Photoinduced bio-based coatings for antibacterial applications – sPECTRAL

Infections by pathogenic microorganisms are of great concern in many fields, particularly in medical devices, hospital surfaces/furniture, and surgery equipments. Approximately 64% of hospital-acquired infections worldwide are due to the attachment and the proliferation of bacteria to medical implants, and they are associated with an annual mortality of 100 000 persons in the US as well as an increase in health-care costs. To solve the problem of increasing resistance of bacteria toward antibiotics, much attention has been focused on developing new antimicrobial systems in biomedical industry. Despite the potentially daunting complexity of bacteria populations and of materials surface characteristics, new chemical strategies should be developed to limit and prevent the bacterial colonization of materials surfaces.

The “sPECTRAL” project aims at designing antibacterial coatings by innovative photochemical process for eradicating the bacterial colonization (particularly against Escherichia coli and Staphylococcus aureus) on material surfaces in hospitals.
The novelty of the project rests on a new chemical approach which sets out to reduce the amount of energy required for chemical synthesis of the coatings, eliminate the dispersion of harmful chemicals (volatile organic compounds) in the environment as the coatings are synthesized without solvents, maximise the use of renewable resources for developing low cost coatings which are mechanically resistant with permanent antibacterial properties.
This project completely answers to the development of new methodologies for the production of new coatings which can be conceived and tested at short time. This project also completely answers the question of “green chemistry” process with:
1) The use of the photochemistry method (free radical and cationic photopolymerizations): the photopolymerization process has many obvious advantages, including low energy consumption (visible or sunlight irradiation), ambient temperature operations, and very fast polymerization rate with high conversion.
2) The use of industrially produced vegetable oils (VOs) or newly epoxy/methacrylate bio-based monomers derived from low cost raw materials such as sugars, glycerol or polyphenolic compounds.
3) An easy way to synthesize in-situ metal oxide NPs under visible and UV light irradiation inside the synthesized coatings for increasing their mechanical resistance over time.
4) The use of natural dyes used both as photosensitizers for the initiation of the polymerization and as reactive oxygen species promoter for the synthesis of permanent antibacterial coatings.

Achievement: Design of rapid, low cost and eco-friendly coatings with both interesting mechanical properties (e.g., flexibility and ductility) and long-time antibacterial properties against pathogenic bacteria (essentially with Escherichia coli and Staphylococcus aureus). It can be of prime importance for the development and the use of hybrid antibacterial coatings that are relevant to the general domain of medical devices, hospital safety and pathogenic infection in hospitals.
The new properties of the coatings will be worthwhile to overcome the actual brakes associated with the weak mechanical resistance and the short-time antibacterial properties of the coatings described in literature. Moreover, the proposed methodology for developing hybrid coatings will offer extended life expectancy, thus reducing downtime and maintenance costs. Among the many benefits included:
i) Coating that can easily combine hardness and flexibility
ii) More mechanical resistance
iii) Permanent antibacterial properties
iv) Low cost coatings