Cold Atmospheric Helium Plasma In The Post-Covid Era: A Promising Tool For The Disinfection Of Silicone Endotracheal Prostheses

The COVID-19 pandemic resulted in a high prevalence of laryngotracheal stenosis. The endoluminal tracheal prostheses used to treat this condition are made of medical-grade silicone (MGS). Despite their excellent properties, the main limitation of these prostheses is the formation of a polymicrobial biofilm on their surfaces that interacts with the underlying mucosa, causing local inflammation and interfering with the local healing process, ultimately leading to further complications in the clinical scenario. Cold atmospheric plasma (CAP) shows antibiofilm properties on several microbial species. The present study evaluated the inhibitory effect of CAP on multispecies biofilms grown on MGS surfaces. In addition to the MGS characterization before and after CAP exposure, the cytotoxicity of CAP on immortalized human bronchial epithelium cell line (BEAS-2B) was evaluated. The aging time test reported that CAP could temporarily change the MGS surface wetting characteristics from hydrophilic (80.5{degrees}) to highly hydrophilic (< 5{degrees}). ATR-FTIR shows no significant alterations in the surficial chemical composition of MGS before and after CAP exposure for 5 min. A significant log reduction of viable cells in mono-species biofilms (log CFU/mL) of C. albicans, S. aureus, and P. aeruginosa (0.636, 0.738, and 1.445, respectively) was detected after CAP exposure. Multi-species biofilms exposed to CAP showed significant viability reduction for C. albicans and S. aureus (1.385 and 0.831, respectively). The protocol was not cytotoxic to BEAS-2B. It could be concluded that CAP can be a simple and effective method to delay the multi-species biofilm formation inside the endotracheal prosthesis.