Gas-phase removal of biofilms from various surfaces using carbon dioxide aerosols

Abstract

The present study evaluated the removal of Escherichia coli XL1-blue biofilms using periodic jets of carbon dioxide aerosols (a mixture of solid and gaseous CO2) with nitrogen gas. The aerosols were generated by the adiabatic expansion of high-pressure CO2 gas through a nozzle and used to remove air-dried biofilms. The areas of the biofilms were measured from scanning electron micrographs before and after applying the aerosols. The removal efficiency of the aerosol treatment was measured with various air-drying times of the biofilms before the treatment, surface materials, and durations of CO2 aerosols in each 8-s aerosol–nitrogen cleaning cycle. Nearly 100% of the fresh biofilms were removed from the various surfaces very reliably within 90 s. This technique can be useful for removing unsaturated biofilms on solid surfaces and has potential applications for cleaning bio-contaminated surfaces.