Plasma can reduce Staphylococcus epidermidis biofilm formation on medical polymers

Medical polymers, such as urinary catheters are widely used biomaterials. One of the main problem for using the urinary catheters is biofilm formation on their surface, when they are used in a long time in the body. Virulence and pathogenicity of Staphylococcus epidermidis is often enhanced when growing as a biofilm. Many techniques have been presented to reduce the biofilm formation by surface modification. One of the most revolutionary techniques allowing such surface modifications is the plasma surface modification. In this work, plasma effects on S. epidermidis biofilm formation on urinary catheter surface have been investigated. Plasma was produced in a Pyrex glass tube containing nitrogen with pressure 1.6×10-1 Torr for plasma treatment of a catheter surface. Discharge voltage was about 1.2 kV and current was 150 mA. Each set of plasma treated catheter samples was inoculated by cultivation of S. epidermidis on 50 ml of Tryptic soy broth medium in the shaking incubator for 48 h at 37°C and 100 rpm. Then, amount of biofilm formation on the surface of polymer were assessed by crystal violet binding assay and sonication method. The results of these experiments indicated reduced biofilm formation on the modified surface around 50-60% compared to non-modified surface. This study shows that plasma surface modification can be used to reduce biofilm formation on medical polymers such as urinary catheter.