EFFECT OF PULSE-PERIODIC CORONA DISCHARGE ON VIABILITY OF ESCHERICHIA COLIM17 CELLS IN BIOFILMS

Abstract

Aim. Detection of bactericidal effect of pulse-periodic corona discharge (PPCD) on cells and biofilms of Escherichia mli M17. Materials and methods. A gas-discharge device was created based on PPCD in air with power supply parameters: amplitude values of voltage of 30 - 60 kV, pulse repetition rate of 250 - 400 kHz. Ultrastructure changes in cells and biofilms of E. mli M17, affected by PPCD, generated in air, were studied by typical methods of transmission electron microscopy. Results. Disturbances of integrity of surface and abyssal structures of biofilms, as well as changes of morphological properties of E. mli M17 cells, characteristic for sub-lethal heat impact, were detected. Destructive changes of bacterial cells were developed by formation of focal disturbance of cytoplasmic membrane, extension of periplasmic space, formation of globular structures, characteristic for heat effect, and destruction ofcytoplasm. Conclusion. Bactericidal effect ofPPCD on E. mli M17 cells as part ofbiofilms was shown. Destructive morphological changes in cells and biofilms of E. mli M17 after the effect of PPCD were detected for the first time on electron-microscopic level.

Keywords

• escherichia coli
• pulse-periodic corona discharge
• source of gas discharge of atmospheric pressure
• low temperature air plasma
• plasma disinfection
• bacterial biofilm
• cell destruction mechanism