Engineering Ulvan-Functionalized Surfaces for Tunable Antimicrobial and Antiadhesive Performance

Ulvan, a sulfated marine polysaccharide, holds promise for antiadhesive and antimicrobial surface coatings. We engineered two ulvan-based coating series by covalently grafting ulvan onto poly(allylamine)-modified substrates using EDC/s-NHS or BDDE cross-linking chemistries. Surface analyses confirmed tunable morphology and composition with coating thickness and ulvan density saturated at defined cross-linker thresholds. Adhesion assays with Escherichia coli and Staphylococcus aureus revealed significantly reduced colonization on all ulvan coatings versus uncoated controls. E. coli adhesion decreased exponentially with ulvan density with nanogel-like coatings also inducing membrane damage. S. aureus exhibited weaker transient responses, possibly due to structural resistance. Correlating biological activity with surface chemistry established ulvan content as a key predictor of performance. These coatings offer short-term protection against microbial colonization, particularly effective during the critical early adhesion phase, and provide a chemically tunable platform for anti-infective surfaces in applications such as catheters, wound dressings, and food-contact materials. This work lays the groundwork for designing glycosylated interfaces in biomedical and environmental applications where early stage biofilm prevention is critical.