Oxygen Plasma for Prevention of Biofilm Formation on Silicone Catheter Surfaces: Influence of Plasma Exposure Time

The most common bacterial species responsible for causing catheter-associated urinary tract infection is Escherichia Coli ( E. Coli ) . In the present work, we report an experimental investigation of plasma-induced physico-chemical changes on silicone catheter surfaces and their influence on biofilm formation by uropathogenic E. coli bacterial cells for 7 days incubation period. Catheter substrates were exposed to an oxygen plasma environment from 1 to 30 min under capacitively coupled radio frequency low-pressure discharge. Plasma-modified surfaces have been characterized by Fourier transform infrared spectroscopy for surface chemistry, video contact angle goniometer for wettability and surface free energy, atomic force microscopy, and scanning electron microscopy for surface morphological studies. Chemical composition of oxygen plasma has been investigated using optical emission spectroscopy. Results convey that plasma induced morphological parameters such as average surface roughness ( S a ), the average distance between local peaks ( S ), and average slope of the morphological features ( Δ a ) play dominant role over surface chemistry for reduction in bacterial colonization and biofilm formation. The effectiveness of plasma treatment was evaluated up to 30 days after plasma treatment. Results confirm that oxygen plasma-treated catheter surface is successfully able to prevent biofilm formation with maximum 99.4% reduction in bacterial adhesion for 10 min of plasma exposure. Our study suggests that oxygen plasma treatment alone can be considered as a simple and eco-friendly solution for the prevention of E. coli biofilm formation on silicone catheter surfaces without involving the use of antibiotics or any other complex coating chemistry.