Insights into discharge argon-mediated biofilm inactivation

Abstract

Formation of bacterial biofilms at solid–liquid interfaces creates numerous problems in biomedical sciences. Conventional sterilization and decontamination methods are not suitable for new and more sophisticated biomaterials. In this paper, the efficiency and effectiveness of gas discharges in the inactivation and removal of biofilms on biomaterials were studied. It was found that although discharge oxygen, nitrogen and argon all demonstrated excellent antibacterial and antibiofilm activity, gases with distinct chemical/physical properties underwent different mechanisms of action. Discharge oxygen- and nitrogen-mediated decontamination was associated with strong etching effects, which can cause live bacteria to relocate thus spreading contamination. On the contrary, although discharge argon at low powers maintained excellent antibacterial ability, it had negligible etching effects. Based on these results, an effective decontamination approach using discharge argon was established in which bacteria and biofilms were killed in situ and then removed from the contaminated biomaterials. This novel procedure is applicable for a wide range of biomaterials and biomedical devices in an in vivo and clinical setting.

Keywords:

• bacteria
• biofilm
• inactivation
• biomaterials
• contamination

Abbeviations:

• MTT
• methylthiazolyldiphenyl-tetrazolium bromide, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide
• CV
• crystal violet
• TSBG
• tryptic soy broth supplemented with 0.2% glucose
• CFU
• colony forming unit
• DMSO
• dimethylsulfoxide
• PBS
• phosphate buffered saline

Acknowledgements

This work was supported by NIH grant AI078176 and AI079608. Mr Traba is a recipient of the Stanley Fellowship. Mr Chen is a recipient of the Innovation and Entrepreneurship Doctoral Fellowship. PCL aligned microfiber samples were kindly prepared by Mr Wei Chang in Prof. Xiaojun Yu’s laboratoryb Stevens Tech.