Triazine-Linked N-Halamine Functionalization of Cotton for Rechargeable and Surface-Bound Antibacterial Activity

A hydantoin-based N-halamine biocidal compound was synthesized and covalently bound to cotton via cellulose hydroxyls, yielding a functionalized surface that effectively inhibited the growth of Serratia marcescens. The precursor, 3-allyl-5,5-dimethylhydantoin, was coupled to l-cysteine through a thermally initiated thiol–ene reaction and subsequently linked to cyanuric chloride to form a dichlorotriazine derivative. The compound was grafted to cotton in aqueous media, producing a durable, regenerable biocidal surface. A practical chromogenic assay based on S. marcescens pigment production was developed to evaluate surface colonization. Antibacterial performance correlated with oxidative chlorine content and efficacy was observed with as little as 300 ppm of chlorine on the surface. Surfaces retained 63% of the initial chlorine loading over eight recharge cycles and exhibited less than 16% loss during 3 weeks of dry storage. This work introduces a scalable surface modification strategy yielding durable, rechargeable, and functionally active materials for contact-kill applications against pathogens.