemistry of disinfecting

May 13, 2020

Person cleans table in a coffee shop

" After all plants, fungi, and other eukaryotes have been dealing with microorganisms for millions of years, before we showed up." -- Martin Mulvihill 

With cleaning and sanitizing products flying off the shelves and handwashing jingles becoming ubiquitous, we'd like to consider the chemistry of micro-organism control.

There are many ways to effectively remove pathogens, including coronavirus, from surfaces.

You can find a full list of registered products that have been recommended by the EPA, including Force of Nature (one of Safer Made's Investments), for use against SARS-CoV-2 here.

Most of these products use one of three basic mechanisms to chemically control bacteria and viruses:

Membrane Disruption – chemicals that break apart the outer lining of microorganisms. Regular hand soap works this way and can be an effective way to harm the membranes of most microorganisms when used properly. The novel coronavirus responsible for COVID-19 is particularly susceptible to soap, which disrupts its lipid coating.

Crosslinking – chemicals that crosslink and impair microbial RNA/DNA and other cellular machinery. Crosslinking chemicals can damage any type of cell. In hospital operating rooms for example, crosslinker active ingredient glutaraldehyde is often the sterilant of choice because it can kill not only bacteria and viruses, but also spores and endospores, which may be resistant to other modes of chemical attack. This type of disinfectant is usually too dangerous for consumer use.

Oxidization – chemicals that either destroy or degrade cellular structures or interfere with cellular function through oxidative stress. These chemicals come in a wide range of potency and efficacy and include many of the traditional bleaching agents like chlorine and hydrogen peroxide. These powerful chemical oxidizers are effective against a wide range of viruses and bacteria, but they can also cause skin and/or respiratory tract irritation.

Disinfectants are only a small subset of the larger class of antimicrobial chemicals that are used in consumer products. Apart from disinfecting, antimicrobial chemistries serve essential functions including, odor control, and preserving food and formulated products. These functions are often provided by undesirable chemistries, including parabens, formaldehyde-releasing chemicals, isothiazolinones, and quaternary ammonium compounds.

Over the last two years we came across thirty or so companies developing safer microbial control innovations with personal care, textile, and industrial applications. Each sector has unique sets of performance and cost criteria that require specific solutions. We have noticed some directions or trends in safer antimicrobial control innovation.

One pattern is looking for chemistries that occur in nature. After all plants, fungi, and other eukaryotes have been dealing with microorganisms for millions of years, before we showed up. This approach involves either using natural extracts directly, or artificially re-creating similar chemistries. An example in this category is Mother's Choice that uses natural plant extracts to create effective preservative solutions for personal care products. Other examples include Nagardo, Chinovia (fungal compounds), Life Materials (mint based actives solution for textile fibers), and Aequor (antimicrobials inspired by sea creatures for industrial and medical applications). One note here is that not all naturally occurring chemistries are by default safe to humans and safety needs to be established for every solution.

It is also possible to take an ecosystem approach to controlling microbial populations and a handful of companies have started using beneficial microorganisms to control pathogenic ones. This trend is most developed in nutrition (probiotic supplements and therapies) but also making inroads in agriculture (Boost Biomes), in cleaning products (BioOrg, Aunt Fannies, and Counter Culture), and personal care (Mother Dirt, Persona Biome, Dermala, and Ellis Day).

Another approach to controlling microbial activity involves rethinking product design, for example by removing water from formulations. Companies such as Nohbo, Owa, and Lush are following this approach in personal care. Other companies are developing new coatings and packaging that incorporate design features or chemicals that inhibit bacterial growth. Companies working on antimicrobial surface properties include Cambridge Crops, Reactive Surfaces, Smart Plastic, Tidal Vision, and Sonovia.

As consumer awareness of microbial control grows we expect to see continued demand for new technologies that provide excellent performance in a safe and sustainable way. 

To read more about our work investing in Safer Chemistry read our latest Safermade newsletter.

Dr. Martin Mulvihill (Ph.D. '09, Chem) is the founding general partner of Safer Made and the founding director of the Berkeley Center for Green Chemistry.