WP2 Selection and synthesis of polymerizable antimicrobial agents
Leader of consortium:
Centrum organické chemie s.r.o.
SYNPO, akciová společnost, Univerzita Palackého v Olomouci
Ing. Lubomír Kubáč, Ph.D.
Duration of the work package:
01/2014 – 12/2017
Aim of this work package is the suggestion and design suitable materials able to bond covalently into the carrying polymeric structure. The material will be tailored with respect to the defined applications. The optimization of their structure will be performed according to the application tests. Suggestion of an effective way of synthesis will transfer their preparation into glass pilot plant addressed by WP9. This work package is divided in four tasks, which are supposed to cover all aspects of the material synthesis required by the targeted applications.
Task 2.1, Synthesis and optimization of the structure of polymerizable antimicrobial monomer
Several well-known antimicrobial materials have a suitable reactive group, which enable them to bond via either covalent or ionic bonding with polymeric substrate. There are two possibilities how to anchor these antimicrobial agents into polymeric carries/substrates. The first approach involves the addition of an antimicrobial agent as a monomer during the polymeric synthesis. To succeed with such approach it is necessary to find such antimicrobial agent that possess a suitable monomer group, like radically polymerizable double bonds, alcohols and diols, primary or secondary amines and diamines, aminoalcohols. The second approach expects usage of an antimicrobial agent containing suitable ionic group that enable to anchor it via ionic bonds into the structure of an existing polymer. The latter mentioned approach is much more preferred from the application point of view because there is possible to mix up the basic ionic polymer with a variety of ionic antimicrobial agents. There is possible to use polymeric carriers based on acrylics, polyesters and polyurethane resins with the carboxylic, hydroxyl, amino or isocyanate functional groups. The greatest advantage of such composite material is that the antimicrobial agents bonded in the polymeric structure of the resulting materials have no danger of release from the system and therefore represents no possible danger for surroundings. Moreover, the greatest importance of such composite material based on the structure silver-based material at polymer matrix exhibits long term storage safety without widely discussed danger of the antibacterial activity lost, which could be ascribed to efficient anchoring of the silver-based.
Task 2.2, Synthesis and optimization of phthalocyanine photosensitizer structure
Photosensitive materials exhibit antimicrobial properties that are, however, dependent on the source of irradiation, namely on the application of the radiation with a suitable wavelength. The material gets into contact with photon, which leads into excitement of an electron and during this time the material has different reactivity in contact with its surroundings (mainly humidity and oxygen). For example phthalocyanine derivatives are able to change the basic state of triplet oxygen into excited singled type of oxygen. Singled form of oxygen is highly reactive and it is able to kill majority of microorganism. It has been already found out that singlet oxygen is also able to destroy some pollutants. The lifetime of singlet oxygen in solution is only several microseconds and therefore its field of effect is 20 nm from the surface of the material modified by chosen phthalocyanine derivatives. R&D in this project will be focused on phthalocyanines of zinc, aluminum. These phthalocyanine molecules will be modified in order to enable selected fixation process. In the case phthalocyanine will be a part of polymer reaction, the molecule will be modified for example with vinyl group. Polymer carrier with acidic functional group will be modified with phthalocyanines bearing amines, diamines, aminoalcohols, amides or hydroxy groups. Similarly, alkaline polymers will be substituted with acidic groups such as sulphonic, carboxy or phosphonic groups.
Task 2.3, Synthesis and optimization of silver-based material for polymer modification
Silver nanoparticles (AgNPs) have been widely accepted as one of the most effective inorganic antimicrobial nanoscale agents with a unique application potential. The incorporation of this material onto/into a substrate reacts to a possible risk of the AgNPs release into the environment and at the same time to prolong the lifetime of such antibacterial composute material. As silver is one of the “contact materials”, the active surface of this material must be retained to exhibit the already well-described great antibacterial activity of AgNPs. From the application point of view, the AgNPs are supposed to be covalently bonded into the chosen polymeric matrix. Only then the release of the AgNPs can be prevented. The AgNPs can be trapped into the polymeric substrate both in the mode of the addition of the already existing AgNP-based material and its covalent bonding via suitable function groups or in their generation directly on the suitable function groups of the functionalized polymeric substrate.
Task 2.4 Evaluation of antimicrobial activity of new monomer molecules
The chosen monomolecular materials will investigate the antimicrobial activity against determined bacterial strains. The most important parameters for determination of antimicrobial activity are singlet oxygen production (its quantum yield) and antimicrobial tests. For each compound, values of singlet oxygen quantum yield and antimicrobial tests on selected gram-positive, gram-negative and moulds will be evaluated. Suitable derivatives will be then selected based on the results of both measurements and they will be used for incorporation into polymer structure. However, the incorporation of these antimicrobial agents into polymer can change their behaviour, but the first condition is their antimicrobial activity. It is much likely that ineffective derivatives will not increase their activity after binding into a polymer structure.