CONICET | Buscador de Institutos y Recursos Humanos

Biofilms are microbial communities embedded in an exopolysaccharidic matrix and responsible for undesirable effects including disease and prosthetic device contamination. Cooperative interactions among members of the biofilm make conventional methods of controlling microbial growth often ineffective. Therefore, there is a need to develop novel sterilization techniques and the use of gas discharge plasmas represents an alternative method.My laboratory first studied biofilms produced by Chromobacterium violaceum, a bacterium present in soil and water. Biofilms were subjected to plasma for different exposure times and 99.6% of culturable cells were inactivated after a 5-minute treatment. However, physiological and metabolic determinations, atomic force microscopy (AFM) and fluorescence microscopy showed that non-culturable cells were still alive after short plasma exposure times. These results indicate that viability experiments are indispensable before drawing the conclusion that plasma kills cells based solely on culturability. We are presently studying plasma-mediated inactivation of Pseudomonas aeruginosa biofilms grown on different surfaces such as polycarbonate, stainless steel, and borosilicate. AFM is being used out to study changes in cell morphology and biofilm structure for various plasma exposure times and also to study micromechanical properties of the biofilms. Results indicate nearly 100% of biofilm inactivation after 5-minutes of plasma exposure. (These results will be discussed by Anna Zelaya in her presentation). Results show the potential of plasma as an alternative method for biofilm removal. We expect that our study will provide the fundamental understanding of plasma-assisted biofilm inactivation and its mechanisms and build the basis for the future development of the technology.