Use of radiofrequency electromagnetic radiation to remove biofilms from canvasses

AbstractA method based on the use of electromagnetic radiation (EMR) in the radiofrequency band was experimented to eliminate heterotrophic organisms from biofilms encrusting linen canvasses used for paintings. Artificial biofilms were used for exposure to EMR. Biofilms were grown on fragments of canvasses sampled from the backside of a painting. The fragments, after sterilization, were inoculated with several heterotrophic microorganisms previously isolated from other canvasses used for paintings and identified by molecular analyses as the bacteriaBacillus mycoides andBacillus subtilis, and the microfungiAspergillus versicolor, Cladosporium cladosporioides, Cladosporium oxysporum andFusarium oxysporum. The newly formed biofilms resulted to contain the same microorganisms used for the inocula. They were exposed to EMR obtained by an amplitude-modulating radiofrequency sine wave with a train of rectangular pulses with 200  ns repetition time and 10% duty cycle. The exposure protocol consisted of three applications of two hours each, every other day. Denaturing gradient gel electrophoresis analyses carried out on the EMR-treated biofilms showed that all the microorganisms disappeared after the third application. The amplitude of the adopted EMR was not high enough to cause any significant increase in the temperature of the substrates. Therefore, the methodology showed to be non-invasive for the artefacts and its exposure levels not hazardous for operators and the environment ...
Source: Aerobiologia - Category: Environmental Health Source Type: research