Periodic Reporting for period 1 - NanoSurf (Development of New Nanotechnology Strategies for Surface Disinfection/Decontamination)
Période du rapport: 2021-01-01 au 2022-12-31
It is estimated that within the next 50 years there will be 10 billion people on Earth, leading to food production and supply challenges. These challenges include the need for safe foods. The production of safe foods already poses a challenge today as illustrated by diseases such as salmonellosis, which caused 60,050 cases in the EU in 2021, a 14.3 % increase compared with the previous year. Meanwhile, the use of traditional chemical antimicrobial agents to fight these pathogens has numerous drawbacks. When traditional antimicrobial strategies reach the limits of their effectiveness, innovative combined treatments will offer solutions to combat foodborne pathogens. Such novel antimicrobial strategies will have a profound effect on the global public health.
The Nanosurf project focused an innovative combination of three technologies, i.e (i) cold atmospheric plasma (CAP), (ii) ultrasound (US) and (iii) the synthesis of nanomaterials (Nps) in one technological chain for decontamination and/or disinfection of biotic/abiotic surfaces. The proposed technology is of particular interest since it relies on water as a medium without the need for any electroconductive additives.
Formal objectives of this Marie Skłodowska Curie Action (MSCA) were to (a) achieve an optimization for the nanoparticles (Nps) composition, technological parameters of CAP-US synthesis of Nps under non-equilibrium state; to achieve a combination of CAP-US synthesis of Nps in one chain for treatment of various surfaces; (b) to demonstrate the efficacy of the technological combination of the CAP process with US treatment in one technological chain for decontamination and/or disinfection of biotic/abiotic surfaces; (c) to study physicochemical, toxicological properties and risk assessment of synthesized Nps. Another goal of the MSCA Individual Fellowship is to bring up the development of the individual researcher. In this project, the objectives and goals have been addressed via three specific work packages: (1) development of an integrated plasma-ultrasound treatments; (2) synthesis and characterization of nanoparticles; (3) antimicrobial efficacy, toxicological and risk assessment of synthesized MeOx NPs.
The Nanosurf project focused an innovative combination of three technologies, i.e (i) cold atmospheric plasma (CAP), (ii) ultrasound (US) and (iii) the synthesis of nanomaterials (Nps) in one technological chain for decontamination and/or disinfection of biotic/abiotic surfaces. The proposed technology is of particular interest since it relies on water as a medium without the need for any electroconductive additives.
Formal objectives of this Marie Skłodowska Curie Action (MSCA) were to (a) achieve an optimization for the nanoparticles (Nps) composition, technological parameters of CAP-US synthesis of Nps under non-equilibrium state; to achieve a combination of CAP-US synthesis of Nps in one chain for treatment of various surfaces; (b) to demonstrate the efficacy of the technological combination of the CAP process with US treatment in one technological chain for decontamination and/or disinfection of biotic/abiotic surfaces; (c) to study physicochemical, toxicological properties and risk assessment of synthesized Nps. Another goal of the MSCA Individual Fellowship is to bring up the development of the individual researcher. In this project, the objectives and goals have been addressed via three specific work packages: (1) development of an integrated plasma-ultrasound treatments; (2) synthesis and characterization of nanoparticles; (3) antimicrobial efficacy, toxicological and risk assessment of synthesized MeOx NPs.
Based on validated experimental data, the synthesis of nanoparticles has been optimized in a method that allowed to activate nanoparticles by plasma and direct suspended them in plasma-activated liquid (PAL) in one technological chain. Final antimicrobial solutions contain (see Figure 1) suspended NPs of tungsten oxide in PAL (furthers referred to as NPs+PAL). It was possible to synthesize two types of tungsten oxides, characterised by different colours: yellow (WO3, Fig.1 a) and blue (WO2.72 Fig.1 b). Each colour of tungsten oxide corresponds to a different degree of tungsten oxidation.
Yellow NPs+PAL solutions have a significantly higher estimated W-concentration of 903.0 ± 84.4 mg/L compared to bluish NPs+PAL solutions, with an estimated W-concentration of 332.2 ± 22.1 mg/L. Based on the chemical formula’s of WO3 and WO2.72 for yellow and blue NPs respectively, the WO3-X concentrations were estimated. The calculated concentrations were 1138.7 ±106.4 mg/L for yellow NPs + PAL solutions and 410.86 ±27.3 mg/L for blue NPs + PAL solutions.
The inactivation efficiency highly depends on the solution used. As indicated in Figures 2 (a) and (b), a combination of NPs and PAL exhibits higher inactivation rates compared to separated PAL. This separated PAL in turn exhibits higher inactivation rates than resuspended NPs. An exception to this is the use of yellow PAL on Salmonella. Here, the yellow PAL solution has higher inactivation rates than a solution of yellow NPs and PAL. Resuspended tungsten oxide NPs possess no antibacterial properties. Neither Salmonella nor Listeria show any inactivation when treated with these resuspended NPs. Concentration and reaction time are likely to be the key factors.
The main conclusion was made: nanoparticles of tungsten oxide by themselves do not have antimicrobial activity, only together with the action of PAL they affect microbial inactivation. The synergistic effect between NPs and PAL that was hypothesized in the proposal was observed and confirmed. The patent application: ”Production of aqueous solution of tungsten oxide nanoparticles for antimicrobial application” has been sent to the Department of Intellectual Properties of KU Leuven to assess their patentability.
Yellow NPs+PAL solutions have a significantly higher estimated W-concentration of 903.0 ± 84.4 mg/L compared to bluish NPs+PAL solutions, with an estimated W-concentration of 332.2 ± 22.1 mg/L. Based on the chemical formula’s of WO3 and WO2.72 for yellow and blue NPs respectively, the WO3-X concentrations were estimated. The calculated concentrations were 1138.7 ±106.4 mg/L for yellow NPs + PAL solutions and 410.86 ±27.3 mg/L for blue NPs + PAL solutions.
The inactivation efficiency highly depends on the solution used. As indicated in Figures 2 (a) and (b), a combination of NPs and PAL exhibits higher inactivation rates compared to separated PAL. This separated PAL in turn exhibits higher inactivation rates than resuspended NPs. An exception to this is the use of yellow PAL on Salmonella. Here, the yellow PAL solution has higher inactivation rates than a solution of yellow NPs and PAL. Resuspended tungsten oxide NPs possess no antibacterial properties. Neither Salmonella nor Listeria show any inactivation when treated with these resuspended NPs. Concentration and reaction time are likely to be the key factors.
The main conclusion was made: nanoparticles of tungsten oxide by themselves do not have antimicrobial activity, only together with the action of PAL they affect microbial inactivation. The synergistic effect between NPs and PAL that was hypothesized in the proposal was observed and confirmed. The patent application: ”Production of aqueous solution of tungsten oxide nanoparticles for antimicrobial application” has been sent to the Department of Intellectual Properties of KU Leuven to assess their patentability.
In the near future, humanity will face new challenges caused by climate change, wars, non-uniform and uncontrolled consumption of natural resources as well as the nascence of new harmful microorganism. While we are trying to find a solution to overcome these challenges today, one can doubt our ability to tackle the last challenge. The NanoSurf project has demonstrated an alternative vision on how to combat bacterial food pathogens using a sophisticated approach consisting of nanotechnology, plasma and ultrasound. It is already clear that the concept of the NanoSurf project has potential to play a role in tackling this challenge. Based on the technological solution and promising results, the NanoSurf project can bring new sectors of economic activities in the agricultural sector (plant growth, fungi protection, mineral fertilizer), the medical sector (hybrid antibiotics based on nanoparticles) as well as in the production of various materials with functional coating that have antibacterial, antifungal and antiviral properties. In general, the technology of atmospheric non-equilibrium plasma for the synthesis of nanomaterials in water with ultrasound assistance leads to a near inexhaustible number of technologies that can be designed and tested.