Preparation of antimicrobial wound dressings via thiol–ene photopolymerization reaction

Preparation of poly (urethane-acrylate) based wound dressings with the ability to boost self-healing of skin tissue through physical protection and maintaining hygiene and moist environment over wounded area is described in the present work. The dressings were prepared via a visible-light induced thiol–ene photopolymerization reaction of a mixture consisting methacrylate urethane prepolymers with hydrophilic and hydrophobic backbones, a quaternary ammonium salt containing methacrylate monomer as an antimicrobial agent, hydroxyethyl methacrylate as reactive diluent and a tetra-functional thiol molecule as a transfer agent. The prepared dressings were characterized and their performance as wound dressings were evaluated through measuring their equilibrium water absorption (EWA), water vapor transmission rate (WVTR), mechanical, and biological properties. Based on recorded data, the optimized dressing formulation had suitable tensile strength even at fully hydrated state and it could preserve the appropriate moist environment by balanced EWA and WVTR ratio. MTT assay confirmed proper cytocompatibility of those dressings containing optimized concentration of quaternary ammonium salt containing monomer (20 wt% or less). Examination of antibacterial activity against different Gram positive, Gram negative bacteria and a fungal strain revealed a complete killing ability for those dressings containing at least 20 wt% of quaternary ammonium salt containing monomer.