Plasma and nanomaterials for antimicrobial properties – PLASNANOBIAL

To face the antimicrobial resistance (AR), associated to nearly 5 million deaths worldwide, the World Health Organization in 2014, demands the establishment of proper antibiotics usage practices and the development of new antimicrobial agents. In this context, cold plasmas can be an immensely useful tool. In this type of discharge, the application of high electric fields can excite, ionize, and dissociate molecules of a gas or gas mixture, producing a myriad of highly reactive species. Such species can interact with a material nearby or in contact with the plasma endowing it new chemical and physical characteristics. In this proposal the production of non-antibiotic bactericidal materials will be investigated using both atmospheric- and low- pressure plasmas. In one approach, atmospheric plasma jets fed with vapors of natural extracts (eugenol and carvacrol), will be used to render water and physiological solutions with expressive antimicrobial properties and to synthesize the thin films derived from the extracts, to produce surfaces able to inhibit the adhesion and proliferation of microorganisms. On the other hand, low pressure plasma (magnetron sputtering), will be applied to synthesize multimetallic nanoparticles (NPs) in different liquids to investigate the effect of the fluid on the physicochemical and antimicrobial properties of the NPs. The bactericidal and bacteriostatic effects of the NPs will be evaluated with in vitro microbiological tests using standard strains of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. In such tests, commercial nylon suture threads will be used as scaffolds for the multimetallic NPs. To this end, the threads will be immersed in the prepared colloidal suspensions immediately after activation with atmospheric pressure plasma jets fed with N2 and O2 mixtures. In vivo and in vitro microbiological tests will be conducted to evaluated the antimicrobial performance of the treated threads.