Bottom-up sono-enzymatic approach to build antimicrobial and antifouling nano-enabled coatings on urinary catheters

In this work, an antifouling and antibacterial nano-enabled coating for urinary catheters was synthesised using a bottom-up sono-enzymatic approach. Ceragenin CSA-131, an antimicrobial peptide, and lauryl gallate were nanoformulated into colloidal nanoparticles using high-intensity ultrasound. The obtained nanoparticles (GaCeNPs) were sonochemically deposited, together with sulfobetaine methacrylate (SB), and grafted enzymatically onto APTES-aminated silicone catheter material using laccase. Simultaneously, laccase-oxidised phenolic groups on GaCeNPs mediated the in situ radical polymerisation of the zwitterionic vinyl moieties into polysulfobetaine yielding a functional GaCeNPs_pSB coating. This coating effectively suppressed non-specific protein adsorption, as shown by reduced attachment of FITC-labelled bovine serum albumin, and achieved up to 3-log reduction in the growth of planktonic E. coli and S. aureus after 24 h. Contact angle measurements confirmed surface hydrophilicity (≈85°) of GaCeNPs_pSB-coated silicone for at least 7 days. Biofilm formation on Foley catheters functionalised with GaCeNPs_pSB was reduced by 70% upon incubation for a week in an artificial bladder model with continuous recirculation of infected urine. No adverse effects on fibroblast viability were observed over the same period of time in contact with the coated silicones, demonstrating their excellent biocompatibility (>90%). Altogether, this sono-enzymatically engineered, bio-based coating offers a promising strategy to reduce bacterial colonisation and biofilm formation on urinary indwelling devices and consequently the risk of infection in catheterised patients.