About the Project
Photocatalysts are a known method of surface disinfection. However, their use is restricted by their hydrophilic nature and need for light activation. The project will develop novel superhydrophobic photocatalytic coatings that will be assessed for antimicrobial properties at solid-air and solid-liquid interfaces, enabling point-of-use testing across many environments.
Aims and objectives:
The adhesion and proliferation of bacterial species on surfaces, with subsequent biofilm formation is a major challenge for both healthcare and industrial applications. Photocatalytic disinfection of surfaces has been proven to be an efficient and safe (biocide-free) technology for inactivation of various microorganisms, including bacteria, fungi, viruses and yeasts. However, the use of photocatalytic materials for disinfecting surfaces is limited by several factors. Firstly, the use of photocatalytic surfaces for microorganism deactivation requires continuous irradiation of the surfaces with artificial light sources. Secondly, photocatalytic surfaces are typically characterised with hydrophilic properties that generally favour bacterial adhesion, potentially resulting in reduced cleanability, surface colonisation and biofilm formation, which negate the photocatalytic properties.
In contrast, superhydrophobic surfaces (water contact angle of 150° or higher) reduce the adhesion force between bacteria and the surface and enable easy removal of bacteria before biofilm formation. Therefore, the development of surfaces combining photocatalytic and superhydrophobic properties provides a promising method for prevention or inhibition of biofilm formation.
Biofilms typically grow at solid-liquid interfaces, which would likely be absent on hygienic surfaces, where a solid-air interface might enable surface contamination but discourage biofilm formation due to the lack of moisture and nutrient. Thus, the potential antimicrobial properties of test coatings should be assessed at both solid-air and solid-liquid interfaces, enabling assessment of surface hygiene and cleanability (solid-air interface), and prevention or retardation of biofilm formation, as well as biofilm removal (solid-liquid interface).
The elite-rated Surface Engineering Group has world-class facilities for thin film deposition and extensive experience in the production and characterization of magnetron sputtered photocatalytic coatings. Our preliminary studies have demonstrated for the first time that titania can be co-sputtered with PFTE to produce a unique material, which combines superhydrophobicity with photocatalytic activity. This project will build on these preliminary results and develop and optimise this material and demonstrate its effectiveness against biofilm formation in a range of relevant applications (e.g. hygienic surfaces in food and clinical; water distribution systems, industrial plant, drains/taps etc.).
The coatings will be characterised in terms of their structures and physical properties using techniques, such as SEM, EDX, XRD, Raman spectroscopy, etc. In addition, photocatalytic activity will be measured using a number of standardized testing techniques currently available in the Surface Engineering laboratory.
The Microbiology at Interfaces group is recognised as an elite research area in the University, due to its unique interdisciplinary approach to assessing the interactions occurring between microorganism and inert surfaces. We have developed a range of methods that enable putative antimicrobial surfaces to be tested in systems that relate appropriately to point-of-use, which – when appropriate – also conform to published standards. These methods assess adhesion to surfaces, retention on surfaces, surface cleanability and biofilm formation, and combine a range of quantitative cultural and visualisation techniques.
Project aim:
Deposition and testing of advanced hygienic materials, based on the combination of photocatalytic and superhydrophobic properties for antimicrobial properties at solid-air and solid-liquid interfaces.
Project objectives:
•Develop a magnetron sputtering-based deposition process for materials combining superhydrophobic and photocatalytic properties;
•Characterize phase and morphological properties of the most promising surfaces (XRD, Raman spectroscopy, AFM) and initial screening of them against model pollutants (methylene blue), model microorganisms (Escherichia coli) and hydrophobicity (water CA measurements);
•Identify the optimum deposition conditions (the best performing surfaces);
•Test the surfaces under dark, ambient and intense light for antimicrobial properties at solid-air and solid-liquid interfaces, using a range of relevant pathogens;
•Evaluate the durability of the surfaces (integrity, morphological properties and continued antimicrobial effectiveness of the films on re-use);
•Identify the best routes for future development, scale up and follow-up projects.
The supervisory team for this project will be Prof Peter Kelly and Prof Jo Verran
The closing date for applications is 31st January 2017.
To apply, please use the form on our web page: http://www2.mmu.ac.uk/study/postgraduate/apply/postgraduate-research-course/ - please note, CVs alone will not be accepted.
For informal enquiries, please contact: [Email Address Removed]
Please quote the Project Reference in all correspondence.