Periodic Reporting for period 2 - STOP (Surface Transfer of Pathogens)
Période du rapport: 2024-03-01 au 2025-08-31
The STOP project will develop antimicrobial and antiviral nanocoatings that can be flexibly or permanently applied to high-touch surfaces. These nanocoatings will be derived from a combination of inorganic nanoparticles, antimicrobial peptides and nanoscale laser surface patterning. The nanocoatings will be thoroughly characterised for their efficacy, using both existing international standards and improved testing methods developed within the project (the new testing methods will be proposed to standards agencies for adoption). Several different active substances will be explored (i) to allow formulation in highly flexible, sprayable, and long-lasting coatings, (ii) provide broad spectrum antimicrobial and antiviral activity, and iii) reduce the chances of the development of resistance. To this end, the mode-of-action, and the risk of selection for antimicrobial resistance in bacteria and viruses will be assessed. The flexible nanocoatings will provide a long-lasting (30 days) reduction in bioburden that resembles standards set for microbial colonization of surfaces in hospitals, which can only be reached after intense surface disinfection or permanent introduction of known antimicrobial material such as copper. This effect will be studied in a real-life intervention trail and with epidemiological models. The developed nanocoatings are expected to lead to significant reductions in infectious diseases transmitted from high-touch surfaces, healthcare cost savings, reduction in environmental pollution by disinfectants, and increased preparedness of the EU public health system to future pandemics. The safety of the nanomaterials will be backed up by human and environmental toxicity studies and life cycle analyses. From the beginning, attention will be paid to end-user acceptance, manufacturing scalability, and short-term exploitation by SMEs.
In the first three years of the project hundreds of novel surfaces have been created and screened for antibacterial or antifouling activity. (Since the aim of the project is to prevent the transfer of pathogens between people via surfaces, a surface to which no pathogens can stick is just as effective as a surface that kills pathogens). These surfaces (on metal, plastic or glass) were created either by laser texturing, or the deposition of specially functionalised nanoparticles or polymers, or a combination of both. Antifouling properties are achieved by adjusting the nanoscale surface roughness to get something similar to the well-known ‘lotus effect’, in other words a superhydrophobic surface which is not wetted by water droplets. Bacterial killing properties can be obtained by using synthetic peptides (small protein chains) that mimic the properties of materials found in nature.
During the second reporting period of the project (March 2023 to August 2025), the project members improved the properties of the new antimicrobial coatings (in terms of their antimicrobial efficacy, and their performance in tests intended to simulate applications, such as resistance to abrasion and solvents. The emphasis switched from screening new materials, to more detailed testing of promising materials to confirm that they have no detrimental environmental or human health effects, and to confirm their antimicrobial performance using standard tests for several bacteria and viruses. Given the project’s commitment to carrying out field trials, the necessity to be able to produce many tens of square metres of coated materials had to be prioritized, and was a key factor in deciding which coatings to concentrate most development resources upon. Ethical approval for the field trials was granted for sites in both Finland and Greece (nursing homes or sheltered accommodation).
In parallel, scientific work on understanding how the coatings work (‘mode of action’) began, which will influence further optimization and the selection of use cases. We have also begun the development of numerical models with which we can assess the effectiveness of the coatings in our field trials, and their potential impact upon public health.
During the second reporting period of the project (March 2023 to August 2025), the project members improved the properties of the new antimicrobial coatings (in terms of their antimicrobial efficacy, and their performance in tests intended to simulate applications, such as resistance to abrasion and solvents. The emphasis switched from screening new materials, to more detailed testing of promising materials to confirm that they have no detrimental environmental or human health effects, and to confirm their antimicrobial performance using standard tests for several bacteria and viruses. Given the project’s commitment to carrying out field trials, the necessity to be able to produce many tens of square metres of coated materials had to be prioritized, and was a key factor in deciding which coatings to concentrate most development resources upon. Ethical approval for the field trials was granted for sites in both Finland and Greece (nursing homes or sheltered accommodation).
In parallel, scientific work on understanding how the coatings work (‘mode of action’) began, which will influence further optimization and the selection of use cases. We have also begun the development of numerical models with which we can assess the effectiveness of the coatings in our field trials, and their potential impact upon public health.
The project has confirmed (and in some cases begun to optimize) the antimicrobial activity of a number of types of nanocoating, including those exploiting the photocatalytic behaviour of titanium dioxide, the use of synthetic antimicrobial peptides attached to mesoporous silica nanoparticles, the use of metal particles (silver or copper) surrounded by silica (core-shell structure), and the use of a type of nanoparticle known as an MXene. In particular, the combination of a polypeptide that partially mimics a component of human skin with certain antimicrobial peptides seems highly effective and the project is investigating the practicality of patents for this. Furthermore, we see promise in new photoactivated antimicrobial materials created by the project, although these need further development for indoor use cases.
In order to assess the large number of novel materials, the project has developed special semi-quantitative screening tests to determine in high-throughput whether a material may be effective as an antimicrobial coating or not. In addition, the project developed a novel dry-touch transfer method for the assessment of the efficacy of antimicrobial surfaces. This test can evaluate the efficacy under more realistic conditions than current standards. We believe that this test will be extremely useful to the wider community, and may form the basis of future standards.
In order to assess the large number of novel materials, the project has developed special semi-quantitative screening tests to determine in high-throughput whether a material may be effective as an antimicrobial coating or not. In addition, the project developed a novel dry-touch transfer method for the assessment of the efficacy of antimicrobial surfaces. This test can evaluate the efficacy under more realistic conditions than current standards. We believe that this test will be extremely useful to the wider community, and may form the basis of future standards.