Background and study aims: Biliary stent dysfunction is mainly caused by biliary sludge that forms as a result
of bacterial adherence and subsequent biofilm formation on the inner surface of the
stent. Silver ions arewell known to have excellent antimicrobial activity against
a wide range of microorganisms. In this study, we designed and constructed silver-coated
plastic stent (PS) and investigated whether the silver coating prevented bacterial
adherence and biofilm formation through the use of electron microscopy.
Material and methods: The polyurethane PS with/without silver coating were prepared in 6-inch segments.
The silver-based antimicrobial agents were electrostatically applied onto the stent
surface. The stents were then immersed for 5 weeks in infected human bile juice obtained
from a patient with cholangitis, and electron microscopy was used to investigate the
ability of the modified PS to prevent bacterial adherence and biofilm formation.
Results: The bacterial flora did not change before and after immersion of stents in both the
group with and without silver coating. Electron microscopic observation revealed meshwork-like
structures around the bacteria, characteristic of biofilm-forming bacteria, in all
stents from the control group (6/6, 100 %). On the other hand, a limited number of
bacteria were observed in all stents in the silver-coated group, and no apparent biofilm
formation was observed (0/6, 0 %).
Conclusions: The significance of the findings from our study is the ability of silver-coated PS
to prevent biofilm formation on the stent surface, which results in the prevention
of stent occlusion.
