Large area deposition technologies of multifunctional antibacterial and antiviral nanocoatings

Identification number: Nr.1.1.1.1/21/A/050

Type: ERDF

Project duration: 01.01.2022 - 30.11.2023

Project manager: Dr.hab.phys. Juris Purāns

Partners:

• Latvian Biomedical Research and Study Centre (LBMC)
• SIA SIDRABE Vacuum

Total funding:

The total budget is 500 000 EUR with ERAF contribution of 425 000 EUR.

Project aim:

The aim of this industrial research project is to develop advanced roll-to-roll (hereinafter R2R) physical vapour deposition (PVD) technology for large scale production of a new type of multifunctional antibacterial and antiviral (MABAV) coatings. We propose to produce and investigate MABAV materials in the form of thin films and multilayers with photochromic and transparent conducting multifunctionalities based on rare-earth oxy-hydrides (REHO) and metal oxides (MO) in combination with the metal and other dopants.

Project summary:

COVID-19 pandemic calls for new ways to combat pathogen resistance. The pathogens can persist on several types of surfaces long enough causing transmission of various infectious diseases [1], which are a continuous threat to human health and have a negative impact on the economy. The hospital environment is the epicentre of most antibiotic-resistant infections, especially respiratory pathogens, and where outbreaks occur. According to the European Centre for Disease Prevention and Control, more than four million people are estimated to acquire a healthcare-associated infection (HCAI) every year in Europe [2]. In addition, antimicrobial resistance towards antibiotics is growing everyday due to environmental changes and microbial adaptation abilities. For these reasons, the development of advanced solutions is urgently needed today. The knowledge on the survival of bacteria, fungi, viruses, and protozoa on surfaces, and hence, in a broader sense, in the human environment, is important for planning and implementing tactics for prevention of HCAI [3].

Within the framework of this industrial research project an advanced roll-to-roll (hereinafter R2R) physical vapour deposition (PVD) technology for large scale production of a new type of multifunctional antibacterial and antiviral (MABAV) coatings will be developed. MABAV materials in the form of thin films and multilayers with photochromic and transparent conducting multifunctionalities based on rare-earth oxy-hydrides (REHO) and metal oxides (MO) in combination with the metal and other dopants will be produced and investigatd.

Applications: smart windows/glass, smart foils/sheets (as partitions and barriers in public places) and transparent electronics applications, including medical devices, with the aim to prevent the diseases in terms of reduction of bacteria and virus prevalence with attention to the SARS-CoV-2 to limit and reduce the spread of this virus and consequently caused illness COVID-19.

This project will be implemented by the Institute of Solid State Physics of University of Latvia (ISSP UL), a vacuum coating SME company SIDRABE Vacuum Ltd (SIDRABE) and Latvian Biomedical Research and Study Centre (LBMC). This interdisciplinary project consists of the research activities in Physical (1.3), Chemical (1.4) and Biological (1.6) sciences, and Materials engineering (2.5).

[1] Journal of Hospital Infection 99 (2018) 239-249.
[2] European Centre for Disease Prevention and Control. Point prevalence survey of healthcare-associated infections and antimicrobial use in European acute care hospitals 2011–2012. Stockholm: ECDC; 2013.
[3] Coatings 9 (2019) 654.

Expected scientific results:

• Novel R2R deposition technology of MABAV coatings on flexible substrate (results: new technology, patent);
• Novel REHO and MO thin films and multilayers with advanced MABAV properties (results: scientific articles, new product prototype, patent).

Project progress information

Period: 01.10.2023.- 30.11.2023. | November 30, 2023

During the past research period of the project ISSP UL did research about:

• New photochromic YHO coatings were produced, and YHO was deposited on various substrates, including glass, amorphous quartz, c-sapphire, Si, ITO, FTO, glass/SiO₂, and glass/Si₃N₄, to assess adhesion. The samples were examined using an optical microscope, revealing that the coating adheres well to glass, amorphous quartz, and glass/SiO₂. Additionally, FTO was found to be a more suitable transparent electrode as a substrate compared to ITO due to better adhesion.
• The oxidation conditions of YH₂ (YHO intermediate) were varied: (i) air immediately after fabrication, (ii) air after 2 days, and (iii) pure oxygen (99.999%) immediately after fabrication to evaluate their impact on photochromic properties. Observations indicate that oxidation (i) provides better adhesion, although substrate material and cleanliness are more critical.
• YHO coatings were heated in air for 20 minutes at three different temperatures (50, 100, and 150°C) to assess their thermal stability and the effect of temperature on photochromic properties.
• XRD, UV-Vis-NIR transmittance/reflectance, and photochromic property measurements were conducted on the YHO samples.
• A popular scientific article titled "Latvian Scientists Research and Patent Surface Coatings to Combat Disease Agents" was published on the lsm.lv portal.

SIDRABE performed activities on:

• Two additional series of large-area YHO samples at different pressures were produced. The samples were handed over to the project partners for analysis of physical and antimicrobial parameters.
• A description of the roll-to-roll manufacturing technology of large-area YHO coatings has been created.
• A technical specification for sample series YH01 and YH04/Cu has been prepared.

LBMC research:

• Within the final reporting period, we tested the antibacterial activity YHO/Cu and MoO3/Cu/MoO3, which revealed a very high >5 Log reduction rate against E. coli, S. aureus.  Nevertheless, the reproducibility of the results varied significantly for some samples, demonstrating no optimal stability and homogeneity of the samples. In addition, we finished the assessment of nanocoatings with the wild-type SARS-CoV2 virus. A very high anti-SARS-CoV-2 effect was demonstrated for YHO/Cu (YHO4PO2 and YHO4PO4, large area deposited series) samples with TCID50 reduction rate > 5.7 Log.
• In summary, the data obtained in this project demonstrate the high potential of transparent conducting WO3/Cu/WO3 and MoO3/Cu/MoO3, and photochromic YHO/Cu coatings as novel biocidal materials for various applications.
• Scientific article “Analysis of Antibacterial and Antiviral Properties of ZnO and Cu Coatings Deposited by Magnetron Sputtering: Evaluation of Cell Viability and ROS Production” submitted in Coatings (IF=3,4).

The project was successfully completed with a total of one submission and publication of three scientific articles and one popular scientific article, as well as the submission of two patents:

• K. Korotkaja and A. Zajakina, Recombinant Virus Quantification Using Single-Cell Droplet Digital PCR: A Method for Infectious Titer Quantification, Viruses 15 (2023) 1060, https://doi.org/10.3390/v15051060, IF=4.7
• V. Vibornijs et al., Analysis of Antibacterial and Antiviral Properties of ZnO and Cu Coatings Deposited by Magnetron Sputtering: Evaluation of Cell Viability and ROS Production. Coatings, IF=3.4, ID 2752374 (2023) (under review)
• M. Zubkins et al., A stability study of transparent conducting WO₃/Cu/WO₃ coatings with antimicrobial properties, Surfaces and Interfaces 41 (2023) 103259, https://doi.org/10.1016/j.surfin.2023.103259, IF=6.2
• H. Arslan et al., Reactive pulsed direct current magnetron sputtering deposition of semiconducting yttrium oxide thin film in ultralow oxygen atmosphere: A spectroscopic and structural investigation of growth dynamics, Vacuum 211 (2023) 111942, https://doi.org/10.1016/j.vacuum.2023.111942, IF=4.0
• V. Vibornijs, Latvijas zinātnieki pēta un patentē virsmu pārklājumus cīņai pret slimību ierosinātājiem, Tehnoloģijas un zinātne, LSM.LV, 27/11/2023
• EU patent application EP23158463.2: V. Skvorcova et al., An antimicrobial multilayer thin-film materials coating
• EU patent application EP23210104.8: V. Vibornijs et al., An apparatus and a process for testing of anti‐microbial properties of a surface

The project resulted in one prototype and one new technology. Thanks to the productive and constructive cooperation between ISSP UL, SIDRABE and LBMC, the results obtained in the framework of the project were presented as LSA Achievements in Applied Science for 2023.

Period: 01.07.2023.- 30.09.2023. | September 30, 2023

During the past research period of the project ISSP UL did research about:

• New photochromic three-layer MoO₃/YHO/MoO₃ coatings on glass and PET substrates were deposited. Depending on the thickness of MoO₃ layers, they react differently against St.aureus and E.coli bacteria. Stronger antimicrobial activity was observed against St.aureus, exceeding >3 log reduction (⪅ 100% bacterial reduction) after a 24-hour incubation period. The corresponding samples are not active against E.coli. On the other hand, other samples, which are not active against St.aureus, show moderate activity against E.coli – 0.3 log reduction, or ≈ 50% reduction of bacteria. An YHO film without MoO₃ layers is not active against St.aureus or E.coli.
• Additionally, XRD and UV-Vis-NIR transmittance/reflectance measurements were performed for the coatings.
• The article "The stability study of transparent conducting WO₃/Cu/WO₃ coatings with antimicrobial properties" was published in Surfaces and Interfaces (41 (2023) 103259) journal.
• The manuscript of the scientific article "Analysis of Antibacterial and Antiviral Properties of ZnO and Cu Coatings Deposited by Magnetron Sputtering: Evaluation of Cell Viability and ROS Production" was prepared.
• A patent is prepared on the methodology of testing the antimicrobial properties of surfaces.

SIDRABE performed activities on:

• The magnetron sputtering plant was optimized for operation with the yttrium target. Optimum gas flow rates and working voltages were determined to ensure yttrium oxyhydride (YHO) coatings were manufactured according to specifications.
• Three series of large-area YHO samples at different pressures have been made. Samples were handed over to project partners for analysis of physical and antimicrobial parameters.
• Separately fabricated YHO samples on clean, dried and ion-treated PET film and WO₃-coated PET film.

LBMC research:

Within the reporting period, the nanocoatings were assessed with the wild-type SARS-CoV2 virus. One sample of SO₂PO₆ WO/Cu/WO, which showed higher (>4log) inhibition by bacteria, SFV virus and MS2 bacteriophage, was selected for SARS-CoV2 testing. Incubation of the SARS-CoV2 virus on the test surface was carried out over a period of 30 min and 24 hours. After 30 min incubation, the sample showed no significant inhibition of the virus, while long-term incubation led to a decrease of 2.5 Log, which corresponds to an impressive decrease in viral activity of around 99.67%. It is important to note that the Cu coating showed an effective reduction after just 30 min of incubation. The data obtained indicate a high potential of Cu coating as a fast viral inhibitory surface material and indicate the dynamic nature of the SO₂PO₆ surface with effects over a longer incubation period. In addition to tests with the SARS-CoV2 virus, standard anti-bacterial tests were performed on new Mo and Y-containing samples, some of which showed >4 log bacterial reductions.

Period: 01.04.2023.- 30.06.2023. | June 30, 2023

During the past research period of the project ISSP UL did research about:

• New coatings were deposited on glass and PET substrates - YHO, YHO/Cu, YHO/MoO₃ and MoO₃/Cu/MoO₃ with the aim of combining antimicrobial and photochromic properties. Strong antimicrobial activity was observed for YHO/Cu, YDO/Cu and MoO₃/Cu/MoO₃. The photochromic effect was observed in YHO, YHO/Cu, YDO/Cu and YHO/MoO₃.
• In addition, XRD, UV-Vis-NIR and spectral ellipsometry (SE) measurements have been performed on the samples.
• Solid-state nuclear magnetic resonance measurements have been performed on YDO samples in cooperation with the Latvian Institute of Organic Synthesis.
• The article "The stability study of transparent conducting WO₃/Cu/WO₃ coatings with antimicrobial properties" was submitted to the journal Surfaces and Interfaces, is under review.

SIDRABE performed activities on:

• Adaptation of the vacuum sputtering equipment for the magnetron sputtering of yttrium oxyhydride was carried out. The additional necessary maintenance work of the vacuum system also has been carried out.
• Tested the operation of equipment with an atmosphere of a mixture of argon and hydrogen gases, which is necessary for the production of yttrium oxyhydride coatings.
• Preparation of the PET substrate with WO₃ coating to enchance the adhesion of YHO films.

LBMC research:
Within the reporting period, a method for testing nanocoatings with wild-type SARS-CoV2 virus was developed and validated. Cell cultures expressing the human SARS-CoV2 ACE2 receptor (angiotensin-converting enzyme-2), as well as the TMPRSS2 serine protease, which both contribute to the infectious process, were used to produce the virus. Virus titers of 10^6-10^7 iu/ml were obtained according to TCID50 data, which is shown to be sufficient to detect a virus titer reduction rate of around 5 Log. The validation of the test was carried out using a Cu nanocoated sample, which showed 99.9% virus inhibition (>4 Log) compared to the PET sample. In addition, the recombinant alphavirus (SFV) was synthesized and purified, the titer of which was determined by the newly established digital PCR quantification method. Synthesized SFV and SARS-CoV2 viruses will be used for testing of antiviral properties of nanocoatings.

Period: 01.01.2023.- 31.03.2023. | March 31, 2023

ISSP UL did research about:

• Optimization of the pulsed DC magnetron sputtering process for the development of photochromic ABAV coatings was continued. The parameters of the yttrium metal, oxide and oxy-hydride film production process and the quality of the films were improved.
• The submitted article "Reactive pulsed direct current magnetron sputtering deposition of semiconducting yttrium oxide thin film in ultralow oxygen atmosphere: A spectroscopic and structural investigation of growth dynamics" has been accepted for publication in the journal Vacuum (IF=4.1).
• A draft of a new scientific article on "The stability study of transparent conducting WO₃/Cu/WO₃ coatings with antimicrobial properties" was prepared.

SIDRABE performed activities on:

• Samples were prepared for electron paramagnetic resonance and X-ray diffraction measurements. To prepare these samples, a coating layer covering a large area was removed by abrasive methods and compressed into tablets with a diameter of 5 mm and a thickness of 1.0-1.5 mm.
• Conducted experiments with changes in oxygen concentration, reducing it from a ratio of 1:1 to a ratio of 3:2 during the deposition of the WO₃ coating, while measuring the light transmittance of the coatings in the process.
• A new volume of PET substrate required for the production of the next large-sized samples has been prepared, as well as maintenance work on the vacuum system of the equipment has been carried out.

LBMC research:

• Within the reporting period, the data on the antibacterial (E.coli, S.aureus) and anti-viral (MS2 bacteriophage, SFV virus) properties of WO₃/Cu/WO₃ and ZnO/Cu/ZnO coatings were generalized. Two publications are being prepared.
• In addition, the experiments to analyze the photoactive properties of coatings were started. ZnO-containing samples were irradiated with 365 nm (5-10 mJ/cm²) light. The results did not show an increase of the antibacterial effect. It is planned to optimize the surface nanostructure to enhance the photocatalytic effect.
• The results of the anti-SARS-CoV2 testing showed that the amount of the virus was insufficient for analysis. New genetically modified cell lines and virus samples able to efficiently infect the cells were ordered. The SARS-CoV2 virus infection dose (TCID50) under optimized conditions is expected to be sufficient to perform antiviral tests on selected samples.

Article:

H. Arslan, I. Aulika, A. Sarakovskis, L. Bikse, M. Zubkins, A. Azarov, J. Gabrusenoks, J. Purans

"Reactive pulsed direct current magnetron sputtering deposition of semiconducting yttrium oxide thin film in ultralow oxygen atmosphere: A spectroscopic and structural investigation of growth dynamics"
https://doi.org/10.1016/j.vacuum.2023.111942

Period: 01.10.2022.- 31.12.2022. | December 31, 2022

Performed activities.

The antimicrobial WO₃/Cu/WO₃ coatings were optimized by reducing the thicknesses of both WO₃ films to increase the light transmitance and obtain the surface conductivity, since the conductivity of the previously obtained coatings could only be determined for the inner Cu films. For the optimized coatings, the visible light transmittance reaches 55% at 600 nm with the electrical sheet resistance of 30 Ω/□. The samples show a gradual increase in resistance over time. An in-depth analysis of the structure of the coatings by electron microscopy was initiated. The surface of the coatings, which is smooth and without defects or cracks, consists of grains of a few tens of nanometers. In the cross-section images of the samples, all three layers with appropriate thickness are clearly visible. X-ray photoelectron spectroscopy (XPS) revealed the presence of Cu (≈1 at.%) in the WO₃ films, which may explain the instability of the samples due to Cu migration.

Process optimization and development of photochromic ABAV coatings were initiated. Yttrium metal, oxide, and oxy-hydride films were produced by pulsed-DC magnetron sputtering. The oxidation of yttrium and the formation of different phases were studied by changing the partial pressure of oxygen and the temperature of the substrate. The article “Reactive pulsed direct current magnetron sputtering deposition of semiconducting yttrium oxide thin film in ultralow oxygen atmosphere: A spectroscopic and structural investigation of growth dynamics“ has been submitted to the journal Vacuum (IF=4.1). Photochromic YH_3–2xO_x films were deposited on glass by reactive sputtering from yttrium in a mixed Ar/H₂ atmosphere and oxidized in air.

SIDRABE performed activities on:

• two sets of new, large-sized PET/WO₃/Cu/WO₃ samples were made with roll-to-roll (R2R) equipment UV-80 according to the specification submitted by the partners, varying the thicknesses of the WO₃ and Cu layers.
• To ensure the quality of the samples, drying of the PET substrate has been carried out, and substrate treatment with an ion-gun has also been introduced.

LBMC research:

To evaluate the antibacterial properties of novel nanocoatings the testing methodology was established and approved. The method is based on biocidal activity testing on surfaces according to EN ISO 1276 and EN ISO 16615 with modifications to improve the efficiency of the screening technology. The tests are performed in 12-well plates and the bacteria cultivation is optimized for 96-well plate incubation, which allows fast and reliable initial screening of tested samples. Currently, the protocol is optimised for gram-negative and gram-positive bacteria cultivation: Escherichia coli, Staphylococcus aureus. Preliminary data on biocidal activity of tungsten oxide containing nanocoatings were obtained. Furthermore, to evaluate the antiviral activity of nanocoatings, several model viruses were selected: Semliki forest virus (mammalian enveloped RNA virus), MS2 bacteriophage (RNA non-enveloped virus), Pf1 bacteriophage (circular single-stranded DNA filamentous virus). The respective viruses were produced and quantified.

Period: 01.07.2022.- 30.09.2022. | September 30, 2022

Performed activities.

ISSP UL:

Deposition of new WO₃/Cu/WO₃ samples continued (still ongoing) with the main goal of studying the stability of the coatings. The coatings are deposited on previously specially prepared glass substrates with electrical contacts, in order to be able to measure the electrical conductivity over a longer period of time and to determine the effect of deposition parameters. In addition, the optical properties of these samples are regularly measured by spectral ellipsometry. Both electrical and optical properties are observed to vary with time and correlate with deposition parameters. Manufacturing parameters have been found that guarantee stable films whose physical properties do not change over time. The next steps in the research include determining the physical processes that cause the instability of the described properties. X-ray diffraction, deep modeling of ellipsometry data, Raman and infrared spectroscopy and other techniques will be used for this purpose. The results will provide additional knowledge for the interpretation of antimicrobial activity and for fabricating stable coatings.

SIDRABE:

During the past research period the functionality of the roll-to-roll (R2R) equipment was expanded and large-area PET/WO₃/Cu/WO₃ samples production has been started.

• A linear actuator with a movable screen was designed, manufactured and placed in the sample production plant to ensure the creation of metallic Cu contacts on the sides of the samples.
• Calibration of the equipment was carried out, determining the thickness of the WO₃ layer depending on the oxygen flow, for the production of a new series of PET/WO₃/Cu/WO₃ large-size samples according to the specification submitted by the partners.
• The production of the new series of samples has been started.

LBMC:

Testing activities for anti-bacterial and anti-viral effects include a wide range of testing methodologies and techniques. Performed activity is not limited to the implementation of traditionally used testing methodologies. The methodologies described in the testing standards were adapted to the optimal number of tested samples in their more suitable sizes. Optimizations led to more effective usage of samples and increased overall accuracy of the experiments. The optimized methodology has been approved on several bacterial species and supplemented with methods for determining anti-viral effects. Molecular testing methodologies are used in order to better understand the mechanisms of action of the tested anti-microbial coatings on microorganisms. Changes in the enzymatic activity of bacteria and the production of reactive oxygen species compounds in contact with the coating surface are determined. The experimental work with a wild-type SARS-CoV2 virus (lineage B1.1.7) has been started at BSL3 biosafety laboratory. The methodology for virus cultivation and testing on the PET surface will be developed.

Period: 01.04.2022.- 30.06.2022. | June 30, 2022

Performed activities at ISSP UL:

1. A new set of multilayer (WO₃/Cu, WO₃/Cu/WO₃, WO₃/Cu/W/WO₃, ZnO/Cu/ZnO) coatings was prepared on glass substrate with the goal to improve electrical conductivity, optical transparency and antiviral and antibacterial properties by varying the thickness of individual layers.

2. Spectroscopic ellipsometry measurements revealed:

• Glass/Cu and Glass/WO₃ films are homogeneous
  • Optical properties of Cu and WO₃ are comparable with the data base, however resistivity of Cu is of one order lower (3.1×10^-5 W×cm) respect to the reference data (5.4×10^-6 W×cm);
  • No variation of refractive index and extinction coefficient was observed within the depth of the films;
  • Obtained thickness of the Cu and WO₃ films coincide with the planned values during deposition.
• Glass/WO₃/Cu and Glass/WO₃/Cu/WO₃ films are inhomogeneous:
  • Variation of refractive index and extinction coefficient was observed within the depth of the films due to the Cu diffusion in both WO₃ layers;
  • The second layer of WO₃ (on Cu) is thinner compared to single WO₃ on glass: it is possible that the growth of WO₃ on Cu is slower.

3. Electrical resistance of Cu was measured during the deposition of the Glass/Cu/WO₃ sample. The value obtained indicates the formation of metallic Cu and is constant during the deposition of the WO₃ film. We conclude that no significant oxidation of Cu occurs during the sample preparation process.

In parallel, SIDRABE continued the preparation of R2R equipment for the application of large-area antiviral and antibacterial coatings on PET substrates:

1. Drying of PET substrate has been realized in the R2R device.

2. The supply of gases required for magnetron sputtering processes has been realized.

3. The operation of the R2R device in the:

• Metallic mode of Cu and W coatings (Ar atmosphere) has been established.
• Tungsten oxide (WO₃) sputtering mode (Ar and O₂ atmosphere) has been established.

4. The R2R equipment was calibrated for the thicknesses of the metallic and oxide layers depending on the amount of oxygen supplied to the process, the power of the magnetrons and the pressure in the chamber.

5. The first series of 8 pilot samples has been produced and submitted to the project partners for characterization to further optimize the parameters of coating production.

LBMC analysed antimicrobial properties for a set of ZnO and Cu nanocoatings using two types of bacteria, including Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus:

1. ZnO and ZnOCuZnO coatings did not show a significant antibacterial effect.
2. Cu coated PET samples showed antibacterial activity:

• When analyzing the viability properties of bacterial cells (MTT test), it was found that copper coatings reduce the viability of cells in both cultures.
• The amount of reactive oxygen species (ROS) was measured by cultivating cells on different coatings. As a result, only copper showed an active type of oxygen on the surface, causing a significant antibacterial effect.
• Similar results were obtained in virus experiments using MS2 bacteriophage and replication defective human SFV virus, where only Cu-coated PET samples showed statistically significant antiviral effects.

1. When comparing two bacterial cultures, S. aureus showed a much higher degree of inhibition than E. coli, respectively.
2. Innovative digital PCR quantification method was used to determine the SFV virus titre, which was presented at FEBS3+ conference, 16.06 - 18.06.2022, Tallinn, Estonia. The title of the poster presented was “Quantification of alphaviral vectors using droplet digital PCR”, autors: Ksenija Korotkaja and Anna Zajakina.

Period: 01.01.2022.- 31.03.2022. | March 31, 2022

At the beginning of the project, ISSP UL prepared the thin-film magnetron sputtering equipment, compiled the procurement list of the required metallic and alloyed targets, and did first characterization of the fabricated coatings:

Optimization of magnetron sputtering process, preparation of first single-layer (Cu, ZnO, WO) and multilayer (WO₃/ Cu/WO₃, WO₃/Cu/W/WO₃, ZnO/W ZnO) coatings.

1. A list of targets to be obtained for the development of innovative single-layer and multi-layer MABAV coatings on glass and plastic sheets has been established:
   • Gold (Au) wire, 1 gram, 99.99% purity, 1.0 mm diameter
   • Silver (Ag) wire, 1 foot, 99.99% purity, 1.5 mm diameter
2. UV-VIS-IR spectroscopic measurements of transparent conductive thin films to determine the reflectance, transmission and absorption spectra of the films.
3. Spectroscopic ellipsometry measurements of transparent conductive thin films to evaluate film thickness and quality (dispersion curves of optical constants, band gap, optical gradient, surface roughness).

SIDRABE has adapted the roll-to-roll (R2R) equipment for the sputtering of the thin films required in the project:

1. Tightness and necessary high vacuum condition of the sputtering chamber have been checked, and found shortcomings have been rectified.
2. Magnetron cooling system was cleaned and checked for leaks.
3. Conditioning of the film winding system has been made and stability improved.
4. W and Cu magnetrons have been installed to allow the first coatings to be formed in the pilot mode.

To evaluate the antiviral and antibacterial properties of novel nanocoatings  the testing methodology was established according to EN ISO 1276 and EN ISO 16615 and approved by LBMC on the first samples obtained from ISSP:

1. Currently, the protocol is optimised for gram-negative and gram-positive bacteria cultivation: Escherichia coli, Staphylococcus aureus.
2. Preliminary data on biocidal activity of tungsten oxide containing nanocoatings have been obtained.
3. Furthermore, to evaluate the antiviral activity of nanocoatings, several model viruses have been selected: Semliki forest virus (mammalian enveloped RNA virus), MS2 bacteriophage (RNA non-enveloped virus), Pf1 bacteriophage (circular single-stranded DNA filamentous virus). The respective viruses were produced and quantified.