Antimicrobial polymers

What does “antimicrobial” mean?

An antimicrobial is any substance, whether natural or synthetic, capable of inhibiting the growth or killing a broad spectrum of microorganisms; this includes bacteria, moulds, fungi and even viruses. With such a large spectrum of possible pathogenic microorganisms, it is very important to use the correct antimicrobial product to achieve the desired selectivity and an optimal activity. For example, an antibacterial is a substance that is only effective against bacteria and therefore does not affect other microorganisms.

There are multiple strategies to obtain antimicrobial activity. Although we can find many substances that have this effect, the way they work, act, and how long they last is not universal and their mechanisms of action are very diverse. Each strategy has its advantages and disadvantages and depends on the material used and the process for including it in the final material.

Some examples would be the inclusion of metal oxides and ions (such as silver, copper, zinc) or encapsulated products for a controlled release over time. The definition of an “antimicrobial” refers to having an effect on one or more microorganisms, but it should be noted that the term is not a measure of performance.

Finally, in recent years, different microorganisms have demonstrated the ability to develop resistance to commonly used antimicrobials (known as antimicrobial resistance, AMR), affecting their efficiency. This ability is achieved through the production of biofilms that isolate them from the environment, allowing them to replicate until the colony is ready to disperse and continue growing on other affected surfaces. For this reason, products capable of permeating or breaking down these biofilms (called antibiofilm or antifouling products) are becoming increasingly important, especially in the healthcare sector.

Our solutions

Design of new antimicrobial materials and products

We design new antimicrobial materials or additives, which includes the characterization of the resulting materials and products. The fields of application include thermoplastic polymers, thermosets, composites and coatings.

Evaluation of antimicrobial activity

• Evaluation of the antibacterial activity of plastic materials. These analyses are carried out in accordance with the ISO 22196:2011 standard: Measurement of antibacterial activity on plastics and other non-porous surfaces, in which Staphylococcus aureus (Gram positive) and Escherichia coli (Gram negative) are used as reference strains. This standard specifies the method for evaluating the antibacterial activity of pre-treated plastics or other non-porous surfaces of products (including intermediate products) which have been treated with additives and whose activity we want to verify.
• Evaluation of the antiviral activity of plastic materials. These analyses are carried out in accordance with the ISO 21702:2019 standard: Measurement of antiviral activity on plastics and other non-porous surfaces, using two viruses, one that is relatively sensitive (Influenza A – H3N2) and one that is more resistant (Feline calicivirus). Similar to what was explained above, this test allows for the evaluation of antiviral activity on pre-treated plastics or other non-porous surfaces. In this case, the efficiency can also be tested against other viral strains of interest such as: Adenovirus, Norovirus and Poliovirus. Activity on coronaviruses (such as TGEVor HCoV-OC43) can also be tested.

Application sectors

The WHO has declared antimicrobial resistance as one of the top 10 public health threats that humanity will face, so there are many sectors involved and many people who are or will be involved in antimicrobial technology. The sectors that are most directly affected are clearly the health and food industries, where the presence of pathogenic microorganisms can lead to serious health risks. These sectors are not the only ones affected; others such as packaging (active packaging), the construction sector (paints and varnishes) and the mobility sector (public transport) show an increasing demand for products with this activity. Finally, the agricultural sector is also showing a strong impetus in the development of anti-pest products, especially focusing on bio-based solutions.