(Invited) A Flexible Anti-Biofilm Hygiene Coating for Water Devices

Abstract

Biofilm is a microbiome complex comprising different bacterial colonies that typically adhere to device surfaces in water, which causes serious medical issues such as indwelling infections and outbreaks. Here we introduce a non-nanoparticle, flexible anti-biofilm hygiene coating consisting of lithocholic acid (LCA), zinc pyrithione (Zn) and cinnamaldehyde (Cn) (named as LCA-Zn-Cn) that largely prevents the bacteria adhesion to various water device surfaces such as stainless steel and glass through a synergistic mechanism (ACS Applied Bio Materials, 5 (2022) 3991). The existing chelated groups on LCA and Cn attract plenty of bacteria via hydrophobic interaction. Both bactericidal reaction by grafting biocidal groups from both LCA and Cn and bacteriostatic reaction by inhibiting cell division via zinc ions (Zn) lead to a largely improved bacteria/biofilm prevention. The antibacterial performance was assessed by using JIS Z 2801/ISO 22196 method. The designed LCA-Zn-Cn coating displayed log10 reduction of 4.23 (99.9% reduction) of E. coli and log10reduction of 3.51 (99.8% reduction) of E. faecalis on stainless steel, which are much higher than the control samples, demonstrating a promising colonization inhibition. Due to the strong crosslinked configuration, the coating still showed >90.9% bacterial reduction after 3000 abrasion cycles and over 99.9% bacteria reduction after a high flow velocity of 1.99 m/s test, which confirmed the enhanced mechanical durability. By applying either spray or dip-coating, the designed polymer composite can be coated on a variety of irregular water devices with mass production using auto-controlled robot arm. The desired hybrid coating provides an effective solution to prevent bacterium and biofilm formation on flexible water devices. Keywords: Anti-biofilm; Anti-bacteria; Coating; Water devices; Flexibility